Tönnis angle and acetabular depth ratio: predictors of dislocation following hemiarthroplasty for hip fracture.

Abstract

35 cases of dislocation were identified and 140 random controls were selected. Cases of dislocation had a larger mean TA (8.8° vs. 5.5°, p < 0.001) and lower mean ADR (254 vs. 289, p < 0.001) than controls. 20 out of 35 (57%) cases were considered to have abnormal acetabular morphology, compared to 19 out of 140 (14%) controls. The odds of dislocation is 8.5 times greater (odds ratio = 8.49, 95%CI = 3.73, 19.39) in patients with abnormal TA and/or ADR.