Numerical analysis of the effects of padded pelvic belts as a treatment for sacroiliac joint dysfunction

Background: Pain related to the sacroiliac joint (SIJ) accounts for low back pain in 15%-30% of patients. One of the most common treatment options is the use of pelvic belts. Various types of pelvic belts exist; however, the mechanisms underlying treatment and their effectiveness remain unclear to date. Objective: To analyze stress distribution in the pelvis when a pelvic rubber belt or a padded pelvic belt is applied, to assess the effectiveness of treatment from a numerical biomechanical perspective. Methods: The pressure distribution at the pelvic belts was measured using a device and subsequently modeled with the finite element method of a pelvis with soft tissues. The stress environment when wearing a pelvic belt in a double-leg stance was simulated. Results: With the application of pelvic belts, the innominate bone rotated outward, which was termed an out-flare. This caused the SIJ to compress and cause reduction in sacrotuberous, sacrospinous, interosseous, and posterior sacroiliac ligament loading. Padded pelvic belts decreased the SIJ displacement to a greater extent than in pelvic rubber belts. Conclusion: Pelvic belts aid in compressing the SIJ and reduce its mobility.