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To study the direction and biomechanical consequences of hip center of rotation (HCOR) migration in Crowe type III and VI hips after total hip arthroplasty, post-operative radiographs and CT scans of several unilaterally affected hips were evaluated. Using a three-dimensional model of the human hip, the HCOR was moved in all directions, and joint reaction force (JRF) and abductor muscle force (AMF) were calculated for single-leg stance configuration. Comparing to the normal side, HCOR had displaced medially and inferiorly by an average of 23.4% and 20.8%, respectively, of the normal femoral head diameter. Significant decreases in JRF (13%) and AMF (46.13%) were observed in a presumptive case with that amount of displacement. Isolated inferior displacement had a small, increasing effect on these forces. In Crowe type III and IV hips, the HCOR migrates inferiorly and medially after THA, resulting in a decrease in JRF, AMF, and abductor muscle contraction force.

article i nfo Article history: Received 6 February 2013 Accepted 15 April 2013 A biomechanical computer-based model was developed to simulate the influence of patellar thickness on passive knee flexion after arthroplasty. Using the computer model of a single-radius, PCL-sacrificing knee prosthesis, a range of patella-implant composite thicknesses was simulated. The biomechanical model was then replicated using two cadaveric knees. A patellar-thickness range of 15 mm was applied to each of the knees. Knee flexion was found to decrease exponentially with increased patellar thickness in both the biomechanical and experimental studies. Importantly, this flexion loss followed an exponential pattern with higher patellar thicknesses in both studies. In order to avoid adverse biomechanical and functional consequences, it is recommended to restore patellar thickness to that of the native knee during total knee arthroplasty.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic since early 2020. The coronavirus disease 2019 (COVID-19) has already caused more than three million deaths worldwide and affected people's physical and mental health. COVID-19 patients with mild symptoms are generally required to self-isolate and monitor for symptoms at least for 14 days in the case the disease turns towards severe complications. In this work, we overviewed the impact of COVID-19 on the patients' general health with a focus on their cardiovascular, respiratory and mental health, and investigated several existing patient monitoring systems. We addressed the limitations of these systems and proposed a wearable telehealth solution for monitoring a set of physiological parameters that are critical for COVID-19 patients such as body temperature, heart rate, heart rate variability, blood oxygen saturation, respiratory rate, blood pressure, and cough. This physiological information can be further combined to potentially estimate the lung function using artificial intelligence (AI) and sensor fusion techniques. The prototype, which includes the hardware and a smartphone app, showed promising results with performance comparable to or better than similar commercial devices, thus potentially making the proposed system an ideal wearable solution for long-term monitoring of COVID-19 patients and other chronic diseases.

The aim of survival analysis in healthcare is to estimate the probability of occurrence of an event, such as a patient's death in an intensive care unit (ICU). Recent developments in deep neural networks (DNNs) for survival analysis show the superiority of these models in comparison with other well-known models in survival analysis applications. Ensuring the reliability and explainability of deep survival models deployed in healthcare is a necessity. Since DNN models often behave like a black box, their predictions might not be easily trusted by clinicians, especially when predictions are contrary to a physician's opinion. A deep survival model that explains and justifies its decision-making process could potentially gain the trust of clinicians. In this research, we propose the reverse survival model (RSM) framework that provides detailed insights into the decision-making process of survival models. For each patient of interest, RSM can extract similar patients from a dataset and rank them based on the most relevant features that deep survival models rely on for their predictions.

Background: Several pelvic osteotomy techniques are introduced for the treatment of Developmental Dysplasia of the Hip (DDH). However, there is no agreement on the optimal pelvic osteotomy in DDH. Thus, this study aimed to compare the outcomes of Pemberton Osteotomy (PO) and the Kalamchi Modification of Salter Osteotomy (KMSO). Objectives: Comparison of pemberton osteotomy and kalamchi modification of salter osteotomy in the treatment of developmental dysplasia of the hip. Methods: In a retrospective study, radiographic and clinical outcomes as well as surgical complications were compared between the patients who underwent unilateral DDH surgery using either KMSO or PO. The radiographic measures included the assessment of the acetabular index and the Shenton line. The clinical results of the osteotomies were evaluated by McKay’s criteria modified by Berkeley et al. Also, Kalamchi and MacEwen’s classification was used for the assessment of avascular necrosis. Results: The characteristic features of the patients, such as age and follow-up time, were statistically comparable between the two study groups. One year after the surgery, the Shenton line was intact in 55 patients (84.6%) of the KMSO group and 40 patients (88.9%) of the PO group (P=0.52). The Mean±SD value of the acetabular index was 21.1±5.1 and 20.7±3.9 in the KMSO and PO groups, respectively (P=0.13). Besides, the McKay’s clinical criteria were respectively excellent, good, and fair in 44, 16, and 5 patients (67.7%, 24.6%, and 7.7%, respectively) of the KMSO group, and 31, 12, and 2 patients (70%, 26.6%, and 4.4%, respectively) of the PO group (P=0.4). Moreover, the number of postoperative avascular necrosis did not significantly differ between the two study groups. Conclusion: The PO and KMSO techniques are equally safe and effective osteotomies in the treatment of DDH and can be used interchangeably.

