Abstract
Introduction
Subtle deformities of the acetabulum and proximal femur are recognised as biomechanical risk factors for the development of hip osteoarthritis (OA) as well as a cause of hip and groin pain. We undertook this study to examine relationships between a number of morphological measurements of the acetabulum and proximal femur and the hip pain in a 20-year longitudinal study.
Methods
In 1989 women of 45–64 years of age were recruited. Each had an AP-Pelvis radiograph at Year-2. These radiographs were analysed using a validated programme for measuring morphology. All morphological measurements were read blinded to outcome. At year 3 all participants were asked whether they experienced hip pain (side specific). This was repeated at visits up to and including 20-years. Logistic regression analysis (with robust standard errors and clustering by subject identifier) was performed using hip pain as a binary outcome. The model adjusted for baseline age, BMI and joint space and included only participants who were pain free on initial questioning.
Results
743 participants were included in the analysis. Median age 74.0. Pain was reported in 14.2% of hips. Logistic regression analyses revealed that extrusion index and LCE were significantly associated with hip pain before and after adjusting for covariates (OR 4.88[95%CI 1.32–17.97, p=0.017] and 0.84[95%CI 0.74–0.96, p=0.012] respectively). Modified triangular index height (MTIH) was also significantly associated after adjusting for covariates (OR 1.10[95%CI 1.01–1.20, p=0.022]). Extrusion index and MTIH were independently associated with hip pain at 20-years when used in the same model. No significant interaction was identified.
Conclusions
This study provides evidence that measurements of hip morphology characteristic of previously undiagnosed dysplasia and FAI are predictive of hip pain in a 20-year longitudinal study. MTIH, LCE and Extrusion index were significant predictors of pain. This is the first study to describe these associations between hip morphology and pain in a longitudinal cohort.
