Impact of anterior cruciate ligament and medial collateral ligament injuries on medial unicompartmental knee arthroplasty outcomes

Objective:The objective of the study is to evaluate clinical outcomes of mobile-bearing Oxford phase III unicompartmental knee arthroplasty (UKA) for medial unicompartmental knee OA with/without anterior cruciate ligament (ACL) and/or medial collateral ligament (MCL) injuries and assess minimum clinically important differences (MCIDs).Method: A total of 60 patients (70 knees) with anteromedial OA of the knee, treated between March 2020 and June 2022, were included in this retrospective study.Patients were divided into four groups: a no ligament injury group (n = 15; 15 knees), ACL injury group (n = 18; 18 knees), MCL injury group (n = 12; 12 knees), and ACL + MCL injury group (n = 15; 25 knees).All surgeries were performed under general anesthesia using a medial parapatellar approach.The Oxford phase III unicompartmental knee prosthesis was implanted using bone cement.Post-operative rehabilitation included early mobilization, physical therapy, and pain management as part of an Enhanced Recovery After Surgery (ERAS) protocol.Pre-operative and post-operative data, including the Hospital for Special Surgery (HSS) scores and the American Knee Society Score (AKSS), were compared between the groups.Follow-up visits ranged from 15 to 36 months, with a mean of 28.3 months.The MCIDs for both the HSS and AKSS were also calculated and evaluated.Results: At the final follow-up, significant improvements in the HSS and AKSS scores were observed in all groups compared with pre-operative scores.The mean HSS score increased from 23.3 ± 5.2 preoperatively to 70.7 ± 8.2 postoperatively (p < 0.001), and the AKSS increased from 33 ± 5.35 preoperatively to 85.0 ± 5.35 postoperatively (p < 0.001).These results indicate significant improvements in knee function following UKA, regardless of ligament injury status.Conclusions: Oxford phase III UKA demonstrates good short-term efficacy for medial OA with concomitant ligament injuries.Larger multicenter studies with extended follow-up are needed to validate long-term outcomes.