Summary

This meta-analysis compares return to sports (RTS) between unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) in active adults with knee osteoarthritis. UKA patients achieve RTS more frequently and faster, while HTO patients, especially those with higher preoperative activity levels, maintain higher activity levels and achieve quicker RTS with preoperative Tegner scores >5.

Abstract

Background

Unicompartmental knee replacement (UKR) and high tibial osteotomy (HTO) are widely used surgical options for managing unicompartmental knee osteoarthritis, particularly in active adults. While UKR is often preferred in more advanced intraarticular disease and for its faster recovery, HTO remains a viable option, especially in younger patients with higher activity levels where it may be beneficial to maintain the biological envelope of the knee. This meta-analysis compares return to sports (RTS) outcomes between UKR and HTO, with a focus on identifying patient subsets that might benefit more from one procedure over the other.

Methods

A systematic literature review was conducted using databases such as PubMed, Cochrane Library, and Embase to identify studies comparing RTS outcomes following UKA and HTO. This study was registered in the PROSPERO Database (CRD42024581920). Eligible studies included randomized controlled trials, cohort studies, and case series involving adult patients with knee osteoarthritis. Data on patient demographics, surgical techniques, follow-up duration and RTS outcomes were extracted. The primary outcomes were the proportion of patients achieving RTS, while secondary outcomes included time to RTS. A random-effects model was used for the meta-analysis, with pooled estimates reported as risk ratios (RR) or mean differences (MD) with 95% confidence intervals (CI).

Results

Thirteen studies met the inclusion criteria, involving 2,673 patients—1,356 in the UKA group (mean age 60.6 years, 95% CI [58.9-62.3]) and 1,317 in the HTO group (mean age 55.8 years, 95% CI [54.01-57.59]). The pooled estimate of mean follow-up duration was 6.2 years (95% CI [4.8-7.5]). UKA was associated with a higher RTS rate (RR: 1.42, 95% CI: 1.20-1.67, p<0.001) and shorter time to RTS (SMD: -2.1 months, 95% CI: -2.9 to -1.3 months, p<0.001).

UCLA activity scores indicated that pre-operatively, HTO patients had a mean score of 4.90 (95% CI [3.54-6.92]) compared to 4.4 (95% CI [2.30-5.50]) for UKA patients. Post-operatively, both groups showed a reduction, with HTO patients scoring 3.23 (95% CI [1.37-5.0]) and UKA patients scoring 3.05 (95% CI [1.14-3.957]). Additionally, Tegner activity scale scores showed that HTO patients had a pre-operative mean score of 4.10 (95% CI [2.60-5.71]) compared to 3.32 (95% CI [1.77-3.84]) for UKA patients. At a 2-year follow-up, HTO patients maintained a score of 4.25 (95% CI [3.54-4.95]), while UKA patients experienced a decline to 2.78 (95% CI [1.72-3.89]). Meta-regression analysis revealed that pre-operative Tegner activity scores >5 predicted quicker RTS in patients who underwent HTO compared to UKA, with an inverse variance relationship (β = 0.44, SE = 0.045, 95% CI [0.14–0.78]).

Conclusion

Compared to HTO patients, UKA patients RTS more frequently and over a shorter time period. HTO patients however have higher physical activity levels both pre and post operatively and manage to RTS quicker in the subset with preoperative Tegner activity scores >5. These findings underscore the importance of a personalised treatment strategy with careful consideration given to patient activity levels and return to sport expectations.