Open reduction and augmentation of internal fixation with an injectable skeletal cement for the treatment of complex calcaneal fractures

Objectives: To describe the surgical handling, potential complications, and remodeling of an injectable, osteoconductive calcium phosphate cement (Nor ian SRS) for joint depression-type calcaneal fractures in humans, and to il lustrate the clinical efficacy of this cement with special reference to ear ly postoperative full weight bearing. Design: Prospective cohort study. Setting: Level I trauma centers in Bochum and Leipzig, Germany. Intervention: Thirty-six joint depression type calcaneal fractures in thirt y-two patients were augmented with the calcium phosphate cement after stand ard open reduction with internal fixation. Postoperative full weight bearin g was allowed progressively earlier, and as the study progressed, the last patients were bearing full weight as early as three weeks postoperatively. Biopsies for histologic analysis were performed at time of hardware removal after one year (seven biopsies) or in case of infection at time of debride ment (five biopsies). Main outcome measures: Clinical outcome was evaluated according to a calcan eal scoring system. Data were compared and statistically analyzed between p atients with postoperative full weight bearing after eight to twelve weeks and three to six weeks, respectively. Histologic findings are described. Results: Cement injection averaged ten cubic centimeters and could easily b e performed under fluoroscopic control. Progressively earlier full weight-b earing was achieved without loss of reduction. There was no statistical dif ference in clinical outcome scores in patients with full weight bearing bef ore or after six weeks postoperatively. The infection rate was 11 percent, possibly related to the skin incisions. The biopsies from clinically satisf actory cases showed nearly complete bone apposition, areas of vascular pene tration, and reversal lines illustrating progressive cycles of resorption a nd new bone formation. Biopsy specimens from infected cases showed bone and cement surrounded by either fibrous tissue or acute inflammation without e xtensive bone apposition, Conclusions: Calcium phosphate cement augmentation of standard open reducti on with internal fixation in joint-depression type calcaneal fractures allo ws postoperative full weight bearing as early as three weeks postoperativel y. The injectable bone cement can easily be handled surgically under fluoro scopic control and has proved to be remodelable.