Comparison of high, medium and low mobilization forces for increasing range of motion in patients with hip osteoarthritis: A randomized controlled trial.

Background: Manual therapy has been shown to increase range of motion (ROM) in hip osteoarthritis (OA). However, the optimal intensity of force during joint mobilization is not known.

Objective: To compare the effectiveness of high, medium and low mobilization forces for increasing range of motion (ROM) in patients with hip OA and to analyze the effect size of the mobilization.

Design: Randomized controlled trial.

Methods: Sixty patients with unilateral hip OA were randomized to three groups: low, medium or high force mobilization group. Participants received three treatment sessions of long-axis distraction mobilization (LADM) in open packed position and distraction forces were measured at each treatment. Primary outcomes: passive hip ROM assessed before and after each session.

Secondary Outcomes: pain recorded with Western Ontario and McMaster Universities (WOMAC) pain subscale before and after the three treatment sessions.

Results: Hip ROM increased significantly (p < 0.05) in the high-force mobilization group (flexion: 10.6°, extension: 8.0°, abduction:6.4°, adduction: 3.3°, external rotation: 5.6°, internal rotation: 7.6°). These improvements in hip ROM were statistically significant (p < 0.05) compared to the low-force group. There were no significant changes in the low-force and medium-force groups for hip ROM. No significant differences in hip pain were found between treatment groups.

Conclusion: A high force LADM in open packed position significantly increased hip ROM in all planes of motion compared to a medium or low force mobilization in patients with hip OA. A specific intensity of force mobilization appears to be necessary for increasing ROM in hip OA.