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Segmental testicular infarction is a rare diagnosis and there are few documented cases in the literature. Those cases that have been reported are usually in the setting of epididymitis, hypercoaguable states, vasculitis, sickle cell disease, post orchidopexy or vasectomy, and idiopathic. We report a case of a patient who developed segmental testicular infarction that was managed conservatively, following nephrectomy for a ruptured kidney and the associated ultrasonographic appearances. Keywords: Segmental, Testes, Infarction, Nephrectomy, Trauma

Researchers use the Caregiver's Feeding Styles Questionnaire (CFSQ) to categorize parent feeding into authoritative, authoritarian, indulgent, and uninvolved styles. The CFSQ assesses self-reported feeding and classifies parents using median splits which are used in a substantial body of parenting literature and allow for direct comparison across studies on dimensions of demandingness and responsiveness. No national norms currently exist for the CFSQ. This paper establishes and recommends cutoff points most relevant for low-income, minority US samples that researchers and clinicians can use to assign parents to feeding styles. Median scores for five studies are examined and the average across these studies reported. [ABSTRACT FROM AUTHOR]

Aims: Mid-level constraint designs for total knee arthroplasty (TKA) are intended to reduce coronal plane laxity. Our aims were to compare kinematics and ligament forces of the Zimmer Biomet Persona posterior-stabilized (PS) and mid-level designs in the coronal, sagittal, and axial planes under loads simulating clinical exams of the knee in a cadaver model., Methods: We performed TKA on eight cadaveric knees and loaded them using a robotic manipulator. We tested both PS and mid-level designs under loads simulating clinical exams via applied varus and valgus moments, internal-external (IE) rotation moments, and anteroposterior forces at 0°, 30°, and 90° of flexion. We measured the resulting tibiofemoral angulations and translations. We also quantified the forces carried by the medial and lateral collateral ligaments (MCL/LCL) via serial sectioning of these structures and use of the principle of superposition., Results: Mid-level inserts reduced varus angulations compared to PS inserts by a median of 0.4°, 0.9°, and 1.5° at 0°, 30°, and 90° of flexion, respectively, and reduced valgus angulations by a median of 0.3°, 1.0°, and 1.2° (p ≤ 0.027 for all comparisons). Mid-level inserts reduced net IE rotations by a median of 5.6°, 14.7°, and 17.5° at 0°, 30°, and 90°, respectively (p = 0.012). Mid-level inserts reduced anterior tibial translation only at 90° of flexion by a median of 3.0 millimetres (p = 0.036). With an applied varus moment, the mid-level insert decreased LCL force compared to the PS insert at all three flexion angles that were tested (p ≤ 0.036). In contrast, with a valgus moment the mid-level insert did not reduce MCL force. With an applied internal rotation moment, the mid-level insert decreased LCL force at 30° and 90° by a median of 25.7 N and 31.7 N, respectively (p = 0.017 and p = 0.012). With an external rotation moment, the mid-level insert decreased MCL force at 30° and 90° by a median of 45.7 N and 20.0 N, respectively (p ≤ 0.017 for all comparisons). With an applied anterior load, MCL and LCL forces showed no differences between the two inserts at 30° and 90° of flexion., Conclusion: The mid-level insert used in this study decreased coronal and axial plane laxities compared to the PS insert, but its stabilizing benefit in the sagittal plane was limited. Both mid-level and PS inserts depended on the MCL to resist anterior loads during a simulated clinical exam of anterior laxity., Competing Interests: M. B. Cross reports royalties or licenses from Depuy Synthes and PSI, consulting fees from Depuy Synthes, Exactech, and 3M, payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Depuy Synthes and 3M, and stock or stock options in Ospitek, PSI, and Intellijoint, all of which are unrelated to this article. D. J. Mayman reports royalties or licenses from Orthalign and Smith & Nephew, and stock or stock options in Imagen, Orthalign, Smith & Nephew, Wishbone, Micare Path, and Cymedica, all of which are unrelated to this article. C. W. Imhauser reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Corin Medical, unrelated to this study. P. K. Sculco reports consulting fees from Zimmer Biomet, Intellijoint Surgical, Lima Corporate, Depuy Synthes, and ATEC, payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Zimmer Biomet, stock or stock options in Parvizi Surgical Innovation and Intellijoint Surgical, and receipt of equipment, materials, drugs, medical writing, gifts or other services, all of which are unrelated to this study., (© 2023 Author(s) et al.)

Background: Recent advances in high-throughput DNA sequencing technologies have made it possible to characterize the microbial profile in anatomical sites previously assumed to be sterile. We used this approach to explore the microbial composition within joints of osteoarthritic patients., Methods: This prospective multicenter study recruited 113 patients undergoing hip or knee arthroplasty between 2017 and 2019. Demographics and prior intra-articular injections were noted. Matched synovial fluid, tissue, and swab specimens were obtained and shipped to a centralized laboratory for testing. Following DNA extraction, microbial 16S-rRNA sequencing was performed., Results: Comparisons of paired specimens indicated that each was a comparable measure for microbiological sampling of the joint. Swab specimens were modestly different in bacterial composition from synovial fluid and tissue. The 5 most abundant genera were Escherichia, Cutibacterium, Staphylococcus, Acinetobacter, and Pseudomonas. Although sample size varied, the hospital of origin explained a significant portion (18.5%) of the variance in the microbial composition of the joint, and corticosteroid injection within 6 months before arthroplasty was associated with elevated abundance of several lineages., Conclusions: The findings revealed that prior intra-articular injection and the operative hospital environment may influence the microbial composition of the joint. Furthermore, the most common species observed in this study were not among the most common in previous skin microbiome studies, suggesting that the microbial profiles detected are not likely explained solely by skin contamination. Further research is needed to determine the relationship between the hospital and a "closed" microbiome environment. These findings contribute to establishing the baseline microbial signal and identifying contributing variables in the osteoarthritic joint, which will be valuable as a comparator in the contexts of infection and long-term arthroplasty success., Level of Evidence: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/H489)., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

Mid-flexion instability (MFI) in total knee arthroplasty refers to a distinct clinical entity where the knee is stable at full extension and 90° of flexion, but unstable somewhere between these 2 points. The presentation of MFI is often vague, and studies defining objective clinical or intraoperative measurements are limited. In this review, we aim to properly define the condition, describe diagnostic criteria and risk factors contributing to MFI, review current implant design, and present outcomes of revision surgery performed for MFI. [ Orthopedics . 2023;46(1):e13-e19.].

Background: The clearance of medical devices by the US Food and Drug Administration (FDA) has remained largely unchanged since 1976, when the Medical Device Amendments Act established a system classifying devices into 3 categories based on safety risk to the consumer. The system allows for the clearance of many orthopedics devices through the 510(k) premarket pathway, which is based on "predicate ancestors," previously cleared devices that are "substantially equivalent." Purpose : We sought to trace the predicate ancestors of modern total knee arthroplasty (TKA) devices, specifically those recently cleared for marketing by the 510(k) pathway that claim substantial equivalence to prior devices, despite potential differences in material science and design. In addition, we aimed to document which TKA devices cleared by the 510(k) pathway have substantial equivalence to devices that have since been recalled by the FDA. Methods : To create a comprehensive list of TKA devices, we used FDA Classification Process Codes corresponding to knee arthroplasty to search the FDA's databases from May 28, 1976, the start of the 510(k) process, to May 1, 2021. Of 1309 resulting devices, 89 were excluded as not related to arthroplasty. For each of the remaining devices, we analyzed the descendant devices that claimed substantial equivalence, either directly or indirectly. We used data of recalled designs to determine both the absolute number of recalled devices and the number of currently cleared devices that presented substantial equivalence claims upon predicates that have since been recalled. Results : Of 1220 knee devices cleared or approved, 6 (0.5%) were approved through the premarket approval application (PMA) process, and 1214 (99.5%) were cleared through the 510(k) pathway. Of the 1214 cleared devices, 217 (17.9%) have been recalled and 204 (16.8%) have ties to at least 1 recalled predicate device linked through generational claims of substantial equivalence. We found 90 devices (7.4%) linked directly to a recalled predicate device. Conclusions : Most knee arthroplasty devices are cleared for marketing through reliance on a complex web of equivalency to previously cleared predicates. We found that many TKA devices thus connected were cleared decades apart, with multiple iterations of design and material modifications. Many currently marketed TKA devices have claimed equivalency to predicates that have been recalled. Our findings suggest the need for novel regulatory strategies that might further patient safety while balancing the unwanted effects of regulatory burden., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Neil P. Sheth, MD, has relationships with Medacta, Microport, Smith & Nephew, Zimmer, Elsevier, AAOS and the Eastern Orthopaedic Association. Michael Cross, MD, has relationships with 3M, DePuy A Johnson & Johnson Company, Exactech, Flexion Therapeutics, Intellijoint, Smith & Nephew, BICMD, Imagen, Insight Medical, Parvizi Surgical Innovation, Flexion Therapeutics, Bone and Joint Journal 360, the Journal of Orthopaedics and Traumatology, and Techniques in Orthopaedics. Alejandro Gonzalez Della Valle, MD, has relationships with Johnson & Johnson, Link Orthopaedics, Naviswiss, OrthoDevelopment, and OrthoSensor. Andrew Zhu, BSE, Xiaohan Ying, BS, Christian A. Pean, MD, MS, and Ajay Premkumar, MD, MPH, declared no potential conflicts of interest., (© The Author(s) 2022.)

