We developed a new type of bioactive bone cement, CAP (Hydroxyapatite composite resin; composed of 77% w/w hydroxyapatite granules and bisphenol-A glycidyl methacrylate-based resin) for bony defect filling. Elastic modulus of CAP is similar to a cortical bone, while it is injectable before hardening and physiologically bonding with bone in 4 to 8 weeks. We present a new method of treatment for unstable Colles’ fracture with this material in clinical use.

Experimental comminuted Colles’ fracture was produced in three fresh frozen cadavara. Fracture was reduced and fixed percutaneously with K-wires. 4.5mm drill hole was opened on the radial cortex 3cm proximal to the fracture site. Comminuted fragments were pushed-up to the subchondral area with a blunt rod and CAP was injected through the same way. After cement hardening, K-wires were removed. X-ray photos were examined before fracture, after fracture and after reconstruction with CAP, in order to evaluate the shape of the radius. CT was examined to evaluate the placement of CAP.

Radiographic parameters of radii were well recovered after reconstruction with CAP. Over correction of the radial length was observed in one bone but good reduction was generally achieved (Table). This means realignment of the distal radioulnar joint, which results in good outcome clinically. In transverse section of CT, 41 to 69% (average 55%) of subchondral area was filled with CAP. Filling of CAP was better in an osteoporotic bone. These results show the usefulness of this material for treatment of unstable Colles’ fracture especially in osteoporotic patients.