Pain, not structural impairments may explain activity limitations in people with gluteal tendinopathy or hip osteoarthritis: A cross sectional study.

Question: What are the functional differences between people with greater trochanteric pain syndrome (GT), hip osteoarthritis (OA) or an asymptomatic population as measured by walking, Time Up and Go, single leg standing and strength?

Design: Cross sectional study with blinded measurers.

Participants: 38 participants with GT, 20 with end stage hip OA and 21 asymptomatic healthy control (AS) participants. All participants were women.

Outcome Measures: Pain (numeric rating scale), Walking speed (m/s), cadence (steps/min) and step length (m) measured via the 10m walk test and the Timed Up and Go; balance via single leg stance (s) duration; and hip abduction, adduction, medial and lateral rotation strength, standardized to body mass (BM) via the body mass average index (BMavg), measured via a wall mounted dynamometer.

Results: The two symptomatic groups reported similar pain levels (p=0.226), more pain then the AS group (p<0.000). Compared to the AS participants, participants with GT or hip OA demonstrated lower walking speed (10mwt and TUG, p<0.001), lower cadence and shorter duration single leg stance on the affected leg (p<0.05). Participants with GT or hip OA also demonstrated bilaterally weaker hip abduction than the AS group (p≤0.005). Compared to AS and GT participants, participants with hip OA demonstrated adduction weakness on the affected side (p=0.008 and p=0.002 respectively).

Conclusion: There is a significant level of dysfunction and impairments associated with GT and hip OA. As activity limitations do not appear to be differentiated by structural impairments, we suggest that pain, rather than the underlying pathology may be the driving impairment that leads to walking and single leg standing dysfunction.