Background: The challenges of culture-negative periprosthetic joint infection (PJI) have led to the emergence of molecular methods of pathogen identification, including next-generation sequencing (NGS). While its increased sensitivity compared with traditional culture techniques is well documented, it is not fully known which organisms could be expected to be detected with use of NGS. The aim of this study was to describe the NGS profile of culture-negative PJI., Methods: Patients undergoing revision hip or knee arthroplasty from June 2016 to August 2020 at 14 institutions were prospectively recruited. Patients meeting International Consensus Meeting (ICM) criteria for PJI were included in this study. Intraoperative samples were obtained and concurrently sent for both routine culture and NGS. Patients for whom NGS was positive and standard culture was negative were included in our analysis., Results: The overall cohort included 301 patients who met the ICM criteria for PJI. Of these patients, 85 (28.2%) were culture-negative. A pathogen could be identified by NGS in 56 (65.9%) of these culture-negative patients. Seventeen species were identified as common based on a study-wide incidence threshold of 5%. NGS revealed a polymicrobial infection in 91.1% of culture-negative PJI cases, with the set of common species contributing to 82.4% of polymicrobial profiles. Escherichia coli, Cutibacterium acnes, Staphylococcus epidermidis, and Staphylococcus aureus ranked highest in terms of incidence and study-wide mean relative abundance and were most frequently the dominant organism when occurring in polymicrobial infections., Conclusions: NGS provides a more comprehensive picture of the microbial profile of infection that is often missed by traditional culture. Examining the profile of PJI in a multicenter cohort using NGS, this study demonstrated that approximately two-thirds of culture-negative PJIs had identifiable opportunistically pathogenic organisms, and furthermore, the majority of infections were polymicrobial., Level of Evidence: Diagnostic Level II . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H102 )., (Copyright © 2022 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: The orthopedic in-training examination (OITE) continues to evolve over time. It is important for orthopedic residents and residency programs to have an up-to-date understanding of the content and resources being used on the OITE to study and tailor curricula accordingly. This study presents an updated analysis of the OITE hand domain from 2014 to 2019., Methods: All OITE questions related to hand surgery from 2014 to 2019 were analyzed for topic, subtopic, taxonomy, imaging modalities, and bibliometric factors related to cited references., Results: Of the 1600 OITE questions, there were 113 hand surgery questions (7.1%) over a 6-year period. The most commonly tested topics were nerve (n = 22; 19%), fracture/dislocation (n = 21; 19%), and tendon/ligament (n = 19; 17%). Complex clinical management questions were the most common taxonomic category (n = 66; 58%). Two hundred fifty-two references were cited, the most common of which were from the Journal of Hand Surgery (American Volume) (n = 76; 30%), Journal of the American Academy of Orthopaedic Surgeons (n = 27; 11%), and Hand Clinics (n = 21; 8%). Publication lag decreased over the study period ( P = .009). Twenty-five questions (22%) used imaging modalities, and 21 (19%) used clinical photos. Compared with a prior analysis from 2002 to 2006, there were more questions related to nerves (19.5% vs 9.8%, P = .041)., Conclusions: Residents and residency programs can benefit from an updated understanding of OITE hand surgery content and resources. The current analysis identifies high-yield topics and resources that can guide resident preparation for the OITE.

Background: Congenital heart defects, such as atrial septal defects (ASDs) and patent foramen ovale (PFO), may increase the risk of embolic events in total hip or knee arthroplasty (THA/TKA). The objective of this study was to determine the 90-day incidence of intraoperative and postoperative embolic events and all other complications in patients with a known ASD/PFO who underwent primary hip and knee arthroplasty., Methods: This is a retrospective review of 160 patients with ASD/PFO undergoing 196 primary arthroplasties (94 THAs, 102 TKAs) at a single institution. The mean age was 64 years (standard deviation [SD] 11.1), 40.6% were male, and average body mass index was 31 kg/m 2 (SD 7.2). The mean follow-up period was 19 months (SD 16). Forty-three percent of patients were on anticoagulation preoperatively. All patients received postoperative thromboprophylaxis (48% aspirin, 31% direct oral anticoagulants, 18% warfarin, 3% enoxaparin)., Results: There were no embolic events identified. Fourteen patients (7%) developed complications within 90 days. Three had bleeding complications, and 8 had other nonoperative complications, which were all managed conservatively and had uneventful recoveries. Additionally, 3 patients had complications requiring reoperations: 2 for periprosthetic fractures (1 THA, 1 TKA) and 1 for a periprosthetic infection (TKA)., Conclusions: In this cohort of patients with a known ASD/PFO undergoing THAs and TKAs, there were no cases of embolic events. However, it would be advisable to have a thorough cardiology evaluation to assess potential risks and benefits of defect repair prior to total joint arthroplasty and to reduce the risk of paradoxical embolic events and the necessity of potent anticoagulation., Level of Evidence: Prognostic Level IV., (© 2022 The Authors.)

Background: In TKA, soft tissue balancing is assessed through manual intraoperative trialing. This assessment is a physical examination via manually applied forces at the ankle, generating varus and valgus moments at the knee while the surgeon visualizes the lateral and medial gaps at the joint line. Based on this examination, important surgical decisions are made that influence knee stability, such as choosing the polyethylene insert thickness. Yet, the applied forces and the assessed gaps in this examination represent a qualitative art that relies on each surgeon's intuition, experience, and training. Therefore, the extent of variation among surgeons in conducting this exam, in terms of applied loads and assessed gaps, is unknown. Moreover, whether variability in the applied loads yields different surgical decisions, such as choice of insert thickness, is also unclear. Thus, surgeons and developers have no basis for deciding to what extent the applied loads need to be standardized and controlled during a knee balance exam in TKA., Questions/purposes: (1) Do the applied moments in soft tissue assessment differ among surgeons? (2) Do the assessed gaps in soft tissue assessment differ among surgeons? (3) Is the choice of insert thickness associated with the applied moments?, Methods: Seven independent human cadaveric nonarthritic lower extremities from pelvis to toe were acquired (including five females and two males with a mean age of 73 ± 7 years and a mean BMI of 25.8 ± 3.8 kg/m 2 ). Posterior cruciate ligament substituting (posterior stabilized) TKA was performed only on the right knees. Five fellowship-trained knee surgeons (with 24, 15, 15, 7, and 6 years of clinical experience) and one chief orthopaedic resident independently examined soft tissue balance in each knee in extension (0° of flexion), midflexion (30° of flexion), and flexion (90° of flexion) and selected a polyethylene insert based on their assessment. Pliable force sensors were wrapped around the leg to measure the loads applied by each surgeon. A three-dimensional (3D) motion capture system was used to measure knee kinematics and a dynamic analysis software was used to estimate the medial and lateral gaps. We assessed (1) whether surgeons applied different moments by comparing the mean applied moment by surgeons in extension, midflexion, and flexion using repeated measures (RM)-ANOVA (p < 0.05 was assumed significantly different); (2) whether surgeons assessed different gaps by comparing the mean medial and lateral gaps in extension, midflexion, and flexion using RM-ANOVA (p < 0.05 was assumed significantly different); and (3) whether the applied moments in extension, midflexion, and flexion were associated with the insert thickness choice using a generalized estimating equation (p < 0.05 was assumed a significant association)., Results: The applied moments differed among surgeons, with the largest mean differences occurring in varus in midflexion (16.5 Nm; p = 0.02) and flexion (7.9 Nm; p < 0.001). The measured gaps differed among surgeons at all flexion angles, with the largest mean difference occurring in flexion (1.1 ± 0.4 mm; p < 0.001). In all knees except one, the choice of insert thickness varied by l mm among surgeons. The choice of insert thickness was weakly associated with the applied moments in varus (β = -0.06 ± 0.02 [95% confidence interval -0.11 to -0.01]; p = 0.03) and valgus (β = -0.09 ± 0.03 [95% CI -0.18 to -0.01]; p= 0.03) in extension and in varus in flexion (β = -0.11 ± 0.04 [95% CI -0.22 to 0.00]; p = 0.04). To put our findings in context, the greatest regression coefficient (β = -0.11) indicates that for every 9-Nm increase in the applied varus moment (that is, 22 N of force applied to the foot assuming a shank length of 0.4 m), the choice of insert thickness decreased by 1 mm., Conclusion: In TKA soft tissue assessment in a human cadaver model, five surgeons and one chief resident applied different moments in midflexion and flexion and targeted different gaps in extension, midflexion, and flexion. A weak association between the applied moments in extension and flexion and the insert choice was observed. Our results indicate that in the manual assessment of soft tissue, changes in the applied moments of 9 and 11 Nm (22 to 27 N on the surgeons' hands) in flexion and extension, respectively, yielded at least a 1-mm change in choice of insert thickness. The choice of insert thickness may be more sensitive to the applied moments in in vivo surgery because the surgeon is allowed a greater array of choices beyond insert thickness., Clinical Relevance: Among five arthroplasty surgeons with different levels of experience and a chief resident, subjective soft tissue assessment yielded 1 to 2 mm of variation in their choice of insert thickness. Therefore, developers of tools to standardize soft tissue assessment in TKA should consider controlling the force applied by the surgeon to better control for variations in insert selection., Competing Interests: All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2022 by the Association of Bone and Joint Surgeons.)

