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Cody C Wyles,1 Matthew T Houdek,2 Atta Behfar,3 Rafael J Sierra,21Mayo Medical School, 2Department of Orthopedic Surgery, 3Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USAAbstract: Osteoarthritis (OA) is a painful chronic condition with a significant impact on quality of life. The societal burden imposed by OA is increasing in parallel with the aging population; however, no therapies have demonstrated efficacy in preventing the progression of this degenerative joint disease. Current mainstays of therapy include activity modification, conservative pain management strategies, weight loss, and if necessary, replacement of the affected joint. Mesenchymal stem cells (MSCs) are a multipotent endogenous population of progenitors capable of differentiation to musculoskeletal tissues. MSCs have a well-documented immunomodulatory role, managing the inflammatory response primarily through paracrine signaling. Given these properties, MSCs have been proposed as a potential regenerative cell therapy source for patients with OA. Research efforts are focused on determining the ideal source for derivation, as MSCs are native to several tissues. Furthermore, optimizing the mode of delivery remains a challenge both for appropriate localization of MSCs and for directed guidance toward stemming the local inflammatory process and initiating a regenerative response. Scaffolds and matrices with growth factor adjuvants may prove critical in this effort. The purpose of this review is to summarize the current state of MSC-based therapeutics for OA and discuss potential barriers that must be overcome for successful implementation of cell-based therapy as a routine treatment strategy in orthopedics.Keywords: mesenchymal stem cell, osteoarthritis, treatment, regenerative medicine, cell therapy

Matthew T Houdek,1 Cody C Wyles,2 John R Martin,1 Rafael J Sierra11Department of Orthopedic Surgery, 2School of Medicine, Mayo Clinic, Rochester, MN, USAAbstract: Avascular necrosis (AVN) of the femoral head is a progressive disease that predominantly affects younger patients. Although the exact pathophysiology of AVN has yet to be elucidated, the disease is characterized by a vascular insult to the blood supply of the femoral head, which can lead to collapse of the femoral head and subsequent degenerative changes. If AVN is diagnosed in the early stages of the disease, it may be possible to attempt surgical procedures which preserve the hip joint, including decompression of the femoral head augmented with concentrated bone marrow. The use of autologous stem cells has shown promise in halting the progression of AVN of the femoral head, and subsequently preventing young patients from undergoing total hip arthroplasty. The purpose of this study was to review the current use of stem cells for the treatment of AVN of the femoral head.Keywords: avascular necrosis, femoral head, osteonecrosis, stem cells, concentrated bone marrow

Background: Acetabular retroversion has been identified in mature patients with sequelae of Legg-Calvé-Perthes (LCP) disease. Whether this is a contributing etiologic factor that leads to the disease process or result of the head deformity is not known. The prominence of the ischial spine (PRIS) sign, which reflects retroversion, can be observed before ossification of the anterior and posterior walls in a skeletally immature patient and could help determine whether the retroverted acetabulum is present before or after head involvement in patients with LCP disease.Questions/purpose: We therefore determined (1) the prevalence of the PRIS sign in patients with LCP disease compared with healthy control subjects, (2) whether the PRIS sign is seen at the time of head involvement in patients with LCP disease, and (3) the prevalence of bilaterality of the PRIS sign in patients with LCP disease and control subjects.Patients and Methods: Of 295 patients with LCP disease, 47 (49 hips) met our inclusion criteria. Of these, 39 (41 hips) had open triradiate cartilage and comprised the study group. Twenty-five pediatric patients with polytrauma (50 hips) with standardized radiographs comprised the control group.Results: A positive PRIS sign was noted in 37 of the 41 skeletally immature hips compared with only 16 of the 50 control hips. We observed a positive PRIS sign early in the LCP disease process with eight of nine patients in the fragmentation phase having a positive PRIS sign. The PRIS sign was seen bilaterally in 25 of 39 patients with unilateral LCP disease and in only five of 25 control patients.Conclusions: Acetabular retroversion, as evidenced by a positive PRIS, was present in nine of 10 children with LCP disease. It is uncertain if retroversion is a cause or a sequela of the disease, but it was seen early in the disease process at the time of head involvement in the majority of patients.Level Of Evidence: Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Blood perfusion to the femoral head might be endangered during the surgical approach or the preparation of the femoral head or both in hip resurfacing arthroplasty. The contribution of the intramedullary blood supply to the femoral head in osteoarthritis is questionable. Therefore, the contribution of the extraosseous blood supply to osteoarthritic femoral heads was measured intraoperatively to question if there is measurable blood flow between the epiphysis and metaphysis in osteoarthritic hips in case of extraosseus vessel damage. At defined points during surgery we acquired the epiphyseal and metaphyseal femoral head perfusion by high-energy laser Doppler flowmetry. Complete femoral neck osteotomy sparing the retinacular vessels to simulate intraosseous blood disruption showed unchanged epiphyseal blood flow compared to initial measurement after capsulotomy. The pulsatile signal disappeared after transection of the retinacular vessels. Based on these acute measurements, we conclude intramedullary blood vessels to the femoral head do not provide measurable blood supply to the epiphysis once the medial femoral circumflex artery or the retinacular vessels have been damaged. We recommend the use of a safe surgical approach for hip resurfacing and careful implantation of the femoral component to respect blood supply to the femoral head and neck region in hip resurfacing arthroplasty. [ABSTRACT FROM AUTHOR]

Femoroacetabular impingement may occur in patients with so-called acetabular retroversion, which is seen as the crossover sign on standard radiographs. We noticed when a crossover sign was present the ischial spine commonly projected into the pelvic cavity on an anteroposterior pelvic radiograph. To confirm this finding, we reviewed the anteroposterior pelvic radiographs of 1010 patients. Nonstandardized radiographs were excluded, leaving 149 radiographs (298 hips) for analysis. The crossover sign and the prominence of the ischial spine into the pelvis were recorded and measured. Interobserver and intraobserver variabilities were assessed. The presence of a prominent ischial spine projecting into the pelvis as diagnostic of acetabular retroversion had a sensitivity of 91% (95% confidence interval, 0.85%-0.95%), a specificity of 98% (0.94%-1.00%), a positive predictive value of 98% (0.94%-1.00%), and a negative predictive value of 92% (0.87%-0.96%). Greater prominence of the ischial spine was associated with a longer acetabular roof to crossover sign distance. The high correlation between the prominence of the ischial spine and the crossover sign shows retroversion is not just a periacetabular phenomenon. The affected inferior hemipelvis is retroverted entirely. Retroversion is not caused by a hypoplastic posterior wall or a prominence of the anterior wall only and this finding may influence management of acetabular disorders. [ABSTRACT FROM AUTHOR]

Background: Unicompartmental knee arthroplasty (UKA) is a reliable procedure to treat medial compartment knee osteoarthritis (OA). The reported survivorship of UKA has varied in the literature 3-7 . In part, the higher failure rates of UKA seen in registries could be related to the caseload and experience of the reporting surgeon 8 . The introduction of techniques that make procedures more reliable, especially in the hands of inexperienced surgeons, can decrease the rate of failure. With the Oxford UKA implant (Zimmer Biomet), the recommended surgical technique involves cutting the tibia first, followed by the femoral preparation. However, a technique that allows for preparation of the femur first, as well as the use of the femoral component as a reference for the tibial cut, may reduce the common technical errors seen with the procedure. We have utilized the femur-first technique in cases of medial Oxford UKA., Description: The femur-first method outlined in the present article does not require any unique instruments beyond what is supplied by the manufacturer. Before beginning, the femoral positional guide needs to be decoupled from its base. To start, the intramedullary guide is introduced approximately 1 cm anterior and medial to the intercondylar notch. Once the femoral osteophytes are removed, the surgeon identifies the center of the femoral condyle and marks it. The posterior tibial cartilage is then removed with a saw to facilitate the placement of the appropriately sized femoral spherical guide. The size of the femoral component is determined by selecting the implant that aligns best with the width of the femoral condyle. The femoral drill guide is detached from its base because there is not enough space for the base, as the tibia has not yet been resected. The decoupled femoral guide is connected to the intramedullary rod, allowing the precise positioning of the femoral component in approximately 10° of flexion relative to the femoral sagittal plane and drilling of the 2 peg holes. The posterior condylar resection guide is impacted into position, and the osteotomy of the posterior condyle is made. The distal femur is then milled with use of a number-0 spigot, and the femoral component trial is positioned into place. The femoral condyle is "resurfaced" with the femoral component, which restores joint obliquity and the natural height, a critical element of the femur-first technique. Following this, the 1-mm (size-dependent) spherical gauge is placed around the femoral component trial. The tibial guide is secured with the G-clamp and a number-0 resection block, and is pinned into place. We recommend swapping the number-0 cutting guide for a +2 when making the cut in order to avoid over-resection. Recutting is advised if a minimum 3-mm feeler gauge does not adequately occupy the flexion space. The final step is to balance the flexion and extension gaps in the usual fashion., Alternatives: The alternative technique is a traditional tibia-first approach, in which tibial resection is performed prior to femoral resection. As described in the original manufacturer's manual, the tibial cut is accomplished with use of a number-0 cutting guide, and the tibial rotation is based on the axis formed by the anterior superior iliac spine and knee center, irrespective of the femoral condyle., Rationale: The femur-first technique is advantageous in several ways. When performing the femoral cut first, the surgeon can better align the drill guide at the center of medial femoral condyle. This will result in the femoral component being positioned more in line with the coronal plane of the femoral condyle. Additionally, the tibial resection is made with the femoral trial in place; therefore, the depth of resection can be more accurate, potentially avoiding excessive bone resection. Finally, with the femoral trial in place, the surgeon can judge the rotation and medial-lateral position of the tibial component more precisely, hence lowering the possibility of bearing spin-out, impingement, and dislocation or unexplained pain., Expected Outcomes: The femur-first technique is a bone-preserving procedure that results in thinner bearings when compared with a tibia-first approach 1 . The femur-first approach also improves radiographic outcomes, including femoral coronal, femoral sagittal, and tibial sagittal alignments, while tibial coronal alignment does not differ. There is an early trend toward improved 5-year survivorship with the femur-first (98%) versus tibia-first (94%, p = 0.35) techniques. There has been no significant difference reported in Knee Society Scores between techniques., Important Tips: Perform a preliminary cut of the posterior tibial cartilage in order to allow insertion of the femoral drill guide under the femoral condyle.Make sure the femoral drill guide lies in the center of the marked medial femoral condyle.Align the tibial sagittal cut with the femoral component trial in order to avoid bearing impingement.Be conservative in the tibial cutting by utilizing a +2 cutting guide (since the coupling is performed with the intramedullary guide in place, which drives the tibial guide distally)., Acronyms and Abbreviations: UKA = unicompartmental knee arthroplastyFF = femur-firstM-L = medial-lateralAP = anteroposteriorPA = posteroanteriorASA = acetylsalicylic acid (aspirin)BID = bis in die, twice a dayPT = physical therapyTF = tibia-firstFCA = femoral coronal angleFSA = femoral sagittal angleTSA = tibial sagittal angleIM = intramedullaryOA = osteoarthritis., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSEST/A442)., (Copyright © 2024 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Periacetabular osteotomy (PAO) is a well-established surgical treatment for hip dysplasia, but very few studies report the impact of peri-operative management strategies on early pain and function. The purpose of this study is to describe peri-operative management variability among a group of experienced surgeons and review the literature supporting these practice patterns., Methods: We surveyed 16 surgeons that perform PAO to document various aspects of peri-operative management at four stages: pre-operative, intra-operative, post-operative in the hospital, and at discharge. Our goal was to report current surgical pain management strategies, adjunct medications, type of anesthesia, deep venous thrombosis and heterotopic ossification prophylaxis strategies, initiation of physical therapy, and use of continuous passive motion (CPM). We reviewed current literature to identify studies supporting these perioperative strategies and identify knowledge gaps that would benefit from further investigation., Results: Of the 16 surgeons surveyed, 75% had been in practice greater than 10 years and most had not altered their post-operative protocol for more than 3 years. 15/16 surgeons felt that length of stay could be reduced at their institution with improved peri-operative pain management. 6/16 were considering or had already implemented outpatient PAO as a part of their practice. We found significant variability in the pain medications provided at all peri-operative stages. 14/16 utilized general anesthesia, and many utilized epidural or peripheral nerve blocks. 6/16 surgeons utilized surgical field block (also referred to as periarticular block). These surgeons advocated that surgical field block was an effective intervention with no/minimal complication risk. There is very little literature critically evaluating efficacy of these perioperative management strategies for PAO., Conclusion: There is significant practice variability in peri-operative management of PAO surgery. We report various strategies utilized by a group of experienced surgeons and review supporting literature. There are significant knowledge gaps in best surgical pain management strategies, adjunct medications, surgical field blocks, and use of CPM that need further investigation. Level of Evidence: IV ., Competing Interests: Disclosures: The authors report no potential conflicts of interest related to this study., (Copyright © The Iowa Orthopaedic Journal 2024.)

