Date of Award
Doctor of Philosophy (PhD)
Clinical and Translational Rehabilitation Health Sciences
Neumann, Donald A.
Femoroacetabular impingement syndrome (FAIS) is a clinical hip disorder that represents symptomatic contact between the proximal femur and rim of the acetabulum during normal hip range of motion. FAIS has been described as a precursor to hip joint osteoarthritis (OA), and results in physical impairments and functional limitations in young individuals and active adults. Despite tremendous growth in arthroscopic hip surgery for FAIS, little is known about how this disorder affects dynamic hip joint function. The purpose of this dissertation was to investigate hip joint function, during clinical and functional activities, both before and after arthroscopic hip surgery for FAIS. The first aim compared hip joint function in people with FAIS to that of healthy matched controls. The results show that hip flexion muscle strength is reduced in people with FAIS, although, this loss of hip strength is not associated with gait kinetics or patient reported outcomes. These findings indicate that despite hip strength being impaired, people with FAIS can meet the functional demands of gait. However, during double and single leg squat tasks, significant alterations in hip joint biomechanics were found, and became greater as the control demand of the squat task were progressed. These findings indicate that FAIS alters hip biomechanics, however, tasks that require greater joint demand such as single leg squat are needed to bring about these alterations in joint function. The second aim examined hip joint function before and after hip arthroscopic surgery for FAIS. Arthroscopic hip surgery for FAIS did improve joint range of motion and muscle strength. Additionally, sagittal plane hip joint kinetics and hip joint kinematic control during gait changed after arthroscopic hip surgery, although, hip joint biomechanics remain different than healthy controls. The aims of this dissertation demonstrate that clinical hip function is altered in people with FAIS and arthroscopic hip surgery improves this function. Tasks that involve end ranges of hip motion and single leg control are required to bring about alterations in hip joint biomechanics in people with FAIS. Gait biomechanics after arthroscopic hip surgery for FAIS change, however, may require an extended period to normalize after surgery.