What factors predict ceramic liner malseating after ceramic-on-ceramic total hip arthroplasty?

Background: There is a lack of evidence about the risk factors associated with the malseating of the acetabular liner after ceramic-on-ceramic (CoC) total hip arthroplasty (THA). Therefore, we performed a complementary retrospective case-control study to determine the factors predicting the malseating of the acetabular liner after CoC THA and to evaluate the relationship between malseating and (1) osteoarthritis, (2) particularly in terms of the new radiographic parameter "bone sclerotic length" of the acetabular bone. Hypothesis: Osteoarthritis, particularly bone sclerotic length, was an independent risk factor for malseating of ceramic liners. Patients and methods: In total, 219 CoC THAs (174 women and 45 men) were evaluated to determine the risk factors influencing the malseating of the acetabular ceramic liner. An average patient age at the time of surgery was 55.9 +/- 9.5 years (range, 23 to 75 years). Data on patient background and preoperative radiographs, such as Tonnis grades; Crowe classification; and indices of acetabular osteoarthritis change; including bone cyst, osteophyte and bone sclerosis, were assessed. The bone sclerotic length in patients with osteoarthritis was measured as the slant distance between the bilateral edges of the sclerosis lesion of the acetabulum on the anteroposterior view. Results: Preoperative less hip flexion (hazard ratio [HR]: 0.98; 95% CI: 0.97-0.99), osteoarthritis (HR: 3.15; 95% CI: 1.02-9.70) and the bone sclerotic length (HR: 1.83; 95% CI: 1.35-2.48) were independent risk factors determining the malseating of ceramic liners. Receiver operating characteristic curve analysis showed that a bone sclerotic length of 24.6 mm was defined as the cut-off point for the malseating of the ceramic liner. Discussion: Age, preoperative less flextion, osteoarthritis, and the bone sclerotic were independent risk factors determining malseating of ceramic liners. The acetabular shell can also deform upon insertion of the cup with sclerotic bone of the acetabulum and prevent correct seating of liners. Therefore, these factors must be taken into consideration when seating the ceramic liner. (C) 2019 Elsevier Masson SAS. All rights reserved.