Addressing acetabular deficiency during arthroplasty of dysplastic hips is challenging. We assessed outcomes of a protocol for choosing either impaction or structural graft for this purpose.This retrospective study included 59 patients (71 hips) with a dysplastic hip and over 30% uncoverage that underwent cementless total hip arthroplasty. Morselized impaction grafting was performed for hips where initial stability of the acetabular cup was achieved. In others, a shelf graft was inserted before implantation of the acetabular cup. Outcomes were assessed at a minimum follow-up of 4 years.Fifty-seven (80.3%) hips underwent impaction grafting and 14 (19.7%) received a structural graft. Mean age at surgery was 48.1 ± 13.5 (18-68) years for impaction and 48.6 ± 14 (24-70) years for shelf grafts. Mean increase in Harris Hip Score was 51.5 ± 9.3 and 50 ± 11.2 for the impaction and structural groups, respectively, at a mean follow-up of 92 (49-136) months (P = .6). Heterotopic ossification occurred in 16 patients in the impaction group vs none in the structural group (P = .004). Radiologically, mean percentages of cup coverage provided by the graft were 47.8 ± 10.9% and 48.9 ± 13.3% in the impaction and structural groups, respectively (P = .75). All but one of shelf grafts united to host bone and all impaction grafts incorporated. There was one case of cup loosening in the structural graft group.Most dysplastic acetabula with over 30% defect can be addressed using a cementless cup and impaction grafting, with good results in the midterm. In about 20% of cases, initial press-fit is not attainable and structural support-like shelf graft becomes necessary.IV.

To compare the stresses at bone–arthroplasty interface of constrained and semi-constrained knee prostheses, using the finite element (FE) method as a predictor of the survivorship of the implants. Three-dimensional FE models of the knee implanted with rotating hinge (RHK) and legacy constrained condylar (LCCK) prostheses were generated to study the loads and stresses for two situations: medial- and lateral collateral ligament deficiencies in full extension. On average, the shear stress developed at bone–implant interface dropped from 16.9 to 13.7 MPa (18.9%), and the interface von Mises stress lowered from 37.6 to 30.2 MPa (19.6%) in RHK compared to those in LCCK prostheses. RHK design also resulted in a more uniform stress distribution at the interfaces in both femur and tibia. The average polyethylene liner stress dropped from 9.6 to 2.6 MPa (a 72.7% decrease) in RHK design when compared to that in LCCK design. The more uniform interface stress suggests fewer density changes at the periprosthetic regions due to bone remodelling. Moreover, the lower polyethylene stresses are likely to reduce wear and damage. These findings reveal that the RHK design may have more favorable mechanical features compared to LCCK design in full extension boundary conditions, implying a potentially better survivorship. However, the findings should be interpreted cautiously as other configurations were not investigated.

The purpose of this study was to determine if there is an anatomic relationship between pelvic geometry and acetabular depth. One hundred and fifty-one anteroposterior pelvic radiographs (157 hip joints) were selected and analyzed in a retrospective fashion. Six parameters, including iliac offset, ischial offset, acetabular offset, pelvic height, center-edge (CE) angle of Wiberg, and acetabular index (AI) angle of Tonnis were measured for each of the hip joints. Based on the defined variables, three formulas (formulas 1, 2, and 3) were calculated to represent the hemi-pelvis slope. There was a strong relationship between the hemi-pelvis slope and probability of acetabular dysplasia. Wider upper pelvis was associated with deeper acetabulum and wider lower pelvis was associated with dysplastic acetabulum. Pelvic anatomic dimensions and the relationship between them are strongly correlated with hip dysplasia indices. Dysplastic hips tend to be found in pelvises with lower slope (low width of the upper pelvis at the level of iliac crest and high width of the lower part at the level of ischium).

