Is medial pivot total knee arthroplasty suitable for patients with valgus knee osteoarthritis?

Purpose Medial pivot total knee arthroplasty (MP-TKA) is characterized by the ball-in-socket medial tibiofemoral articulation to achieve low wear and to reproduce the medial pivot motion similar to that in the normal knee, and there have been reports of favorable long-term postsurgical outcomes. However, most of these cases concerned varus knees, and the outcomes of MP-TKA in valgus knees are unknown. The objective of this study was to investigate the postoperative outcomes in end-stage valgus knee OA patients who underwent MP-TKA, through comparisons with those who underwent TKA using the same prosthesis for varus deformity. Methods This retrospective, single-center, cohort study analyzed 171 knees of 121 patients who were divided into two groups (valgus knee group: 15 knees (13 patients), varus knee group: 156 knees (109 patients)). Primary outcome measures included the knee joint range of motion (evaluated preoperatively and at every year postoperatively). Secondary outcomes included operative time, laboratory data, estimated blood loss, clinical outcome measures and adverse events. Results There were no significant differences in age, sex and body mass index, as well as in the postoperative primary and secondary outcome measures between the two groups. Conclusion The use of MP-TKA featuring ball-in-socket medial tibiofemoral articulation in patients with valgus knee OA showed equally favorable clinical outcomes more than 2 years after surgery, compared to patients with varus knees who received MP-TKA.