The radiographic prevalence of cAM morphology in Thai patients undergoing total hip replacement: A 15-year review

Abstract

© JOURNAL OF THE MEDICAL ASSOCIATION OF THAILAND| 2019 Background: Total hip replacement (THR) is a common procedure that can relieve the pain and improve the functions of patients with advanced osteoarthritis (OA) of the hip. Femoroacetabular impingement (FAI), with either a cam or pincer morphology, produces chondral or labral damage that can develop into hip OA. This condition, which is commonly unrecognized, can be identified in some patients undergoing a THR. Objective: The present study aimed to determine the radiographic prevalence of cam morphology and the causes of THR during a 15-year period. Materials and Methods: The authors retrospectively reviewed the medical records of all THR cases at a tertiary hospital in Thailand between 2002 and 2017 to identify the causes of the THRs. For patients with primary hip OA, pre-operative radiographs were reviewed by two orthopedic surgeons to detect cam and pincer morphologies. The patients were subsequently classified into three groups: “abnormal morphology”, “no abnormal morphology”, and “indeterminate morphology”. The descriptive statistics for this study were summarized. Results: Of the 1,250 patients (providing 1,475 hips that underwent THR) in the study, 856 (68%) were female. The mean age of the study cohort was 54.4+15.1 years. Idiopathic avascular necrosis (AVN) was the most common etiology (390 cases; 27%). The most common disease among the very young age patients (<30 years) was AVN due to drugs (40 cases; 35%). Of the 167 patients with primary hip OA, 37 hips (22%) had abnormal morphology (34 hips with cam morphology, 4 hips with pincer morphology, and one patient with both morphologies). Conclusion: Idiopathic AVN was the most common cause of the THRs. Cam morphology was found in at least one-fifth of the cases with advanced primary hip OA.