Background: Several commonly prescribed medications have known antifibrotic properties and have been shown to reduce postoperative scar formation in other clinical areas, but it is unknown whether the use of such medications perioperatively in patients undergoing TKA may improve rates of postoperative stiffness., Methods: A large US employer-sponsored healthcare database (Truven Marketscan) was queried for patients who underwent elective primary TKA for primary osteoarthritis between 2015-2019. Demographic information and comorbidities were recorded, along with whether patients were prescribed one of several medications with known antifibrotic properties during the three months before or after surgery., Results: Complete data were available for 101,366 patients undergoing TKA, of which 4,536 underwent MUA (4.5%). Perioperative use of any antifibrotic medication was associated with a lower likelihood of undergoing MUA (P < .001). When controlling for age, sex, comorbidities, opioid use, length of stay, among other variables, perioperative use of specific ACE inhibitors (OR 0.91, CI 0.84-1, P = .042), COX-2 inhibitors (OR 0.88, CI 0.81-0.96, P = .002), and angiotensin II receptor blockers, specifically losartan (OR 0.80, CI 0.70-0.91, P = .007) all remained significantly associated with lower rates of MUA., Conclusion: This study, spanning over a hundred thousand primary TKA procedures over a recent five-year period, demonstrates an association between perioperative use of specific medications with antifibrotic properties and a decreased rate of MUA. These data will help inform future studies aimed to prospectively evaluate the potential of antifibrotic medications in preventing postoperative stiffness in high-risk patients undergoing knee arthroplasty., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Surgeons may resect additional distal femur during primary posterior-stabilized (PS) total knee arthroplasty (TKA) to correct a flexion contracture. However, the resultant joint line elevation (JLE) increases mid-flexion laxity. We determined whether a mid-level constraint (MLC) insert reduced mid-flexion laxity after JLE., Methods: Six computational knee models were developed using computed tomography scans and average soft tissue properties yielding balanced extension gaps but with a 10° flexion contracture. Distal femoral resections of +2 and +4 mm were simulated with PS and MLC inserts. Varus-valgus ±10 Nm moments were applied at 30°, 45°, and 60° of flexion. Coronal laxity (the sum of varus-valgus angulation) and coupled axial rotation (the sum of internal/external rotation) were measured and compared between insert models., Results: At 30° of flexion, coronal laxities with the PS insert at the +2 and +4 mm resections averaged 7.9° ± 0.6° and 11.3° ± 0.6°, respectively, and decreased by 0.8° (P = .06) and 1.0° (P = .07), respectively, with the MLC insert. PS rotational laxities at the +2 and +4 mm resections averaged 11.1° ± 3.9° and 12.5° ± 4.6°, respectively, and decreased by 5.6° (P = .01) and 7.1° (P = .02), respectively, with the MLC insert. Similar patterns were observed at 45° and 60° of flexion., Conclusion: With additional distal femoral resections to alleviate a flexion contracture, utilizing an MLC insert substantially reduced coupled axial rotation but had a minimal impact on coronal laxity compared to a PS insert. Efforts should be taken to avoid JLE in primary total knee arthroplasty as even MLC inserts may not mitigate coronal laxity., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background : The 2010 American Academy of Orthopaedic Surgeons Clinical Practice Guidelines report insufficient evidence to address the diagnostic efficacy of magnetic resonance imaging (MRI) for periprosthetic joint infection (PJI). Questions/Purposes : The purpose of this study was to determine the utility of MRI with multiacquisition variable-resonance image combination (MAVRIC) metal artifact suppression techniques in diagnosing PJI in the setting of total hip arthroplasty (THA). Methods : Multiacquisition variable-resonance image combination MRIs obtained of THAs between November 2012 and November 2016 were queried. Radiology reports were classified as positive (suspicious for infection), negative (no features of infection), or inconclusive (infection cannot be excluded or correlation with aspiration suggested if clinically concerned). Chart review identified cases of deep PJI according to the modified Musculoskeletal Infection Society criteria. Results : Of 2156 MRIs of THAs included, MRI was concerning for infection in 1.8% (n = 39), inconclusive in 1.2% (n = 26), and negative in 97.0% (n = 2091). Deep PJI was identified in 53 (2.5%) patients, 30 of whom (56.6%) had conclusively positive finding on MRI (false-negative rate: 43.4%, sensitivity: 56.6%). Of 2103 aseptic THAs, only 9 (0.4%) MRIs were read as suspicious for infection (false-positive rate: 0.4%; specificity: 99.6%). Conclusion : Magnetic resonance imaging with MAVRIC is a highly specific test for PJI with a low false-positive rate. This indicates that when clinicians are provided with an MRI that unexpectedly suggests infection, a formal evaluation for infection is indicated. In patients with otherwise equivocal diagnostic findings, MRI may help confirm, but not refute, a diagnosis of PJI. Prospective study with more experienced image reviewers may further support the use of MRI in PJI., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Ashley E. Levack, MD, MAS, reports research support from the National Institutes of Health. Michael B. Cross, MD, reports relationships with DePuy Synthes, Exactech Inc, Flexion Therapeutics, Intellijoint, KCI, Smith & Nephew, Bone and Joint Journal 360, Journal of Orthopaedics and Traumatology, Techniques in Orthopaedics, Imagen, Insight Medical, and Parvizi Surgical Innovation. Chelsea Koch, BS, and Harold G. Moore, BS, declare that they have no potential conflicts of interest., (© The Author(s) 2021.)

Introduction: Revision total hip arthroplasty (rTHA) is becoming a more common procedure due to the increasing volume of primary total hip arthroplasty. Diabetes mellitus (DM) is currently projected to affect 4.4% of the global population by 2030. Diabetes has been associated with poor outcomes for a variety of surgical interventions. However, the impact of insulin dependence has yet to be fully understood. The aim of this study was to determine the impact of insulin dependence on acute postoperative complications following rTHA., Methods: A retrospective cohort study was conducted using the American College of Surgeons National Quality Improvement Program database. All patients who underwent rTHA between 2006 and 2016 were identified and recorded as having non-insulin-dependent DM (NIDDM), insulin-dependent DM (IDDM) or no DM. Univariate and multivariate analysis were used to evaluate the incidence of multiple adverse events within 30 days after rTHA., Results: A total of 7685 patients were evaluated (No DM = 6651, NIDDM = 700, IDDM = 334). Univariate analysis revealed that all patients with DM had significantly higher incidences of postoperative complications (NIDDM: p  < 0.001; IDDM: p  < 0.001) and extended hospital length of stay (NIDDM: p  = 0.015; IDDM: p  < 0.0001). NIDDM was associated with increased rates of superficial surgical site infection (SSI) ( p  = 0.001), deep SSI ( p  = 0.038), and stroke ( p  = 0.013), while IDDM was associated with increased rates of pneumonia ( p  < 0.001), renal failure ( p  < 0.001), and postoperative transfusion ( p  < 0.001). On multivariate analysis, insulin-dependence was determined to be an independent risk factor for extended hospital length of stay (OR 1.905; 95% CI, 1.410-2.577; p  < 0.001), pneumonia (OR 4.016; 95% CI, 1.799-8.929; p  = 0.001), renal failure (OR 7.143; 95% CI, 2.203-23.256; p  = 0.001) and postoperative transfusion (OR 1.366; 95% CI, 1.076-1.733; p  = 0.01)., Conclusions: Insulin dependence is an independent risk factor for numerous short-term postoperative complications following rTHA. When assessing risk and planning perioperative management, surgeons should consider insulin-dependent diabetics as a sub-cohort within the diabetic population.

