Abstract:[Objective] To compare the short-term clinical outcomes of unicompartmental knee arthroplasty (UKA) versus total knee ar-throplasty (TKA) for medial compartment osteoarthritis of the knee. [Methods] A retrospective analysis was performed on 457 patients whoreceived arthroplasty for medial compartment osteoarthritis of the knee in our hospital from January 2021 to August 2023. By propensityscorematching (PSM) method, 88 patients underwent UKA and 88 received TKA were finally included in this study. The document regard-ing perioperative period, follow-up and auxiliary examinations were compared between the two groups. [Results] The UKA group proved sig-nificantly superior to the TKA group in terms of operation time [(74.6±8.1) min vs (85.4±8.7) min, P<0.001], incision length [(7.1±0.9) cm vs(14.4 + 2.6) cm, P<0.001], intraoperative blood loss [(174.6 ±33.5) ml vs (305.7± 68.9) ml, P<0.001], postoperative drainage [(22.7±3.6) mlvs (43.5±6.7) ml, P<0.001], ambulation time [(2.7±0.5) hours vs (4.7±1.1) hours, P<0.001], as well as incision healing grade, hospital stayand treatment cost. In addition, the patients in UKA group resumed full weight-bearing activities significantly earlier than those in TKAgroup (P<0.05). The VAS, HSS, WOMAC scores and ROM significantly improved in both groups over time (P<0.05). The UKA was signifi-cantly better than the TKA group regarding to VAS, HSS, WOMAC score and ROM 1 month postoperatively and at the last follow-up (P<0.05). However, there was no significant difference in the incidence of later complications between the two groups (P>0.05). As for auxiliaryexamination, the UKA group was also significantly better than the TKA group in terms of the levels of TNF-α and TGF-β1 in synovial fluid1 month after surgery (P<0.05). At the last follow-up, the UKA group got significantly better femorotibial angle (FTA), medial proximal tibialangle (MPTA), posterior tibial slope (PTS) and mechanical axis deviation (MAD) on images than the TKA group (P<0.05). [Conclusion] Formedial compartment osteoarthritis of the knee, UKA is less invasive and has better short-term clinical outcomes than TKA.