Improvement of the bone-pin interface strength in osteoporotic bone with use of hydroxyapatite-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 tapered external-fixation pins for the fixation of wrist fractures in patients with osteoporosis.


METHODS
Twenty female patients with osteoporosis and a fracture of the wrist were divided into two paired groups and randomized to receive either standard tapered pins or hydroxyapatite-coated tapered pins. Two pins were inserted in the distal part of the radius, two pins were inserted in the second metacarpal, and an external fixation device was mounted. All fixation devices were removed six weeks after surgery.


RESULTS
The mean pin-insertion torque (and standard deviation) was 461 +/- 254 Nmm in the group managed with standard pins and 332 +/- 176 Nmm in the group managed with hydroxyapatite-coated pins (p = 0.01). The mean pin-extraction torque was 191 +/- 155 Nmm in the group managed with standard pins 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 corresponding insertion torque at each pin position in the group managed with standard pins (p < 0.05), whereas the mean extraction torque was higher than the corresponding insertion torque at each pin position in the group managed with hydroxyapatite-coated pins (p = 0.001). Two patients managed with standard pins and no patient managed with hydroxyapatite-coated pins had a pin-track infection. Pain during pin removal did not differ between the two groups.


CONCLUSIONS
The present study showed that hydroxyapatite-coated tapered external-fixation pins provided improved fixation in the treatment of wrist fractures in patients with osteoporosis.
Moroni
A
A
Department of Orthopaedic Surgery, Bologna University, Rizzoli Orthopaedic Institute, Italy. a.moroni@ior.it
Faldini
C
C
Marchetti
S
S
Manca
M
M
Consoli
V
V
Giannini
S
S
D000368:Aged; D001696:Biomechanical Phenomena; D001858:Bone Nails; D017886:Durapatite; D005260:Female; D005592:Fracture Fixation / Q000295:instrumentation* / Q000379:methods; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D010024:Osteoporosis / Q000150:complications*; D011446:Prospective Studies; D011474:Prosthesis Design; D016896:Treatment Outcome; D014954:Wrist Injuries / Q000601:surgery*
D017886:Durapatite