Aims It may not be possible to undertake revision total hip arthroplasty (THA) in the presence of massive loss of acetabular bone stock using standard cementless hemispherical acetabular components and metal augments, as satisfactory stability cannot always be achieved. We aimed to study the outcome using a reconstruction cage and a porous metal augment in these patients. Patients and Methods A total of 22 acetabular revisions in 19 patients were performed using a combination of a reconstruction cage and porous metal augments. The augments were used in place of structural allografts. The mean age of the patients at the time of surgery was 70 years (27 to 85) and the mean follow-up was 39 months (27 to 58). The mean number of previous THAs was 1.9 (1 to 3). All patients had segmental defects involving more than 50% of the acetabulum and seven hips had an associated pelvic discontinuity. Results Three failures were observed in two hips, both of which had undergone a previous resection of a tumour affecting the acetabulum. Other complications included a late arterial injury, a sciatic nerve palsy, a dislocation treated with a femoral revision, a deep infection treated with irrigation and debridement and a fracture of the greater trochanter treated conservatively. The mean Oxford Hip Score significantly increased from 13.9 (2 to 23) to 28.7 (13 to 38) (p < 0.00001). The mean vertical distance between the centre of rotation of the hip and its normal location decreased from 30 mm to 10 mm. Conclusions Acceptable early survivorship can be achieved using this novel technique, but it may be unsuitable for use in patients who have previously undergone the resection of a tumour involving the acetabulum. Cite this article: Bone Joint J 2017;99-B:607–13.

No abstract available Keywords: allograft; bone defects; cement extraction; cement retrieval; femoral bone stock; nonantibiotic impregnated allograft; reimplantation; reimplantation timing; resection arthroplasty; stable cement mantle; two-stage exchange arthroplasty.

Background The benefit of suction drains (SD) for the first 24-48 hours following joint replacement surgery is controversial. We aimed to determine if there is any difference in the early outcome of revision TKA when performed with, or without SD. Methods 83 cases indicated for revision knee arthroplasty were randomized to receive (42) or not receive (41) a deep intra-articlular drain. First-stage revisions for treating periprosthetic infection were excluded. Patients were statistically compared for demographic parameters, early complications and early knee functional outcome. The assessed outcomes included total blood loss, number of transfusions, fever and wound complication rate at 24 months follow-up. In addition, the change in knee society score at 12 weeks postoperatively was compared between the groups. Results There were no significant difference in demographic factors, wound complications, knee scores at 12 weeks and infection rate 24 months after surgery in either group. Average blood loss was 1856ml and 1533ml for the drain and no drain groups, respectively (P value=0.0470). The need for transfusion was significantly less in the no-drain group with an average of 0.15 unit/patient as compared to an average 0.37 unit/patient for the drain group (P value=0.0432). Conclusion We were unable to find a point of superiority for using a drain for revision knee arthroplasty. Future studies with longer follow-up and larger population of patients are needed to make a valid conclusion.

This study examined the success and factors associated with failure, of using cement spacers impregnated with high-dose Ceftazidime and Vancomycin when performing two-stage revision for infected total knee arthroplasty (TKA).A retrospective analysis was performed using a prospectively collected database of 82 patients (median age 68 years, range 39-87) with a confirmed deep TKA infection treated with a two-stage revision. All cement spacers were impregnated with high-dose Ceftazidime and Vancomycin. The rate of success was recorded-an association between failure of treatment, and patient factors, previous surgical treatment, and microbial characteristics was sought.The mean time to infection from index arthroplasty was 45 months (range 3-240). The initial two-stage revision was successful in 70/82 patients (85.4 %), who remained free of infection at average follow-up of 36.2 months (range 24-85). A second two-stage revision for infection was required in 12/82 patients (14.6 %), which was successful in 4/12 (33 %). A third two-stage revision was performed in three patients, all of whom had a polymicrobial infection of which only one patient had successful eradication of infection. Recurrent infection was correlated with irrigation and debridement with implant retention prior to initial two-stage revision (p 0.01), polymicrobial infections (p = 0.035), and infections presenting6 months after index surgery (p = 0.031). No correlation was seen with age, BMI, type of organism, diabetes mellitus, or Charlson Comorbidity Index.The findings of this study suggest that the combination of Ceftazidime and Vancomycin in cement spacers is as efficacious as other published single or combined antibiotic mixtures, which is clinically relevant to clinicians treating this difficult problem in the setting of patients with compromised renal function.

