Belkoff S M, Millis D L, Probst C W
Orthopaedic Biomechanics Laboratory, School of Medicine, University of Maryland, Baltimore 21201.
Am J Vet Res. 1993 Oct;54(10):1770-3.
Biomechanical strength and stiffness of 2 fixation treatments used to repair acute slipped capital femoral epiphysis were evaluated in bone specimens form immature dogs. A servohydraulic testing machine was used to create slipped capital femoral epiphysis in 7 pairs of femurs by shearing the capital femoral epiphysis along the physis in a craniocaudal direction. The slip was reduced and repaired with one 3.5-mm-diameter screw placed in lag fashion or 2 double-pointed, 1.6-mm (0.062 inch)-diameter smooth pins and retested. Strength and stiffness of each intact femur (which served as the control) and repaired femur were compared. Results of the study indicated that the failure strength of 2-pin fixation was significantly (P < 0.05) weaker than its control and the 1-screw fixation. There was no significant difference between failure strength of the 1-screw fixation and its control. The stiffness of 1-screw and 2-pin fixations was not significantly different, compared with each other, but was significantly (P < 0.05) less, compared with their respective controls.
在未成熟犬的骨标本中评估了用于修复急性股骨头骨骺滑脱的两种固定治疗方法的生物力学强度和刚度。使用伺服液压试验机通过在颅尾方向沿骺板剪切股骨头骨骺，在7对股骨中制造股骨头骨骺滑脱。通过以拉力方式置入一枚直径3.5毫米的螺钉或两枚直径1.6毫米（0.062英寸）的双尖光滑针来复位并修复滑脱，然后再次进行测试。比较了每根完整股骨（作为对照）和修复后股骨的强度和刚度。研究结果表明，双针固定的破坏强度显著低于其对照和单螺钉固定（P<0.05）。单螺钉固定的破坏强度与其对照之间无显著差异。单螺钉和双针固定的刚度彼此之间无显著差异，但与各自的对照相比显著降低（P<0.05）。
