Markel M D, Nunamaker D M, Wheat J D, Sams A E
Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis 95616.
Am J Vet Res. 1988 Apr;49(4):586-93.
The stiffness, load to failure, and bending moments of adult intact equine humeri and humeri repaired with 3 fixation techniques were determined in vitro. Bones were tested in axial compression (30 pairs), mediolateral 3-point bending (15 pairs), and caudocranial 3-point bending (15 pairs). An oblique osteotomy of 1 humerus of each pair was performed to simulate the long spiral oblique fractures that occur clinically in horses. Bones were repaired in 3 ways: group 1--nylon band cerclage fixation (20 bones); group 2--multiple intramedullary pinning (20 bones); and group 3--nylon band cerclage fixation and multiple intramedullary pinning (20 bones). Intact bones were significantly (P less than 0.05) stronger than repaired bones in each testing mode. Bones repaired with bands only were significantly less stiff in bending than were bones repaired with pins only or with pins and bands. In compression, only specimens repaired with pins and bands were significantly stiffer than were bones repaired with bands only. Bones repaired with bands only required significantly less load to failure in compression and in caudocranial bending than did bones repaired with pins only or with pins and bands. Bones repaired with pins only deformed through the full displacement of the actuator (5 cm), and pins deformed plastically. Bones repaired with pins and bands were stiffer and had higher bending moments than did bones repaired with pins only, but the differences were not significant.
在体外测定了成年马完整肱骨以及采用3种固定技术修复的肱骨的刚度、破坏载荷和弯矩。对骨骼进行轴向压缩测试（30对）、内外侧三点弯曲测试（15对）和头尾侧三点弯曲测试（15对）。对每对中的1根肱骨进行斜行截骨，以模拟临床上马发生的长螺旋斜形骨折。骨骼以3种方式修复：第1组——尼龙带环扎固定（20根骨骼）；第2组——多根髓内针固定（20根骨骼）；第3组——尼龙带环扎固定加多个髓内针固定（20根骨骼）。在每种测试模式下，完整骨骼均显著（P<0.05）强于修复后的骨骼。仅用带环扎修复的骨骼在弯曲时的刚度显著低于仅用髓内针或髓内针与带环扎修复的骨骼。在压缩测试中，仅用髓内针与带环扎修复的标本刚度显著高于仅用带环扎修复的骨骼。仅用带环扎修复的骨骼在压缩和头尾侧弯曲时达到破坏所需的载荷显著低于仅用髓内针或髓内针与带环扎修复的骨骼。仅用髓内针修复的骨骼在致动器完全位移（5厘米）时发生变形，髓内针发生塑性变形。髓内针与带环扎修复的骨骼比仅用髓内针修复的骨骼刚度更高、弯矩更大，但差异不显著。
