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Aims: Treatment of end-stage anteromedial osteoarthritis (AMOA) of the knee is commonly approached using one of two surgical strategies: medial unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA). In this study we aim to investigate if there is any difference in outcome for patients undergoing UKA or TKA, when treated by high-volume surgeons, in high-volume centres, using two different clinical guidelines. The two strategies are 'UKA whenever possible' vs TKA for all patients with AMOA., Methods: A total of 501 consecutive AMOA patients (301 UKA) operated on between 2013 to 2016 in two high-volume centres were included. Centre One employed clinical guidelines for the treatment of AMOA allowing either UKA or TKA, but encouraged UKA wherever possible. Centre Two used clinical guidelines that treated all patients with a TKA, regardless of wear pattern. TKA patients were included if they had isolated AMOA on preoperative radiographs. Data were collected from both centres' local databases. The primary outcome measure was change in Oxford Knee Score (OKS), and the proportion of patients achieving the patient-acceptable symptom state (PASS) at one-year follow-up. The data were 1:1 propensity score matched before regression models were used to investigate potential differences., Results: The matched cohort included 400 patients (mean age 67 years (SD 9.55), 213 (53%) female, mean BMI 30.2 kg/m 2 , 337 (84%) American Society of Anesthesiologists grade ≤ 2). We found a mean adjusted difference in change score of 3.02 points (95% confidence interval (CI) 1.41 to 4.63; p < 0.001) and a significantly larger likeliness of achieving PASS (odds ratio 3.67 (95% CI 1.73 to 8.45); p = 0.001) both in favour of the UKA strategy., Conclusion: UKA and TKA are both good strategies for treating end-stage AMOA. However, when compared as a strategy, UKA achieved larger improvements in OKS, and were more likely to reach the PASS value at one-year follow-up. Cite this article: Bone Jt Open  2022;3(5):441-447.

Background: Isolated lateral compartment knee arthritis is less prevalent than medial. While the reported results of medial unicompartmental knee replacement (UKR) have been good and comparable to total knee replacement, the results of lateral UKR have been mixed. We present the short-term results and survivorship of a fixed-bearing UKR designed specifically for the lateral compartment., Methods: We report the result of 130 primary fixed-bearing lateral Oxford (FLO) UKRs (123 patients) performed between 2015 and 2019 with a minimum follow-up of 1 year. The indications for lateral UKR were: isolated lateral osteoarthritis (n = 122), post-trauma (n = 5) and osteonecrosis (n = 3). The mean age was 69.1 (± 11.6), mean BMI 28.4 (± 4.9), 66.9% female, 60% right-sided, and mean follow-up 3 (range 1-4.8 years, standard deviation ± 1) years. The primary outcome measure was the Oxford knee score (OKS). Survival analysis was performed with "revision for any reason", "reoperation", and "implant failure" as the endpoints., Results: Six patients died from unrelated reasons. None of the implants failed. One required the addition of a medial UKR for medial arthritis. There were no other reoperations. At 4 years, the survival for implant failure was 100% and for both revision and all reoperations was 99.5% (95% CI 96.7-99.9%). At the last review, at a mean of 3 years, the mean Oxford knee score was 41., Conclusion: The good survivorship and outcome scores suggest that UKR designed for the lateral compartment is an excellent alternative to total knee replacement in selected patients with isolated lateral tibiofemoral arthritis at short-term follow-up., (© 2022. The Author(s).)

Background: Mobile-bearing medial-unicompartmental knee arthroplasty (mUKA) has a documented learning curve. New instrumentation has been designed with the aim of reducing the technical challenges of this procedure. The primary aim of this study was to evaluate the technical performance of mUKA using new (Microplasty) versus older (Phase III) instrumentation, performed by expert surgeons and trainees. Secondary aims were to evaluate functional outcome and mid-term survivorship., Methods: A time-based comparative cohort study was performed between 2009 and 2015 at a high-volume centre. 273 patients (273 knees, 49.5% female) of mean age 67.8 (standard deviation 10.1) years underwent mUKA. 153 (56.0%) procedures used Microplasty instruments and 120 procedures (44.0%) used Phase III instruments., Results: Non-optimal bearing usage was less frequent with Microplasty than Phase III instruments (24 knees [15.7%] versus 33 knees [27.5%], p = 0.024), with differences due to improved trainee performance. Femoral component sagittal alignment outliers were less frequent with Microplasty, but this was not statistically significant (9 knees [5.9%] versus 13 knees [10.8%], p = 0.18). Post-operative Oxford Knee Scores (OKS) were better with Microplasty (median 42 points [interquartile range 38-44]) compared to Phase III (median 39.5 points [IQR 33-44]), which was statistically significant (p = 0.023), but not clinically meaningful. The overall 5-year Kaplan-Meier (KM) survival estimate was 99.3% (95% CI 97.0-99.8%), with no differences between Microplasty and Phase III instrumentation., Conclusions: New instrumentation improved the reliability of the proximal tibial resection in trainees. Further research is warranted to investigate whether Microplasty instrumentation shortens the learning curve for medial UKA., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objectives: We investigated trends and regional variation in the rate of arthroscopic knee surgery performed in England from 1997-1998 to 2016-2017., Design: Cross-sectional study of the national hospital episode statistics (HES) for England., Methods: All hospital episodes for patients undergoing a knee arthroscopy between 1 April 1997 and 31 March 2017 were extracted from HES by procedure code. Age and sex-standardised rates of surgery were calculated using Office for National Statistic population data as the denominator. Trends in the rate of surgery were analysed by procedure both nationally and by Clinical Commissioning Group (CCG)., Results: A total of 1 088 872 arthroscopic partial meniscectomies (APMs), 326 600 diagnostic arthroscopies, 308 618 knee washouts and 252 885 chondroplasties were identified (1 759 467 hospital admissions; 1 447 142 patients). The rate of APM increased from a low of 51/100 000 population (95% CI 51 to 52) in 1997-1998 to a peak at 149/100 000 (95% CI 148 to 150) in 2013-2014; then, after 2014-2015, rates declined to 120/100 000 (95% CI 119 to 121) in 2016-2017. Rates of arthroscopic knee washout and diagnostic arthroscopy declined steadily from 50/100 000 (95% CI 49 to 50) and 47/100 000 (95% CI 46 to 47) respectively in 1997-1998, to 4.8/100 000 (95% CI 4.6 to 5.0) and 8.1/100 000 (95% CI 7.9 to 8.3) in 2016-2017. Rates of chondroplasty have increased from a low of 3.2/100 000 (95% CI 3.0 to 3.3) in 1997-1998 to 51/100 000 (95% CI 50.6 to 51.7) in 2016-2017. Substantial regional and age-group variation in practice was detected. In 2016-2017, between 11% (22/207) and 16% (34/207) of CCGs performed at least double the national average rate of each procedure., Conclusions: Over the last 20 years, and likely in response to new evidence, rates of arthroscopic knee washout and diagnostic arthroscopy have declined by up to 90%. APM rates increased about 130% overall but have declined recently. Rates of chondroplasty increased about 15-fold. There is significant variation in practice, but the appropriate population intervention rate for these procedures remains unknown., Competing Interests: Competing interests: All authors have completed the Unified Competing Interest form (available on request from the corresponding author). Andrew Judge has received consultancy fees from Freshfields Bruckhaus Deringer (on behalf of Smith & Nephew Orthopaedics Limited) and is a member of the Data Safety and Monitoring Board (which involved receipt of fees) from Anthera Pharmaceuticals, Inc. All other authors declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, no other relationships or activities that could appear to have influenced the submitted work., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)