Aims

We have previously demonstrated raised cobalt and chromium levels in patients with larger diameter femoral heads, following metal-on-polyethylene uncemented total hip arthroplasty. Further data have been collected, to see whether these associations have altered with time and to determine the long-term implications for these patients and our practice.

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The optimum clearance between the bearing surfaces of hip arthroplasties is unknown. Theoretically, to minimize wear, it is understood that clearances must be low enough to maintain optimal contact pressure and fluid film lubrication, while being large enough to allow lubricant recovery and reduce contact patch size. This study aimed to identify the relationship between diametrical clearance and volumetric wear, through the analysis of retrieved components.

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There is a lack of long-term data for minimally invasive acromioclavicular (AC) joint repair. Furthermore, it is not clear if good early clinical results can be maintained over time. The purpose of this study was to report long-term results of minimally invasive AC joint reconstruction (MINAR) and compare it to corresponding short-term data.

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The aims of this study were to validate the outcome of total elbow arthroplasty (TEA) in patients with rheumatoid arthritis (RA), and to identify factors that affect the outcome.

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Although bone cement is the primary mode of fixation in total knee arthroplasty (TKA), cementless fixation is gaining interest as it has the potential of achieving lasting biological fixation. By 3D printing an implant, highly porous structures can be manufactured, promoting osseointegration into the implant to prevent aseptic loosening. This study compares the migration of cementless, 3D-printed TKA to cemented TKA of a similar design up to two years of follow-up using radiostereometric analysis (RSA) known for its ability to predict aseptic loosening.

Between 1982 and 1997, 403 consecutive patients (522 elbows) with rheumatoid arthritis underwent Souter-Strathclyde total elbow replacement. By the end of 2007, there had been 66 revisions for aseptic loosening in 60 patients. The mean time of follow-up was 10.6 years (0 to 25) The survival rates at five-, ten, 15 and 19 years were 96% (95%, confidence interval (CI) 95 to 98), 89% (95% CI 86 to 92), 83% (95% CI 78 to 87), and 77% (95% CI 69 to 85), respectively. The small and medium-sized short-stemmed primary humeral components had a 5.6-fold and 3.6-fold risk of revision for aseptic loosening respectively, compared to the medium-sized long-stemmed component. The small and medium-sized all-polyethylene ulnar components had respectively a 28.2-fold and 8.4-fold risk of revision for aseptic loosening, compared to the metal-backed ulnar components. The use of retentive ulnar components was not associated with an increased risk of aseptic loosening compared to non-retentive implants

The aim of this study was to examine the functional outcome at ten years following lateral closing wedge high tibial osteotomy for medial compartment osteoarthritis of the knee and to define pre-operative predictors of survival and determinants of functional outcome. . 164 consecutive patients underwent high tibial osteotomy between 2000 and 2002. A total of 100 patients (100 knees) met the inclusion criteria and 95 were available for review at ten years. Data were collected prospectively and included patient demographics, surgical details, long leg alignment radiographs, Western Ontario and McMaster Universities osteoarthritis index (WOMAC) and Knee Society scores (KSS) pre-operatively and at five and ten years follow-up. At ten years, 21 patients had been revised at a mean of five years. Overall Kaplan–Meier survival was 87% (95% confidence interval (CI) 81 to 94) and 79% (95% CI 71 to 87) at five and ten years, respectively. When compared with unrevised patients, those who had been revised had significantly lower mean pre-operative WOMAC Scores (47 (21 to 85) vs 65 (32 to 99), p < 0.001), higher mean age (54 yrs (42 to 61) vs 49 yrs (26 to 66), p = 0.006) and a higher mean BMI (30.2; 25 to 39 vs 27.9; 21 to 36, p = 0.005). Each were found to be risk factors for revision, with hazard ratios of 10.7 (95% CI 4 to 28.6; pre-operative WOMAC < 45), 6.5 (95% CI 2.4 to 17.7; age > 55) and 3.0 (95%CI 1.2 to 7.6; BMI > 30). Survival of patients with pre-operative WOMAC > 45, age < 55 and BMI < 30 was 97% at five and ten years. WOMAC and KSS in surviving patients improved significantly between pre-operative (mean 61; 32 to 99) and five (mean 88; 35 to 100, p = 0.001) and ten years (mean 84; 38 to 100, p = 0.001). Older patients had better functional outcomes overall, despite their higher revision rate. This study has shown that improved survival is associated with age < 55 years, pre-operative WOMAC scores > 45 and, a BMI < 30. In patients over 55 years of age with adequate pre-operative functional scores, survival can be good and functional outcomes can be significantly better than their younger counterparts. We recommend the routine use of pre-operative functional outcome scores to guide decision-making when considering suitability for high tibial osteotomy. Cite this article: Bone Joint J 2014;96-B:1491–7

