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. 2022 May;3(5):441-447.
doi: 10.1302/2633-1462.35.BJO-2021-0174.R1.

Comparing surgical strategies for end-stage anteromedial osteoarthritis : total versus unicompartmental knee arthroplasty

Mette Mikkelsen  1 , Hannah A Wilson  2 , Kirill Gromov  1 , Andrew J Price  2 , Anders Troelsen  1
Affiliations

Comparing surgical strategies for end-stage anteromedial osteoarthritis : total versus unicompartmental knee arthroplasty

Mette Mikkelsen et al. Bone Jt Open. 2022 May.

Abstract

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/m2, 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.

Keywords: Anesthesiologists; Anteromedial osteoarthritis; BMI; Knee; Knee replacement; Oxford Knee Score; Oxford Knee Scores; Patient-reported outcome measurement; Unicompartmental knee arthroplasty; Unicompartmental knee arthroplasty (UKA); anteromedial osteoarthritis; patient-acceptable symptom state (PASS); preoperative radiographs; propensity score matching; total knee arthroplasty (TKA).

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Conflict of interest statement

ICMJE COI statement: A. Troelsen reports consultancy payments, a research support grant, payment for lectures including service on speakers bureaus, travel/accommodation/meeting expenses, and advisory board membership from Zimmer Biomet, unrelated to the study. A. J. Price reports consultancy payments from Zimmer Biomet, unrelated to the study. K. Gromov reports research support and institutional support grants from Zimmer Biomet, unrelated to the study.

Figures

Fig. 1
Fig. 1
Flowchart of selection process for total knee arthroplasty (TKA) patients. AMOA, anteromedial osteoarthritis; OKS, Oxford Knee Score.
Fig. 2
Fig. 2
Density plot showing the distribution of preoperative and one-year postoperative Oxford Knee Score stratified by surgical strategy. TKA, total knee arthroplasty; UKA, unicompartmental knee arthroplasty.
See this image and copyright information in PMC

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