Related Experiment Video
Updated: May 26, 2025
The Transition to an Anterior-Based Muscle Sparing Approach Improves Early Postoperative Function but is Associated with a Learning Curve
Published on: September 7, 2022
Clinical outcomes following total hip arthroplasty for bony ankylosed hips: a propensity score-matched analysis
Sakumo Kii1, Ryo Takamatsu2, Motoki Sonohata3
1Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga City, Saga, 849-8501, Japan.
Background:
Total hip arthroplasty (THA) is one of the most effective treatments for hip arthritis. However, postoperative outcomes of THA in patients with bony ankylosed hips remain inconclusive. We aimed to examine the postoperative results of THAs for bony ankylosed hips using propensity score matching.
Methods:
A propensity score was calculated using logistic regression analysis for a bony-ankylosed group (40 hips, 38 patients) and a non-ankylosed (control) group (829 hips, 729 patients). Patients were followed up for more than 10 years after primary THA. The propensity score used five covariates: age, sex, height, weight, and body mass index. Propensity matching was performed, with each bony ankylosed hip being matched to a non-ankylosed control hip. The clinical outcomes of the Japanese Orthopaedic Association (JOA) hip scores and complications were investigated.
Results:
The propensity-matched population consisted of 40 bony ankylosed hips (38 patients) and 40 hips (40 patients) of matched controls. In both groups, the postoperative JOA hip scores at the last follow-up significantly improved compared to the preoperative scores. The JOA hip scores at the last follow-up for all components in the bony-ankylosed group were significantly lower than those in the control group. The number of hips with postoperative complications was significantly higher in the bony-ankylosed group than that in the control group.
Conclusions:
THA for patients with bony ankylosed hips achieved positive results, including improved JOA hip scores; however, these scores were inferior to those observed in patients with non-ankylosed hips. This should be preoperatively communicated to patients with bony ankylosed hips who undergo THA.
