Better immediate and early postoperative outcomes of unicompartmental knee replacement comparing with total knee replacement: A matched cohort of patients with medial knee osteoarthritis

Abstract

Introduction: This study compared the immediate and early postoperative outcomes of medial compartment knee osteoarthritis patients receiving unicompartmental knee replacement (UKR) with a matched cohort of total knee replacement (TKR). Methods: 26 UKR patients were matched with 26 TKR patients based on age, body mass index, pre-operative radiographic severity, range of motion (ROM), Knee Society score (KSS) and Feller patella score. Immediate postoperative outcomes were reflected by postoperative pain, blood loss, length of stay and the number of physiotherapy sessions attended. Early postoperative outcomes (ROM and KSS) were measured at 3 months and 1 year post-operatively. Results: UKR patients had less hemoglobin drop (UKR: 1.2 g/dL, TKR: 1.6 g/dL, p = 0.04), shorter length of stay (UKR: 4.3 days, TKR: 6.0 days, p < 0.001) and required less physiotherapy sessions for recovery (UKR: 6.9 sessions, TKR: 9.3 sessions, p < 0.05). There were no statistically significant differences in early post-operative pain score and postoperative analgesia use ( p > 0.05) between the two groups. Patients receiving UKR had significantly higher post-operative KSS (UKR: 155.9, TKR: 142.4, p = 0.005) and ROM (UKR: 115.8o, TKR: 98.8o, p < 0.001) at 3 months. The KSS and ROM of UKR group at 3 months was better than TKR group at 1-year follow-up. Conclusion: In patients with medial knee osteoarthritis, UKR showed less postoperative analgesic use and blood loss, shorter length of stay, shorter course of rehabilitation and faster recovery with better early KSS and ROM than TKR. Follow up is necessary for comparison in long term outcome and survivorship between the two groups.