Statistical and Biomechanical Analysis of Hip Dysplasia

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Collaborating Investigators: Dr. Jeffrey Weiss, Dr. Andrew Anderson

Hip dysplasia is a misalignment in the hip joint that causes abnormal stress and wear to tissues in and around the joint.¹ It may be the leading cause of premature osteoarthritis of the hip.² The biomechanics of this condition and the process of joint degeneration that results are still poorly understood. The SCI Institutes's Musculoskeletal Research Laboratory is working in conjunction with the CIBC software development team to create subject specific finite element models of normal and dysplastic hip joints in order to study hip joint biomechanics in simulation.

Hip joint wear points during walking, descending and climing stairs

Hip joint wear points during walking, descending and climing stairs

In this study, 3D models of hip joints are produced based on CT scans from three populations, subjects with no hip dysplasia, those suffering traditional hip dysplasia, and those with retroverted hip dysplasia. The data will be segmented and meshed into accurate 3D models using Seg3D and BioMesh3D. The models will then be imported into a simulation environment that will put the virtual joints through normal activities such as walking, stair climbing and descending stairs and allow researchers to visualize where abnormal stress loads occur. Many models from each population will be statistically combined to create single models that represent the average in morphology for each population. These models will serve as a baseline average example against which any given patient specific model can be quantifiably compared.

Development of the tools and methods needed for rapidly generating patient specific simulation models of dysplastic hips will not only improve our understanding of the disease itself, it will also greatly improve the quality of treatment and allow early detection of the disease. Early treatment may not require surgery and is much more likely to result in complete recovery. ^3,4 Patient specific anatomical simulation methods may also be applied in the future to wide range of other conditions.

1. D. A. Michaeli, S. B. Murphy, and J. A. Hipp. Comparison of predicted and measured contact pressures in normal and dysplastic hips. Med Eng Phys, 19(2):180-6., 1997.

2. D. R. Cooperman, R. Wallensten, and S. D. Stulberg. Acetabular dysplasia in the adult. Clin Orthop, 175:79-85., 1983.

3. A. H. Johnson, R. J. Aadalen, V. E. Eilers, and R. B. Winter. Treatment of congenital hip dislocation and dysplasia with the pavlik harness. Clin Orthop, 155:25-9, 1981.

4. F. Grill, H. Bensahel, J. Canadell, P. Dungl, T. Matasovic, and T. Vizkelety. The pavlik harness in the treatment of congenital dislocating hip: report on a multicenter study of the european paediatric orthopaedic society. J Pediatr Orthop, 8(1):1-8, 1988.