Outcomes of total knee arthroplasty, with revision surgery as an endpoint, following previous periarticular osteotomy or unicompartmental knee arthroplasty

Aims: This study evaluates the risk of revision of total knee arthroplasty (TKA) in patients with a history of previous periarticular osteotomy compared with those with a history of unicompartmental knee arthroplasty (UKA). Understanding the differences in TKA outcome following these procedures is important for informed decision-making and patient counselling when considering osteotomy or UKA in the management of single-compartment osteoarthritis in young, high-demand patients. Methods: We conducted a retrospective analysis using data from the New Zealand Joint Registry, identifying 1,895 TKAs performed after prior osteotomy and 1,391 after previous UKA. We compared TKA revision rates and patient-reported outcome using the Oxford Knee Score (OKS), between the two groups at six months. Adjusted hazard ratios (HRs) were calculated to account for differences in demographic details. Results: The revision rate for TKA following osteotomy was significantly lower than TKA following UKA with rates of 0.88 per 100 component years (95% CI 0.74 to 1.03) versus 1.38 per 100 component years (95% CI 1.15 to 1.19), respectively. Adjusted HR calculations indicated that previous UKA more than doubled the risk of revision of TKA compared with previous osteotomy (HR 2.29, 95% CI 1.66 to 3.17; p < 0.001). In patients aged under 55 years, the risk of revision for TKA was nearly 2.5-fold for those with previous UKA compared with those with previous osteotomy (1.32, 95% CI 1.01 to 1.71 vs 3.25, 95% CI 2.01 to 4.97; p < 0.001). The mean-adjusted OKS scores at six months demonstrated a significant difference between the two groups, with improved OKS in the previous osteotomy group (34.85 (SD 0.36) vs 36.64 (SD 0.48); p < 0.001). However, this did not reach the minimal important clinical level of difference for the OKS. Conclusion: Patients undergoing TKA after periarticular osteotomy exhibit a lower risk of revision compared to those with previous UKA, particularly in younger patients. Our study enhances the understanding of the risk of revision of a TKA following previous procedures, and confirms that TKA after osteotomy performs significantly better compared with previous unicompartmental arthroplasty.