Comparison of high, medium and low mobilization forces for increasing range of motion in patients with hip osteoarthritis: A randomized controlled trial – Duke Center of Excellence in Manual and Manipulative Therapy

Author Names

Estébanez-de-Miguel, E., Fortún-Agud, M., Jimenez-del-Barrio, S., Caudevilla-Polo, S., Bueno-Gracia, E., Tricás-Moreno, J.M.

Reviewer Name

Jake Isaac, SPT

Reviewer Affiliations

Duke University School of Medicine, Doctor of Physical Therapy Division

Paper Abstract

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.

NIH Risk of Bias Tool

Quality Assessment of Controlled Intervention Studies

Was the study described as randomized, a randomized trial, a randomized clinical trial, or an RCT

Was the method of randomization adequate (i.e., use of randomly generated assignment)?

Was the treatment allocation concealed (so that assignments could not be predicted)?

Were study participants and providers blinded to treatment group assignment?

Were the people assessing the outcomes blinded to the participants’ group assignments?

Were the groups similar at baseline on important characteristics that could affect outcomes (e.g., demographics, risk factors, co-morbid conditions)?

Was the overall drop-out rate from the study at endpoint 20% or lower of the number allocated to treatment?

Was the differential drop-out rate (between treatment groups) at endpoint 15 percentage points or lower?

Was there high adherence to the intervention protocols for each treatment group?

Were other interventions avoided or similar in the groups (e.g., similar background treatments)?

Cannot Determine, Not Reported, or Not Applicable

Were outcomes assessed using valid and reliable measures, implemented consistently across all study participants?

Did the authors report that the sample size was sufficiently large to be able to detect a difference in the main outcome between groups with at least 80% power?

Were outcomes reported or subgroups analyzed prespecified (i.e., identified before analyses were conducted)?

Were all randomized participants analyzed in the group to which they were originally assigned, i.e., did they use an intention-to-treat analysis?

Key Finding #1

Effectiveness of long axis distraction mobilizations for increasing ROM in patients with hip OA appears to be dependent on a particular intensity.

Key Finding #2

A high force LADM compared to a medium or low force mobilization resulted in significant increases in multi-planar hip ROM in patients with hip OA.

Key Finding #3

The study considered a high force mobilization to be a force that exceeded the initial marked resistance (first stop) resulting in a stretch of the surrounding soft tissues.

Key Finding #4

No significant difference was found in pre and post treatment pain levels between the three groups.

Please provide your summary of the paper

This study evaluated the comparative effectiveness of low, medium, and high force long axis distraction mobilization (LADM) on increasing hip range of motion in patients with hip osteoarthritis (OA). The randomized controlled trial included 60 patients (mean age 63 + 9.7 years, 58.3% male) with unilateral hip OA. The participants were randomly assigned to a low, medium, or high force group with each consisting of 20 patients. Each group received three treatment sessions of LADM with distraction forces varying dependent on force classification (low, medium, or high). A force provided before the slack was taken up was utilized for the low force group. A force applied until marked resistance was felt was given to the medium force group. A force that exceeded marked resistance was applied to the high force group. The primary outcome studied was passive hip ROM pre and post treatment. Secondary outcomes included pre and post treatment pain levels recorded with Western Ontario and McMaster Universities (WOMAC) pain subscale. The study found statistically significant (p < 0.05) multiplanar passive ROM increases in the high force mobilization group compared to the low or medium force groups. There was no significant difference found in pain levels pre and post treatment between groups.

Please provide your clinical interpretation of this paper. Include how this study may impact clinical practice and how the results can be implemented.

This study demonstrates that specific intensity is needed to improve effectiveness of long axis distraction mobilizations in patients with hip OA. Although this study utilized dynamometry to measure forces, it included descriptions of each force level dependent on individual patient presentation (i.e. force exceeding marked resistance) which allows for easier application in a clinical setting. The clinical relevance of this study indicates that high force mobilization may be necessary to provide enough distraction force to result in significant ROM increases when using LADMs in those with hip OA. The results also indicate that the resulting ROM gains were not due to hypoalgesic effects, as there was no significant difference in pre and post treatment pain levels between groups. This study can be used as a guide for clinicians aiming to improve passive hip ROM in their patients presenting with hip OA, or those looking to improve the effectiveness of their long axis distraction mobilizations.