A Prospective Randomized Controlled Trial of a Bioresorbable Calcium Phosphate Paste (α-BSM) in Treatment of Displaced Intra-Articular Calcaneal Fractures

Background: Displaced intra-articular calcaneal fractures are devastating injuries and pose a therapeutic challenge. The purpose of this study was to determine whether open reduction internal fixation (ORIF) plus an injectable bioresorbable calcium phosphate paste (alpha-BSM [bone substitute material]) is superior to ORIF alone in the treatment of calcaneal bone voids encountered after operative treatment of displaced intra-articular calcaneal fractures. Methods: We prospectively randomized 47 patients with 52 closed displaced intra-articular fractures necessitating operative fixation to receive ORIF alone (n = 28) or ORIF plus alpha-BSM (n = 24). The maintenance of Bbhler's angle was evaluated at follow-up visits for more than I year. Secondary outcome measures included the SF-36 and lower extremity measure every 6 months, and the Oral Analog Scale (OAS) score at 2 years. Results: There was no difference between the groups in the degree of collapse of Bohler's angle at 6 weeks and 3 months when compared with initial postoperative values. However, at 6 months, the mean collapse of the a-BSM and ORIF group was 5.6 degree (SD, 4.5 degree) and ORIF alone was 9.1 degree (SD, 5.8 degree), which was statistically significant (P = 0.03). Final radiographic evaluation after 1 year revealed a Bohler's angle loss of 6.2 degree (SD 5.9 degree) and 10.4 degree (SD 7.1 degree) in a-BSM and ORIF and ORIF alone groups, respectively, (p = 0.05). There was no difference between the two groups in regards to secondary outcome measures of general health, limb specific function, and pain past 2 years. Conclusion: These results support the use of an injectable, in situ hardening calcium phosphate paste to fill the bone void after a displaced intra-articular calcaneal fracture. There was no impact on general health, limb specific function, and pain past 2 years and no associated complications with a-BSM use, supporting it safety as an augment to ORIF.