Variations in Hip Shape Are Associated with Radiographic Knee Osteoarthritis: Cross-sectional and Longitudinal Analyses of the Johnston County Osteoarthritis Project

Abstract

Objective Hip shape by statistical shape modeling (SSM) is associated with hip radiographic OA (rOA); we examined associations between hip shape and knee rOA given the biomechanical inter-relationships between these joints. Methods Bilateral baseline hip shape assessments (for those with at least 1 hip with Kellgren-Lawrence grade [KLG] 0 or 1) from the Johnston County Osteoarthritis Project were available. Proximal femur shape was defined on baseline pelvis radiographs and evaluated by SSM, producing mean shape and continuous variables representing independent modes of variation (14 modes=95% of shape variance). Outcomes included prevalent (baseline KLG >=2 or total knee replacement [TKR]), incident (baseline KLG 0/1 with follow-up >=2), and progressive (KLG increase of >=1 or TKR) knee rOA. Limb-based logistic regression models for ipsilateral and contralateral comparisons were adjusted for age, sex, race, body mass index (BMI), and hip rOA, accounting for intra-person correlations. Results We evaluated 681 hips and 682 knees from 342 individuals (61% women, 82% white, mean age 62 years, BMI 29 kg/m2). Ninety-nine knees (15%) had prevalent rOA (4 knees with TKR). Lower mode 2 and 3 scores were associated with ipsilateral prevalent knee rOA; only lower mode 3 scores were associated with contralateral prevalent knee rOA. No statistically significant associations were seen for incident or progressive knee rOA. Conclusions Variations in hip shape were associated with prevalent, but not incident or progressive, knee rOA in this cohort, and may reflect biomechanical differences between limbs, genetic influences, or common factors related to both hip shape and knee rOA.

Statistical shape modelling of hip and lumbar spine morphology and their relationship in the MRC National Survey of Health and Development

“…; Nelson et al. ), dual energy X‐ray absorptiometry (DXA) (Goodyear et al. ), CT/pQCT (Bredbenner et al.…”

“…; Nelson et al. ), and knee and lumbar spine in the Chingford study (Hassett et al. ), no studies have yet created shape models from different regions in the same people.…”

“…Statistical shape modelling (SSM) is a method of image analysis employing pattern recognition statistics to describe and quantify such shapes from images, mostly in two dimensions but increasingly in 3D (Neogi et al 2013;Barr et al 2016). This method has been used to describe and quantify the variations in the shape of complex anatomical structures, such as the knee, hip and spine (Smyth et al 1999;Gregory et al 2004;Meakin et al 2008; Barr et al 2009), using a wide range of imaging modalities including radiography (Barr et al 2012;Nelson et al 2016a), dual energy X-ray absorptiometry (DXA) (Goodyear et al 2013), CT/pQCT (Bredbenner et al 2014;Varzi et al 2015) and magnetic resonance imaging (MRI; Meakin et al 2009;Neogi et al 2013;Pavlova et al 2014). The power of SSM lies in its ability to quantify variations in morphology and it has recently shown promise as a biomarker for a number of musculoskeletal disorders.…”

“…All of these joints, however, are connected in the kinetic chain of the weight-bearing skeleton. Whereas links between different regions have been observed in disorders such as osteoarthritis (for example between hip shape and knee osteoarthritis in the study of osteoporotic fractures and the Johnston County studies; Wise et al 2014;Nelson et al 2016a), and knee and lumbar spine in the Chingford study (Hassett et al 2006), no studies have yet created shape models from different regions in the same people.…”

3‐dimensional metrics of proximal femoral shape deformities in Legg–Calvé–Perthes disease and slipped capital femoral epiphysis

“…The growth and maintenance of hip shape is vital to the proper function of the lower limb, as abnormalities in shape have been associated with an increased risk of early osteoarthritis not only in the hip, 1,2 but also in the knee. 3 In the hip joint, two common pediatric disorders that result in altered proximal femoral morphology are Legg-Calv e-Perthes disease (LCPD) and slipped capital femoral epiphysis (SCFE), [4][5][6] which have an incidence of 5.5 and 10.8 cases per 100,000 children in North America, respectively. 7,8 These diseases have been studied extensively, but treatment regimens remain controversial, depending on age of disease onset, stage of disease, and other factors.…”