Assessing the impact of a long-term physiotherapy program on hip function in patients with osteoarthritis: the role of patient-reported and assessor-observed outcome measures

Introduction
Because there are few trials evaluating rehabilitation effects in people with hip osteoarthritis, it is important to increase the body of research and develop assessment methods improving the objectivity of evaluation.

Aim of the research
To evaluate the effect of a long-term, land-based physiotherapy program on the hip-related function in patients with hip osteoarthritis, and to assess the relationship of self-reported and assessor-observed functional outcome measures.

Material and methods
The trial was conducted prospectively over a 12-month period. The study cohort consisted of 37 people of both genders. The intervention included three rounds of 3-week physiotherapist-supervised treatment and two 5-month intervals of an unsupervised maintenance program in between. The functional assessment was performed 4 times using the Hip Dysfunction and Osteoarthritis Outcome Score (HOOS) and a set of performance-based tests (PBTs): the 30-Second Chair Stand Test (30secCST), 40-Metre Fast-paced Walk Test (40mFPWT), and Stair Climb Test (SCT). The hip joint was evaluated twice structurally using the Scoring Hip Osteoarthritis with MRI (magnetic resonance imaging).

Results
A significant improvement in hip-related function was observed in HOOS among MRI progressors, exclusively physical workers. Non-progressors, mostly sedentary workers, were characterized by improvement of PBTs. There was a correlation between HOOS and 40mFPWT and SCT at the baseline, 3-week, and 6-month follow-ups. The outcomes for 30secCST were not consistent. We observed a positive effect of rehabilitation on hip function in the studied population, although progressors and non-progressors achieved different outcomes. The relationship of PBTs and HOOS was marked, but not unequivocal.

Conclusions
The improvement in self-reported measures may mask disease progression in MRI progressors.