Comparison of the clinical outcomes following total knee arthroplasty in osseous ankylosed and non-ankylosed knees using propensity-score matching

Objectives Few studies have compared the clinical outcomes and complications of total knee arthroplasty (TKA) in patients with and without osseous ankylosed knees. Thus, we investigated the clinical outcomes and complications of TKA in patients with osseous ankylosed knees using a propensity-score matching method. Methods Thirteen knees in the osseous ankylosed-knees group and 13 knees in the non-ankylosed-knees group were included after excluding those with less than 2 years of follow-up or a lack of data and after propensity-score matching. The American Knee Society Score-knee (AKSS-knee), AKSS-function, knee-flexion angle, knee-extension angle, knee range of motion (ROM) before and after TKA, and the number of knees with postoperative complications were evaluated as primary outcomes. Results The AKSS-knee, AKSS-function, knee-flexion angle, and knee ROM in the osseous ankylosed-knees group after TKA were significantly lower than those in the non-ankylosed-knees group. The knee-extension angle after TKA and number of knees with postoperative complications within 2 years were not significantly different between the two groups. Conclusions The clinical results of TKA in patients with osseous ankylosed knees were inferior to those in patients with non-ankylosed knees.