Jiong Mei1, Fei Yan2, Ming Ni3, Hua Wang4, Fangfang Zhang4, Zhaobin Wang4. 1. Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China. Electronic address: meijiong@sjtu.edu.cn. 2. Laboratory of Biomechanical Engineering, Department of Applied Mechanics, Sichuan University, Room 503, Yifu Science and Technology Building, Yihuan Road, Chengdu 610065, China; Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, ST 405, No.11, Yuk Choi Road, Hung Hom, Kowloon 999077, Hong Kong, China. 3. Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, ST 405, No.11, Yuk Choi Road, Hung Hom, Kowloon 999077, Hong Kong, China. 4. Department of Orthopaedics, Tongji Hospital, Tongji University School of Medicine, Shanghai 200065, China.
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 mm Hg, an increase in IAP caused a reduction in blood flow. When the IAP was relatively high (above 60 mm 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.
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 mm Hg, an increase in IAP caused a reduction in blood flow. When the IAP was relatively high (above 60 mm 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.