Aiming for a combined cup and stem anteversion within a target range is one way to assess appropriate prosthetic component orientation and restoration of functional range of motion. We describe a surgical technique that allows the surgeon to assess the combined anteversion using a handheld accelerometer-based navigation system for total hip arthroplasty through a posterior approach. The femur is prepared first, at which time the femoral version is estimated by the surgeon. The acetabular component is then positioned using the navigation system to estimate anteversion, with the goal of providing a combined version of 37° ± 7°. The described technique allows surgeons to achieve the desired intraoperative combined anteversion., Level of Evidence: IV (technical note)., (© 2023 The Authors.)

Dual-mobility (DM) implants reduce the risk of dislocation in patients who have undergone total hip arthroplasty (THA); however, DM implants are at risk for large-head dislocation and intraprosthetic dissociation (IPD), where the inner femoral head dissociates from the outer polyethylene head. This study aimed to report the incidence of DM dislocation and IPD, evaluate the rate of recognition of IPD before and after reduction, investigate the outcomes of these complications, and provide treatment recommendations for their management., Methods: Between 2010 and 2021, 695 primary and 758 revision THAs were performed with DM constructs at a single institution. There were 44 large-head dislocations (3.0%) and 10 IPDs (0.7%). Four additional IPDs occurred during attempted closed reduction, increasing the IPD incidence to 0.96%. We reviewed prior instability history, dislocation management, success of reduction, recognition of IPD, and subsequent rates of revision and complications. The mean follow-up was 2.5 years., Results: Nine of 10 IPDs were missed at presentation and thus not treated as such. Sixty-three percent of attempted closed reductions in the emergency department failed and led to 4 IPDs and 1 periprosthetic fracture. Reduction success was associated with the following factors: use of general anesthesia with paralysis (p = 0.02), having the reduction performed by an orthopaedist (p = 0.03), and undergoing only 1 reduction attempt (p = 0.015). Two-thirds of dislocations required revision. The rate of redislocation was 33%, and 5 hips required subsequent revision at a mean of 1.8 years after the initial dislocation., Conclusions: We present an evaluation of DM-implant dislocation and dissociation along with management recommendations based on these data. Given the low success and high complication rates of attempted closed reduction and the need for eventual revision, we recommend that all patients with dislocated DM implants be brought to the operating room for closed reduction as well as potential revision if the reduction fails., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence., (Copyright © 2023 The Authors. Published by The Journal of Bone and Joint Surgery, Incorporated. All rights reserved.)

Purpose: To develop a multimodal machine learning-based pipeline to predict patient-specific risk of dislocation following primary total hip arthroplasty (THA)., Materials and Methods: This study retrospectively evaluated 17 073 patients who underwent primary THA between 1998 and 2018. A test set of 1718 patients was held out. A hybrid network of EfficientNet-B4 and Swin-B transformer was developed to classify patients according to 5-year dislocation outcomes from preoperative anteroposterior pelvic radiographs and clinical characteristics (demographics, comorbidities, and surgical characteristics). The most informative imaging features, extracted by the mentioned model, were selected and concatenated with clinical features. A collection of these features was then used to train a multimodal survival XGBoost model to predict the individualized hazard of dislocation within 5 years. C index was used to evaluate the multimodal survival model on the test set and compare it with another clinical-only model trained only on clinical data. Shapley additive explanation values were used for model explanation., Results: The study sample had a median age of 65 years (IQR: 18 years; 52.1% [8889] women) with a 5-year dislocation incidence of 2%. On the holdout test set, the clinical-only model achieved a C index of 0.64 (95% CI: 0.60, 0.68). The addition of imaging features boosted multimodal model performance to a C index of 0.74 (95% CI: 0.69, 0.78; P = .02)., Conclusion: Due to its discrimination ability and explainability, this risk calculator can be a potential powerful dislocation risk stratification and THA planning tool. Keywords: Conventional Radiography, Surgery, Skeletal-Appendicular, Hip, Outcomes Analysis, Supervised Learning, Convolutional Neural Network (CNN), Gradient Boosting Machines (GBM) Supplemental material is available for this article. © RSNA, 2022., Competing Interests: Disclosures of conflicts of interest: B.K. No relevant relationships. P.R. No relevant relationships. H.M.K. National Institutes of Health (NIH) grants. D.R.L. No relevant relationships. Q.J.J. No relevant relationships. S.F. No relevant relationships. W.K.K. NIH funds for research paid to institution; author provides statistical analyses to Data Safety Monitoring Boards; mutual funds or similar. B.J.E. Chair of Research Committee for Society for Imaging Informatics in Medicine; consultant to the editor for Radiology: Artificial Intelligence. R.J.S. Royalties or licenses from Zimmer Biomet, OrthAlign, and Link Orthopedics; consulting fees from Think Surgical and OrthAlign; patent planned, issued, or pending with Zimmer Biomet; leadership or fiduciary role with the American Association of Hip and Knee Surgeons, Muller Foundation, and the Academic Network of Conservational Hip Outomes Research; receipt of equipment, materials, drugs, medical writing, gifts, or other services from Springer. M.J.T. No relevant relationships. C.C.W. No relevant relationships., (© 2022 by the Radiological Society of North America, Inc.)

Background: There is a paucity of literature examining patients' and health-care providers' perception of surgical scars after total hip arthroplasty (THA). This study examined perception of surgical scars after direct anterior (DAA) or posterior approach (PA) for THA using validated scar-assessment scales., Material and Methods: Seventy-five DAA and 75 PA THA patients underwent scar assessment using the Patient Observer Scar Assessment Scale (POSAS) and Stony Brook Scar Evaluation Scales. Mean age was different between the cohorts (DAA 67 vs PA 62 years, P  = .01). All patients had subcuticular running closure, secured with skin adhesive glue. Mean time from THA to scar assessment was 3.1 and 3.6 years for the DAA and PA groups, respectively ( P  = .18)., Results: Scar opinion on the POSAS patient-reported scale was graded closer to normal skin more often for DAA than for PA patients ( P  = .03). More irregularities were graded for the DAA scars on the POSAS observer scale ( P  = .02) and the Stony Brook Scar Evaluation Scales ( P  = .04). Age did not predict scar opinion on any of the scales ( P > .05). Female gender and a history of keloids predicted poorer scar appearance ( P  = .001 and P  = .02). Overall scar appearance was rated as "good" in 93% of the DAA and 91% of the PA patients ( P  = .63)., Conclusion: Differences exist in DAA and PA scar perception based on validated scales. Future randomized trials in scar assessment may control for confounding variables such as age and gender, as well as potential biases when using scar assessment scales., (© 2022 The Authors.)

Hip dysplasia is a common cause of hip pain and a known risk factor for hip osteoarthritis (OA) and early total hip arthroplasty (THA). Unfortunately, little is known about the specific factors associated with an increased risk of OA. The purpose was (i) to report the overall rate of symptomatic hip OA and THA and (ii) to identify radiographic features and patient characteristics associated with the development of symptomatic hip OA. A geographic database was used to identify all patients aged 14-50 years old diagnosed with symptomatic hip dysplasia between 2000 and 2016. Kaplan-Meier analysis was used to determine the rate of symptomatic hip OA, defined as a Tönnis grade of ≥1 on hip radiograph. Univariate and multivariate proportional hazard regression models were performed to determine risk factors for OA. One hundred and fifty-nine hips (144 patients) with hip dysplasia (52 F:107 M) out of 1893 patients with hip pain were included. Of these, 45 (28%) had severe hip dysplasia with a lateral center-edge angle ≤18°. Mean age at time of presentation was 26.1 (±10.1) years. Mean follow-up time was 8.2 (±5) years. The rate of OA was 20%. THA was performed in 11% of patients. Body mass index >29 ( P  = 0.03) and increased age ( P  < 0.01) were risk factors for OA. Patients with symptomatic hip dysplasia are at significant risk of developing hip OA. Body mass index >29 and age ≥35 years at the time of presentation with hip pain were risk factors for hip OA., (© The Author(s) 2022. Published by Oxford University Press.)

Aims: Bone marrow-derived mesenchymal stem cells obtained from bone marrow aspirate concentrate (BMAC) with platelet-rich plasma (PRP), has been used as an adjuvant to hip decompression. Early results have shown promise for hip preservation in patients with osteonecrosis (ON) of the femoral head. The purpose of the current study is to examine the mid-term outcome of this treatment in patients with precollapse corticosteroid-induced ON of the femoral head., Methods: In all, 22 patients (35 hips; 11 males and 11 females) with precollapse corticosteroid-induced ON of the femoral head underwent hip decompression combined with BMAC and PRP. Mean age and BMI were 43 years (SD 12) and 31 kg/m² (SD 6), respectively, at the time of surgery. Survivorship free from femoral head collapse and total hip arthroplasty (THA) and risk factors for progression were evaluated at minimum five-years of clinical follow-up with a mean follow-up of seven years (5 to 8)., Results: Survivorship free from femoral head collapse and THA for any reason was 84% and 67% at seven years postoperatively, respectively. Risk factors for conversion to THA included a high preoperative modified Kerboul angle (grade 3 or 4) based on preoperative MRI (hazard ratio (HR) 3.96; p = 0.047) and corticosteroid use at the time of decompression (HR 4.15; p = 0.039). The seven-year survivorship for patients with grade 1 or 2 Kerboul angles for conversion to THA for articular collapse, and THA for any reason, were 96% and 72%, respectively, versus THA for articular collapse and THA for any reason in patients with grade 3 or 4 Kerboul angles of 40% (p = 0.003) and 40% (p = 0.032)., Conclusion: At seven years, hip decompression augmented with BMAC and PRP provided a 67% survivorship free from THA in patients with corticosteroid-induced ON. Ideal candidates for this procedure are patients with low preoperative Kerboul angles and can stop corticosteroid treatment prior to decompression. Cite this article: Bone Jt Open  2021;2(11):926-931.

