Changes in intraarticular pressure on the blood supply in the retinaculum of the femoral neck.

Abstract

BACKGROUND: This study aimed to analyze the effects of intracapsular pressure (IAP) on blood flow in the femur after a femoral neck fracture. METHODS: Four simplified vascular models were used to measure the effect of vessel length on arterial blood flow in 10 New Zealand white rabbits. Ten models were evaluated under 10 different blood pressures. FINDINGS: IAP increased following fracture of the femoral neck, and deformation had the greatest potential effect on blood flow in the retinacular artery. When blood pressure was fixed at 60&#x202f;mm&#x202f;Hg, an increase in IAP caused a reduction in blood flow. When the IAP was relatively high (above 60&#x202f;mm&#x202f;Hg), and higher than the blood pressure, blood flow continued to drop as intracapsular pressure increased. Shortening of blood vessels had no significant effect on blood supply. However, the p-value was uniformly significant (<0.05) when stretched and twisted blood vessels were compared with normal blood vessels. INTERPRETATION: The results of computational fluid-structure interaction similarly indicated that a smaller blood vessel diameter and twisted blood vessels will result in decreased flow velocity when IAP increases. This study also revealed a close relationship between IAP and the hip joint's position and traction.