Influence of foot orthotics upon duration of effects of spinal manipulation in chronic back pain patients: a randomized clinical trial.

Objective: The purpose of this study was to investigate the effects of 4 weeks of custom foot orthotics on pain, disability, recurrence of spinal fixation, and muscle dysfunction in adult low back pain patients receiving limited chiropractic care.

Methods: Adult volunteers with low back pain of greater than or equal to 1 month's duration were randomized to receive custom orthotics (group A) or a flat insole sham (group B) with limited chiropractic care in 5 visits over 4 weeks. Primary outcome measures are as follows: Quadruple Numerical Pain Rating Scale (for back), the Roland-Morris Disability Questionnaire, the number of muscles grade 4 or lower on manual muscle testing, and the number of spinal fixations detected by motion palpation and vertebral challenge at intake (B1), 2 weeks later before treatment began and orthotic use was initiated (B2) and before each subsequent treatment at approximately days 3, 10, 17, and 24 after B2. Secondary outcome measures are correlations of all primary outcomes.

Results: Both groups improved on all Numerical Pain Rating Scale, Roland-Morris Disability Questionnaire, and the number of muscles from intake (B1) to final visit. Only group B yielded significant improvements in the number of spinal fixations. No outcome measures showed statistical difference between groups at any time point; however, those who wore custom orthotics longer each day showed trends toward greater improvements in some outcome measures.

Conclusions: Both groups improved with chiropractic care including spinal manipulation; however, there were no statistical differences shown between sham and custom orthotic groups. Future studies should formally measure the time that orthotics or shams are worn in a weight-bearing capacity each day.