Association between body mass index change and outcome in the first year after total knee arthroplasty.

There is an association between obesity, osteoarthritis and total knee arthroplasty (TKA), but little is known about how postoperative weight change influences outcomes. Primary TKA patients were identified from an institutional arthroplasty registry. BMI and patient reported outcome measures (PROMs, specifically WOMAC and SF36) were recorded for 1545 patients preoperatively and up to 3 years postoperatively. Mixed effects modelling showed postoperative BMI change had no impact on postoperative WOMAC scores. However, weight gain over 10% had a negative impact on SF36 pain and functional scores although postoperative weight loss was not associated with improved PROMs. Men showed greater improvement in postoperative SF36 function and pain scores, whilst older patients were slower to improve. Postoperative weight gain has a negative association with SF36 pain and function.

Navigation-assisted versus conventional total knee replacement: no difference in patient-reported outcome measures (PROMs) at 1 and 2 years.

INTRODUCTION: Navigation technique for total knee replacement has been shown to improve accuracy of prosthesis alignment in several studies. The purpose was to compare the patient-reported outcome measures in primary total knee replacement (TKR) using navigation versus conventional surgical technique at 1- and 2-year follow-up. MATERIALS AND METHODS: A retrospective review of prospectively collected patient-reported outcome data for 351 consecutively performed primary TKR was included in the study. The study group (N = 113) included patients who had Triathlon TKR using articular surface mounted (ASM Stryker) navigation technique and control group (N = 238) included patients who had Triathlon TKR using conventional jig. In addition to the WOMAC (Western Ontario and McMaster University Osteoarthritis Index) and SF-36 (Medical Outcomes Trust Short Form-36), a short self-report questionnaire evaluating the level of satisfaction, quality of life and whether patients would undergo knee replacement again. RESULTS: WOMAC: no significant difference between the groups was noted in mean WOMAC pain, function and stiffness scores at 1- and 2-year follow-up. SF-36: no significant difference between the groups was seen except in the physical function component of score at 1 year (p = 0.019). Navigation group mean 56.78 (CI 51.06-62.5) versus conventional group mean 48.34 (44.68-52.01) but this difference was not observed at 2-year follow-up. CONCLUSIONS: The overall patient-reported outcome scores improved after total knee replacement but appear to be comparable in both groups at 1- and 2-year follow-up.

Early results of a novel technique: Hindfoot fusion in talus osteonecrosis prior to ankle arthroplasty: A case series.

BACKGROUND: The purpose of this study was to evaluate the clinical outcome of a two staged approach of subtalar arthrodesis followed by TAR for patients with ankle arthritis and AVN talus. METHODS: Out of total 210 TARs performed at our institute; 7 patients underwent a two staged procedure between 2006 and 2010. All patients had over 3 years of follow up (except one). The clinical results were assessed using AOFAS, WOMAC, SF-36 and patient satisfaction scores. RESULTS: The mean follow up was 3 years. There was significant improvement in AOFAS and WOMAC (pain and stiffness) from pre-op to 3 years post-op (P<0.05). SF 36 scores improved from pre-op to 3 years post-op for 6/8 domains. 5 patients were satisfied at 3 years for overall surgical outcomes, 4 were satisfied with pain relief. Radiological signs of talar subsidence were noted in 2 patients at year 1. This did not progress at 3 years and did not deteriorate clinical outcome. CONCLUSION: We recommend our two staged approach to deal with this difficult clinical problem. We believe this approach is safe for TAR surgery where talar vascularity and bone quality is questionable leading to reduced talar subsidence, ischaemic pain and improvement in longevity of TAR. LEVEL OF EVIDENCE: Evidence IV (Retrospective case series).

Influence of body mass index (BMI) on functional improvements at 3 years following total knee replacement: a retrospective cohort study.

BACKGROUND: The number of patients presenting for total knee replacement who are classified as obese is increasing. The functional benefits of performing TKR in these patients are unclear. AIM: To assess the influence pre-operative body mass index has upon knee specific function, general health status and patient satisfaction at 3 years following total knee replacement. DESIGN: Retrospective comparative cohort study using prospectively collected data from an institutional arthroplasty register. METHODS: 1367 patients were assessed using the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and Medical Outcomes Trust Short Form-36 (SF-36) scores supplemented by a validated measure of satisfaction pre-operatively and subsequently at 1,2 and 3 year post-operatively. Comparisons were made by dividing the cohort into 4 groups based on body mass index (BMI) 18.5-25.0 kg/m(2) (n = 253);>25.0-30.0 kg/m(2) (n = 559);>30.0-35.0 kg/m(2) (n = 373);>35.0 kg/m(2) (n = 182). RESULTS: Despite lower pre-operative, 1 and 3 year WOMAC and SF-36 scores patients with the highest BMIs >35.0 kg/m(2) experienced similar improvements to patients with a 'normal' BMI (18.5-25.0 kg/m(2)) at 1 year (Difference in WOMAC improvement = 0.0 (95%CI -5.2 to 5.2), p = 1.00) and this improvement was sustained at up to 3 years (Difference in 1 year to 3 year improvement = 2.2 (95%CI: -2.1 to 6.5), p = 1.00). This effect was also observed for the SF-36 mental and physical component scores. Despite equivalent functional improvements levels of satisfaction in the >35.0 kg/m(2) group were lower than for any other BMI group (>35.0 kg/m(2) = 84.6% satisfied versus 18.5-5.0 kg/m(2) = 93.3% satisfied,p = 0.01) as was the proportion of patients who stated they would have the operation again (>35.0 kg/m(2) = 69.6% versus 18.5-25.0 kg/m(2) = 82.2%,p = 0.01). CONCLUSION: Obese and morbidly obese patients gain as much functional benefit from total knee replacement as patients with lesser body mass indexes. This benefit is maintained for up to 3 years following surgery. However, these patients are less satisfied with their knee replacement and almost a third would not have the operation again.