Functional Testing Provides Unique Insights into the Pathomechanics of Femoroacetabular Impingement and an Objective Basis for Evaluating Treatment Outcome
Rylander J, Shu B, Favre J, Safran M, Andriacchi T. J Orthop Res 2013 Apr 26 [Epub ahead of print]
Take Home Message: Objective measurements may provide added perspective to the rehabilitation of femoroacetabular impingement not otherwise measured by self-report surveys and clinical passive range of motion.
Femoroacetabular impingement (FAI) is very common in some sports and can affect not only athletic activity but also activities of daily living. Despite functional impairments, we often evaluate the success of a treatment for FAI not with functional assessments but with just patient-reported pain levels and activity scales, post-surgical femoral head and acetabular rim shape, and clinical passive range-of-motion measurements. If we can develop new functional assessments to monitor FAI then this may improve our current treatment strategies. Rylander et. al. used 3-dimensional motion capture techniques to measure walking and stair climbing among 17 patients diagnosed with FAI prior to surgery and 1 year post-operatively. The authors also evaluated 17 age-, gender-, body mass index-matched volunteers, who reported no history of hip pain or lower extremity injury (assessed at one time point). The primary outcomes were active hip and pelvis range of motion during walking and stair climbing. Pre-operatively, patients with FAI had abnormal hip and pelvic kinematics during walking (i.e., reduced hip flexion, internal rotation, and abduction) and stair climbing (i.e., reduced hip extension and internal rotation but increased pelvic anterior tilt and rotation) compared with healthy volunteers. At one year after surgery, patients with FAI improved their range of motion for walking, but not for stair climbing. Over time, patients after surgery improved their hip flexion and internal rotation during walking but not hip abduction. The authors found no hip or pelvic motion differences between pre- and post-surgery during stair climbing. However, despite the lack of changes in kinematic profile, 16 of 17 patients reported decreased pain in the surgical limb.
These results suggest that surgery may improve patient-reported outcomes and hip range of motion during walking but not during more challenging tasks (e.g., stair climbing). The lack of post-operative changes in hip and pelvic range of motion during stair climbing show that something other than the abnormal morphology that is addressed during surgery may contribute to the kinematic differences noted in FAI patients. This could be other structural abnormalities that are not addressed in surgery or evidence that we need to further optimize our rehabilitation strategies. Post-operative rehabilitation may play a large role in the full recovery of patients with symptomatic FAI. It is important to address all angles of rehabilitation, as partial recovery may lead to reinjury, re-occurrence of pain, and/or osteoarthritis.
Questions for Discussion: How, or will, these results guide your approach to treating FAI patients? Are these deficits able to be addressed through rehabilitation?
Written by: Meghan Maume Miller
Reviewed by: Jeffrey Driban
Rylander, J., Shu, B., Favre, J., Safran, M., & Andriacchi, T. (2013). Functional Testing Provides Unique Insights Into the Pathomechanics of Femoroacetabular Impingement and an Objective Basis for Evaluating Treatment Outcome Journal of Orthopaedic Research DOI: 10.1002/jor.22375