It is unclear whether treatment of intraarticular pathology should be performed during periacetabular osteotomy (PAO) to improve outcomes. Therefore, we asked: (i) What are the clinical results of PAO in patients with and without intraarticular intervention? (ii) Is there a difference in reoperations with and without intraarticular intervention? and (iii) Is there a difference in clinical results and reoperations depending on preoperative Tönnis Grade if intraarticular intervention is performed? Prospective evaluation of 161 PAO in 146 patients was performed. The cohort was 84.5% female, mean age was 26.7 ± 7.9 years and mean follow-up was 2.4 years; 112 hips had Grade 0 changes and 49 hips had Grade 1 changes. Patients were classified into three groups based on treatments during PAO: major (labral repair, femoral head-neck osteochondroplasty), minor (labral debridement, femoral/acetabular chondroplasty) or no intervention. A subset of eight patient-reported outcome measures (PROMs) was analyzed to determine whether the minimal clinically important difference (MCID) was achieved. Major, minor and no intervention groups exceeded the MCID in 5, 8 and 8, of 8 PROMs ( P  ≥ 0.20), respectively; intraarticular interventions did not influence reoperation-free survival ( P  ≥ 0.35). By Tönnis Grade, PROMs exceeding MCID decreased in Grade 1 versus 0 receiving no intervention ( P  < 0.001) but did not decrease for either intervention ( P  ≥ 0.14); intraarticular interventions did not influence reoperation-free survival ( P  ≥ 0.38). Overall, intraarticular intervention was associated with excellent PROMs and reoperation-free survival. Although Grade 1 patients had fewer PROM which achieved MCID, intraarticular interventions attenuated this decrease, suggesting a therapeutic advantage of intraarticular procedures for more advanced pathology., (© The Author(s) 2021. Published by Oxford University Press.)

Objective: Shared decision-making (SDM) is a strongly endorsed approach by which patients and clinicians work together to formulate a sensible care plan. The present study was undertaken to conduct a systematic review of SDM trials in patients considering knee arthroplasty (KA) to characterize how SDM was supported and the impact on care received., Methods: We searched multiple bibliographic databases from inception to December 31, 2019. A pair of reviewers working independently selected studies for inclusion, extracted data, and evaluated each trial's risk of bias., Results: We found 6 eligible randomized trials (4 included KA and hip arthroplasty), all of which tested the same proprietary decision aid (DA) (Treatment Choices for Hip or Knee Osteoarthritis), with some adding other materials to support SDM. These trials, all of which had moderate-to-high risk of bias, focused on assessing the effect of the DA on patient knowledge about the options while not explicitly supporting other aspects of SDM, such as choice awareness, deliberation, or decision-making. One trial found an increase in the number of African American patients undergoing KA in the 12 months following the intervention. No other trials found that SDM impacts clinical outcomes., Conclusion: Evidence for SDM in patients considering KA is mostly limited to a single DA. While use of this DA improves patient knowledge about their treatment options, this tool has not been shown to promote SDM, impact treatment decisions, or satisfaction with care. Future work should seek to support SDM directly and assess effects on treatment decisions, functional outcomes, and satisfaction., (© 2020, American College of Rheumatology.)

Periacetabular osteotomy (PAO) is effective in the management of developmental dysplasia of the hip and femoroacetabular impingement secondary to acetabular retroversion. During anteverting PAO for acetabular retroversion, the need for both labral treatment and femoral head-neck junction osteochondroplasty remains equivocal. Accordingly, this study evaluated patient-reported outcome measures (PROM) and reoperation rates after anteverting PAO with or without intraarticular intervention. Cases of anteverting PAO performed at a single institution between November 2009 and January 2016 were retrospectively reviewed. Patients were divided into three groups: no intervention and intraarticular intervention with arthrotomy or arthroscopy. Subsequently, patients were reclassified by the intraarticular procedure performed at surgery into major (labral repair, femoral head-neck osteochondroplasty) and minor (labral debridement, femoral/acetabular chondroplasty) groups. The cohort was 75% female, median age was 19.5 years and mean body mass index was 25.0 kg/m 2 . Preoperative to postoperative improvement was compared to minimal clinically important differences (MCID) for eight PROM. Patients receiving major interventions exceeded MCID in a greater proportion of PROM compared to minor and no intervention groups ( P  < 0.007); major or minor interventions did not increase the risk of reoperation over no intervention ( P  ≥ 0.39). Based on the current data, surgeons performing anteverting PAO for acetabular retroversion should perform arthroscopic or open labral repair and assess for impingement after the correction and perform a head-neck junction osteochondroplasty if indicated., (© The Author(s) 2021. Published by Oxford University Press.)

Background: Hip dysplasia is a common source of hip pain and a known cause of early osteoarthritis of the hip., Purpose: To (1) define the population-based incidence of hip dysplasia diagnosis in young patients presenting with hip pain in a large geographically defined cohort, (2) analyze trends regarding presentation and diagnosis of hip dysplasia, and (3) report the rate and type of surgical interventions used to treat this population., Study Design: Cross-sectional study; Level of evidence, 3., Methods: A geographic epidemiological database was queried to identify patients aged 14 to 50 years with hip pain between the years 2000 and 2016. Patient medical records were analyzed, and demographic, imaging, clinical, and treatment history were recorded. Incidence trends were examined by use of linear regression with confidence intervals for age and calendar year., Results: Overall, 1893 patients were included. Of these, 156 patients (196 hips) had a diagnosis of hip dysplasia. The incidence of hip dysplasia diagnosis in patients who reported hip pain was 12.7 per 100,000 person-years. Patients with dysplasia had a mean age of 26.7 ± 9.8 years, while the highest age-adjusted incidence occurred at age 14 to 18 years in both male and female patients. Female patients had double the age-adjusted incidence of male patients (cases per 100,000 person-years: 16.8 [95% CI, 13.9-19.7] vs 8.7 [95% CI, 6.6-10.8]; P < .01). Of the patients who underwent magnetic resonance imaging, 77% had imaging consistent with labral pathology. Patients were treated with physical therapy (67%), intra-articular steroid injection (29%), hip arthroscopy (10%), and periacetabular osteotomy (9%). The use of hip arthroscopy significantly increased over time ( P < .01), whereas the use of steroid injection and periacetabular osteotomy did not ( P < .28 and P < .08, respectively)., Conclusion: The incidence of hip dysplasia diagnosis in patients presenting with hip pain was 12.7 per 100,000 person-years. Female patients had twice the age-adjusted incidence of male patients, and the highest age-adjusted incidence occurred in the age range of 14 to 18 years in both sexes. The use of hip arthroscopy to treat patients with hip dysplasia significantly increased over time., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This study was partially funded by a grant from the National Institute of Arthritis and Musculoskeletal and Skin Diseases for the Musculoskeletal Research Training Program (T32AR56950). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH. M.D.L. has a family member who has received consulting fees from Linvatec, Ossur, and Smith & Nephew and royalties from Arthrex, Smith & Nephew, and Thieme. R.J.S. has received consulting fees from Orthaligh and Zimmer and royalties from Zimmer. R.T.T. has received consulting fees from Medical Device Business Services and Medtronic and royalties from DePuy. B.A.L. has received research support from Biomet, Smith & Nephew, and Stryker; consulting fees from Smith & Nephew; speaking fees from Linvatec; and royalties from Arthrex. A.J.K. has received research support from Aesculap/B.Braun, Arthritis Foundation, Ceterix, Exactech, Gemini Medical, and Histogenics; consulting fees from Arthrex, DePuy, JRF Ortho, and Vericel; and royalties from Arthrex; has stock/stock options in Responsive Arthroscopy; and is a board or committee member for the Musculoskeletal Transplantation Foundation. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

A variety of options exist for management of patients with developmental dysplasia of the hip (DDH). Most studies to date have focused on clinical outcomes; however, there are currently no data on comparative cost of these techniques. The purpose of this study was to evaluate in-hospital costs between patients managed with periacetabular osteotomy, hip arthroscopy or a combination for DDH. One hundred and nine patients were included: 35 PAO + HA, 32 PAO and 42 HA. There were no significant differences in the demographic parameters. Operative times were significantly different between groups with a mean of 52 min for PAO, 100 min for HA and 155 min for PAO + HA, ( P  < 0.001). Total direct medical costs were calculated and adjusted to nationally representative unit costs in 2017 inflation-adjusted dollars. Total in-hospital costs were significantly different between each of the three treatment groups. PAO + HA was the most expensive with a median of $21 852, followed by PAO with a median of $15 124, followed by HA with a median of $11 582 ( P  < 0.001). There was a significant difference between outpatient median costs of $11 385 compared with $24 320 for inpatients ( P  < 0.001). Procedures with greater complexity were more expensive. However, a change from outpatient to inpatient status with HA moved that group from the least expensive to similar to PAO and PAO + HA. These data provide an important complement to clinical outcomes reports as surgeons and policymakers aim to provide optimal value., (© The Author(s) 2020. Published by Oxford University Press.)

Unicompartmental knee arthroplasty (UKA) is a viable option for patients with symptomatic knee arthritis isolated to 1 compartment. Previous articles have suggested that mobile-bearing UKA should not be performed in patients without bone-on-bone arthritis. The purpose of this study was to compare the clinical outcomes and survivorship of mobile-bearing UKA in patients with severe osteoarthritis with bone-on-bone contact and patients with severe osteoarthritis but without bone-on-bone contact., Methods: We retrospectively reviewed a single surgeon's experience with medial compartment mobile-bearing UKA in 219 patients (271 knees) who underwent the procedure between 2007 and 2015. Anteroposterior and posteroanterior radiographs were reviewed, and arthritis was graded using the International Knee Documentation Committee (IKDC) grading system. Only patients with grade D (severe arthritis) were studied. Of the patients who had grade-D arthritis, there were 81 patients (94 knees) with bone-on-bone arthritis and 82 patients (91 knees) without bone-on-bone contact. Functional outcomes were assessed using the Knee Society pain and function scores. Survivorship free of revision in these 2 groups was determined using Kaplan-Meier curves at 8 years., Results: There were no significant differences between the 2 groups in terms of age (p = 0.91), sex (p = 0.21), or body mass index (p = 0.63). At the time of the final follow-up, there was no significant difference in Knee Society pain scores (p = 0.59) or Knee Society function scores (p = 0.9) between the 2 groups. There were 5 revisions in the group with bone-on-bone contact and 2 revisions in the group without bone-on-bone contact. The survivorship free of revision at 8 years was 95% for the group with bone-on-bone contact and 98% for the group without bone-on-bone contact (p = 0.45)., Conclusions: Patients with severe knee arthritis (IKDC grade D) without bone-on-bone contact had similar outcomes of mobile-bearing UKA compared with patients with bone-on-bone contact. UKA is a safe and reliable option in patients with severe osteoarthritis who do not have bone-on-bone contact on preoperative radiographs and it should therefore not be considered a contraindication for mobile-bearing UKA as long as the patient's symptoms are severe enough to warrant surgical intervention., Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence., (Copyright © 2020 The Authors. Published by The Journal of Bone and Joint Surgery, Incorporated. All rights reserved.)

