Date of Award

January 2015

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Daniel R. Cooperman

Subject Area(s)

Medicine

Abstract

EXPLORING FEMOROACETABULAR IMPINGEMENT AND ITS IMPLICATIONS FOR THE DEVELOPMENT OF OSTEOARTHRITIS. Raghav Badrinath, Daniel R. Cooperman. Section of Pediatric Orthopedics, Department of Orthopedics and Rehabilitation, Yale University, School of Medicine, New Haven, CT

Femoroacetabular impingement (FAI) has been recently elucidated as an explanation for cases of hip osteoarthritis (OA) that were previously categorized as "idiopathic". We examine three questions related to FAI - the antiquity of the cam deformity, the role of overcoverage in hip osteoarthritis and the mechanism of impingement with acetabular retroversion.

To examine the antiquity of the cam deformity, we performed proximal femoral measurements on 175 femora obtained from 8th-11th century humans living in present-day Ohio. Besides descriptive analysis of central tendencies, we also compare these to measurements on modern femurs.

For the other two questions, we looked at hip radiographs in patients below the age of 35, and compared these to OA-free hips from patients above 65 years of age, to determine the hips that "make it" to 65 without developing OA. We also do this same comparison looking at the difference in the prevalence of retroverted hips between the two populations. Proportions of hips with retroversion signs or desired CE angles were compared using chi-squared tests.

We found that the femurs from the Libben collection were significantly more varus and anteverted than modern femurs. Additionally, the mean alpha angle was 35o, significantly lower than the mean 45o in modern humans. None of the femurs in the Libben collection had a cam deformity. It appears that the cam deformity is a relatively new deformity.

With overcoverage, there were 477 younger patients (mean CE angle 35o) and 446 older patients (mean CE angle 37o). The proportion of overcovered hips (hips with a CE angle > 45o) was not statistically different between the two populations, suggesting that an overcovered hip does not automatically predispose individuals to arthritis.

Finally, we found that the proportion of retroverted hips with a CE angle over 30o were significantly different between the old and young groups. It appears that retrovertion does, in fact, lead to accelerated arthritis. However, this seems to require a threshold of coverage to cause impingement.

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This is an Open Access Thesis.

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