This study reports the clinical outcome of reconstruction of deficient abductor muscles following revision total hip arthroplasty (THA), using a fresh–frozen allograft of the extensor mechanism of the knee. A retrospective analysis was conducted of 11 consecutive patients with a severe limp because of abductor deficiency which was confirmed on MRI scans. The mean age of the patients (three men and eight women) was 66.7 years (52 to 84), with a mean follow-up of 33 months (24 to 41). Following surgery, two patients had no limp, seven had a mild limp, and two had a persistent severe limp (p = 0.004). The mean power of the abductors improved on the Medical Research Council scale from 2.15 to 3.8 (p < 0.001). Pre-operatively, all patients required a stick or walking frame; post-operatively, four patients were able to walk without an aid. Overall, nine patients had severe or moderate pain pre-operatively; ten patients had no or mild pain post-operatively. At final review, the Harris hip score was good in five patients, fair in two and poor in four. We conclude that using an extensor mechanism allograft is relatively effective in the treatment of chronic abductor deficiency of the hip after THA when techniques such as local tissue transfer are not possible. Longer-term follow-up is necessary before the technique can be broadly applied. Cite this article: Bone Joint J 2015;97-B:1050–5.

The use of distal femoral replacement (DFR) prosthesis is an option for treating distal femoral periprosthetic fracture (PPF). It is particularly helpful when the distal femoral bone is small and not amenable to rigid fixation. We report the results of 13 distal femoral PPFs at an average age of 77.5 years that were treated by this technique. At a mean follow-up of 30.5 months, the average Knee Society Score and functional score were 82 and 20, respectively. All patients who were ambulatory before fracture, regained their ability to walk after the surgery. There was a revision surgery for treating patellar instability. DFR is a reliable treatment for distal femoral PPFs with poor bone stock that allows for early ambulation in an elderly and low-demand group of patients.

The use of ilioischial cage reconstruction for pelvic discontinuity has been replaced by the Trabecular Metal (Zimmer, Warsaw, Indiana) cup-cage technique in our institution, due to the unsatisfactory outcome of using a cage alone in this situation. We report the outcome of 26 pelvic discontinuities in 24 patients (20 women and four men, mean age 65 years (44 to 84)) treated by the cup-cage technique at a mean follow-up of 82 months (12 to 113) and compared them with a series of 19 pelvic discontinuities in 19 patients (18 women and one man, mean age 70 years (42 to 86)) treated with a cage at a mean follow-up of 69 months (1 to 170). The clinical and radiological outcomes as well as the survivorship of the groups were compared. In all, four of the cup-cage group (15%) and 13 (68%) of the cage group failed due to septic or aseptic loosening. The seven-year survivorship was 87.2% (95% confidence interval (CI) 71 to 103) for the cup-cage group and 49.9% (95% CI 15 to 84) for the cage-alone group (p = 0.009). There were four major complications in the cup-cage group and nine in the cage group. Radiological union of the discontinuity was found in all successful cases in the cup-cage group and three of the successful cage cases. Three hips in the cup-cage group developed early radiological migration of the components, which stabilised with a successful outcome. Cup-cage reconstruction is a reliable technique for treating pelvic discontinuity in mid-term follow-up and is preferred to ilioischial cage reconstruction. If the continuity of the bone graft at the discontinuity site is not disrupted, early migration of the components does not necessarily result in failure. Cite this article: Bone Joint J 2014;96-B:195–200.

In this retrospective study we evaluated the proficiency of shelf autograft in the restoration of bone stock as part of primary total hip replacement (THR) for hip dysplasia, and in the results of revision arthroplasty after failure of the primary arthroplasty. Of 146 dysplastic hips treated by THR and a shelf graft, 43 were revised at an average of 156 months, 34 of which were suitable for this study (seven hips were excluded because of insufficient bone-stock data and two hips were excluded because allograft was used in the primary THR). The acetabular bone stock of the hips was assessed during revision surgery. The mean implant–bone contact was 58% (50% to 70%) at primary THR and 78% (40% to 100%) at the time of the revision, which was a significant improvement (p < 0.001). At primary THR all hips had had a segmental acetabular defect > 30%, whereas only five (15%) had significant segmental bone defects requiring structural support at the time of revision. In 15 hips (44%) no bone graft or metal augments were used during revision. A total of 30 hips were eligible for the survival study. At a mean follow-up of 103 months (27 to 228), two aseptic and two septic failures had occurred. Kaplan-Meier survival analysis of the revision procedures demonstrated a ten-year survival rate of 93.3% (95% confidence interval (CI) 78 to 107) with clinical or radiological failure as the endpoint. The mean Oxford hip score was 38.7 (26 to 46) for non-revised cases at final follow-up. Our results indicate that the use of shelf autografts during THR for dysplastic hips restores bone stock, contributing to the favourable survival of the revision arthroplasty should the primary procedure fail. Cite this article: Bone Joint J 2013;95-B:777–81.

