Improvement of the bone-pin interface strength in osteoporotic bone with use of hydroxypatite-coated tapered external-fixation pins - A prospective, randomized clinical study of wrist fractures

Background: Achieving adequate fixation strength in osteoporotic bone is a challenge. In this study, we examined the use of hydroxyapatite-coated tape red external-fixation pins for the fixation of wrist fractures in patients with osteoporosis. Methods: Twenty female patients with osteoporosis and a fracture of the wri st were divided into two paired groups and randomized to receive either sta ndard tapered pins or hydroxyapatite-coated tapered pins. Two pins were ins erted in the distal part of the radius, two pins were inserted in the secon d metacarpal, and an external fixation device was mounted. All fixation dev ices were removed six weeks after surgery. Results: The mean pin-insertion torque land standard deviation) was 461 +/- 254 Nmm in the group managed with standard pi ns a nd 332 +/- 176 Nmm in t he group managed with hydroxyapatite-coated pins (p = 0.01). The mean pin-e xtraction torque was 191 +/- 155 Nmm in the group managed with standard pin s and 600 +/- 214 Nmm in the group managed with hydroxyapatite-coated pins (p < 0.0001, power 95%). The mean extraction torque was lower than the corr esponding insertion torque at each pin position in the group managed with s tandard pins (p < 0.05), whereas the mean extraction torque was higher than the corresponding insertion torque at each pin position in the group manag ed with hydroxyapatite-coated pins (p = 0.001). Two patients managed with s tandard pins and no patient managed with hydroxyapatite-coated pins had a p in-track infection. Pain during pin removal did not differ between the two groups. Conclusions: The present study showed that hydroxyapatite-coated tapered ex terna I-fixation pi ns provided improved fixation in the treatment of wrist fractures in patients with osteoporosis.