Abstract Objective To evaluate the clinical effect of unicompartment knee arthroplasty in treatment of osteochondritis dissecans of the femoral condyle.Methods The clinical data of 11 cases with osteochondritis dissecans of the femoral condyle were retrospectively reviewed. The American Knee Society(KSS),Visual analogy score (VAS),range of motion(ROM) were observed and compared before operation and 1 months, 3 months, 6 months, and 12 months after the operation. Results (1)The average operation time in this group was 52.48±10.21min. The average hospitalization time was 7.34±1.70d;(2)Compared with preoperative, KSS scores, VAS scores and ROM of knee at different time points were all better than those before treatment, and the differences were statistically significant (P<0.01). The scores of 1 month were better than those before the operation, and the difference was statistically significant (P<0.05). The scores of 3 months were significantly better than that of 1 month , and the difference was statistically significant (P<0.01). The scores of 6 months and 12 months were significantly better than that of 3 months , but the difference was not statistically significant (P>0.05).Conclusion lateral unicompartment knee arthroplasty could significantly alleviate the knee function of patients with severe osteochondritis dissecans of the femoral condyle with less surgical trauma and few complications.