Trabecular metal (TM) augments are a relatively new option for reconstructing segmental bone loss during acetabular revision. We studied 34 failed hip replacements in 34 patients that were revised between October 2003 and March 2010 using a TM acetabular shell and one or two augments. The mean age of the patients at the time of surgery was 69.3 years (46 to 86) and the mean follow-up was 64.5 months (27 to 107). In all, 18 patients had a minor column defect, 14 had a major column defect, and two were associated with pelvic discontinuity. The hip centre of rotation was restored in 27 patients (79.4%). The Oxford hip score increased from a mean of 15.4 points (6 to 25) before revision to a mean of 37.7 (29 to 47) at the final follow-up. There were three aseptic loosenings of the construct, two of them in the patients with pelvic discontinuity. One septic loosening also occurred in a patient who had previously had an infected hip replacement. The augments remained stable in two of the failed hips. Whenever there was a loose acetabular component in contact with a stable augment, progressive metal debris shedding was evident on the serial radiographs. Complications included another deep infection treated without revision surgery. Good clinical and radiological results can be expected for bone-deficient acetabula treated by a TM cup and augment, but for pelvic discontinuities this might not be a reliable option.Cite this article: Bone Joint J 2013;95-B:166–72.

Background Valgus cut angle (VCA), defined as the angle between the anatomical and the mechanical axes of femur, is an important parameter upon which a critical step of knee arthroplasty is based. Some variables have been proposed to affect the magnitude of this cut. However, little information is available regarding whether a generic value can be used, or if a patient-specific value from a long leg X-ray, or factors that can be determined preoperatively, is necessary to accurately set the VCA. Methods Standard standing 3-joint views were used to measure a number of anatomical measurements in 358 limbs, 202 patients (116 women, 86 men). Neck-shaft angle, medial offset, femoral length (FL), distal femoral articular angle, and VCA were measured. Demographic data including gender and height were extracted from hospital charts. The correlation of VCA with each of the other factors was evaluated using linear regression and t-test and finally multivariate analysis. Results The average VCA was 5.76° (range 4-8). Gender and distal femoral articular angle were not related to VCA ( P = .343 and .995). FL was found to be a function of height with similar effects on multivariate analysis. Only the height (or FL) and femoral offset were identified as independent factors, with a negative correlation for the former ( P P Conclusion Femoral offset and height are the 2 independent factors determining VCA. Other parameters are indirectly related to these 2 factors. Tall patients with a small femoral offset have smaller VCA and short patients with a large offset have larger VCA. The wide variety of VCA values does not support using a generic value for all patients during knee arthroplasty.

Background: Total hip arthroplasty (THA) is regarded as the most successful and common surgical approach in orthopedic surgeries. Several surgical approaches have been described for THA to introduce minimally invasive surgical exposures. Posterolateral and lateral approaches are traditional and still most commonly used approaches for primary THA. In deciding which approach to use, consideration of complications, and clinical and radiological outcomes, using one approach or another should be evaluated. Objectives: The purpose of this study was to compare the early postoperative outcomes of posterolateral and lateral surgical approaches. Patients and Methods: The current study was conducted on a group of 134 primary hip arthroplasty of 120 patients who had undergone THA surgery at Shafa Orthopedic Hospital in Tehran, Iran, from March 2011 to October 2014. The lateral approach was used in 79 hips and, posterolateral approach was used in 55 hip based on surgeon’s preference. Two groups were assessed considering the following outcomes: clinical evaluation including Harris hip score (HHS), blood loss, blood transfusion, hemoglobin level, infections, deep vein thrombosis (DVT) and dislocation, as well as radiological evaluation including the proximal femur fracture, limb length discrepancy and cup inclination angle. The follow-up for both groups was at 6, 12, 24, 36 and 48 weeks after the surgery. Results: There was no significant difference between the two approaches regarding demographic characteristics, HHS, blood loss, transfusion, hemoglobin level, dislocation and cup inclination angle. However, there was a significant difference in the incidences of infections, DVT, proximal femur fracture and discrepancy of limb length between the two approaches. Conclusions: The results of this study indicate that both lateral and posterolateral approaches offer similar early clinical outcomes and some different radiological outcomes.

