Combined partial knee arthroplasty versus total knee arthroplasty: A systematic review and meta-analysis of randomised control trials.

Abstract

Total knee arthroplasty (TKA), the standard surgical treatment for knee osteoarthritis (OA) which resurfaces all three compartments, has disadvantages including inferior kinematics and high patient dissatisfaction rates. Combined Partial Knee Arthroplasty (CPKA), which encompasses Bicompartmental knee arthroplasty (BCA) and Bi-unicompartmental knee arthroplasty (Bi-UKA), is a tissue-sparing alternative for patients with bicompartmental disease. High quality evidence is limited, therefore this systematic review and meta-analysis aims to synthesise randomised controlled trial (RCT) data comparing outcomes and complications between BCA or Bi-UKA and TKA. A systematic review and meta-analysis were conducted following PRISMA guidelines, searching Medline, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL) and the Cochrane Database of Systematic Reviews from inception to July 14, 2025. RCTs comparing CPKA with TKA were included. Seven publications (four unique RCTs) were selected: four comparing BCA-M (medial) to TKA and three comparing Bi-UKA to TKA. Data on patient-reported outcome measures (PROMs), range of motion (ROM), functional tests and complications were extracted and analysed. A random-effects model was used for meta-analysis of revision risk. TKA showed a statistically significant advantage compared to Bi-UKA in the total and clinical New Knee Society Score (NKSS) at two years. BCA-M patients had superior ROM but an increased incidence of patellar subluxation and meta-analysis found a significantly higher risk of revision compared with TKA (RR 1.75, 95% CI 1.17-2.61, <i>p</i> = 0.007). No other significant differences in PROMs, functional tests or gait analysis were identified. Outcomes of CPKA are comparable to TKA with few statistically significant differences. While BCA-M showed a greater postoperative ROM, there was a higher incidence of patellar subluxation and meta-analysis found a higher risk of revision. However, current evidence is limited therefore larger long-term RCTs are needed to define the role of CPKA in managing bicompartmental knee OA.