Analysis and Optimization of the Pavlik Harness Treatment of Neonates with Hip Dysplasia

The University Of Central Florida Board Of Trustees, Orlando FL

Investigators

Abstract

PI: Kassab Proposal 1160179 The Pavlik harness is the standard orthopaedic device utilized worldwide to non-surgically correct congenital hip dysplasia (CHD) in infants, but its mechanism of action has not been studied, and is therefore little understood. As a result, treatment with this device fails for about 15% of the patients. Nearly 76% of hip osteoarthritis cases are attributed to untreated hip dysplasia at an early stage in life and this disability usually requires total hip replacement before the age of 50. It is estimated that nearly 1/20 full term infants are born with some type of hip instability, of which 2-3 out of 1000 will require treatment, and that nearly 15% will fail treatment for CHD with the Pavlik Harness leading to disability as the ultimate consequence. Accepting the rate of failure of this device as a leading cause of disability as a result of hip osteoarthritis, we propose to use the results of our year-long preliminary study as the foundation to engage in the hereby proposed research project where we will use engineering fundamentals to develop a case-specific approach to the treatment of CHD based on data extracted from individual CT-scans of infants afflicted by the condition. To do this we propose to: (1) develop a finite element model of the dynamic physiological response of the hip due to loads imposed by the Pavlik harness based on patient specific infant geometry, accounting for large deformation and non-linear behavior of the musculature, (2) formulate an automated algorithm based on the principle of minimum energy to determine optimum Pavlik harness load components necessary to successfully vector the femoral heads into their correct physiological position in the acetabula, while maintaining hip reduction for the full length of treatment, and (3) establish the proposed FEM-optimization methodology as a planning tool to achieve the goal of computationally determining patient-specific optimal configuration of the Pavlik harness allowing the optimum configuration to be transferred to the recipient infant, aiding in the success of the treatment. This will also serve in training physicians to successfully use and apply the Pavlik Harness. Intellectual Merit: The primary intellectual merit of this project is the expectation that our study will provide insight into the mechanisms of the successful treatment of CHD and suggest feasible clinical methods aimed at reducing the rate of failure of the treatment with the Pavlik Harness. Because no characterization has been made of the mechanism of action of this common orthopaedic device, the results of this project would constitute a breakthrough in the understanding and treatment of CHD. We have devised a multi-disciplinary framework, bringing together engineering analysis via finite element modeling, to predict optimal configuration of the Pavlik Harness geometry for each patient and serving to guide treatment planning. Although the ?optimal? configuration is not universal, we will have devised a universal patient-specific treatment planning procedure. Another intellectual merit is that this is truly an interdisciplinary research program bringing together medical professionals and engineers in an integrated and complementary approach providing a physics-based framework to approach a practical medical problem whose solution has a critical impact on a large patient population. Broader Impact: The primary impact of this project on society will be to ultimately improve the quality of life of patients with CHD that are undergoing corrective treatment using the Pavlik Harness. This study offers a practical solution to achieve effective treatment that draws from engineering expertise and modeling capabilities integrated with medical input and knowledge. Moreover, since 120,000 total hip replacements are performed annually in the United States, early detection and non-surgical correction of CHD in infants can potentially prevent enormous subsequent health-related costs. Also, graduate and undergraduate students will be immersed into a highly interdisciplinary working environment as by its very nature, the project requires students to synthesize learning from several engineering courses and physical sciences in a real-life problem of importance to society. Students are very eager to get involved in such projects that are at the interface of engineering and medicine. The bioengineering research activities of the Co-PIs have attracted a number of students including several females and Hispanic, several of whom have won science and engineering technical competitions, one on a pilot study of the very topic of this grant proposal. The College of Engineering and Computer Science (CECS) at UCF is ranked as the 3rd college of choice for Hispanics in the US by the Hispanics Business Magazine, and this project offers a unique means of recruiting such students in the field of bioengineering.