Background: Anatomy education in US medical schools has seen numerous changes since the call for medical education reform in 2010. The purpose of this study was to survey US medical schools to assess recent trends in anatomy education, the impact of the COVID-19 pandemic on anatomy teaching, and future directions of medical school anatomy curricula., Methods: We sent a 29-item survey to anatomy course directors of 145 AAMC-associated allopathic medical schools inquiring about their schools' anatomy curricula. The survey contained objective discrete questions concerning the curricula changes preceding COVID-19 and those directly related to COVID-19. We also asked subjective and open-ended questions about the impact of COVID-19 and future directions of anatomy education., Results: A total of 117/143 course directors (82%) completed the survey. Most schools (60%) reported a major change to their anatomy course within the past five years, including a decrease in total course time (20%), integration of anatomy into other courses (19%), and implementation of a "flipped classroom" (15%) teaching style. Due to COVID-19, there was a decrease in the fraction of course time dedicated to "hands-on" learning (p < 0.01) and teaching of clinical correlates (p = 0.02) and radiology (p < 0.01). Most course directors (79%) reported that COVID-19 had a negative impact on quality of learning due to decreased interactive or in-person (62%) learning and lack of dissection (44%). Incorporation of virtual-reality applications or 3D anatomy software (23%) and a decrease in cadaver dissection (13%) were the most common future anticipated changes., Conclusion: The constraints conferred by COVID-19 highlight the importance of maximizing interactive learning in the discipline of anatomy. In an era of social distancing and decreased emphasis on conventional anatomy dissection, adaptations of new technologies and teaching modalities may allow for traditional educational rigor to be sustained., (© 2022. The Author(s).)

Background: In the United States, the most overwhelming medical devices, including hip arthroplasty devices, are cleared for human use by demonstration of "substantial equivalence" to a predicate, previously approved marketed device. This study examined the predicate approval lineages of modern hip arthroplasty devices., Methods: The FDA 510(k) and premarket approval databases were searched to identify all approved hip arthroplasty devices since the database's inception in May 28, 1976. Ancestral predicate lineages were created using approval documentation, and FDA recall data were used to identify recalled devices., Results: Evaluating 2,118 hip arthroplasty devices approved from 1976 to 2020, we found that the number of descendant devices for each approved device varied from 0 to 242. Many descendant devices served as predicates for other devices, leading to frequent indirect connections of equivalency across a wide range of implants. Two hundred forty-six (11.6%) devices were recalled for various reasons, with 34 (1.6%) related to implant design. Evaluating the predicate lineage of 51 hip arthroplasty devices approved between May 1, 2019, and May 1, 2020, 32 of 51 (62.7%) devices were linked, directly or indirectly, to predicates which were recalled for design issues., Conclusions: The lineage of hip arthroplasty device predicates reflects a complex ancestral web of equivalency across a wide range of implants, although their material and design properties may be different. Several currently approved devices were approved on substantial equivalence claims to products that were subsequently recalled from the market for implant design issues. These findings present several policy considerations for regulators, physicians, and the medical device industry., (Copyright © 2021 by the American Academy of Orthopaedic Surgeons.)

Introduction: The Orthopaedic In-Training Examination (OITE), produced by the American Academy of Orthopaedic Surgeons (AAOS), plays an important role in the educational mission of orthopaedic residency programs nationwide. An up-to-date understanding of this examination is critical for programs to develop an appropriate curriculum and for individuals to identify learning resources. This study presents an updated analysis of the basic science section of the OITE from 2014 to 2019., Methods: All questions from the OITE from 2014 to 2019 were reviewed. Each question from the basic science section was categorized by topic and taxonomy. The use of radiographic images or other clinical media was recorded. The reference section was analyzed for bibliometric factors. Pearson chi-square tests were used as appropriate for statistical comparison., Results: In total, 185 of 1,600 questions in the basic science section were used over the 6-year study period (11.6%). The proportion of basic science questions ranged from 10.7% to 12.0% from year to year. The most frequently tested topics were cellular and molecular biology (23.8%), physiology/pathophysiology (16.8%), and pharmacology (10.8%). There was an increase in the number of biostatistics questions from 2017 to 2019 compared with the number from 2014 to 2016 (P = 0.02). The most common taxonomic category was knowledge recall (89.7%). A total of 383 references were cited from 122 sources. The 3 most common sources accounting for 44.4% of all citations were produced by the AAOS., Discussion: The basic science section of the OITE accounts for approximately 11% of all questions, with the most common taxonomy being knowledge recall (89.7%). Recent tests have emphasized biostatistics, highlighting the importance of incorporating biostatistics into residency education. Reference materials produced by the AAOS were highly cited in this section., (Copyright © 2021 by the American Academy of Orthopaedic Surgeons.)

Background: Over 1 million Americans undergo joint replacement each year, and approximately 1 in 75 will incur a periprosthetic joint infection. Effective treatment necessitates pathogen identification, yet standard-of-care cultures fail to detect organisms in 10% to 20% of cases and require invasive sampling. We hypothesized that cell-free DNA (cfDNA) fragments from microorganisms in a periprosthetic joint infection can be found in the bloodstream and utilized to accurately identify pathogens via next-generation sequencing., Methods: In this prospective observational study performed at a musculoskeletal specialty hospital in the U.S., we enrolled 53 adults with validated hip or knee periprosthetic joint infections. Participants had peripheral blood drawn immediately prior to surgical treatment. Microbial cfDNA from plasma was sequenced and aligned to a genome database with >1,000 microbial species. Intraoperative tissue and synovial fluid cultures were performed per the standard of care. The primary outcome was accuracy in organism identification with use of blood cfDNA sequencing, as measured by agreement with tissue-culture results., Results: Intraoperative and preoperative joint cultures identified an organism in 46 (87%) of 53 patients. Microbial cfDNA sequencing identified the joint pathogen in 35 cases, including 4 of 7 culture-negative cases (57%). Thus, as an adjunct to cultures, cfDNA sequencing increased pathogen detection from 87% to 94%. The median time to species identification for cases with genus-only culture results was 3 days less than standard-of-care methods. Circulating cfDNA sequencing in 14 cases detected additional microorganisms not grown in cultures. At postoperative encounters, cfDNA sequencing demonstrated no detection or reduced levels of the infectious pathogen., Conclusions: Microbial cfDNA from pathogens causing local periprosthetic joint infections can be detected in peripheral blood. These circulating biomarkers can be sequenced from noninvasive venipuncture, providing a novel source for joint pathogen identification. Further development as an adjunct to tissue cultures holds promise to increase the number of cases with accurate pathogen identification and improve time-to-speciation. This test may also offer a novel method to monitor infection clearance during the treatment period., Level of Evidence: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/G619)., (Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.)