Introduction: Prosthetic joint infection (PJI) due to Streptococcus bovis group (SBG), specifically S. bovis biotype I ( S. gallolyticus ), is rare and associated with colorectal carcinoma. Little has been published regarding SBG PJI. We analyzed nine cases of SBG PJI at our institution, the largest series to date. Methods : The medical records of patients diagnosed with SBG PJI between 2000-2017 were reviewed. Patients were followed until death, failure, or loss to follow-up. Mean follow-up was 37 months (range 0.5-74 months). Results: Nine PJI in 8 patients with mean prosthesis age at diagnosis of 8 years (range 4 weeks-17 years) were identified. The median duration between symptom onset and treatment was 38 weeks (range 0.3 weeks-175 weeks). 8/9 had their PJI eradicated with treatment based on acuity of symptoms. Acute PJI (2) was treated with DAIR, and chronic PJI (7) was treated with 2-stage revision arthroplasty. 1 PJI with chronic PJI developed recurrent infection after initial treatment. All patients received post-operative IV antibiotics. 7/8 patients received Ceftriaxone. Three patients received lifelong oral antibiotics. 7/8 patients underwent colonoscopy. 5/7 patients were found to have polyps following PJI diagnosis with one carcinoma and two dysplastic polyps. The two patients without polyps had identifiable gastrointestinal (GI) mucosal abnormality: tooth extraction prior to symptom onset and diverticulosis on chronic anticoagulation. Conclusion: SBG PJI is typically due to hematologic seeding. Colonoscopy should be pursued for patients with SBG PJI. Surgical treatment dictated by infection acuity and 6-week course of Ceftriaxone seems sufficient to control infection., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Background: The pathophysiology of osteonecrosis of the femoral head (ONFH) is poorly understood, and the diagnosis is idiopathic in as many as 40% of patients. Genetic and epigenetic etiologies have been postulated, yet no single nucleotide polymorphisms (SNPs) with intuitive biologic implications have been elucidated., Questions/purposes: (1) Do individuals with ONFH share common biologically relevant genetic variants associated with disease development? (2) What is the mechanism by which these SNPs may impact the expression or function of the affected gene or protein?, Methods: This retrospective genome-wide association study (GWAS) evaluated participants from the Mayo Clinic Biobank and Mayo Clinic Genome Consortium between August 2009 and March 2017. We included every patient with atraumatic ONFH in each of these respective registries and every control patient in a previous GWAS with an acceptable platform to perform statistical imputation. The study was performed in two phases, with an initial discovery cohort and a subsequent validation cohort. The initial discovery cohort consisted of 102 patients with ONFH and 4125 controls. A logistic regression analysis was used to evaluate associations between SNPs and the risk of ONFH, adjusted for age and sex. Seven SNPs were identified in a gene of biological interest, peroxisome proliferator-activated receptor gamma (PPARG), which were then evaluated in a subsequent validation cohort of 38 patients with ONFH and 464 controls. Age, sex, race, and previous steroid exposure were similar between patients with ONFH and controls in both the discovery and validation cohorts. Separate from the two-phase genetic investigation, we performed targeted pharmacosurveillance to evaluate the risk association between the use of antidiabetic thiazolidinediones, a class of PPARG agonists, and development of ONFH by referencing 9,638,296 patient records for individuals treated at Mayo Clinic., Results: A combined analysis of the discovery and validation cohorts revealed that seven SNPs were tightly clustered adjacent to the 3' end of PPARG, suggesting an association with the risk of ONFH (p = 1.58 x 10-5.50 x10). PPARG gene-level significance was achieved (p = 3.33 x 10) when all seven SNPs were considered. SNP rs980990 had the strongest association with the risk of ONFH (odds ratio [OR], 1.95; 95% CI, 1.46-2.59; p = 5.50 x 10).The seven identified SNPs were mapped to a region near the PPARG gene and fell in a highly conserved region consisting of several critical transcription factor binding sites. Nucleotide polymorphisms at these sites may compromise three-dimensional chromatin organization and alter PPARG 3' end interactions with its 5' promoter and transcription start site. Pharmacosurveillance identified that patients who were exposed to thiazolidinediones had an increased relative risk of developing ONFH of 5.6 (95% CI, 4.5-7.1)., Conclusions: We found that disruption of PPARG regulatory domains is linked to an increased risk of ONFH. Mechanistically, aberrant regulation of PPARG compromises musculoskeletal differentiation because this master regulator creates a proadipogenic and antiosteogenic state. Furthermore, PPARG alters steroid metabolism and vasculogenesis, processes that are inextricably linked with ONFH. Pharmacologically, predisposition to ONFH was further exposed with thiazolidinedione use, which upregulates the expression of PPARG and is known to alter bone metabolism. Collectively, these findings provide a foundation to perform confirmatory studies of our proposed mechanism in preclinical models to develop screening diagnostics and potential therapies in patients with limited options., Level of Evidence: Level III, prognostic study.

Background: There is limited information on the complications and costs of conversion THA after hemiarthroplasty for femoral neck fractures. Previous studies have found that patients undergoing conversion THA experience higher risk complications, but it has been difficult to quantify the risk because of small sample sizes and a lack of comparison groups. Therefore, we compared the complications of patients undergoing conversion THA with strictly matched patients undergoing primary and revision THA., Questions/purposes: (1) What are the risks of complications, dislocations, reoperations, revisions and periprosthetic fractures after conversion THA compared with primary and revision THA and how has this effect changed over time? (2) What are the length of hospital stay and hospital costs for conversion THA, primary THA, and revision THA?, Methods: Using a longitudinally maintained total joint registry, we identified 389 patients who were treated with conversion THA after hemiarthroplasty for femoral neck fractures between 1985 and 2014. The conversion THA cohort was 1:2 matched on age, sex, and year of surgery to 778 patients undergoing primary THA and 778 patients undergoing revision THA. The proportion of patients having at least 5-year followup was 73% in those who underwent conversion THA, 77% in those who underwent primary THA, and 76% in those who underwent revision THA. We observed a significant calendar year effect, and therefore, compared the three groups across two separate time periods: 1985 to 1999 and 2000 to 2014. We ascertained complications, dislocations, reoperations, revisions and periprosthetic fractures from the total joint registry. Cost analysis was performed using a bottom-up, microcosting methodology for procedures between 2003 and 2014., Results: Patients who converted to THA between 1985 and 1999 had a higher risk of complications (hazard ratio [HR], 2.3; 95% confidence interval [CI], 1.7-3.1; p < 0.001), dislocations (HR, 2.3; 95% CI, 1.3-4.2; p = 0.007), reoperations (HR, 1.7; 95% CI, 1.2-2.5, p = 0.005), and periprosthetic fractures (HR, 3.8; 95% CI, 2.2-6.6; p < 0.001) compared with primary THA. However, conversion THAs during the 1985 to 1999 time period had a lower risk of reoperations (HR, 0.7; 95% CI, 0.5-1.0; p = 0.037), revisions (HR, 0.6; 95% CI, 0.5-0.9; p = 0.014), and periprosthetic fractures (HR, 0.6; 95% CI, 0.4-0.9; p = 0.007) compared with revision THA. The risk differences across the three groups were more pronounced after 2000, particularly when comparing conversion THA patients with revision THA. Conversion THA patients had a higher risk of reoperations (HR, 1.9; 95% CI, 1.0-3.4; p = 0.041) and periprosthetic fractures (HR, 1.7; 95% CI, 1.0-2.9; p = 0.036) compared with revision THA, but there were no differences in the complication risk (HR, 1.4; 95% CI, 0.9-2.1; p = 0.120), dislocations (HR, 1.5; 95% CI, 0.7-3.2; p = 0.274), and revisions (HR, 1.4; 95% CI, 0.7-3.0; p = 0.373). Length of stay for conversion THA was longer than primary THA (4.7 versus 4.0 days; p = 0.012), but there was no difference compared with revision THA (4.7 versus 4.5 days; p = 0.484). Similarly, total inpatient costs for conversion THA were higher than primary THA (USD 22,662 versus USD 18,694; p < 0.001), but there was no difference compared with revision THA (USD 22,662 versus USD 22,071; p = 0.564)., Conclusions: Over the 30 years of the study, conversion THA has remained a higher risk procedure in terms of reoperation compared with primary THA, and over time, it also has become higher risk compared with revision THA. Surgeons should approach conversion THA as a challenging procedure, and patients undergoing this procedure should be counseled about the elevated risks. Furthermore, hospitals should seek appropriate reimbursement for these cases., Level of Evidence: Level III, therapeutic study.

Background: Instability remains one of the most common indications for revision THA. However, little is known about the efficacy of surgery for and the complications associated with revision THA for patients with a chronically dislocated THA, which we define as a dislocation of more than 4 weeks., Questions/purposes: For patients with a chronically dislocated THA undergoing revision THA, we asked (1) What is the survivorship free from additional revision for these procedures? (2) What complications are associated with revision THA in this setting? (3) What are the clinical outcomes as measured by the Harris hip score in these procedures?, Methods: From 1998 to 2014, 1084 patients who underwent revision THA for instability were reviewed and 33 patients (33 hips) were identified who had a hip that had been dislocated for more than 4 weeks. Median time dislocated was 4 months (range, 1-120 months), and the mean distance of the femoral head above hip center at presentation was 45 mm. Mean patient age was 67 ± 17 years, and 79% of patients (26 of 33) were women. During the period in question, we used four approaches: Treatment with acetabular component revision in 18 of 33 patients (55%), head and liner exchange in nine patients (27%), both-component revision in five patients (15%), and isolated femoral component revision in one patient (3%). A constrained liner was used in 17 patients (52%), including six of the patients treated with acetabular component revision, and three of those who had both-component revisions. During the period in question, our general indications were hip pain and/or unacceptable function with the chronically dislocated prosthesis. Our sample size was too small to evaluate the association of the procedure choice on survivorship or complication risk. We used Kaplan-Meier survivorship analysis to estimate survivorship free from complication, reoperation, or revision. Mean followup was 4.4 years (range, 2-10 years)., Results: Survivorship free from any revision, complication, or reoperation was 61% at 5 years (95% CI, 43-82). Survivorship free from revision was 83% at 5 years (95% CI, 67-98). Etiology for revision was aseptic loosening in three of 33 hips (9%), recurrent dislocation in two hips (6%), and deep periprosthetic joint infection in two hips (6%). Five complications (15%) did not result in a reoperation, including one dislocation and one incomplete peroneal nerve palsy in a patient after an anterolateral approach. The Harris hip score improved from mean 50 ± 17 preoperatively to mean 80 ± 11 at 5 years., Conclusions: Chronically dislocated THAs can be successfully managed with revision THA. We recommend close evaluation of the components for aseptic loosening, performing revision surgery only on patients with pain and poor function, and thoroughly counseling patients that survivorship is modest and complications are common., Level of Evidence: Level IV, therapeutic study.

