Performance of Antibiotic Impregnated Calcium Sulfate: A Prospective Randomized Controlled Trial

There is a tremendous burden of disease associated with infected bone defects and infected nonunions and their management is challenging. Infected bone defects and nonunions have a profound clinical and economic impact and outcomes are limited by high rates of re-operation and poor functional outcomes. Reconstruction of infected bone defects or nonunions is difficult with multiple treatment options that may be considered. A comprehensive approach includes the treatment of infection, the management of dead space, skeletal stabilization, stimulation of soft tissue healing and healing of the bone defect or nonunion.

There is little evidence and a distinct lack of consensus regarding the definitive management of infected bone defects and infected nonunions. A two stage approach is still the gold standard for management and it remains unclear when alternative approaches should be considered. The first stage of the procedure includes adequate debridement, skeletal stabilization as required and placement of a polymethyl methacrylate cement spacer with or without antibiotics at the site of the bone defect. The second stage typically occurs between 6-8 weeks later with removal of the cement spacer and bone grafting into the preserved defect. There is no clear preferred management strategy and there remains a significant evidence gap.

There has been a significant interest in the use of bone graft substitutes for defect management as part of the management of infected bone defects and infected nonunions. The use of calcium sulfate as an alternative synthetic bone graft material has long been established (1-4), and the combination of calcium sulfate with antibiotics has been reported in the literature almost as long as antibiotics have been available (5, 6).

The clinical performance of calcium sulfate in combination with a single antibiotic, Tobramycin, is well documented (7, 8). However, in recent years, the use of calcium sulfate in combination with multiple antibiotics has grown in use as a means of providing protection from bacterial colonization by a wider variety of gram negative and gram positive pathogens (9-12). This study will evaluate the clinical performance of a high purity calcium sulfate bone void filler, STIMULAN® Rapid Cure. STIMULAN® Rapid Cure is intended to be gently packed into bony voids or gaps of the skeletal system (i.e., extremities, pelvis, and posterolateral spine). STIMULAN® Rapid Cure provides a bone graft substitute that resorbs and is replaced with bone during the healing process. STIMULAN® Rapid Cure is biodegradable and biocompatible and may be used at an infected site.

The proposed study is a multi-centered, prospective, randomized controlled trial, comparing current standard of care for defect management to placement of antibiotic loaded Stimulan as a bone void filler in patients undergoing treatment of infected tibial defects or infected tibial nonunions. Patients with an infected tibial bone defect or infected tibial nonunion meeting inclusion criteria will be randomized to receive either standard of care for defect management (Group A) or placement of antibiotic loaded Stimulan (10cc Stimulan Rapid Cure, 1g Vancomycin, 240mg Tobramycin) as a bone void filler (Group B), with a standardized intervention and post-intervention protocol.