Defect Reconstruction in Articular Calcaneus Fractures with a Novel Calcium Phosphate Cement

Abstract

Background: Major osseous defects in trauma or tumor patients require surgical reconstruction. While transplantation of autogenous or allogenous bone is still regarded as the standard, a multitude of alternative substitute materials has been developed in the recent years. Currently, the majority of commercially available products is based on calcium phospate minerals which are known to be osteoconductive, but in which resorption occurs slowly, if at all. A new class of calcium phosphate cements has recently been introduced that may offer better resorbability due to their nanocrystalline structure. Patients and Methods: In a prospective study of eleven patients with twelve joint depression calcaneal fractures requiring open reduction and internal stabilization, the subchondral defects were filled with a novel nanocrystalline calcium phosphate cement (Biobon®). Nine patients with ten fractures underwent a 1-year clinical and radiologic follow-up. Results: The postoperative course was uneventful except for one postoperative infection. On follow-up X-rays, the contours of the cement material became blurred and its size decreased. Biopsies taken after 6–8 months during plate removal demonstrated residual cement with intense osseointegration. Signs of inflammatory tissue response were absent, and part of the material had been replaced by new bone. Conclusions: The substitute material investigated in this study has a high biocompatibility and may represent an interesting alternative to bone grafts. Compared to sintered calcium phosphates, the resorbability of the new cement appears superior due to its nanocrystalline structure. The low compressive strength, however, does not permit early weight bearing and requires additional stabilization with osteosynthetic implants.