Altuntas Altay O, Dagge Benjamin, Chin Terence Y P, Palamara Joseph E A, Eizenberg Norman, Wolfe Rory, Graham H Kerr
J Child Orthop. 2011 Jun;5(3):225-30. doi: 10.1007/s11832-011-0335-5. Epub 2011 Mar 25.
Lengthening of soft-tissue contractures is frequently required in children with a wide variety of congenital and acquired deformities. However, little is known about the biomechanics of surgical procedures which are commonly used in contracture surgery, or if variations in technique may have a bearing on surgical outcomes. We investigated the hypothesis that the site of intramuscular tenotomy (IMT) within the muscle-tendon-unit (MTU) of the tibialis posterior (TP) would affect the lengthening characteristics.
We performed a randomized trial on paired cadaver tibialis posterior muscle-tendon-units (TP-MTUs). By random allocation, one of each pair of formalin-preserved TP-MTUs received a high IMT, and the other a low IMT. These were individually tensile-tested with an Instron(®) machine under controlled conditions. A graph of load (Newtons) versus displacement (millimetres) was generated for each pair of tests. The differences in lengthening and load at failure for each pair of TP-MTUs were noted and compared using paired t tests.
We found 48% greater lengthening for low IMT compared to high IMT for a given load (P = 0.004, two tailed t test). Load at failure was also significantly lower for the low IMT. These findings confirm our hypothesis that the site of the tenotomy affects the amount of lengthening achieved. This may contribute to the reported variability in clinical outcome.
Understanding the relationship between tenotomy site and lengthening may allow surgeons to vary the site of the tenotomy in order to achieve pre-determined surgical goals. It may be possible to control the surgical "dose" by altering the position of the intramuscular tenotomy within the muscle-tendon-unit.
患有各种先天性和后天性畸形的儿童常常需要进行软组织挛缩延长术。然而，对于挛缩手术中常用的外科手术的生物力学，或者技术差异是否会对手术结果产生影响，我们知之甚少。我们研究了这样一个假设，即胫后肌（TP）的肌腱肌肉单元（MTU）内的肌内肌腱切断术（IMT）部位会影响延长特性。
我们对成对的尸体胫后肌腱肌肉单元（TP-MTUs）进行了一项随机试验。通过随机分配，每对用福尔马林保存的TP-MTUs中的一个接受高位IMT，另一个接受低位IMT。在受控条件下，使用英斯特朗（®）机器对它们分别进行拉伸测试。为每对测试生成载荷（牛顿）与位移（毫米）的图表。记录每对TP-MTUs在延长和失效载荷方面的差异，并使用配对t检验进行比较。
我们发现，在给定载荷下，低位IMT的延长比高位IMT大48%（P = 0.004，双侧t检验）。低位IMT的失效载荷也显著更低。这些发现证实了我们的假设，即肌腱切断术的部位会影响实现的延长量。这可能导致所报道的临床结果的变异性。
了解肌腱切断术部位与延长之间的关系，可能使外科医生能够改变肌腱切断术的部位，以实现预定的手术目标。通过改变肌内肌腱切断术在肌腱肌肉单元内的位置，有可能控制手术“剂量”。