Total knee replacement (TKR) and unicompartmental knee replacement (UKR) are successful procedures for patients with knee arthritis. While strict criteria were proposed early on for UKR, some surgeons have expanded these indications to include younger and heavier patients. The purpose of this study is to analyze trends in usage of TKR and UKR in the United States. This retrospective study analyzed an insurance administrative dataset. Patients who underwent primary TKR and UKR were identified via current procedural terminology codes. Information on incidence, obesity, use of computer navigation, and surgical setting were collected. We analyzed 7,194 UKRs and 128,849 TKRs performed from 2007 to 2016. Prevalence of obesity in both groups increased over the study period. Utilization of computer navigation increased for UKR but declined for TKR. The rate of outpatient procedures significantly increased for UKR but remained constant for TKR. Both TKR and UKR are being performed at increasing rates and on heavier patients. The use of computer navigation and outpatient surgical setting is increasing for UKR but not for TKR. Knowledge of these trends is important for surgeons and policy-makers to help inform surgical indications and resource allocation., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: Periprosthetic infection (PJI) after total knee arthroplasty (TKA) places a significant burden on hospitals. We sought to describe the proportion of patients undergoing revision for PJI at a different hospital within one year of primary TKA and whether patient characteristics or hospital volume were associated with this change., Methods: Medicare data from 2005 to 2014 was retrospectively reviewed using PearlDiver. All patients over 64 years undergoing revision for PJI within one year of primary TKA were stratified by the revision occurring within 90 days. Hospitals were grouped by annual TKA volume as Low (<50), Medium (51-100), High (101-200), and Very High (>200). Associations of patient characteristics and hospital volume with revision at a different hospital were assessed using Chi-squared tests and Somers' D., Results: Of 8,337 patients undergoing revision within 90 days of TKA, 1,370 (16%) were revised at a different hospital. Changing hospitals was associated with having primary TKA at a lower volume hospital (24% for low, 15% medium, 12% high, and 12% very high; P < 0.001). Of 7,608 patients undergoing revision between 91 and 365 days, 1,110 (15%) were revised at a different hospital. Changing hospitals was associated with having primary TKA at a lower volume hospital (26% for low, 14% medium, 10% high, and 9% very high; P < 0.001). Changing hospitals was not associated with sex or age., Conclusion: Patients frequently undergo revision for PJI at a different hospital, even within 90 days of TKA. Further research is needed to understand these implications of this care pathway shift., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Several studies have reported lower perioperative complications with unicompartmental knee arthroplasty (UKA) than with total knee arthroplasty (TKA). However, there is a paucity of data analyzing the incidence of periprosthetic joint infection (PJI) in similar patients undergoing UKA and TKA. As such, we sought to analyze the incidence of UKA and TKA PJI in a large matched population., Material and Methods: The Mariner data set of the PearlDiver database was queried for all patients undergoing UKA or TKA during 2010-2017. Included patients were required to have at least 2 years of database inclusion after surgery. Patients were then matched at a 1:3 ratio (UKA:TKA) on age, gender, Elixhauser Comorbidity Index, tobacco use, and obesity. Rates of PJI requiring operative intervention within 90 days and 1 year were calculated., Results: In total, 5636 patients having undergone UKA were matched to 16,890 patients having undergone TKA. Fifteen (0.27%) after UKA and 79 (0.47%) after TKA had a PJI surgically managed within 90 days (risk ratio = 0.57, 95% confidence interval = 0.33-0.99, P = .04). Thirty (0.53%) after UKA and 136 (0.81%) after TKA had a PJI surgically managed within 1 year (risk ratio = 0.66, 95% confidence interval = 0.45-0.98, P = .04)., Conclusions: In a large group of rigorously matched patients, UKA was associated with a significantly lower rate of surgically managed PJI than TKA at 90 days and 1 year; however, the rate of PJI in both groups remained low at <1% at 90 days and 1 year., (© 2021 The Authors.)

Background: Revision total knee arthroplasty (rTKA) is associated with significant risk of wound-related morbidity. The present study aimed to evaluate the 1) efficacy of closed-incision negative-pressure therapy (ciNPT) vs silver-impregnated antimicrobial dressing (AMD) in mitigating postoperative surgical site complications (SSCs), 2) the effect of ciNPT vs AMD on certain postoperative health utilization parameters, and on 3) patient-reported outcomes (PROs) improvement at 90-day postoperative follow-up., Methods: This multicenter randomized controlled trial was conducted between December 2017 and August 2019. Patients ≥22 years, at high risk for SSC, and receiving rTKA with full exchange and reimplantation of new prosthetic components or open reduction and internal fixation of periprosthetic fractures were screened for inclusion. Eligible patients were randomized to receive a commercially available ciNPT system or a silver-impregnated AMD (n = 147, each) for minimum of 5-day duration. Primary outcome was the 90-day incidence of SSCs with stratification in accordance with revision type (aseptic/septic). Secondary outcomes were the 90-day health care utilization parameters (readmission, reoperation, dressing changes, and visits) and PROs., Results: Of 294 patients randomized (age: 64.9 ± 9.0 years, female: 59.6%), 242 (82.0%) patients completed the study (ciNPT: n = 124; AMD: n = 118). The incidence of 90-day SSCs was lower for the ciNPT cohort (ciNPT: 3.4% vs AMD: 14.3%; odds ratio (OR): 0.22, 95% confidence interval (0.08, 0.59); P = .0013). Readmission rates (3.4% vs 10.2%, OR: 0.30(0.11, 0.86); P = .0208) and mean dressing changes (1.1 ± 0.3 vs 1.3 ± 1.0; P = .0003) were lower with ciNPT. The differences in reoperation rates, number of visits, and PRO improvement between both arms were not statistically significant (P > .05)., Conclusion: ciNPT is effective in reducing the 90-day postoperative SSCs, readmission, and number of dressing changes after rTKA. Recommending routine implementation would require true-cost analyses., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Aims: Surgeons commonly resect additional distal femur during primary total knee arthroplasty (TKA) to correct a flexion contracture, which leads to femoral joint line elevation. There is a paucity of data describing the effect of joint line elevation on mid-flexion stability and knee kinematics. Thus, the goal of this study was to quantify the effect of joint line elevation on mid-flexion laxity., Methods: Six computational knee models with cadaver-specific capsular and collateral ligament properties were implanted with a posterior-stabilized (PS) TKA. A 10° flexion contracture was created in each model to simulate a capsular contracture. Distal femoral resections of + 2 mm and + 4 mm were then simulated for each knee. The knee models were then extended under a standard moment. Subsequently, varus and valgus moments of 10 Nm were applied as the knee was flexed from 0° to 90° at baseline and repeated after each of the two distal resections. Coronal laxity (the sum of varus and valgus angulation with respective maximum moments) was measured throughout flexion., Results: With + 2 mm resection at 30° and 45° of flexion, mean coronal laxity increased by a mean of 3.1° (SD 0.18°) (p < 0.001) and 2.7° (SD 0.30°) (p < 0.001), respectively. With + 4 mm resection at 30° and 45° of flexion, mean coronal laxity increased by 6.5° (SD 0.56°) (p < 0.001) and 5.5° (SD 0.72°) (p < 0.001), respectively. Maximum increased coronal laxity for a + 4 mm resection occurred at a mean 15.7° (11° to 33°) of flexion with a mean increase of 7.8° (SD 0.2°) from baseline., Conclusion: With joint line elevation in primary PS TKA, coronal laxity peaks early (about 16°) with a maximum laxity of 8°. Surgeons should restore the joint line if possible; however, if joint line elevation is necessary, we recommend assessment of coronal laxity at 15° to 30° of knee flexion to assess for mid-flexion instability. Further in vivo studies are warranted to understand if this mid-flexion coronal laxity has negative clinical implications. Cite this article: Bone Joint J  2021;103-B(6 Supple A):87-93.

Introduction: The purpose was to compare robotic assisted (RA), computer navigated (CN), and conventional UKA techniques., Methods: Databases were queried for data on study characteristics, UKA systems, complications, and tibiofemoral alignment., Results: Four RA and six CN RCTs were identified. No significant differences were found in operative time, tibiofemoral alignment, and reoperation rates when comparing RA or CN to conventional UKA. RA UKA resulted in a significantly lower risk of complications compared to conventional UKA., Conclusions: RA UKA results in fewer complications than conventional UKA with a clinically significant increase in operative time. All groups were similar in remaining evaluated parameters., (© 2021 Professor P K Surendran Memorial Education Foundation. Published by Elsevier B.V. All rights reserved.)

