The use of a composite osteochondral device for simulating partial hemiarthroplasty was examined. The device was composed of a polyvinyl alcohol hydrogel and a titanium fibre mesh, acting as artificial cartilage and as porous artificial bone, respectively. The titanium fibre mesh was designed to act as an interface material, allowing firm attachment to both the polyvinyl alcohol gel (through injection moulding) and the femoral joint surface (through bony ingrowth). We implanted 22 of these devices into canine femoral heads. Histological findings from the acetabular cartilage and synovial membrane, as well as the attachment of the prosthesis to bone, were examined up until one year after operation.

No marked pathological changes were found and firm attachment of the device to the underlying bone was confirmed. The main potential application for this device is for partial surface replacement of the femoral head after osteonecrosis. Other applications could include articular resurfacing and the replacement of intervertebral discs.

We prepared a composite of D,L-lactic acid oligomer and dideoxykanamycin B for use as a biodegradable antibiotic delivery system with sustained effect. The composite was implanted in the distal portion of the rabbit femur, and the effective concentration of the antibiotic was measured in the cortex, the cancellous bone, and the bone marrow. In all bone tissues around the implant, the concentration of antibiotic exceeded the minimum inhibitory concentration for the common causative organisms of osteomyelitis for six weeks. Most of the implant material had been absorbed and the bone marrow had been repaired to a nearly normal state within nine weeks of implantation. The implant caused no systemic side effects, and it is likely to prove clinically useful as a drug delivery system for treating chronic osteomyelitis.