A silver-containing hydroxyapatite (Ag-HA) coating has been developed using thermal spraying technology. We evaluated the osteoconductivity of this coating on titanium (Ti) implants in rat tibiae in relation to bacterial infection in joint replacement.

At 12 weeks, the mean affinity indices of bone formation of a Ti, an HA, a 3%Ag-HA and a 50%Ag-HA coating were 97.3%, 84.9%, 81.0% and 40.5%, respectively. The mean affinity indices of bone contact of these four coatings were 18.8%, 83.7%, 77.2% and 40.5%, respectively. The indices of bone formation and bone contact around the implant of the 3%Ag-HA coating were similar to those of the HA coating, and no significant differences were found between them (bone formation, p = 0.99; bone contact, p = 0.957). However, inhibition of bone formation was observed with the 50%Ag-HA coating.

These results indicate that the 3%Ag-HA coating has low toxicity and good osteoconductivity, and that the effect of silver toxicity on osteoconductivity depends on the dose.

We studied perioperative pain and postoperative neurological changes after surgery for hallux valgus in 50 patients operated on under local ankle block. Patients were randomised to have the pneumatic tourniquet either at calf level or just above the ankle. The cuffs were inflated to 100 mmHg above systolic blood pressure. One patient was withdrawn from the study after randomisation. Areas of pain, paraesthesia and numbness were marked by patients on a diagram of the foot before operation and at six and ten weeks after operation. Both positions of the tourniquet gave an excellent bloodless field. The proximal tourniquet gave significantly greater discomfort (p < 0.01) during the operation, after 10, 20 and 30 minutes. Application of the cuff at the ankle gave no relative increase in areas of numbness and paraesthesia at six and ten weeks. An ankle tourniquet gives less discomfort with no increase in the incidence of nerve injury