Diagnosis of persistent infection at the time of reimplantation for staged revision of infected arthroplasties is challenging. Implant sonication culture for the diagnosis of prosthetic joint infection (PJI) has improved sensitivity compared to standard periprosthetic tissue culture. We report our experience with periprosthetic tissue culture and sonication culture of antimicrobial agent-containing cement spacers (ACSs) collected during second stages of staged revisions for arthroplasty infection. We studied 87 ACSs from 66 patients undergoing two-stage revision arthroplasty for PJI submitted for sonication culture, along with conventional periprosthetic tissue cultures. Two or more positive periprosthetic tissue cultures with the same organism were considered a positive tissue culture. For sonication culture, ≥20 CFU of bacteria per 10 ml of sonicate fluid was considered positive. The sensitivity and specificity of periprosthetic tissue and ACS sonication culture in detecting persistent infection, as well as their association with outcome, were assessed. Persistent infection occurred in 26% of cases. Periprosthetic tissue and sonicate fluid culture had specificities of 96.3 and 100% ( P =  0.50), respectively, and sensitivities of 31.6 and 26.3% ( P =  1.00), respectively, for the diagnosis of persistent infection. Thirteen subjects deemed not to have persistent infection at time of reimplantation and who had negative periprosthetic tissue and sonicate fluid cultures subsequently developed overt infection. Sonication culture of cement spacers identifies a similar proportion of patients with persistent infection during staged revisions, as detected by periprosthetic tissue cultures; both have low sensitivities to detect persistent infection., (Copyright © 2019 American Society for Microbiology.)

Periacetabular osteotomies (PAOs) are used to treat acetabular dysplasia in younger patients, but are not without morbidity. Lateral femoral cutaneous nerve (LFCN) injuries are commonly associated with the approach for PAOs, but the true incidence and rate of resolution is not known. The purpose of this prospective study was to determine the incidence of LFCN injuries after PAO using an innovative nerve conduction study (NCS) and to report the patient-reported outcomes. We prospectively enrolled 23 patients (24 hips) undergoing PAOs to have pre- and post-operative NCSs at a mean of 12 weeks post-operative. Patients were followed prospectively. Patients were contacted 3 years post-operatively via phone to determine the presence and severity of symptoms. Patient-reported outcome scores were also correlated with patient symptoms. Patients (91%) reported one or more LFCN symptoms post-operatively. The most common symptoms were numbness (91%), tingling (36%), pain (18%) and burning (9%). Patients (67%) had evidence of LFCN injury based on NCSs. Symptoms (40%) resolved 4 months post-operatively. Two-thirds of patients had continued symptoms at 3 years. Only 1 patient required treatment. The incidence of LFCN injury after PAO is 90%, two-thirds of which can be identified objectively by NCS. Numbness is the most common symptom. LFCN symptoms (40%) resolve by 4 months, but two-thirds of patients may continue to have thigh numbness up to 3 years after surgery. Fortunately, symptoms are not clearly associated with outcome score and treatment for this complication is rare.

Background: Unicompartmental knee arthroplasty restores function and improves pain in appropriately selected patients. Scant evidence exists regarding the treatment of periprosthetic joint infection (PJI) after unicompartmental knee arthroplasty (UKA)., Questions/purposes: (1) What was the overall survivorship free from reinfection? (2) What is the survivorship free of all-cause revision? (3) What are the Knee Society scores (KSS) and complications after surgical treatment of UKA PJI?, Methods: This retrospective study with data drawn from a longitudinally maintained institutional registry identified 15 UKA PJIs between 1992 and 2014. The median age at PJI diagnosis was 58 years (range, 41-82 years), nine of 15 were men, and the median body mass index was 29 kg/m (range, 23-36 kg/m). Ten patients (10 of 15) satisfied major Musculoskeletal Infection Society diagnostic criteria. There were five patients (five of 15) with early postoperative infections, five (five of 15) with acute hematogenous infections, and five (five of 15) with chronic PJIs. Two-stage exchange was performed in four patients with PJIs (four of 15), and débridement, antibiotics, and implant retention (DAIR) was performed in 11 patients (11 of 15) with PJIs. We performed Kaplan-Meier survivorship analysis for reinfection and revision procedures. Thirteen patients had a minimum of 2 years' followup and were included in the clinical analysis. Median followup was 4 years (range, 2-6 years). We calculated KSS., Results: Infection-free survivorship was 71% at 5 years (95% confidence interval [CI], 46%-96%). Treatment success was higher for patients undergoing two-stage exchange (100% at 5 years; 95% CI, 100%-100%) versus DAIR (61% at 5 years; 95% CI, 31%-92%). Four of 11 patients undergoing DAIR had developed a reinfection at final followup. Survivorship free of any revision was 49% at 5 years (95% CI, 19%-79%). One patient from the two-stage exchange cohort underwent femoral component revision for aseptic loosening 5 years after PJI treatment, and two patients from the DAIR group were converted to TKA for disease progression at a mean of 4 years. In patients with a minimum of 2 years' followup, median KSS improved from 73 (range, 50-93) before index UKA to 94 (range, 55-100; p = 0.016)., Conclusions: Treatment of UKA PJI with DAIR was associated with a lower infection-free survivorship at 5 years compared with two-stage exchange with conversion to TKA. Among those patients who were infection-free, a number needed reoperations for disease progression (in the DAIR group) or component loosening (in both groups). UKA PJI results in substantial morbidity, and patients with these infections should be followed closely for aseptic causes of failure in addition to infection recurrence., Level of Evidence: Level IV, therapeutic study.

Periacetabular osteotomy (PAO) remains the gold standard procedure for joint preservation in symptomatic developmental dysplasia of the hip (DDH). Hip arthroscopy (HA) and open arthrotomy have been used to correct intra-articular pathology at the time of PAO, but there is limited data regarding differences in outcomes between these techniques when performed at the time of PAO. The aim of this study was to determine if short-term clinical outcomes differed between patients managed with HA versus arthrotomy to evaluate and treat intra-articular pathology at the time of PAO to discern if one technique is associated with better pain and functional results. Data were retrospectively reviewed from two surgeons at one institution managing DDH patients from September 2013 to December 2015. One surgeon treated patients with PAO and arthrotomy ( N  = 32), while the other performed PAO and HA ( N  = 39). There were 87% women, median age was 28 years and mean BMI was 25. Seventy-five percent of all patients received an intra-articular intervention. Patients completed 13 PROs at the pre-operative and 1-year post-operative clinical visits. Pre-operatively, there were no differences in any of the 13 PROs between patients treated with HA versus arthrotomy ( P  ≥ 0.076). Patients treated with PAO and arthrotomy experienced greater mean improvement in two out of the 13 PROs; the other 11 showed no differences. No treatment effect was observed for any of the 13 PROs using multivariable modelling that accounted for severity of dysplasia and degree of arthritis. Few differences were shown in short-term clinical outcomes between HA and arthrotomy at the time of PAO. This work highlights the need for a high quality randomized clinical trial to provide definitive guidance on whether hip preservation surgeons should address intra-articular pathology at the time of PAO for DDH and which technique best serves this purpose.

Background: Revision THA to treat recurrent instability can itself be complicated by recurrent instability, and when this occurs, this problem is difficult to treat. Some patients' THAs will continue to dislocate despite use of a constrained liner. One option in this difficult-to-treat group is conversion to a dual-mobility (DM) construct, but there are few data on this approach., Questions/purposes: (1) What were the Harris hip scores in a small group of patients whose constrained liners were converted to DM constructs to treat recurrent dislocation? (2) What were the redislocation, rerevision, and DM construct retention rates in these patients?, Methods: We conducted a retrospective analysis of a longitudinally maintained institutional database maintained by individuals other than the treating surgeons to identify patients undergoing conversion of constrained liners to DM constructs in revision THA from 2011 to 2014. We identified 16 patients who underwent revision of dislocated constrained liners to DM constructs. Two patients died before 2-year followup, leaving 14 patients available for followup at a minimum of 24 months and a median of 37 months (range, 24-71 months). Indications for conversion to DM constructs included patients with dislocation of multiple prior constrained liners, patients with at least partial abductor functioning and soft tissue tensioning, and patients at very high risk for recurrent instability as an alternative to resection arthroplasty. Ten patients (10 of 14) underwent DM conversion at the time of cup revision, whereas four patients (four of 14) had a DM construct cemented into a preexisting cup. Median age was 65 years (range, 53-93 years). Median number of prior hip surgeries was five (range, three to 10) and seven patients (seven of 14) had dislocated more than one constrained liner., Results: Harris hip score improved from a median of 57 (range, 55-67) to 84 (range, 68-96) postoperatively (p < 0.001). Three patients (three of 14) experienced a redislocation. Two (two of 14) of these patients were closed reduced and treated successfully nonoperatively; one (one of 14) patient experienced an intraprosthetic dislocation and underwent modular exchange. One patient (one of 14) underwent early resection arthroplasty for acetabular loosening after complex acetabular reconstruction. Overall, all other patients (13 of 14) retained a DM construct at final followup., Conclusions: Conversion to a DM construct shows promise as a salvage option in high-risk, multiply operated on patients with dislocated constrained liners undergoing revision THA for recurrent instability. The ability to close reduce a dislocated DM construct is a distinct advantage over constrained liners. However, longer followup is required given that three of 14 redislocated, and one of those underwent revision for persistent instability at short-term followup., Level of Evidence: Level IV, therapeutic study.

Background: The choice of surgical approach for THA remains controversial. Some studies suggest that the direct anterior approach (DAA) leads to less muscle damage than the miniposterior approach (MPA), but there is little high-quality evidence indicating whether this accelerates recovery, or whether this approach-which may be technically more demanding-is associated with component malposition or more complications., Questions/purposes: (1) Does the DAA result in faster return to activities of daily living than the MPA? (2) Does the DAA have superior patient-reported outcome measures than the MPA? (3) Does the DAA result in improved radiographic outcomes than the MPA? (4) Does the DAA have a higher risk of complications than the MPA?, Methods: Between March 1, 2013, and May 31, 2016, 116 patients undergoing primary unilateral THA were randomized to either the DAA or MPA; 15 patients withdrew after randomization, and one died 6 months after surgery from a stroke unrelated to the procedure. Recruitment stopped when 52 patients had been randomized into the DAA group and 49 in the MPA group (n = 101). After patient randomization, one high-volume surgeon performed all of the DAAs and three high-volume surgeons performed the MPA THAs. The groups did not differ in age (65 years; SD 11; range, 38-86 years), sex (52% women), or body mass index (mean 29 kg/m; SD 6 kg/m; range, 21-40 kg/m; all p > 0.40). Functional results included time to discontinue gait aids, discontinue all narcotics, and independence with various activities of daily living; accelerometer data evaluated activity level. Clinical and radiographic outcomes, Hip disability and Osteoarthritis Outcome Score, SF-12, and Harris hip scores to 1 year were also tabulated. The minimum followup was 365 days (mean ± SD, 627 ± 369 days)., Results: There were slight differences in early functional recovery that favored the DAA versus the MPA: time to discontinue walker use (10 versus 15 days, p = 0.01) and time to discontinue all gait aids (17 versus 24 days, p = 0.04). There were no other differences in early functional milestones, although at 2 weeks after surgery, mean steps per day were 3897 (SD 2258; range, 737-11,010) for the DAA versus 2235 for the MPA (SD 1688; range, 27-7450; p < 0.01). There was no difference in activity monitoring at 1 year. There were no differences in patient-reported outcome scores between the groups. There was no difference in the radiographic parameters measured in the two groups, including leg length discrepancy, component position, or offset, and there was no subsidence observed in any hip. There was no difference in complications between the DAA and the MPA groups (8% [four of 52] versus 10% [five of 49]; p = 0.33)., Conclusions: Both the DAA and MPA approaches provided excellent early recovery with a low risk of complications. Patients undergoing the DAA had a slightly faster recovery, as measured by milestones of function and quantified by activity monitor data, but no substantive differences were evident at 2 months. Because the DAA is the less studied approach, longer term (> 1 year) complications may yet accrue, will be important to quantify, and may offset early benefits., Level of Evidence: Level I, therapeutic study.

