German Congress of Orthopaedics and Traumatology (DKOU 2025)
UKA outperforms TKA in PROMs: Better function and satisfaction at short-term follow-up
2Department of Orthopaedic Surgery, Sana Hospital Sommerfeld, Kremmen, Deutschland
3Department of Orthopaedic and Trauma Surgery, Sana Hospital Lichtenberg, Berlin, Deutschland
Text
Objectives and questions: Unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) are established surgical options for end-stage osteoarthritis (OA) refractory to non-operative management. However, the optimal choice remains debated, with conflicting reported evidence on outcomes and satisfaction. This study aims to compare UKA and TKA for the treatment of OA based on different patient-reported outcome measures.
Material and methods: This retrospective cohort study compared 463 patients who underwent UKA with 1292 patients who TKA between August, 2022 and April, 2024. Preoperative data included age, BMI, KOOS12 and its subscores (pain, activities of daily living [ADL], quality of life [QoL]), Oxford Knee Score (OKS), and Forgotten Joint Score-12 (FJS12). One-year outcomes were assessed using KOOS12, OKS, FJS12, satisfaction, and willingness to repeat the procedure. Follow-up was completed in 80% of patients. Statistical comparisons were performed using Mann-Whitney U and Chi-square test. A p-value < 0.05 was considered statistically significant.
Results: UKA and TKA patients differed significantly in age (65.99 vs. 69.18 years, p < 0.05) and BMI (30.93 vs. 32.00 kg/m², p < 0.05), with no significant preoperative differences in KOOS12 (31.36 vs. 30.21, p > 0.05) its subscores (pain: 35.1 vs. 34.6, ADL: 37.2 vs. 35.6, QoL: 22.9 vs. 21.1; all p > 0.05), OKS (22.78 vs. 22.15, p > 0.05) or FJS-12 (15.71 vs. 15.15, p > 0.05).
At the one-year follow-up, UKA patients had significantly higher OKS (32.51 vs. 30.92, p < 0.05) and FJS12 (53.01 vs. 49.69, p < 0.05). KOOS12 (70.19 vs. 71.04, p > 0.05) and its subscores (pain: 16.76 vs. 16.16, ADL: 74.5 vs. 74.7, QoL: 66.9 vs. 66.3; all p > 0.05) showed no significant differences.
Satisfaction was high in both groups, with 91.2% of UKA and 91.8% of TKA patients reporting being either “very satisfied” or “satisfied” (p > 0.05) and 89.4% of UKA vs. 90.9% of TKA patients stated they would undergo the same procedure again (p = 0.511). UKA patients were more often “very satisfied” (66.7% vs. 61.3%, p > 0.05) and significantly more likely to “definitely” repeat the procedure (81.8% vs. 73.4%, p < 0.05).
Discussion and conclusions: Both UKA and TKA led to high satisfaction and comparable pain relief. UKA patients reported better function (OKS, FJS12) and greater confidence in their procedure, despite similar KOOS12 scores. This questions KOOS12’s sensitivity in evaluating arthroplasty outcomes. These findings support UKA as a strong alternative to TKA.
