Unpicking observational relationships between hip shape and osteoarthritis: hype or hope?

Abstract

To review recent findings concerning the observational relationship between hip shape and hip osteoarthritis (HOA) and their shared genetic influences, and the potential for clinical application. Recent findingsRecent observational studies have strengthened the evidence that specific shape deformities, such as cam and acetabular dysplasia, are related to HOA. Statistical shape modelling has emerged as a method to measure hip shape holistically, with the added advantage that this can be applied to DXA scan images. This has led to several additional aspects of hip shape variation being identified, such as a wider femoral neck and larger lesser trochanter, in association with HOA. Furthermore, this method has formed the basis of genetic studies identifying novel genetic influences on hip shape, several of which are shared with known genetic risk factors for HOA. SummaryShared genetic influences of hip shape and HOA raise the possibility that hip shape plays a casual role in the development of HOA, justifying preventative approaches aiming to combat these adverse consequences.

Cam morphology but neither acetabular dysplasia nor pincer morphology is associated with osteophytosis throughout the hip: findings from a cross-sectional study in UK Biobank

“…Hip osteoarthritis (OA) is a common condition that causes considerable morbidity often leading to costly total hip replacements (THR) 1 , 2 . Differences in hip morphology have long been postulated as risk factors, including acetabular dysplasia (AD), and cam and pincer morphologies 3 . AD is associated with under-coverage of the acetabulum over the femoral head and is considered a consequence of milder forms of developmental dysplasia of the hip (DDH) 4 , 5 .…”

“…An individual's hip morphology develops through gestation, childhood and adolescence well before the onset of OA 3 , 10 . Genetic loci have been associated with different hip morphologies including DDH indicating a genetic predisposition 11 , 12 .…”

Subregional statistical shape modelling identifies lesser trochanter size as a possible risk factor for radiographic hip osteoarthritis, a cross-sectional analysis from the Osteoporotic Fractures in Men Study

“…Hip shape variations, in the form of developmental dysplasia of the hip (DDH) 6 , femoro-acetabular impingement (FAI) syndrome comprising cam and pincer morphologies measured geometrically 7 and similar morphologies measured via statistical shape modelling (SSM), have strong associations with hip OA 8,9 . Better knowledge of these shape variations and their origins could potentially offer new pathways to prediction 10,11 and prevention of hip OA, the later based on interventions that mediate the effects of hip shape 12 .…”

Growth orientations, rather than heterogeneous growth rates, dominate jaw joint morphogenesis in the larval zebrafish

“…This process by which joints acquire their shapes has important ramifications for joint health and function. For example, sub‐optimal hip joint shape is believed to be a key risk factor in early‐onset osteoarthritis (Faber et al, 2020 ; Sandell, 2012 ). However, the mechanisms underlying the emergence of joint shape remain poorly understood.…”