Background: Randomized trials have shown the benefits of injecting bone marrow-derived mesenchymal stem cells (BmMSCs) after standard hip decompression in patients with osteonecrosis of the femoral head. However, the combination of BmMSCs and platelet-rich plasma (PRP) injected into the femoral head after decompression has not been reported previously. This study reports the results in a preliminary series of patients with osteonecrosis of the femoral head treated with BmMSCs plus PRP., Questions/purposes: (1) What is the survivorship free from reoperation, hip arthroplasty, and femoral head collapse in a preliminary series of patients with osteonecrosis of the femoral head treated with BmMSCs plus PRP? (2) Is there a change in the degree of femoral head involvement based on modified Kerboul angle? (3) What were the scores observed for pain and function at last followup? (4) Was there a difference in survivorship free from reoperation as a function of in vitro MSC count and viability?, Methods: Twenty-two consecutive patients (35 hips; 11 men and 11 women) with corticosteroid-induced osteonecrosis who met study inclusion criteria were enrolled; none declined participation, and none was lost to followup, although one patient (two hips) died within a year of the procedure for reasons unrelated to it, and five patients (seven hips) did not undergo MRI at the 1-year followup. All patients had precollapse osteonecrosis, rated either University of Pennsylvania Stage 1 (n = 4) or Stage 2 (n = 31 hips). Mean age and body mass index were 43 years and 31 kg/m, respectively. Patients underwent pre- and postoperative radiographs and MRI to assess femoral head involvement using the modified Kerboul angle. Absolute cell count and colony-forming unit (CFU) assays were used to assess MSC abundance and viability of the bone marrow obtained at the time of surgery. Patients were followed at regular intervals to assess clinical response to treatment with a mean followup of 3 years (range, 2-4 years). The change in femoral head involvement was assessed with the modified Kerboul angle; the Harris hip score was used to assess clinical outcome; and conversion to THA, reoperation, and survivorship free from femoral head collapse were analyzed with the Kaplan-Meier method on a per-hip basis., Results: Survivorship free from THA, any procedure, and femoral head collapse was 84% (95% confidence interval [CI], 75%-93%), 67% (95% CI, 55%-79%), and 93% (95% CI, 76%-98%), respectively, at 3 years postoperatively; two patients (four hips) underwent a second decompression and MSC injection for persistent pain without signs of radiographic collapse. All patients with collapse underwent THA. The mean modified Kerboul angle improved from 205° ± 47° to 172° ± 48° postoperatively (mean change -30° ± 6°, p = 0.01). A greater proportion of patients who underwent an additional procedure had a modified Kerboul grade of 3 or 4 preoperatively (80% [four of five] versus 13% [four of 30 Grade 1 or 2; odds ratio, 26; 95% CI, 2-296; p = 0.005). Preoperatively the mean Harris hip score was 57 ± 12, which improved to 85 ± 15 (mean change 28 ± 3, p < 0.001) at most recent followup. Patients undergoing a reoperation or THA had a lower mean concentration of nucleated cells/mL (5.5 x 10 ± 2.8 x 10 cells/mL versus 2.3 x 10 ± 2.2 x 10 cells/mL, p = 0.02) and lower mean CFUs (13 ± 6 versus 19 ± 7, p = 0.04) compared with those who did not., Conclusions: Core hip decompression with injection of concentrated bone marrow plus PRP improved pain and function; > 90% of hips in this series were without collapse at a minimum of 2 years. In this preliminary study, successful results were seen when nucleated cell count was high and modified Kerboul grade was low. Further randomized studies are needed to determine this procedure's efficacy versus core decompression or nonoperative treatment alone., Level of Evidence: Level II, therapeutic study.

Background: The success of hip surgery in treating acetabular retroversion depends on the severity of the structural deformity and on selecting the correct patient for open or arthroscopic procedures., Purpose: To compare a group of patients with retroverted hips treated successfully with hip arthroscopy with a group of patients with retroverted hips that failed arthroscopic surgery, with special emphasis on (1) patient characteristics, (2) perioperative radiographic parameters, (3) intraoperative findings and concomitant procedures, and (4) patient sex., Study Design: Case-control study; Level of evidence, 3., Methods: We retrospectively reviewed the charts of 47 adult patients (47 hips) with acetabular retroversion who had undergone hip arthroscopy. Retroversion was based on the presence of an ischial spine sign in addition to either a crossover or posterior wall sign on a well-positioned anteroposterior pelvic radiograph. A total of 24 hips (50%) (16 females, 8 males; mean patient age, 31 years) had failed arthroscopy, defined as modified Harris Hip Score (mHHS) <80 or need for subsequent procedure. Twenty-three hips (8 females, 15 males; mean patient age, 29 years) were considered successful, defined as having no subsequent procedures and an mHHS >80 at the time of most recent follow-up. Perioperative variables, radiographic characteristics, and intraoperative findings were compared between the groups, in addition to a subgroup analysis based on sex., Results: The mean follow-up for successful hips was 30 months (SD, 11 months), with a mean mHHS of 95. In the failure group, 6 patients required subsequent procedures (4 anteverting periacetabular osteotomies and 2 total hip arthroplasties). The mean overall time to failure was 21 months, and the mean time to a second procedure was 24 months (total hip arthroplasty, 29.5 months; periacetabular osteotomy, 21.2 months); 18 hips failed on the basis of a low mHHS (mean, 65; range, 27-79) at last follow-up. Factors significantly different between the success and failure groups included patient sex, with males being more likely than females to have a successful outcome ( P < .02), as well as undergoing femoral osteoplasty ( P < .02). Intraoperative variables that were associated with worse outcome included isolated labral debridement ( P < .002). In a subgroup analysis, males were more likely than their female counterparts to have a successful outcome with both isolated cam and combined cam-pincer resection ( P < .05). Level of crossover correction on postoperative radiographs had no correlation with outcome., Conclusion: Acetabular retroversion remains a challenging pathoanatomy to treat arthroscopically. If hip arthroscopy is to be considered in select cases, we recommend labral preservation when possible. Male patients with correction of cam deformities did well, while females with significant retroversion appeared to be at greater risk for failure of arthroscopic treatment., Competing Interests: The authors declared that they have no conflicts of interest in the authorship and publication of this contribution.

Osteochondral defects of the femoral head are rare. Several treatment options have been described, though there is currently no consensus on the appropriate management of these lesions. Five patients underwent femoral head osteochondral autograft transfer for treatment of ipsilateral femoral head osteochondral defects via surgical hip dislocation between 2011 and 2014 at our institution. The mean age of the patients was 24.8 (16-37) years. There were four females and one male. Mean follow-up was 53.8 (30-64) months. Four patients reported complete resolution of preoperative pain, return to baseline activities and were satisfied with their results. Harris hip scores improved from a mean 60.8 (30-87) to 86.6 (44-100). There was no radiographic evidence of progression of the femoral head defects. There were no operative complications. Osteochondral autograft transfer from the ipsilateral femoral head using a surgical hip dislocation demonstrated good clinical and radiographic outcomes at midterm follow-up in our cohort and may be considered a suitable option for management of these lesions in select patients. Further research and follow-up is warranted to more clearly define the indications and outcomes of this procedure.

Background: Periprosthetic infections are devastating for patients and more efficacious preventive strategies are needed. Surface-modified implants using antibacterial coatings represent an option to cope with this problem; however, manufacturing limitations and cytotoxicity have curbed clinical translation. Among metals with antibacterial properties, copper has shown superior in vitro antibacterial performance while maintaining an acceptable cytotoxicity profile. A thin film containing copper could prevent early biofilm formation to limit periprosthetic infections. This pilot study presents the in vitro antibacterial effect, cytotoxicity, and copper ion elution pattern of a thin film of titanium-copper oxide (TiCuO)., Questions/purposes: (1) Do titanium alloy (Ti6Al4V) discs coated with a thin film of TiCuO reduce Staphylococcus epidermidis biofilm and planktonic cell density compared with uncoated discs? (2) Do Ti6Al4V discs coated with a thin film of TiCuO affect normal human osteoblast viability compared with untreated cells? (3) Is copper ion concentration generated by coated discs lower than previously published copper ion concentrations that cause 50% toxicity in similar human cell lines in vitro (TC50)?, Methods: Ninety Ti6Al4V discs (12.5 mm diameter; 1.25 mm thick) were used in this study. Seventy-two Ti6Al4V discs were coated with a thin film of either titanium oxide (TiO) or TiCuO containing 20%, 40%, or 80% copper using high-power impulse magnetron sputtering (HiPIMS). Eighteen Ti6Al4V discs remained uncoated for control purposes. We tested antibacterial properties of S epidermidis grown on discs in wells containing growth medium. After 24 hours, planktonic bacteria as well as biofilms removed by sonication were quantitatively cultured. Annexin/Pi staining was used to quantify in vitro normal human osteoblast cell viability at 24 hours and Day 7, respectively. Copper elution was measured at Days 1, 2, 3, 7, 14, and 28 using an inductively coupled plasma mass spectrometer to analyze aliquots of culture medium. Copper ion concentration achieved at 24 hours was compared with previously published TC50 for gingival fibroblast, a phenotypically similar cell line with available data regarding copper ion exposure., Results: Discs coated with TiCuO 80% copper showed greater biofilm and planktonic cell density reduction when compared with other tested compositions (analysis of variance [ANOVA]; p < 0.001). Discs coated with TiCuO 80% copper showed mean biofilm and planktonic cell density of 4.0 log 10 (SD = 0.4) and 5.7 log 10 (SD = 0.2). Discs coated with TiCuO 80% showed a mean difference in biofilm and planktonic cell density of 2.5 log 10 (95% confidence interval [CI], 1.9-3.1 log 10; p < 0.001) and 1.2 (95% CI, 0.6-1.8; p < 0.001), respectively, when compared with uncoated discs. Normal human osteoblast viability did not differ among all groups at 24 hours (ANOVA; p = 0.2) and Day 7 (ANOVA; p = 0.7). Discs coated with TiCuO 80% copper showed a mean difference (95% CI) in relative cell viability (%) at 24 hours and Day 7 of 31.1 (95% CI, -19.4 to 81.7; p = 0.4) and -5.0 (95% CI, -7.8 to 17.9; p = 0.9), respectively, when compared with untreated cells. For all TiCuO-coated discs, copper ion elution peaked at 24 hours and slowly decreased in a curvilinear fashion to nearly undetectable levels by Day 28. Discs coated with TiCuO 80% copper showed mean copper ion concentration at 24 hours of 269.4 µmol/L (SD = 25.2 µmol/L) and this concentration was lower than previously published TC50 for similar human cell lines at 24 hours (344 µmol/L, SEM = 44 µmol/L)., Conclusions: This pilot study demonstrates a proof of concept that a thin-film implant coating with TiCuO can provide a potent local antibacterial environment while remaining relatively nontoxic to a human osteoblast cell line. Further research in an animal model will be necessary to establish efficacy and safety of this technique and whether it might be useful in the design of implants., Clinical Relevance: A thin film coating with TiCuO demonstrates high antibacterial activity and low cellular cytotoxicity to human osteoblasts in vitro. Taken together, these properties represent a potential strategy for preventing periprosthetic infection if further work in animal models can confirm these results in vivo.