Mobile-bearing unicompartmental knee replacements (UKRs) with a flat tibial plateau have not performed well in the lateral compartment, owing to a high dislocation rate. This led to the development of the Domed Lateral Oxford UKR (Domed OUKR) with a biconcave bearing. The aim of this study was to assess the survival and clinical outcomes of the Domed OUKR in a large patient cohort in the medium term. We prospectively evaluated 265 consecutive knees with isolated disease of the lateral compartment and a mean age at surgery of 64 years (32 to 90). At a mean follow-up of four years (. sd. 2.2, (0.5 to 8.3)) the mean Oxford knee score was 40 out of 48 (. sd. 7.4). A total of 12 knees (4.5%) had re-operations, of which four (1.5%) were for dislocation. All dislocations occurred in the first two years. Two (0.8%) were secondary to significant trauma that resulted in ruptured ligaments, and two (0.8%) were spontaneous. In four patients (1.5%) the UKR was converted to a primary TKR. Survival at eight years, with failure defined as any revision, was 92.1% (95% confidence interval 81.3 to 100). . The Domed Lateral OUKR gives good clinical outcomes, low re-operation and revision rates and a low dislocation rate in patients with isolated lateral compartmental disease, in the hands of the designer surgeons. Cite this article: Bone Joint J 2014;96-B:59–64

Objectives. Preservation of posterior condylar offset (PCO) has been shown to correlate with improved functional results after primary total knee arthroplasty (TKA). Whether this is also the case for revision TKA, remains unknown. The aim of this study was to assess the independent effect of PCO on early functional outcome after revision TKA. Methods. A total of 107 consecutive aseptic revision TKAs were performed by a single surgeon during an eight-year period. The mean age was 69.4 years (39 to 85) and there were 59 female patients and 48 male patients. The Oxford Knee Score (OKS) and Short-form (SF)-12 score were assessed pre-operatively and one year post-operatively. Patient satisfaction was also assessed at one year. Joint line and PCO were assessed radiographically at one year. Results. There was a significant improvement in the OKS (10.6 points, 95% confidence interval (CI) 8.8 to 12.3) and the SF-12 physical component score (5.9, 95% CI 4.1 to 7.8). PCO directly correlated with change in OKS (p < 0.001). Linear regression analysis confirmed the independent effect of PCO on the OKS (p < 0.001) and the SF-12 physical score (p = 0.02). The overall rate of satisfaction was 85% and on logistic regression analysis improvement in the OKS (p = 0.002) was a significant predictor of patient satisfaction, which is related to PCO; although this was not independently associated with satisfaction. Conclusion. Preservation of PCO should be a major consideration when undertaking revision TKA. The option of increasing PCO to balance the flexion gap while maintaining the joint line should be assessed intra-operatively. Cite this article: N. D. Clement, D. J. MacDonald, D. F. Hamilton, R. Burnett. Posterior condylar offset is an independent predictor of functional outcome after revision total knee arthroplasty. Bone Joint Res 2017;6:172–178. DOI: 10.1302/2046-3758.63.BJR-2015-0021.R1

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The aim of this study was to develop a novel computational model for estimating head/stem taper mechanics during different simulated assembly conditions.

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Two-stage exchange arthroplasty is the most common definitive treatment for prosthetic joint infection (PJI) in the USA. Complications that occur during treatment are often not considered. The purpose of this study was to analyze complications in patients undergoing two-stage exchange for infected total knee arthroplasty (TKA) and determine when they occur.

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The primary aim of this paper was to outline the processes involved in building the Partners Arthroplasty Registry (PAR), established in April 2016 to capture baseline and outcome data for patients undergoing arthroplasty in a regional healthcare system. A secondary aim was to determine the quality of PAR’s data. A tertiary aim was to report preliminary findings from the registry and contributions to quality improvement initiatives and research up to March 2019.

Survival analysis is an important tool for assessing the outcome of total joint replacement. The Kaplan-Meier method is used to estimate the incidence of revision of a prosthesis over time, but does not account appropriately for competing events which preclude revision. In the presence of competing death, this method will lead to statistical bias and the curve will lose its interpretability. A valid comparison of survival results between studies using the method is impossible without accounting for different rates of competing events. An alternative and easily applicable approach, the cumulative incidence of competing risk, is proposed. Using three simulated data sets and realistic data from a cohort of 406 consecutive cementless total hip prostheses, followed up for a minimum of ten years, both approaches were compared and the magnitude of potential bias was highlighted. The Kaplan-Meier method overestimated the incidence of revision by almost 4% (60% relative difference) in the simulations and more than 1% (31.3% relative difference) in the realistic data set. The cumulative incidence of competing risk approach allows for appropriate accounting of competing risk and, as such, offers an improved ability to compare survival results across studies

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CERAMENT|G is an absorbable gentamicin-loaded biocomposite used as an on-site vehicle of antimicrobials for the treatment of chronic osteomyelitis. The purpose of the present study was to investigate the sole effect of CERAMENT|G, i.e. without additional systemic antimicrobial therapy, in relation to a limited or extensive debridement of osteomyelitis lesions in a porcine model.

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Current treatments of prosthetic joint infection (PJI) are minimally effective against Staphylococcus aureus biofilm. A murine PJI model of debridement, antibiotics, and implant retention (DAIR) was used to test the hypothesis that PlySs2, a bacteriophage-derived lysin, can target S. aureus biofilm and address the unique challenges presented in this periprosthetic environment.