ePoster #739 - ISHA Annual Scientific Meeting 2016

Cam Shape in Male and Female Patients with Femoroacetabular Impingement

Dawn Groves, PhD, Leeds UNITED KINGDOM
Michael Bowes, PhD, Manchester UNITED KINGDOM
Marcus J. K. Bankes, FRCS (Orth), London UNITED KINGDOM
Seo Kiat Goh, FRCS, Singapore SINGAPORE
Philip Robinson, FRCR, Leeds UNITED KINGDOM
Sophie Williams, PhD, Leeds UNITED KINGDOM

Institute of Medical and Biological Engineering, University of Leeds, Leeds, UNITED KINGDOM

FDA Status Not Applicable

Summary: Volumetric CT images from male and female cam-FAI patients were segmented and the 3D shape models were quantitatively compared, the outcome of which showed associated changes in trochanter morphology and that female cam lesions were smaller and more defuse than males.

Introduction Correction of the anatomical deformity associated with cam-type femoroacetabular impingement (FAI) is frequently undertaken using arthroscopic surgery. The morphology of FAI is largely understood, however, geometrical differences between male and female cam lesions are less well reported. The aim of this study was to quantify and compare the geometry of the cam lesion using 3D imaging and statistical shape models (SSMs), in male and female patients with a clinical diagnosis of FAI. Method Volumetric CT images from two groups of symptomatic patients (male; n=41 and female; n=26) with a clinical diagnosis of cam-type FAI were segmented using EndPoint software (Imorphics Ltd., UK), creating accurate 3D reconstructions of the proximal femur. A SSM was then generated for each group to identify and quantify any 3D variations in cam shape. Bone was segmented using an automatic edge detection tool to maintain repeatability, and segmentations were checked for accuracy by a consultant musculoskeletal radiologist. Results Bony material located in an anterosuperior position at the femoral head-neck junction was observed in both groups, however, the male SSM identified a well-defined cam whereas the female cam was smaller and much more diffuse. Additionally, abnormal morphology in both groups affecting the posterior aspect of the femur around the greater trochanter and intertrochanteric crest also appeared to be associated with the cam lesion. Discussion Variations in 3D geometry of the cam lesion in male and female FAI patients was compared and quantified using CT imaging and SSMs, the results of which indicate that gender-related geometric differences exist. Key findings were the associated changes in trochanter morphology, and that cam lesions in female patients were found to be smaller and poorly defined compared to males. This could have important implications when treating female cam-FAI patients, who may be at greater risk of being underdiagnosed and treated.