In this study we present our experience with four generations of uncemented total knee arthroplasty (TKA) from SmithNephew: Tricon M, Tricon LS, Tricon II and Profix, focusing on the failure rates correlating with each design change. Beginning in 1984, 380 Tricon M, 435 Tricon LS, 305 Tricon 2 and 588 Profix were implanted by the senior author. The rate of revision for loosening was 1.1% for the Tricon M, 1.1% for the Tricon LS, 0.5% for the Tricon 2 with a HA coated tibial component, and 1.3% for the Profix TKA. No loosening of the femoral component was seen with the Tricon M, Tricon LS or Tricon 2, with no loosening seen of the tibial component with the Profix TKA. Regarding revision for wear, the incidence was 13.1% for the Tricon M, 6.6% for the Tricon LS, 2.3% for the Tricon 2, and 0% for the Profix. These results demonstrate that improvements in the design of uncemented components, including increased polyethylene thickness, improved polyethylene quality, and the introduction of hydroxyapatite coating, has improved the outcomes of uncemented TKA over time.

Patients who have hip dysplasia are often young and active. Hence, total hip replacement in this group needs meticulous planning to obtain satisfactory fixation with good long-term outcome. Acetabular reconstruction is often complex because of acetabular bone deficiency. Various techniques to deal with the deficiency of acetabular bone stock have been described, including cemented and cementless cups with or without bone graft, impaction bone grafting, perforating the medial acetabular wall (the cotyloplasty technique), and a small-diameter cup at elevated hip center. Multiple studies have reported long-term results of various techniques for acetabular reconstruction.

The cup-cage reconstruction is indicated in massive acetabular bone loss with or without pelvic discontinuity during revision hip arthroplasty. We report the results of 26 pelvic discontinuities treated by this technique at a mean follow up of 46.6 months. The average Harris hip score was 76.6. Three constructs failed all within the first postoperative year. Complications included one deep infection, two dislocations and one peroneal neuropathy. Cup-cage construct is a reliable technique for treating pelvic discontinuity in mid-term follow-up.

The authors have reported on the prospective measurements of intraand post-operative blood loss of 96 total knee arthroplasty cases and have analyzed the relationship between these values and demographical factors of the series. Mean intraoperative blood loss and postoperative drainage were determined to be 147.1 ± 97.4 mL and 494.4 ± 188.1 mL, respectively. Male and obese patients had significantly higher intraoperative blood loss, whereas male sex and older age were associated with a greater drop in hemoglobin (Hb), on the first postoperative day. No predictors of the need for transfusion were found.

Synovial chondromatosis is a benign lesion of the synovium, and giant solitary synovial chondromatosis (GSSCM) is a rare presentation of it. In this article, we describe clinical, imaging, and pathologic features of a hip GSSCM with an unusual histologic presentation.

with the introduction of an illegal, steroid-containing opioid drug, Temgesic. The correlation of risk factors associated with the course of ONFH has yet to be determined. Objectives: The purpose of the present study was to assess the effects of etiologic factors on the course of ONFH after emergence of symptoms. Patients and Methods: We retrospectively assessed patients with untreated ONFH due to one of the four etiologies of steroid medication, Temgesic abuse, trauma and idiopathic. Patients with multiple risk factors and those without collapse at the last follow-up visit were excluded. The effect of age, gender, etiology of osteonecrosis, opium addiction and smoking on the time interval between pain onset and radiologic collapse were investigated. Results: In total, 110 patients (174 hips) were categorized into four etiologic groups. The average time between onset of pain to radiologic collapse in different etiologic groups was 12.8 months for all groups, 12.4 months for steroid, 8.7 months for Temgesic, 18.5 months for trauma and 16.6 months for idiopathic groups. Thirteen hips had collapse in less than six months. Patients who used steroid and Temgesic had shorter time interval to collapse, which was statistically significant (P Values < 0.001 and < 0.001, respectively). Smoking had a statistically significant association with the time to femoral head collapse (P Value = 0.003). Conclusions: Steroid medications and Temgesic abuse are associated with shorter time interval to femoral head collapse. Smoking is also a factor associated with shorter time interval to collapse. These factors should be considered in any joint preserving treatments for patients with FHON.