Background: Structural hip deformities including developmental dysplasia of the hip (DDH) and femoroacetabular impingement (FAI) are thought to predispose patients to degenerative joint changes. However, the natural history of these malformations is not clearly delineated., Questions/purposes: (1) Among patients undergoing unilateral THA who have a contralateral hip without any radiographic evidence of hip disease, what is the natural history and progression of osteoarthritis in the native hip based on morphological characteristics? (2) Among patients undergoing unilateral THA who have a contralateral hip without any radiographic evidence of hip disease, what are the radiographic parameters that predict differential rates of degenerative change?, Methods: We identified every patient 55 years of age or younger at our institution who received unilateral primary THA from 1980 to 1989 (n = 722 patients). Preoperative radiographs were reviewed on the contralateral hip and only hips with Tönnis Grade 0 degenerative change that had minimum 10-year radiographic followup were included. A total of 172 patients met all eligibility criteria with the following structural diagnoses: 48 DDH, 74 FAI, and 40 normal morphology, and an additional 6% (10 of the 172 patients) met all eligibility criteria but were lost to followup before the 10-year minimum. Mean age at the time of study inclusion was 47 years (range, 18-55 years), and 56% (91 of 162) of the patients in this study were female. Mean followup was 20 years (range, 10-35 years). Radiographic metrics, in conjunction with the review of two experienced arthroplasty surgeons, determined the structural hip diagnosis as DDH, FAI, or normal morphology. Every available followup AP radiograph was reviewed to determine progression from Tönnis Grade 0 to 3 until the time of last followup or operative intervention with THA. Survivorship was analyzed by Kaplan-Meier methodology, hazard ratios, and multistate modeling. Thirty-five patients eventually underwent THA: 16 (33%) DDH, 13 (18%) FAI, and six (15%) normal morphology., Results: Degenerative change was most rapid in patients with DDH followed by FAI and normal morphology. Among patients who recently developed Tönnis 1 degenerative change, the probability of undergoing THA in 10 years based on hip morphology was approximately one in three for DDH and one in five for both FAI and normal morphology hips, whereas the approximate probability at 20 years was two in three for DDH and one in two for both FAI and normal morphology hips. The likelihood of radiographic degeneration was increased in patients with the following findings: femoral head lateralization > 8 mm, femoral head extrusion index > 0.20, acetabular depth-to-width index < 0.30, lateral center-edge angle < 25°, and Tönnis angle > 8°., Conclusions: Degenerative change occurred earliest in patients with DDH, whereas the natural history of patients with FAI was quite similar to structurally normal hips. However, patients with cam deformities and concomitant acetabular dysplasia developed osteoarthritis more rapidly. Although the results of this study cannot be directly correlated to highly active patients with FAI, these findings suggest that correction of FAI to a normal morphology may only minimally impact the natural history, especially if intervention takes place beyond Tönnis 0. Analysis of radiographic parameters showed that incremental changes toward dysplastic morphology increase the risk of degenerative change., Level of Evidence: Level III, prognostic study.

Background: Serum markers of inflammation and muscle damage have shown clinical utility in some areas of medicine, but their value in determining the invasiveness or in predicting the early functional outcomes after total hip arthroplasty (THA) has not been demonstrated., Questions/purposes: (1) Do serum markers of inflammation/muscle damage predict pain or early functional outcomes after contemporary THA performed through a direct anterior or miniposterior approach? (2) Do early functional outcomes as measured by in-hospital outcomes and clinical milestones differ between a contemporary direct anterior and miniposterior approach for THA?, Methods: Between August 31, 2013, and September 1, 2014, all patients presenting as candidates for THA at our institution who had not already had preoperative blood draws (161) were recruited for this study. Forty-two patients failed these exclusion criteria, eight patients declined enrollment, and 11 were consented but did not complete the required preoperative blood tests. Recruitment stopped when 50 patients had been enrolled in both the direct anterior group and the miniposterior group (2n = 100) based on a priori power analysis. One high-volume surgeon performed all of the direct anterior approaches and three high-volume surgeons performed the miniposterior approaches. Groups did not differ with the numbers available in mean age (63 years; SD 10; range, 35-86 years), sex (52% female), or mean body mass index (mean 31 kg/m 2 ; SD 7 kg/m 2 ; range, 20-73 kg/m 2 ). Serum markers measured including hemoglobin, hematocrit, myoglobin, creatine kinase (CK), C-reactive protein, interleukin-6, and tumor necrosis factor-α were collected at the preoperative clinic visit and on postoperative days 1 and 2 and compared with operative details, in-hospital complications, therapy progress, pain scores, and functional results from a milestone diary. Functional results evaluated included time to discontinue all narcotics and gait aids, independence with activities of daily living, return to driving a motor vehicle, and return to work., Results: Serum markers after contemporary THA were not correlated with early functional outcomes either in-hospital or postdischarge. Specifically, no serum marker was predictive of the time to discontinue gait aids or narcotics, return to driving, climb stairs, or independence in activities of daily living (all p > 0.08). The patients receiving the direct anterior approach did have lesser elevations of CK levels than the patients undergoing the miniposterior approach (436 ± 312 [direct anterior {DA}] versus 1071 ± 459 [miniposterior {MP}], difference in means: -635; 95% confidence interval [CI], -809 to -462; p < 0.001), myoglobin levels (168 ± 114 [DA] versus 378 ± 151 [MP], difference in means: -210, 95% CI, -269 to -151; p < 0.001), C-reactive protein (79 ± 57 [DA] versus 124 ± 58 [MP], difference in means: -46, 95% CI, -71 to -21; p < 0.001), and interleukin-6 (45 ± 34 [DA] versus 80 ± 53 [MP], difference in means: -35, 95% CI, -54 to -16; p < 0.001), but not in other serum markers. In the hospital, patients undergoing the direct anterior approach ambulated 35 steps farther with physical therapy (178 feet DA versus 142 feet MP, p < 0.01, difference in means: 35, 95% CI, 9-62; p = 0.009) and had visual analog scale pain scores 1.1 less (4.8 DA versus 5.9 MP, difference in means: -1.1, 95% CI, 2.0 to -0.2; p = 0.02) than patients undergoing the miniposterior approach. There were no differences between approaches in other in-hospital outcomes or in posthospital clinical milestones., Conclusions: Serum markers including CK, myoglobin, C-reactive protein, interleukin-6, and tumor necrosis factor-α did not predict early pain/function after contemporary THA approaches. Although lesser elevations in myoglobin, CK, C-reactive protein, and interleukin-6 were found after direct anterior THA, that difference was not clinically meaningful. Further reporting of serum biomarkers as a measure of physiological burden after orthopaedic surgical procedures should be viewed as suspect until clear linear or threshold values are established., Level of Evidence: Level III, diagnostic study.

Background: The outcome of patients with Pseudomonas prosthetic joint infection (PS PJI) has not been well studied. The aim of this retrospective cohort study was to assess the outcome of patients with Pseudomonas PJI and to review risk factors associated with failure of therapy. Methods: Between 1/1969 and 12/2012, 102 episodes of PS PJI in 91 patients were identified. Results : The mean age at the time of diagnosis was 67.4 years; forty three percent had knee involvement. Over 40 percent had either diabetes mellitus or a history of gastrointestinal or genitourinary surgery. Nearly half (48 out of 102 episodes) received aminoglycoside monotherapy, while 25% received an anti-pseudomonal cephalosporin. The 2-year cumulative survival free from failure was 69% (95% CI, 56%-82%). Patients treated with resection arthroplasty, two-stage exchange, and debridement with implant retention had a 2-year cumulative survival free from failure of 80% (95% CI, 66%-95%), 83% (95% CI, 60%-100%), and 26% (95% CI, 23%-29%) respectively (P=0.0001). Conclusions: PS PJI's are associated with a high failure rate. Patients treated with debridement and implant retention had a worse outcome., Competing Interests: Competing Interests: No conflicts of interest are present between this work and any of the authors. This work was supported by Grant Number UL1 TR000135 from the National Center for Advancing Translational Sciences (NCATS). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH.

Background: Local infiltration analgesia and peripheral nerve blocks are common methods for pain management in patients after THA but direct head-to-head, randomized controlled trials (RCTs) have not been performed. A network meta-analysis allows indirect comparison of individual treatments relative to a common comparator; in this case placebo (or no intervention), epidural analgesia, and intrathecal morphine, yielding an estimate of comparative efficacy., Questions/purposes: We asked, when compared with a placebo, (1) does use of local infiltration analgesia reduce patient pain scores and opioid consumption, (2) does use of peripheral nerve blocks reduce patient pain scores and opioid consumption, and (3) is local infiltration analgesia favored over peripheral nerve blocks for postoperative pain management after THA?, Methods: We searched six databases, from inception through June 30, 2014, to identify RCTs comparing local infiltration analgesia or peripheral nerve block use in patients after THA. A total of 35 RCTs at low risk of bias based on the recommended Cochrane Collaboration risk assessment tool were included in the network meta-analysis (2296 patients). Primary outcomes for this review were patient pain scores at rest and cumulative opioid consumption, both assessed at 24 hours after THA. Because of substantial heterogeneity (variation of outcomes between studies) across included trials, a random effect model for meta-analysis was used to estimate the weighted mean difference (WMD) and 95% CI. The gray literature was searched with the same inclusion criteria as published trials. Only one unpublished trial (published abstract) fulfilled our criteria and was included in this review. All other studies included in this systematic review were full published articles. Bayesian network meta-analysis included all RCTs that compared local infiltration analgesia or peripheral nerve blocks with placebo (or no intervention), epidural analgesia, and intrathecal morphine., Results: Compared with placebo, local infiltration analgesia reduced patient pain scores (WMD, -0.61; 95% CI, -0.97 to -0.24; p = 0.001) and opioid consumption (WMD, -7.16 mg; 95% CI, -11.98 to -2.35; p = 0.004). Peripheral nerve blocks did not result in lower pain scores or reduced opioid consumption compared with placebo (WMD, -0.43; 95% CI, -0.99 to 0.12; p = 0.12 and WMD, -3.14 mg, 95% CI, -11.30 to 5.02; p = 0.45). However, network meta-analysis comparing local infiltration analgesia with peripheral nerve blocks through common comparators showed no differences between postoperative pain scores (WMD, -0.36; 95% CI, -1.06 to 0.31) and opioid consumption (WMD, -4.59 mg; 95% CI, -9.35 to 0.17), although rank-order analysis found local infiltration analgesia to be ranked first in more simulations than peripheral nerve blocks, suggesting that it may be more effective., Conclusions: Using the novel statistical network meta-analysis approach, we found no differences between local infiltration analgesia and peripheral nerve blocks in terms of analgesia or opioid consumption 24 hours after THA; there was a suggestion of a slight advantage to peripheral nerve blocks based on rank-order analysis, but the effect size in question is likely not large. Given the slight difference between interventions, clinicians may choose to focus on other factors such as cost and intervention-related complications when debating which analgesic treatment to use after THA., Level of Evidence: Level I, therapeutic study.