Preoperative flexion contracture is a risk factor for patient dissatisfaction following primary total knee arthroplasty (TKA). Previous studies utilizing surgical navigation technology and cadaveric models attempted to identify operative techniques to correct knees with flexion contracture and minimize undesirable outcomes such as knee instability. However, no consensus has emerged on a surgical strategy to treat this clinical condition. Therefore, the purpose of this study was to develop and evaluate a computational model of TKA with flexion contracture that can be used to devise surgical strategies that restore knee extension and to understand factors that cause negative outcomes. We developed six computational models of knees implanted with a posteriorly stabilized TKA using a measured resection technique. We incorporated tensions in the collateral ligaments representative of those achieved in TKA using reference data from a cadaveric experiment and determined tensions in the posterior capsule elements in knees with flexion contracture by simulating a passive extension exam. Subject-specific extension moments were calculated and used to evaluate the amount of knee extension that would be restored after incrementally resecting the distal femur. Model predictions of the extension angle after resecting the distal femur by 2 and 4 mm were within 1.2° (p ≥ 0.32) and 1.6° (p ≥ 0.25), respectively, of previous studies. Accordingly, the presented computational method could be a credible surrogate to study the mechanical impact of flexion contracture in TKA and to evaluate its surgical treatment., Competing Interests: Conflict of Interest Statement Michael Cross, Andrew Pearle, Timothy Wright, and Geoffrey Westrich are consultants and/or receive royalties with Exactech Inc., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: In addition to the significant morbidity and mortality associated with periprosthetic joint infection (PJI), the cost of treating PJI is substantial. Prior high-quality national estimates of the economic burden of PJI utilize data up to 2009 to project PJI growth in the United States through 2020. Now in the year 2020, it is appropriate to evaluate these past projections and incorporate the latest available data to better understand the current scale and burden of PJI in the United States., Methods: The Nationwide Inpatient Sample (2002-2017) was used to identify rates and associated inpatient costs for primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) and PJI-related revision TKA and THA. Poisson regression was utilized to model past growth and project future rates and cost of PJI of the hip and knee., Results: Using the most recent data, the combined annual hospital costs related to PJI of the hip and knee were estimated to be $1.85 billion by 2030. This includes $753.4 million for THA PJI and $1.1 billion for TKA PJI, in that year. Increases in PJI costs are mainly attributable to increases in volume. Although the growth in incidence of primary THA and TKA has slowed in recent years, the incidence of PJI and the cost per case of PJI remained relatively constant from 2002 to 2017., Discussion: Understanding the current and potential future financial burden of PJI for surgeons, patients, and healthcare systems is essential. There is an urgent need for efficacious preventive strategies in reducing rates of PJI after THA and TKA., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: It is vital for orthopedic residents and residency programs to have a current understanding of the materials and resources utilized on the Orthopedic In-Training Examination (OITE) to tailor resident educational curricula accordingly. This study presents an updated analysis of the hip and knee section of the OITE., Methods: All OITE questions related to hip and knee reconstruction over six examinations between 2014 and 2019 were analyzed for topic, subtopic, taxonomy, imaging modalities, resident performance, and references., Results: There were 166 hip and knee reconstruction questions of 1600 OITE questions (10.4%) over a six-year period. The most commonly tested topics include mechanical properties of total knee and hip implants (10.8%), instability after THA (10.8%), periprosthetic fracture (10.2%), and prosthetic joint infection (10.2%). A total of 362 references were cited from 68 different sources. The most common sources were JOA, JBJS, JAAOS, and CORR, which were collectively responsible for 68% of all citations. There was an average publication lag of 7.1 years, with 75% of all citations falling within 10 years of the question date. Compared with a prior analysis from 2005 and 2009, there were significantly more complex multistep questions regarding treatment and fewer one-step knowledge recall questions (P = .003). Similarly, recent tests had significantly more questions involving interpretation of radiographs (55%, P < .001) and advanced imaging (9.6%, P < .001), compared with a decade ago., Conclusions: The OITE continues to evolve over time, incorporating recent literature and topics. The current analysis identifies high-yield topics and resources that can guide resident preparation for the OITE hip and knee section., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: The early months of the coronavirus disease 19 (COVID-19) pandemic in New York City led to a rapid transition of non-essential in-person health care, including outpatient arthroplasty visits, to a telemedicine context. Questions/Purposes: Based on our initial experiences with telemedicine in an outpatient arthroplasty setting, we sought to determine early lessons learned that may be applicable to other providers adopting or expanding telemedicine services. Methods: A cross-sectional study was performed by surveying all patients undergoing telemedicine visits with 8 arthroplasty surgeons at 1 orthopedic specialty hospital in New York City from April 8 to May 19, 2020. Descriptive statistics were used to analyze demographic data, satisfaction with the telemedicine visit, and positive and negative takeaways. Results: In all, 164 patients completed the survey. The most common reasons for the telemedicine visit were short-term (less than 6 months), postoperative appointment ( n = 88; 54%), and new patient consultation ( n = 32; 20%). A total of 84 patients (51%) noted a reduction in expenses versus standard outpatient care. Several positive themes emerged from patient feedback, including less anxiety and stress related to traveling ( n = 82; 50%), feeling more at ease in a familiar environment ( n = 54; 33%), and the ability to assess postoperative home environment ( n = 13; 8%). However, patients also expressed concerns about the difficulty addressing symptoms in the absence of an in-person examination ( n = 28; 17%), a decreased sense of interpersonal connection with the physician ( n = 20; 12%), and technical difficulties ( n = 14; 9%). Conclusions: Patients were satisfied with their telemedicine experience during the COVID-19 pandemic; however, we identified several areas amenable to improvement. Further study is warranted., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Drake G. LeBrun, MD, MPH, Christina Malfer, BA, Mallory Wilson, BA, Kaitlin M. Carroll, BA, and Victoria Wang declare that they have no conflicts of interest. David J. Mayman, MD, reports stock or stock options from Imagen, Wishbone, and Insight; stock or stock options and royalties from Orthalign; and personal fees, royalties, and research support from Smith and Nephew, outside the submitted work. Michael B. Cross, MD, reports personal fees from Depuy, Smith and Nephew, and Flexion Therapeutics; personal fees and research support from Exactech; personal fees and stock or stock options from Imagen; personal fees, research support, and stock or stock options from Intellijoint; personal fees and research support from KCI; and stock or stock options from Parvizi Surgical Innovation, outside the submitted work. Michael M. Alexiades, MD, reports personal fees and royalties from DJ Orthopedics, outside the submitted work. Seth A. Jerabek, MD, reports stock or stock options from Imagen, personal fees and research support from Stryker, outside the submitted work. Fred D. Cushner, MD, reports personal fees from Acelity and Smith and Nephew, stock or stock options from Canary Medical, personal fees and stock or stock options from Orthalign, outside the submitted work. Jonathan M. Vigdorchik, MD, reports personal fees and research support from Corin, personal fees and stock or stock options from Intellijoint, and personal fees from Medacta, Motion Insights, and Zimmer, outside the submitted work. Steven B. Haas, MD, reports personal fees from Smith and Nephew, outside the submitted work. Michael P. Ast, MD, reports personal fees from Conformis, Stryker, and Surgical Care Affiliates; personal fees, stock or stock options, and royalties from Orthalign; stock or stock options from OSSO VR; and personal fees and research support from Smith and Nephew, outside the submitted work., (© The Author(s) 2020.)

Background: The aim of this study was to determine the impact of operative time on the development of early postoperative complications in patients undergoing revision total hip arthroplasty (THA)., Methods: In this retrospective cohort study, data were collected through the American College of Surgeons National Quality Improvement Program Database. All patients who underwent revision THA between 2007 and 2016 were identified and stratified into groups based on operative time|: 0-60 min, 61-120 min, 121-180 min, and > 180 min. The incidence of early postoperative adverse events with 30 days, including cardiac, pulmonary, renal, septic, thromboembolic, urinary tract, and wound complications, death, length of stay > 7 days, and unplanned return to the operating room were collected. The complications rates following revision THA were evaluated with univariate and multivariate analyses with significance set at p < 0.05., Results: A total of 6271 revision THA patients were included for analysis. Patients who had > 120 min of operative time had a significantly increased risk of the development of pulmonary (OR: 1.339; 95% CI: 1.08-1.661; p = 0.008) and thromboembolic complications (OR: 1.34; 95% CI: 1.053-1.707; p = 0.017) and also had an extended length of stay greater than 7 days (OR: 1.413; 95% CI: 1.295-1.541; p < 0.001)., Conclusions: Increased operative time (> 120 min) during revision THA is associated with increased risk of pulmonary and thromboembolic complications, and prolonged hospitalizations (greater than seven days).

Background: An updated analysis of the pediatrics section of the Orthopaedic In-Training Examination (OITE) is helpful for resident education and preparation for the OITE. The purpose of this study is to provide an updated evaluation of the pediatric category of the OITE, and to explore trends in question topics and taxonomy compared with the previously published analysis from 2011 to 2014., Methods: Five years (2015-2019) of OITE questions, answers, and references were reviewed. The number of pediatric questions per year was recorded, and questions were subcategorized based on topic tested. The presence or absence of imaging or a clinical photograph was noted. Each question was also assigned a cognitive taxonomy level, based on a previously published classification system., Results: The percentage of pediatric questions on the 2015-2019 OITEs averaged 11.4% compared with 12.6% from 2011 to 2014 (P=0.349). The 3 most commonly tested pediatric topics were general trauma (17.8%), elbow trauma (13.2%), and genetic disorders/syndromes (11.2%). There was a significant increase in questions that required diagnosis and interpretation (27.6% vs. 8%, P<0.001) and a slight but not significant decrease in the questions requiring simple knowledge recall (26.3% vs. 35.5%, P=0.120) and decisions about management (46.1% vs. 56.5%, P=0.077). Overall, 65% of questions utilized clinical photographs or imaging studies compared with 62% from 2011 to 2014 (P=0.621). The most common references were the Journal of Pediatric Orthopaedics, Journal of American Academy of Orthopaedic Surgeons, and Journal of Bone and Joint Surgery. Textbooks were cited less frequently than in the past., Conclusions: While the percentage of pediatric questions on the OITE has remained consistent over time, the percentage of questions requiring diagnosis and interpretation has increased. In addition, questions testing genetic disorders/syndromes have become more prevalent in recent years. The most commonly cited resources were high-impact journal articles, with textbooks cited less frequently than in previous years., Clinical Relevance: Knowledge of the most frequently tested topics and resources cited may assist orthopaedic residents in preparing for the OITE and orthopaedic faculty to focus didactic sessions on the most commonly tested topics.

