Sports Medicine Research: In the Lab & In the Field: Functional Testing Provides New Insights into Femoroacetabular Impingement (Sports Med Res)
Monday, June 3, 2013

Functional Testing Provides New Insights into Femoroacetabular Impingement

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

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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

5 comments:

Anonymous said...

Perhaps the deficits in stair climbing are neuromuscular and not inert? Due to the avoidance of active hip flexion activities in early phases of rehab? A NM Shutdown of hip flexors and IRs?

Meghan M. Miller said...

That could very well be the case and that additional attention for strengthening is needed in more advanced stages of the rehabilitation progression. It may also be the case that leading up to surgery, these neuromuscular deficits contributed to the lack of kinematic outcomes. Both are necessary avenues of further investigation.

Poul Haacker said...

I have seen good improvements in functional ROM by working on muscle activation => endurance => strength =>complex movements. And by doing simple manual mobilizations of the hip joint. A simple traction oftentimes results in large increases in ROM.

Jason Shermer said...

Obviously mechanics play in important role in impingement. I wonder how practicing more complex functional activities with serious focus on proper mechanics would result in a study like this?

Meghan M. Miller said...

Thanks for your comment, Jason. It could be assumed that more practice put into a task should yield a greater task performance improvement. This article seems to suggest that current rehabilitation programs do not show much skill transfer. That's to say that the exercises most commonly utilized may not apply to improving everyday tasks not incorporated into the program. You raise a great point about focusing on mechanics, as that likely has a large roll to play in rehabilitative outcomes. Further research is warranted to determine what those functional skills may be that would transfer from rehab to daily life.

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