The benefit of suction drains (SD) for the first 24-48 hours following joint replacement surgery is controversial. We aimed to determine if there is any difference in the early outcome of revision TKA when performed with, or without SD.83 cases indicated for revision knee arthroplasty were randomized to receive (42) or not receive (41) a deep intra-articlular drain. First-stage revisions for treating periprosthetic infection were excluded. Patients were statistically compared for demographic parameters, early complications and early knee functional outcome. The assessed outcomes included total blood loss, number of transfusions, fever and wound complication rate at 24 months follow-up. In addition, the change in knee society score at 12 weeks postoperatively was compared between the groups.There were no significant difference in demographic factors, wound complications, knee scores at 12 weeks and infection rate 24 months after surgery in either group. Average blood loss was 1856ml and 1533ml for the drain and no drain groups, respectively (P value=0.0470). The need for transfusion was significantly less in the no-drain group with an average of 0.15 unit/patient as compared to an average 0.37 unit/patient for the drain group (P value=0.0432).We were unable to find a point of superiority for using a drain for revision knee arthroplasty. Future studies with longer follow-up and larger population of patients are needed to make a valid conclusion.

We retrospectively reviewed 44 consecutive patients (50 hips) who underwent acetabular re-revision after a failed previous revision that had been performed using structural or morcellised allograft bone, with a cage or ring for uncontained defects. Of the 50 previous revisions, 41 cages and nine rings were used with allografts for 14 minor-column and 36 major-column defects. We routinely assessed the size of the acetabular bone defect at the time of revision and re-revision surgery. This allowed us to assess whether host bone stock was restored. We also assessed the outcome of re-revision surgery in these circumstances by means of radiological characteristics, rates of failure and modes of failure. We subsequently investigated the factors that may affect the potential for the restoration of bone stock and the durability of the re-revision reconstruction using multivariate analysis. At the time of re-revision, there were ten host acetabula with no significant defects, 14 with contained defects, nine with minor-column, seven with major-column defects and ten with pelvic discontinuity. When bone defects at re-revision were compared with those at the previous revision, there was restoration of bone stock in 31 hips, deterioration of bone stock in nine and remained unchanged in ten. This was a significant improvement (p < 0.001). Morselised allografting at the index revision was not associated with the restoration of bone stock. In 17 hips (34%), re-revision was possible using a simple acetabular component without allograft, augments, rings or cages. There were 47 patients with a mean follow-up of 70 months (6 to 146) available for survival analysis. Within this group, the successful cases had a minimum follow-up of two years after re-revision. There were 22 clinical or radiological failures (46.7%), 18 of which were due to aseptic loosening. The five and ten year Kaplan–Meier survival rate was 75% (95% CI, 60 to 86) and 56% (95% CI, 40 to 70) respectively with aseptic loosening as the endpoint. The rate of aseptic loosening was higher for hips with pelvic discontinuity (p = 0.049) and less when the allograft had been in place for longer periods (p = 0.040). The use of a cage or ring over structural allograft bone for massive uncontained defects in acetabular revision can restore host bone stock and facilitate subsequent re-revision surgery to a certain extent. Cite this article: Bone Joint J 2014;96-B:319–24.

The conventional method for reconstructing acetabular bone loss at revision surgery includes using structural bone allograft. The disadvantages of this technique promoted the advent of metallic but biocompatible porous implants to fill bone defects enhancing initial and long-term stability of the acetabular component. This paper presents the indications, surgical technique and the outcome of using porous metal acetabular augments for reconstructing acetabular defects. Cite this article: Bone Joint J 2013;95-B, Supple A:103–8.

