Peer-review started: December 25, 2017
First decision: January 6, 2018
Revised: January 12, 2018
Accepted: February 4, 2018
Article in press: February 5, 2018
Published online: March 18, 2018
To investigate that the increased intracapsular pressure, during the delay period, can interrupt the blood flow to the femoral head.
An observational retrospective study included a group of 17 patients with traumatic hip dislocation, their ages at time of injury averaged 26 (range from 3 to 70) years. Outcomes were assessed clinically and radiographically at a period averaged 11.5 (range from 4 to 20) years.
Minor trauma caused dislocation in seven and severe trauma in ten patients. All dislocations were posterior, six isolated dislocation and 11 were associated with other injuries. The negligence period averaged 2.5 (ranged from 1 to 4) d. At the latest visit, the radiography revealed normal hip in 11 and avascular necrosis (AVN) in six patients. Clinically, eight patients were rated as excellent, three good, three fair and three poor.
We believe the factors that contribute to increased intracapsular pressure also increase the influence of delayed reduction toward the development of AVN.
Core tip: Factors influencing outcomes of traumatic hip dislocation include reduction time, the severity of trauma, patients’ ages and direction of dislocation. Although these factors have been thoroughly investigated, any of them was not assigned as the causative for the development of the avascular necrosis (AVN). Does the increased intracapsular pressure is the foremost factor? We believe that the factors as hemarthrosis, the position of the limb during the pre-reduction period particularly in posterior dislocation and traction in post-reduction period can increase the intracapsular pressure to a level sufficient for occlusion of intracapsular blood vessels. Delayed reduction accentuates influence of increased intracapsular pressure in favour of the development of AVN.