Measured resection is a common technique for obtaining symmetric flexion and extension gaps in posterior-stabilized (PS) total knee arthroplasty (TKA). A known limitation of measured resection, however, is its reliance on osseous landmarks to guide bone resection and component alignment while ignoring the geometry of the surrounding soft tissues such as the medial collateral ligament (MCL), a possible reason for knee instability. To address this clinical concern, we introduce a new geometric proportion, the MCL ratio, which incorporates features of condylar geometry and MCL anterior fibers. The goal of this study was to determine whether the MCL ratio can predict the flexion gaps and to determine whether a range of MCL ratio corresponds to balanced gaps. Six computational knee models each implanted with PS TKA were utilized. Medial and lateral gaps were measured in response to varus and valgus loads at extension and flexion. The MCL ratio was related to the measured gaps for each knee. We found that the MCL ratio was associated with the flexion gaps and had a stronger association with the medial gap (β = -7.2 ± 3.05, P < .001) than with the lateral gap (β = 3.9 ± 7.26, P = .04). In addition, an MCL ratio ranging between 1.1 and 1.25 corresponded to balanced flexion gaps in the six knee models. Future studies will focus on defining MCL ratio targets after accounting for variations in ligament properties in TKA patients. Our results suggest that the MCL ratio could help guide femoral bone resections in measured resection TKA, but further clinical validation is required., (© 2020 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)

Aims: The aim of this study was to determine the impact of the severity of anaemia on postoperative complications following total hip arthroplasty (THA) and total knee arthroplasty (TKA)., Methods: A retrospective cohort study was conducted using the American College of Surgeons National Quality Improvement Program (ACS-NSQIP) database. All patients who underwent primary TKA or THA between January 2012 and December 2017 were identified and stratified based upon hematocrit level. In this analysis, we defined anaemia as packed cell volume (Hct) < 36% for women and < 39% for men, and further stratified anaemia as mild anaemia (Hct 33% to 36% for women, Hct 33% to 39% for men), and moderate to severe (Hct < 33% for both men and women). Univariate and multivariate analyses were used to evaluate the incidence of multiple adverse events within 30 days of arthroplasty., Results: Following adjustment, patients in the THA cohort with moderate to severe anaemia had an increased odds of 6.194 (95% confidence interval (CI) 5.679 to 6.756; p < 0.001) for developing any postoperative complication. Following adjustment, patients in the TKA cohort with moderate to severe anaemia had an increased odds of 5.186 (95% CI 4.811 to 5.590; p < 0.001) for developing any postoperative complication. Among both cohorts, as severity increased, there was an increased risk of postoperative complications., Conclusion: Preoperative anaemia is a risk factor for complications following primary arthroplasty. There is a significant relationship between the severity of anaemia and the odds of postoperative complications. Patients who had moderate to severe anaemia were at increased risk of developing postoperative complications relative to patients with mild anaemia. When considering elective primary THA or TKA in a moderately or severely anaemic patient, surgeons should strongly consider correcting anaemia prior to surgery if possible. Cite this article: Bone Joint J 2020;102-B(4):485-494.

Introduction: Polyethylene wear and subsequent osteolysis remain obstacles to the long-term survivorship of total hip arthroplasty (THA). Highly cross-linked polyethylene (XLPE) with radical quenching represents a massive leap forward with dramatically improved wear rates compared to ultra-high molecular weight polyethylene (UHMWPE). In this study we evaluate the wear of UHMWPE and XLPE coupled with oxidized zirconium (OxZr) femoral heads., Methods: A longitudinal, retrospective analysis was performed identifying consecutive patients who received a 28-mm OxZr-on-polyethylene primary THA from 2003 to 2004 by a single, high-volume arthroplasty surgeon. Patients were divided into two groups: those that received (1) UHMWPE liner and (2) a highly XLPE liner. Patients were included if clinical follow-up was complete to 2014 or later. Radiographic analysis was performed by two blinded observers. Measures included cup position, annual linear wear rate, and presence of osteolysis. Pairwise comparisons, correlations, and inter-rater reliability were calculated., Results: Eighty patients were in the UHMWPE group with an average follow-up of 10 ± 1.23 years and 88 patients in the XLPE group with an average of 10 ± 1.03-year follow-up. Average age (68) was similar between groups (p = 0.288). Observer reliability was excellent for cup abduction (ICC = 0.940), anteversion (ICC = 0.942), and detection of osteolysis (ICC = 0.811). Annual linear wear rates were significantly higher (p = 1 × 10 -19 ) with UHMWPE (0.21 ± 0.12 mm/year) compared to XLPE (0.05 ± 0.03 mm/year). Linear wear rate was significantly correlated to decreasing acetabular abduction (p = 0.035). Osteolysis was noted only in the UHMWPE group, with 17 patients (21.2%) exhibiting acetabular osteolysis and 37 (46.3%) patients exhibiting femoral osteolysis., Conclusions: OxZr coupled with XLPE showed minimal wear and no osteolysis at 10-year follow up. The yearly linear penetration rate is similar to that seen in other studies of XLPE THA. A careful longitudinal follow-up will be required to determine if advanced bearings such as OxZr or ceramic can show improved performance in the second decade of implantation., (© The Authors, published by EDP Sciences, 2020.)

Background: Residents' and fellows' participation in orthopedic surgery is a potential source of anxiety and concern for patients. The purpose of this study was to determine patients' attitudes toward trainee involvement in orthopedic surgery, surgeons as educators, and disclosure of trainee involvement., Methods: Three hundred two consecutive patients with preoperative and postoperative appointments at three arthroplasty practices in academic medical centers were surveyed with an anonymous, self-administered questionnaire. The questionnaire was developed in consultation with an expert in survey design., Results: Two hundred thirty-four patients completed the questionnaire (response rate 77.5%). Respondents were 60.5% female, 79.6% white, 66.5% privately insured, and 82.8% had at least some college education. About 65.9% of the respondents felt that surgeons who teach are better surgeons. Nearly all felt residents and fellows should perform surgeries as part of their education (94.1% and 95.3%, respectively). However, 39.7% of the respondents were not satisfactory with a second-year resident assisting in their own surgery. Patients dissatisfied with their most recent orthopedic surgery were more likely to respond that they did not want residents helping with their surgery. Respondents agreed that resident or fellow involvement in surgery should be disclosed (92.2% and 90.1%, respectively)., Conclusions: Insured and educated patients in the United States overwhelmingly desire disclosure of trainee involvement in their surgery. To address the need for orthopedic training in the context of a patient population that is not fully comfortable with trainee involvement in their own surgery, an open discussion between patients and surgeons regarding trainees' roles may be the best course of action., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: The purpose of this study was to evaluate the thickness of medial and lateral posterior femoral condylar bone resected with five implant systems using posterior referencing jigs set at 3° of external rotation. The hypothesis was that posterior condylar resection thickness on the medial side would be equal to the thickness of the femoral implant posteriorly, regardless of implant system., Methods: Posterior referencing femoral sizers were used on right femur sawbones models for five different implant systems. Each sawbones model was sized using a femoral sizer for the specific implant system. Sizing guides were set at 3° of external rotation for the right femur. Each system's 4-in-1 cutting block was then used to make posterior condylar cuts. The thicknesses of the cut bones were measured using a manual calliper., Results: The amount of bone resected from both medial (P = 0.0004) and lateral (P < 0.0001) posterior condyles differed significantly across the five implant systems. The mean thickness of bone resected from the posteromedial femoral condyle ranged from 9.4 ± 0.5 to 12.4 ± 0.9 mm. The mean thickness of the posterolateral condyle cut ranged from 6.7 ± 0.6 to 10.2 ± 0.3 mm. The difference in thicknesses between the bone resection from the posteromedial condyle and the implant thickness of the posterior condyles ranged from 0.6 to 2.9 mm., Conclusions: The thickness of bone removed from the posterior femoral condyles varied by up to 3 mm across the five TKA implant systems. For each system, the posteromedial condyle resection was larger than the thickness of the posterior condyle of the actual implant. As the difference between the posterior bone resection and the implant thickness increases, the flexion gap will likely loosen and should be accounted for during gap balancing. In commonly used knee implant systems, resected bone is greater than implant thickness and may lead to flexion instability.

