Effect of Back Supports on Back Strength in Patients With Osteoporosis: A Pilot Study

Abstract

To determine the effect of application of back supports on back strength in subjects with osteoporosis. In a prospective, randomized, controlled study, we compared compliance and evaluated changes in back strength in 45 women with osteoporosis who were older than 40 years of age and were randomly assigned to one of three groups: (1) postural exercise only, (2) postural exercise and a conventional thoracolumbar support, or (3) postural exercise and a Posture Training Support (PTS) (a weighted kypho-orthosis). Of the 45 study participants, 15 were assigned to a PTS group, 15 to conventional thoracolumbar support, and 15 to no orthosis. All subjects were instructed in basic body mechanics and postural exercises. Back extensor strength, grip strength, and patient's physical activity were measured at baseline and at subsequent 8-week intervals for a 16-week period. Each patient's compliance during the study period was also recorded. compliance was poor among the thoracolumbar group; only 5 of the 15 subjects completed the study (P<0.001), in comparison with 11 of the 15 patients in the control group and all 15 in the PTS group. Analysis revealed statistically significant mean increases in back strength in the PTS group (23%) and the control group (13%) and a nonsignificant increase in the thoracolumbar group (15%), although poor compliance in the thoracolumbar group yielded insufficient power to detect a significant difference in this group. No statistically significant difference was found between the improvements in the PTS and control groups, possibly because of the small sample size in this pilot study. One patient who wore the PTS for only 4 hours a day rather than 8 hours had the largest percentage increase in back extensor strength of this group (78%). At 16 weeks, decreases in back strength of more than 5% below the initial measurements were noted in 1 of 11 subjects (9%) who completed the control arm of the study, 2 of 14 (14%) who completed the PTS arm, and 2 of 5 (40%) who completed the thoracolumbar arm. Compliance with use of the PTS was better than that with the thoracolumbar support. Back extensor strength may increase in patients who comply with the PTS and postural exercise program. We caution, however, that this pilot study requires replication in a larger series to determine the clinical and statistical generalizability of these findings to a wider population.