Email updates

Keep up to date with the latest news and content from Journal of Orthopaedic Surgery and Research and BioMed Central.

Open Access Research article

Effects of hip joint position and intra-capsular volume on hip joint intra-capsular pressure: a human cadaveric model

Chi-Hung Yen1, Hon-Bong Leung2* and Paul Yun-Tin Tse1

Author Affiliations

1 Department of Orthopaedics and Traumatology, Kwong Wah Hospital, 25 Waterloo Road, Yaumatei, The Hong Kong Special Administrative Region

2 Department of Orthopaedics and Traumatology, Queen Mary Hospital, Pokfulam, The Hong Kong Special Administrative Region

For all author emails, please log on.

Journal of Orthopaedic Surgery and Research 2009, 4:8  doi:10.1186/1749-799X-4-8

Published: 2 April 2009

Abstract

Background

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.

Methods

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.

Results

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.

Conclusion

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.