Yen Chi-Hung, Leung Hon-Bong, Tse Paul Yun-Tin
Department of Orthopaedics and Traumatology, Queen Mary Hospital, Pokfulam, The Hong Kong Special Administrative Region.
J Orthop Surg Res. 2009 Apr 2;4:8. doi: 10.1186/1749-799X-4-8.
Increase in hip intra-capsular pressure has been implicated in various hip pathologies, such as avascular necrosis complicating undisplaced femoral neck fracture. Our study aimed at documenting the relationship between intra-capsular volume and pressure in various hip positions.
Fifty-two cadaveric hips were studied. An electronic pressure-monitoring catheter recorded the intra-capsular hip pressure after each instillation of 2 ml of normal saline and in six hip positions.
In neutral hip position, the control position for investigation, intra-capsular pressure remained unchanged when its content was below 10 ml. Thereafter, it increased exponentially. When the intra-capsular volume was 12 ml, full abduction produced a 2.1-fold increase (p = 0.028) of the intra-capsular hip joint pressure; full external rotation and full internal rotation increased the pressure by at least 4-fold (p < 0.001). Conversely, there was a 19% (p = 0.046) and 81% (p = 0.021) decrease in intra-capsular hip joint pressure with flexion of the hip joint to 90-degree and 45-degree, respectively.
Intra-capsular pressure increases with its volume, but with a wide variation with different positions. It would be appropriate to recommend that hips with haemarthrosis or effusion should be positioned in 45-degree flexion.
髋关节囊内压力升高与多种髋关节病变有关，如无移位股骨颈骨折并发的缺血性坏死。我们的研究旨在记录不同髋关节位置时囊内容积与压力之间的关系。
对52个尸体髋关节进行研究。每次注入2毫升生理盐水后，在六个髋关节位置使用电子压力监测导管记录髋关节囊内压力。
在髋关节中立位（研究的对照位置），当囊内容积低于10毫升时，囊内压力保持不变。此后，压力呈指数级增加。当囊内容积为12毫升时，髋关节完全外展使囊内髋关节压力增加2.1倍（p = 0.028）；完全外旋和完全内旋使压力至少增加4倍（p < 0.001）。相反，髋关节分别屈曲至90度和45度时，囊内髋关节压力分别降低19%（p = 0.046）和81%（p = 0.021）。
囊内压力随其容积增加，但在不同位置变化很大。建议有血关节积血或积液的髋关节应处于45度屈曲位。
