A zinc calcium phosphorous oxide ceramic and malic acid-Ca(OH)/sub 2/-vitamin E composite for repairing bone defects

Abstract

The objective of this investigation was to develop a resorbable zinc calcium phosphorous ceramic oxide (ZCAP) organic acid-vitamin E composite containing an antibiotic for orthopedic and/or dental application, including nearly all cases of trauma of hard tissues. A composite consisting of 3.0 g ZCAP, 1.2 g malic acid, 0.6 g Ca(OH)/sub 2/, 9.6 mg gentamicin sulfate and 20 pl of vitamin E oil was compressed in a 5/16" die into 0.1 g pellets at a load of 2000 lbs in a hydraulic press. The right femur of experimental animals was accessed by routine surgical procedures. A mid-diaphyseal fracture was created under direct vision using a surgical bone saw. A 0.62 threaded K-wire was inserted into the intramedullary canal and retrograded through the knee using a drill. The implant was placed between the two ends of the fracture and the K-wire antegraded through the pellet into the proximal end of the femur and tested to assure good fixation. The K-wire protruding from the bone was cut flush with the end of the bone using wire cutters. The surgical site was closed using routine surgical procedures. Post surgery, each rat showed normal movement during the ten week experimental period. Gross morphological examination of euthanized animals showed filling of the defect. Radiographic examination of the bones showed resorption of the composite, evidence of bone healing and cancellous bone ingrowth. However, the new bone ingrowth appeared less dense than the cortical bone on either side of the defect. The data collected to date suggest that ZCAP composites can be used as osteoconductive fillers between two fractured ends of a bone.