Aims: The aim of this study was to determine the general postoperative opioid consumption and rate of appropriate disposal of excess opioid prescriptions in patients undergoing primary unilateral total knee arthroplasty (TKA)., Patients and Methods: In total, 112 patients undergoing surgery with one of eight arthroplasty surgeons at a single specialty hospital were prospectively enrolled. Three patients were excluded for undergoing secondary procedures within six weeks. Daily pain levels and opioid consumption, quantity, and disposal patterns for leftover medications were collected for six weeks following surgery using a text-messaging platform., Results: Overall, 103 of 109 patients (94.5%) completed the daily short message service (SMS) surveys. The mean oral morphine equivalents (OME) consumed during the six weeks post-surgery were 639.6 mg (sd 323.7; 20 to 1616) corresponding to 85.3 tablets of 5 mg oxycodone per patient. A total of 66 patients (64.1%) had stopped taking opioids within six weeks of surgery and had the mean equivalent of 18 oxycodone 5 mg tablets remaining. Only 17 patients (25.7%) appropriately disposed of leftover medications., Conclusion: These prospectively collected data provide a benchmark for general opioid consumption after uncomplicated primary unilateral TKA. Many patients are prescribed more opioids than they require, and leftover medication is infrequently disposed of appropriately, which increases the risk for illicit diversion. Cite this article: Bone Joint J 2019;101-B(7 Supple C):98-103.

Background: Whether anterior referencing (AR) or posterior referencing (PR) produces a more balanced flexion gap in total knee arthroplasty (TKA) using measured resection remains controversial. Our goal was to compare AR and PR in terms of (1) medial and lateral gaps at full extension and 90° of flexion, and (2) maximum medial and lateral collateral ligament (MCL and LCL) forces in flexion., Methods: Computational models of 6 knees implanted with posterior-stabilized TKA were virtually positioned with both AR and PR techniques. The ligament properties were standardized to achieve a balanced knee at full extension. Medial-lateral gaps were measured in response to varus and valgus loading at full extension and 90° of flexion; MCL and LCL forces were estimated during passive flexion., Results: At full extension, the maximum difference in the medial-lateral gap for both AR and PR was <1 mm in all 6 knee models. However, in flexion, only 3 AR and 3 PR models produced a difference in medial-lateral gap <2 mm. During passive flexion, the maximum MCL force ranged from 2 N to 87 N in AR and from 17 N to 127 N in PR models. The LCL was unloaded at >25° of flexion in all models., Conclusion: In measured resection TKA, neither AR nor PR better balance the ligaments and produce symmetrical gaps in flexion. Alternative bone resection techniques and rotation alignment targets are needed to achieve more predictable knee balance., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Proper ligament tension in knee flexion within cruciate-retaining (CR) total knee arthroplasty has long been associated with clinical success; however, traditional balancing principles have assumed that the distal femoral joint line (DFJL) affects only extension. The purpose of this study was to determine the effect DFJL may have on ligament strains and tibiofemoral kinematics of CR knee designs in flexion. A computational analysis was performed using a musculoskeletal modeling system for two different knee implants, the high-flex CR (HFCR) and guided-motion CR (GMCR). Tibiofemoral kinematics and ligament strain were measured at 90-degree knee flexion while the implants' DFJL was incrementally shifted proximally. Femoral implant position and kinematics were used to determine the femur's anteroposterior position relative to the tibia. The change in the femoral medial condyle position relative to the tibia was 0.33 mm and 0.53 mm more anterior per each 1-mm elevation of the DFJL for HFCR and GMCR, respectively. The change in the lateral condyle position was 0.20 mm more anterior and 0.06 mm more posterior for HFCR and GMCR, respectively. The strain in the lateral and medial collateral ligaments changed minimally with elevation of the DFJL. In both implants, strain increased in the anterior lateral and posterior medial bundles of the posterior collateral ligament with elevation of the DFJL, whereas strain decreased in the iliotibial band and iliotibial patellar band. Our findings suggest that DFJL affects ligament tension at 90-degree knee flexion and therefore flexion balance for CR implants. Elevating the DFJL to address tight extension space in a CR knee while flexion space is well balanced could result in increased flexion tension especially when the flexion-extension mismatch is large. To achieve balanced flexion and extension, the amount of DFJL elevation may need to be reduced., Competing Interests: M.B.C.: Acelity: paid consultant, Acelity Surgical Advisory Board: paid consultant, Bone and Joint Journal 360: editorial or governing board, Exactech, Inc: paid consultant, Intellijoint: paid consultant; Stock or stock Options, Journal of Orthopaedics and Traumatology: editorial or governing board, Link Orthopaedics: paid consultant, Smith & Nephew: paid consultant; Research support, Techniques in Orthopaedics: editorial or governing board, Theravance Biopharma: paid consultant, Zimmer: paid consultant. D.H.: Smith & Nephew: employee; Stock or stock Options, S.L.: Smith & Nephew: employee; Stock or stock Options, R.S.: AAOS: board or committee member, American Association of Hip and Knee Surgeons: Board or committee member, Arthroplasty Today: editorial or governing board, Gauss surgical: Stock or stock Options, Intelijoint: paid consultant; Stock or stock Options, Journal of Arthroplasty: editorial or governing board, Smith & Nephew: paid consultant; research support., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Background: Prospective collection of patient-reported opioid consumption and pain levels post-surgically may hold value in highlighting solutions related to the opioid crisis. Traditional methods for collecting patient-reported outcomes after surgery, such as paper surveys, often have poor response rates, and electronic messaging may offer more convenience and therefore yield more robust data., Questions/purposes: The purpose of this study was to evaluate whether a novel mobile phone short message service (SMS) platform would lead to better patient response rates to surveys on pain and opioid use than data-collection tools., Methods: An SMS text messaging platform was created and implemented between September 2017 and May 2018 at an orthopedic specialty hospital. The purpose was to collect reports on opioid consumption and pain levels twice a day for 6 weeks post-surgery from patients who had undergone total hip or knee arthroplasty or a single-level lumbar microdiscectomy or decompression spine surgery. Patients who responded to fewer than 50% of the text messages were excluded., Results: Our mobile phone text messaging platform was used by 183 patients, demonstrating a significantly higher response rate (96.1%) than our institution's post-operative email registry capture, as well as the majority of published response rates for post-operative outcomes captured through electronic and traditional data-collection systems. Response rate remained consistently high among the various surgeons and across patients, regardless of age., Conclusions: This application of a widely available technology can improve the measurement of post-operative patient-reported outcomes. Such data can in turn be used in the development of strategies to reduce post-operative opioid use. The adoption of novel technologies at a patient level will play a key role in combating the opioid epidemic., Competing Interests: Jeffrey G. Stepan, MD, Msc, Cynthia A. Kahlenberg, MD, and Jason L. Blevins, MD, declare that they have no conflicts of interest. Ajay Premkumar, MD, MPH, and Francis C. Lovecchio, MD, report a surgeon-in-chief grant from the Hospital for Special Surgery in support of this study. Todd J. Albert, MD, reports personal fees from Biomet, FacetLink, Gentis, JP Medical Publishers, Saunders/Mosby-Elsevier, United Healthcare, and Thieme; grants and personal fees from DePuy; stock ownership in ASIP, Biometrix, Breakaway Imaging, Crosstree, FacetLink, Gentis, In ViVo Therapeutics, Paradigm Spine, Spinicity, and Vertech; salary from Weill-Cornell Medical College (professor) and Hospital for Special Surgery (surgeon-in-chief); non-financial support from Scoliosis Research Society (president), Cervical Spine Research Society (past-president), American Orthopaedic Association; grants from AO Foundation/Association for the Study of Internal Fixation, Patient-Centered Outcomes Research Institute, International Spine Study Group, and National Institute of Arthritis and Musculoskeletal and Skin Diseases, all outside the submitted work. Michael B. Cross, MD, reports personal fees from Link Orthopaedics, Smith & Nephew, and Zimmer; personal fees and research support from Acelity, Exactech, Inc., and Flexion Therapeutics; stock or stock options from Imagen, Insight Medical, and Parvizi Surgical Innovation; and personal fees, research support, and stock or stock options from Intellijoint, all outside the submitted work.All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2013.Informed consent was obtained from all patients for being included in this study.Disclosure forms provided by the authors are available with the online version of this article.