Background: Bilateral pelvic discontinuity is characterized by complete dissociation of the superior and inferior pelvis secondary to bone loss or fracture. The end result is a freely mobile inferior pelvis at the level of each discontinuity which presents a significant reconstruction challenge. This clinical entity has not been described previously, and the results of surgical treatment are not known., Methods: We retrospectively reviewed all identified cases of pelvic discontinuity (PD) treated with revision THA at one institution. We identified 133 pelvic discontinuities. Within this group, 6 patients had bilateral simultaneous PDs. Preoperative, intraoperative, and postoperative data and radiographic imaging were reviewed preoperatively and postoperatively for the characteristics of the dissociation and assessing PD healing and fixation of components after surgery., Results: There were no preoperative factors that could distinguish these patients from the rest of the group of discontinuities (3 rheumatoid arthritis, 2 osteonecrosis of the femoral head, 1 developmental dysplasia). The reconstructions performed included 2 cup/cage, 5 posterior plating and uncemented cup, 3 cage alone, and 2 cups only. Ten of 12 hips had at least 1 complication postoperatively. At final follow-up, only 1 patient (17%) had radiographic evidence that both discontinuities had healed (posterior plate with uncemented cup)., Conclusions: Bilateral pelvic discontinuity is rare but presents the surgeon with a major reconstructive challenge. Only 1 patient went on to radiographic healing with current treatment strategies. Continued motion of the contralateral pelvic dissociation may account for the high failure rates. Surgeons should be aware of the challenges presented by this diagnosis and develop strategies to improve outcomes.

Background: Maintaining robust perfusion is an important physiologic parameter in wound healing. The effect of different closure techniques on wound perfusion after total knee arthroplasty (TKA) has not been established previously and may have implications for wound healing., Questions/purposes: We asked whether a running subcuticular, vertical mattress, or skin staple closure technique enables the most robust wound perfusion after TKA as measured by laser-assisted indocyanine green angiography (LA-ICGA) in patients without specific risk factors for wound healing complications., Methods: Forty-five patients undergoing primary TKA without comorbidities known to impact wound healing and perfusion were prospectively randomized to receive superficial skin closure with one of the following techniques: (1) running subcuticular (3-0 monofilament); (2) vertical mattress (2-0 nylon); or (3) skin staples. Twenty procedures were performed by RTT, 15 by RJS, and 10 by FHS. All surgeons used an anterior skin incision over the medial third of the patella in combination with a median parapatellar arthrotomy. Perfusion was assessed with a LA-ICGA device and software system immediately after closure to quantify fluorescence. Twenty-seven points were assessed immediately after closure in the operating room in each patient (nine along the incision and nine pairs medial and lateral to the incision). Mean incision perfusion was determined from the nine points along the incision with higher values indicating greater blood flow. Mean perfusion impairment was determined by calculating the difference between the nine pairs of surrounding skin and the nine points along the incision with smaller values indicating less perfusion impairment. These parameters were compared with analysis of variance (ANOVA) and subsequent pairwise comparisons with an unadjusted analysis as well as a multivariate analysis that adjusted for age, sex, and body mass index. Patients were followed for a mean of 7 months after surgery (range, 3-12 months) for possible incision-related complications. No patents were lost to followup., Results: Running subcuticular closure demonstrated the best overall perfusion. Mean incision perfusion in fluorescent units with SD was as follows: running subcuticular, 64 (16); vertical mattress, 32 (18); and staples, 19 (7) (ANOVA p < 0.001). The running subcuticular closure demonstrated the least impairment of perfusion among the closures compared. Mean perfusion impairment was as follows: running subcuticular, 21 (12); vertical mattress, 37 (24); and staples, 69 (27) (ANOVA p < 0.001). All Tukey-adjusted pairwise comparisons from both metrics likewise favored the subcuticular closure (p < 0.001) both before and after adjusting for age, sex, and body mass index. One patient in the vertical mattress cohort experienced a surgical site infection; no other wound-related complications were observed in this study., Conclusions: The method of closure can influence skin and soft tissue perfusion after TKA. Running subcuticular closure enables the most physiologic robust blood flow, which may improve wound healing. However, the clinical importance of these findings remains uncertain, because patients in this study were selected because they lacked risk factors for wound healing complications. Studies with this modality in specific patient populations at higher risk for wound complications will be necessary to quantify the clinical advantage of using running subcuticular closure., Level of Evidence: Level I, therapeutic study.

This is one of the first documented cases of metal-on-metal (MoM) total hip arthroplasty cobalt cardiac toxicity that has led to patient death. A 69-year-old female presented to our institution with cardiac failure secondary to cobalt toxicity resulting from bilateral MoM total hip arthroplasty. Her presenting metal ion levels were a cobalt level of 199 ppb and a chromium level of 77 ppb. She underwent bilateral femoral revisions to remove the source of cobalt. On postoperative day 7, the patient sustained a cerebral infarct and eventually expired because of the insult. This case represents one of the first documented fatalities related to MoM cobalt cardiac toxicity.

Background: Bone marrow-derived mesenchymal stem cells (bmMSCs) have been used as a cellular therapeutic option for treatment of osteonecrosis of the femoral head. However, use of bmMSCs as a treatment adjuvant for orthopaedic disorders in general has achieved limited success. Adipose-derived MSCs (aMSCs) may be a more-efficient regenerative cell source given their greater quantity and protection from physiologic stress., Questions/purposes: We asked the following questions in a paired analysis of MSCs from patients with osteonecrosis: (1) Is there a difference in proliferation potential between aMSCs and bmMSCs? (2) Is there a difference in osteogenic differentiation potential between aMSCs and bmMSCs? (3) Are genetic pathways differentially expressed between aMSCs and bmMSCs that may govern functional phenotypic discrepancies?, Methods: Periarticular samples of adipose tissue and bone marrow from the femoral canal were obtained from 15 patients undergoing hip replacement for late-stage (Steinberg Stages III-VI) osteonecrosis. MSCs were isolated from both tissue sources and taken through a standardized 20-day cell division protocol to establish cumulative cell count. They also were grown in osteogenic differentiation media for 14 days with subsequent measurement of alkaline phosphatase in units of optical density. RNA was isolated from aMSCs and bmMSCs in five patients to assess differentially expressed genetic pathways using the Affymetrix GeneChip Human Transcriptome Array 2.0 platform., Results: Proliferation capacity was increased by fourfold in aMSCs compared with bmMSCs after 20 days in culture. The mean difference in cumulative cell count was 3.99 × 10(8) cells (SD = 1.67 × 10(8) cells; 95% CI, 3.07 × 10(8)-4.92 × 10(8) cells; p < 0.001). Bone differentiation efficiency as measured by optical density was increased by 2.25-fold in aMSCs compared with bmMSCs. The mean difference in optical density was 1.27 (SD = 0.34; 95% CI, 1.08-1.46; p < 0.001). RNA transcriptome analysis showed 284 genes that met statistical (p < 0.05) and biological (fold change > 1.5) significance cutoffs for differential expression between cell populations. Subsequent network topology of differentially expressed genes showed alterations in pathways critical for musculoskeletal tissue development in addition to many nonspecific findings., Conclusions: aMSCs outperform bmMSCs in growth rate and bone differentiation potential in the setting of osteonecrosis, suggesting they may provide a more-potent regenerative therapeutic strategy in this population. Differential expression of genes and cellular pathways highlighted in this study may provide therapeutic targets for cellular optimization or acellular treatment strategies., Clinical Relevance: aMSCs may provide a more robust cellular therapeutic than bmMSCs for treatment of osteonecrosis. Ideally, a well-designed prospective study will be able to evaluate the efficacy of these cellular therapies side-by-side in patients with bilateral early stage disease.

Osteonecrosis (ON) of the femoral head, also known as avascular necrosis (AVN) of the femoral head, is a progressive disease that predominantly affects younger patients. During early stage of ON, decompression of the femoral head has been commonly used to improve pain. The decompression has been augmented with nonvascularized or vascularized bone grafts, mesenchymal stems cells, and growth factors. The use of adjuvant growth factors to supplement the core decompression has mainly been limited to animal models in an attempt to regenerate the necrotic lesion of ON. Factors utilized include bone morphogenetic proteins, vascular endothelial growth factors, hepatocyte growth factors, fibroblast growth factors, granulocyte colony-stimulating factors, and stem cells factors. In animal models, the use of these factors has been shown to increase bone formation and angiogenesis. Although promising, the use of these growth factors and cell-based therapies clinically remains limited.

Background: Total hip arthroplasty (THA) is increasingly being performed in patients with long life expectancies and active lifestyles. Newer implant bearing surfaces, with superior wear characteristics, often are used in this cohort with the goal of improving longevity of the prosthesis, but comparisons across the numerous available bearing surfaces are limited, so the surgeon and patient may have difficulty deciding which implants to use., Questions/purposes: The purpose of this study was to answer the following question: Is there a short- to mid-term survivorship difference between common THA bearings used in patients younger than age 65 years?, Methods: We conducted a systematic review to identify randomized clinical trials (RCTs) published after 2000 that reported survivorship of ceramic-on-ceramic (CoC), ceramic-on-highly crosslinked polyethylene (CoPxl), or metal-on-highly crosslinked polyethylene (MoPxl) bearings. To qualify for our review, RCTs had to have a minimum 2-year followup and study patients were required to have an average age younger than 65 years. Direct-comparison meta-analysis and network meta-analysis were performed to combine direct and indirect evidence., Results: Direct-comparison meta-analysis found no differences among the bearing surfaces in terms of the risk of revision; this approach demonstrated a risk ratio for revision of 0.65 (95% confidence interval [CI], 0.19-2.23; p = 0.50) between CoC and CoPxl and a risk ratio for revision of 0.40 (95% CI, 0.06-2.63; p = 0.34) between CoC and MoPxl. Network meta-analysis (with post hoc modification) likewise found no differences in survivorship across the three implant types, demonstrating the following probabilities of most effective implant with 95% credible intervals (CrI): CoC = 64.6% (0%-100%); CoPxl = 24.9% (0%-100%); and MoPxl = 9.9% (0%-100%). The CrIs ranged from 0% to 100% for all three bearing surfaces. Direct-comparison meta-analysis allowed for pooling of five RCTs, including 779 THAs, whereas network meta-analysis (before post hoc analysis) enabled pooling of 18 RCTs, including 2599 THAs., Conclusions: Current published evidence does not support survivorship differences among commonly used bearing surfaces in patients younger than age 65 years undergoing THA at short- to mid-term followup. Long-term RCT data will be needed to determine if a survivorship benefit is realized in younger, more active patients over time., Level of Evidence: Level I, therapeutic study.