Kettunen Jukka, Kröger Heikki, Bowditch Mark, Joukainen Jaakko, Suomalainen Olavi
Department of Surgery, Kuopio University Hospital, Box 1777, FIN-70211 Kuopio, Finland.
J Orthop Sci. 2003;8(6):772-6. doi: 10.1007/s00776-003-0718-7.
Bone mineral density (BMD) was measured on three occasions following removal of metal plates used to fixate diaphyseal forearm fractures in eight patients (mean age 38.5 years). At plate removal the mean BMD of the distal radius/ulna and the ulnar shaft sites were, respectively, 10.2% and 2.1% lower than on the nonfractured side. The apparent volumetric BMD (BMDvol) at the ulnar fracture site was 4.3% lower. At 6 months follow-up ( n = 5) the mean ulnar shaft BMD had increased by 6.4% ( P = 0.04), resulting in complete recovery of BMD, whereas the increase in BMDvol did not reach the BMDvol of the control side. No recovery was found at the distal radius/ulna site. We conclude that there is a small, partially reversible bone density deficit in the ulnar shaft that has been underneath the plate. Although the decreased bone density may in part be responsible for increased refracture risk at the fracture site immediately after plate removal, it is negligible after 6 months. The cessation of the effects of stress shielding is probably responsible for the increased bone density after plate removal.
在八名患者（平均年龄38.5岁）的骨干前臂骨折固定金属板取出后，分三次测量了骨密度（BMD）。取出钢板时，桡骨远端/尺骨和尺骨干部位的平均骨密度分别比未骨折侧低10.2%和2.1%。尺骨骨折部位的表观体积骨密度（BMDvol）低4.3%。在6个月的随访中（n = 5），尺骨干平均骨密度增加了6.4%（P = 0.04），骨密度完全恢复，而BMDvol的增加未达到对照侧的BMDvol。桡骨远端/尺骨部位未发现恢复情况。我们得出结论，钢板下方的尺骨干存在小的、部分可逆的骨密度缺陷。虽然骨密度降低可能部分导致取出钢板后骨折部位立即增加再骨折风险，但6个月后这种影响可以忽略不计。应力屏蔽作用的停止可能是取出钢板后骨密度增加的原因。