It is common practice in many centers to avoid performing a clean case in a room in which an infected procedure has just taken place. No studies of which we are aware speak to the necessity of this precaution.The purposes of this study were to identify (1) the risk of infection in a group of patients who underwent arthroplasties performed immediately after a first-stage arthroplasty for joint infection; and (2) the risk of superficial and deep infections in these patients compared with a matched group of patients who underwent arthroplasties not performed after an infected surgery.Eighty-three patients (85 arthroplasties) who underwent arthroplasties (primary or revision) immediately after patients with known infections underwent surgery in the same operating room (OR) were analyzed for 12 months after surgery to determine the incidence of infection. They were matched for demographic factors and surgery type with a control group of 321 patients (354 arthroplasties) who underwent surgery in an OR that had not just been used for surgery involving patients with infections. We compared the risk of superficial and deep infections between the groups.Patients in the study group were not more likely to have infections develop than those in the control group. One patient in the study group (1.17%) and three in the control group (0.84%) had deep infections develop; the infection in the patient in the study group was caused by a different organism than that of the patient with an infection whose surgery preceded in the OR. Two superficial infections (2.35%) were detected in the study group and 17 (4.8%) were detected in the control group.With the numbers available, we found that a deep infection was not more likely to occur in a patient without an infection after an arthroplasty that followed surgery on a patient with an infection than in one who had surgery after a clean case. Although sample size was a potential issue in this study, the results may serve as hypothesis generating for future studies.Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Introduction Failed acetabular reinforcement rings (ARR) (roof rings and antiprotrusion cages) may require another ARR reconstruction or another type of acetabular device with or without a bone graft. The purpose of this study was to propose surgical options for salvage of failed ARRs and to compare the failure rate of each surgical option. Materials and methods We reviewed 33 first ARRs (12 roof rings and 21 antiprotrusion cages) which were revised and converted to a new acetabular reconstruction. Operative reports, radiographs, and clinical data were evaluated. Minimum follow-up was 24 months (average 57 months; range 24-209 months). Results 33 failed first ARRs were converted to one of three types of acetabular reconstruction, Trabecular Metal (TM) cup in 14, cup-cage in 7 and a second ARR in 12. The TM cup group (TM cup and cup-cage) had a significantly longer survival than the second ARR group (P = 0.025) on log-rank analysis. Discussion Treatment of a failed first ARR by a TM cup and a cup-cage provides better results when compared to treatment by a second ARR. Restoration of bone stock is the main factor in determining whether a TM cup or cup-cage rather than another conventional ARR can be used.

Long-term outcomes of cemented and uncemented cups were compared in patients with hip dysplasia who had undergone revision hip arthroplasty. Patients had uncontained superolateral acetabular defects reconstructed with a structural allograft. This retrospective study compared 18 cemented acetabular cups to 27 uncemented acetabular cups. Average follow-up was 216 months (range, 96-312). Nineteen acetabular cups (42%) failed due to loosening and were revised. The 10- and 20-year cup survival was 88% and 76% in the uncemented group and 67% and 36% in the cemented group. Log rank analysis showed this difference to be significant (P = .0077). Uncemented acetabular cups performed significantly better than cemented cups.

Osteoblastoma is a relatively rare benign bone tumor, most often located in the vertebral column or metaphysis of the long bones, particularly the femur and the tibia. Periosteal osteoblastoma is the least common type. Exostosis-like appearance is not common even in periosteal osteoblastoma, a very rare type of this tumor. In addition, an intraarticular location is uncommon for osteoblastomas. Here we report the case of a 25-year-old man with intra-articular exostosis-like periosteal osteoblastoma of the hip that resulted in impingement and osteoarthritis.

Both synovial chondromatosis and femoroacetabular impingement present with hip pain and may lead to hip osteoarthritis. We present a small case series and describe the clinical presentation, investigation, and treatment of patients with synovial chondromatosis who also had cam-type femoroacetabular impingement involving the same hip. Five patients (four men and one woman with a mean age of thirty-four years [range, thirty to thirty-seven years]) with unilateral synovial chondromatosis of the hip presented with clinical and radiographic features of ipsilateral cam-type femoroacetabular impingement. The diagnosis of associated synovial chondromatosis was made on the basis of preoperative imaging in four of the cases. All patients were treated with surgical hip dislocation, excision of the synovial chondromatosis loose bodies, and reshaping of the femoral head-neck junction. These hips exhibited radiographic features that are not typically seen with idiopathic cam-type femoroacetabular impingement, including femoral head hypertrophy, lateralization of the femoral head, and haziness in the acetabular fossa. None of the hips showed signs of advanced osteoarthritis intraoperatively. The alpha angle improved from a mean of 72.4° preoperatively to 42.6° postoperatively. At a mean of twenty-two months of follow-up, the patients had a mean Harris hip score of 80.6, substantially improved from the preoperative value of 39. Hips with synovial chondromatosis may present with clinical and radiographic features resembling those of cam-type femoroacetabular impingement. As simultaneous treatment of both conditions is best accomplished with surgical hip dislocation rather than other, less-extensive surgical approaches, we recommend preoperative consideration of synovial chondromatosis in patients presenting with unilateral cam-type femoroacetabular impingement. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence. This article was reviewed by the Editor-in-Chief and one Deputy Editor, and it underwent blinded review by two or more outside experts. The Deputy Editor reviewed each revision of the article, and it underwent a final review by the Editor-in-Chief prior to publication. Final corrections and clarifications occurred during one or more exchanges between the author(s) and copyeditors.