L—梯形加压钢板治疗股骨髁上骨折及其力学原理

我院从1986年采用L—梯形加压钢板治疗股骨髁上骨折53例54个骨折,髁上粉碎型(A_3)15例(27.7%)及经髁间型(C_1,C_2,C_3)25例26个骨折(48%),占75.7%.随访6个月至8年的44例45个骨折.3例伤口感染,骨折全部愈合.治疗效果优的28个关节,11个良,4个可,2个差,再骨折1例.优良率占86.7%.取两对新鲜尸体股骨,制成Schatzker Ⅲ型骨折,分另以L—TCP及AO/ASIF L—髁钢板固定(L—CCP),分别在CSS—01生物力学试验机上,模拟单、双肢站立负重进行测试,对其应力分布进行分析.结果证明L—TCP的设计符合等强度原理,钢板受力后应力分布均匀,中央增厚部受力明显小于L—CCP,两种钢板固定后,加载中骨断面附近承受的应力比正常骨普遍下降,钢板侧明显.但各点总计的结果证明骨断面周围主要承受压应力,并明显超过正常骨.应力遮挡可通过正常负重克服.

Treatment of Supracondylar Femur Fractures with L-Trapezoid Compression Plate(L-TCP) and Its Mechanical Principles

Fifty-three cases with 54 Supracondylar femur fractures were treated with L-TCP fixatin since 1986k According to the AO/XSIF classification,13 of 54 fractures were type A2,15 (27. 7%)A3 and 25 patients with 06 fractures were type C (48%). Forty-four patients with 45 fractures were followed up in one year to 8 years. Wound infection occurred in 3 open fractures. All the fractures had sound union. Using the authors criteria, 28 joints of the patients were rated excellent, 11 good,4 fair and 2 poor. Mechanical tests were done with a C1 fracture model made of 2 pairs of fresh cadavar femur. It was fixed by L-TCP and AO/ASIF L-condylar compression plate (L-CCP) respectively. The simulation standing tests with single or both legs were done on a CSS-01 Biomechnical Materical Test Machine. The results demonstrated that the design of L-TCP was adhere to the principles of uniform strength, the stress distribution was more even,and the stress concentration was much less at the midthind part. The stress value at the osteotomy site was lower than that at normal bone during loading,but the total compression stress value around the osteotomy site was significantly greater. The stress shielding could be over-come by normal weight-bearing.