Tatsuoki Mashima

Remodelling of bone around hydroxyapatite and titanium in experimental osteoporosis

The affinity of the tibia bone for cylinders of hydroxyapatite (HA) and Ti-6Al-4V was investigated in three experimental animal models: intact rat tibiae, ovariectomized rat tibiae and ovariectomized plus neurectomized rat tibiae. The affinity index (the length of bone directly apposed to the implant/the total length of the bone-implant interface x 100%) was calculated. In intact and ovariectomized tibiae, no significant difference existed between the affinity index of HA and Ti-6Al-4V. In ovariectomized plus neurectomized tibiae, the affinity index of HA was greater than for Ti-6Al-4V from 8 to 24 wk after implantation (8 wk, P < 0.05; 12 wk, P < 0.005; 24 wk, P < 0.05). The affinity index of Ti-6Al-4V in normal tibiae was greater than that in ovariectomized or ovariectomized plus neurectomized tibiae. There was no significant difference of the affinity index of HA between normal, ovariectomized or ovariectomized plus neurectomized tibiae. Osteoporotic bone demonstrated a greater affinity to HA than Ti-6Al-4V in an experimental animal model.

Recombinant human erythropoietin therapy for autologous blood donation in rheumatoid arthritis patients undergoing total hip or knee arthroplasty.

The effect of recombinant human erythropoietin on autologous blood donation was investigated in 73 rheumatoid arthritis patients who underwent hip or knee arthroplasty. Autologous blood donation of 400 mL was successful with recombinant human erythropoietin (12,000 U per week), and no homologous blood was required. The mean period of blood collection was 33.8 days. Mean hemoglobin levels were 9.7 g/dL before treatment, 10.7 g/dL before surgery, and 10.2 g/dL after surgery. This study confirmed recombinant human erythropoietin is effective for enabling preoperative blood donation in rheumatoid arthritis patients.