Cam Deformity and Acetabular Dysplasia as Risk Factors for Hip Osteoarthritis

Abstract

Objective. Cam deformity and acetabular dysplasia have been recognized as relevant risk factors for hip osteoarthritis (OA) in a few prospective studies with limited sample sizes. To date, however, no evidence is available from prospective studies regarding whether the magnitude of these associations differs according to sex, body mass index (BMI), and age.Methods. Participants in the Rotterdam Study cohort including men and women ages 55 years or older without OA at baseline (n 5 4,438) and a mean follow-up of 9.2 years were included in the study. Incident radiographic OA was defined as a Kellgren/Lawrence grade of ‡2 or a total hip replacement at follow-up. Alpha and center-edge angles were measured to determine the presence of cam deformity and acetabular dysplasia/pincer deformity, respectively. Odds ratios (ORs) were calculated to assess the associations between both deformities and the development of OA.Results. Subjects with cam deformity (OR 2.11, 95% confidence interval [95% CI] 1.55-2.87) and those with acetabular dysplasia (OR 2.19, 95% CI 1.50-3.21) had a 2-fold increased risk of developing OA compared with subjects without deformity, while pincer deformity did not increase the risk of OA. Stratification analyses showed that the associations of cam deformity and acetabular dysplasia with OA were driven by younger individuals, whereas BMI did not influence the associations. Female sex appears to modify the risk of hip OA related to acetabular dysplasia.Conclusion. Individuals with cam deformity and those with acetabular dysplasia are predisposed to OA; these associations were independent of other well-known risk factors. Interestingly, both deformities predisposed to OA only in relatively young individuals. Therefore, early identification of these conditions is important.Osteoarthritis (OA) of the hip is one of the main causes of musculoskeletal disability with pain and dysfunction in the elderly (1). Epidemiologic studies have identified several risk factors predisposing to hip OA, including increasing age, male sex (after age 55 years, hip OA is more common in women), excess body weight (which has a stronger association with knee OA), trauma, mechanical workload (occupational) and leisure-time physical activity, and gross bony abnormalities (i.e., congenital hip dislocation, Legg-Calve-Perthes disease, or slipped capital femoral epiphysis) (1-3). Moreover, a review study (4) showed an association between bony abnormalities (e.g., acetabular dysplasia and cam deformity) and hip OA, although the conclusions drawn were based on limited prospective evidence (based on 110 individuals in 1 study of cam deformity, and a total of 1,365 individuals in 5 studies of dysplasia) (5-10).Recent prospective epidemiologic studies have supported the notion that mild acetabular dysplasia is associated with an increased risk of incident hip OA

The Role of Gdf5 Regulatory Regions on Development of Hip Morphology and Susceptibility to Osteoarthritis and Dislocation

“…In this study, we investigated the influence that Gdf5 and its broad regulatory domains have on hip morphology, in the context of shape parameters relevant to OA, DDH, and dislocation. We revealed that: (1) Gdf5 loss results in substantial dysmorphologies to the proximal femur and acetabulum in line with known features involved in hip instability, developmental dislocation, injury, and adult onset OA; (2) Compared to upstream regulatory sequences, downstream regulatory sequences of Gdf5/GDF5 drive stronger, more ubiquitous prenatal hip expression and uniquely control postnatal hip expression; (3) This regulatory structure is functionally important as downstream sequences were capable of restoring Gdf5 loss-of-function phenotypes to normal, a situation not observed when using the upstream region. These latter two findings have important ramifications to how we understand GDF5 and its association with OA and hip dysplasia/dislocation.…”

“…(12-14, 16-18) These types of regulatory mutations often have less pleiotropic effects on phenotypes. For example, recent reports have shown substantial variations in these hip morphologic features between subjects with progressive hip OA and matched controls,(2, 23, 24) and candidate association and GWAS studies have repeatedly revealed the association of the GDF5 locus with OA, including that of the hip. In these studies, a large 130 kb haplotype underlies risk of OA at the locus.…”

Investigation of the Relationship Between Susceptibility Loci for Hip Osteoarthritis and Dual X‐Ray Absorptiometry–Derived Hip Shape in a Population‐Based Cohort of Perimenopausal Women

“…There is also considerable interest in the role of shape abnormalities in hip OA, exemplified by cam‐type deformities caused by extra bone growth around the anterolateral aspect of the femoral head, leading to femoroacetabular impingement (FAI) , which are associated with premature onset of OA . In the Rotterdam Study, individuals with cam‐type deformity and acetabular dysplasia were reported to have an ~2‐fold increased risk of radiographic hip OA compared with controls .…”

Clinical Examination, Diagnostic Imaging, and Testing of Athletes With Groin Pain: An Evidence-Based Approach to Effective Management

“…3 In contrast, it appears that the presence of a pincer deformity may have a protective effect against the development of OA. 3,73 Whether these findings can be extrapolated to athletes younger than 40 years of age is currently unknown. In older athletes, hip OA should always be considered and is clinically indicated by hip flexion of 115° or less and hip internal rotation less than 15°, and radiographically verified as joint space narrowing or presence of femoral or acetabular osteophytes.…”