髋关节后外侧入路中软组织松解对髋关节张力的影响

目的 研究髋关节后外侧入路中不同软组织结构松解对髋关节伸直位张力的影响.方法 新鲜冰冻尸体5具10个髋关节,均采用髋关节后外侧入路显露.在骨盆髂前上棘位置垂直于床面固定一枚克氏针,在股骨干侧方固定另一枚克氏针.测量不同软组织松解操作前后两枚克氏针之间的位移变化.结果 单纯进行牵引、外旋肌切断、后关节囊切开和臀大肌止点切断等操作前后,位移没有明显变化.股骨头切除、阔筋膜髂胫束切断、关节囊全部切除和髂腰肌腱切断后,两枚克氏针距离平均延长1.5mm(1～3mm)、8.0mm(2～19mm)、5.5mm(1～13mm)、1.8mm(1～3mm).同时切断关节囊和阔筋膜髂胫束前后位移变化最大,测量距离平均延长13.5 mm(11～20mm).结论 前关节囊、阔筋膜髂胫束和髂腰肌腱的松解可以降低髋关节伸直位的软组织张力,其中前关节囊和阔筋膜髂胫束的作用最大.髋关节周围的软组织对张力的影响相互制约,单一松解其中一种结构不能获得满意的松解效果.阔筋膜和髂胫束的紧张度可以帮助判断肢体的延长情况.

The influence of soft tissue release on the tension around hip joint through posterolateral hip approach

Objective To investigate the influence of selective soft tissue release on the tension around hip joint through posterolateral approach, and to ascertain the sequence of soft tissue release in total hip arthroplasty. Methods Five fresh frozen cadavers with ten intact lower extremities were used in the study. All the pelves of cadavers were fixed on the operating table by a special designed fixer on a lateral position. Femoral supracondylar bone traction was employed for axial traction. The force for traction was 15 kg. Posterolateral approach was used for exposure and two sequences for soft tissue release were studied. One Kirschner wire was fixed at the bone near the anterior superior iliac spine, and the wire was perpendicu-lar to the operating table. Another Kirschner wire was fixed into the bone at lateral femoral shaft. The two Kirschner wires were parallel to each other. The distance between the two Kirschner wires was measured be-fore and after each soft tissue structure release. Results There were no significant changes of the distance measured before and after applying traction alone, releasing external rotation muscles, opening the posterior capsule and releasing the gluteus maximus insertion. There were significant changes of distance measured before and after resection of femoral head, release of tensor fasciae latae and/or iliotibial band, excision of anterior capsule, and release of iliopsoas tendon had. The average lengthened distance was 1.5 mm (range, 1-3 mm) after resection of femoral head, and 8.0 mm (range, 2-19 mm) after release of tensor fasciae latae and/or iliotibial band, 5.5 mm (range, 1-13 mm) after excision of anterior capsule, and 1.8 mm (range, 1-3 mm) after release of iliopsoas tendon respectively. The distance lengthened after both release of tensor fasci-ae latae (and/or iliotibial band) and excision of anterior capsule was the most significant, average 13.5 mm (range, 11-20 mm). Conclusion Release of anterior capsule, tensor fasciae latae and/or iliotibial band, and iliopsoas tendon will decrease the soft tissue tension around hip joint. Among all the soft tissue structures we investigated, the anterior capsule and tensor fasciae latae (iliotibial band) make the most effective result. To maintain the soft tissue tension around hip joint depends on different structures working together, releasing one structure alone may not obtain the optimal result. Careful evaluation of tension of tensor fasciae latae and iliotibial band can help avoiding the limb length discrepancy during hip arthroplasty surgery.