[Comparison of outcomes of mixed unicompartmental knee arthroplasty and total knee arthroplasty in the treatment of medial osteoarthritis of the knee].

Objective: To evaluate outcomes of mixed unicompartmental knee arthroplasty(UKA) and total knee arthroplasty(TKA) in the treatment of medial osteoarthritis(OA) of the knee.

Methods: Retrospective analysis of 156 patients, 44 males and 112 females, aged from 50 to 75 years old with an average of(58.76±4.97) years old, who underwent knee arthroplasty from October 2017 to October 2019. The patients were divided into two groups:81 cases(81 knees) underwent TKA, including 23 males and 58 females, aged from 51 to 75 years old with an average of (58.60±5.01) years old, and 75 case (75 knees) underwent UKA with mixed phase 3 Oxford, including 21 males and 54 females, aged from 50 to 72 years old with an average of (58.92±4.95) years old. The two groups were compared regarding to the clinical outcomes, assessed using surgical information and complications, American Knee Society score(AKSS) clinical score and functional score. Radiographs were assessed using hip-knee-ankle angle(HKA), tibial component valgus/varus angle(TCVA), tibial component posterior slope angle(TCPSA), femoral component valgus/varus angle(FCVA), femoral component posterior slope angle(FCPSA), looking for bearing dislocation, prosthesis loosening, progression of OA in lateral compartment.

Results: Intraoperative bleeding, operative time and hospital days were significantly better in the UKA group than in the TKA group (<0.05), and there were no postoperative complications in either group. Patients in both groups were enrolled with an average follow-up time of (38.01±8.90) months, ranged from 24 to 54 months. AKSS functional, AKSS clinical, HKA in both groups significantly improved at the final follow-up compared with those before operation. At the final follow-up, the UKA group was significantly better than the TKA group in AKSS functional and AKSS clinical, whereas HKA in the TKA group was better. At the final follow-up. TCVA and FCVA between the two groups were not significantly different, while TCPSA and FCPSA in the UKA group were significantly greater than the TKA group. No signs of progression of OA to the lateral compartment were observed.

Conclusion: Mixed phase 3 Oxford UKA in medial unicompartmental knee osteoarthritis was considerably better than TKA for less blood loss, shorter operation time, shorter hospital stay, rapid postoperative recovery, helping achieve satisfactory function, provided satisfactory outcome.