Effects from Extramedullary Design of Femoral Stem on Hip Contact Force: A Musculoskeletal Multi-Body Dynamic Study / 医用生物力学

ABSTRACT

Objective To investigate the effects of design parameters such as neck-shaft angle, femoral offset and anteversion angle of total hip arthroplasty ( THA) prosthesis on contact forces of the hip. Methods A musculoskeletal multi-body dynamic model of THA was established based on AnyBody software. The effects of single or multiple factors on hip contact force were studied when the neck-shaft angle, eccentricity and anteversion angle varied within ±10°, ±20 mm and ±10°, respectively. Results The maximum hip contact force increased by 26. 08% when femoral offset was reduced by 20 mm. The maximum hip contact force increased by 5. 99% when the neck-shaft angle increased by 10°. When the anteversion angle increased by 10°, the hip contact force decreased at 0% -24% of gait cycle, with the peak decreasing by 19. 16% . However, the hip contact force was significantly increased at 38% -70% of gait cycle, with the peak increasing by 67. 78% . Conclusions In extramedullary design of the femoral stem, based on reconstruction of the patient’s anatomical parameters, the offset of the femoral stem can be appropriately increased, and the neck-shaft angle and anteversion angle can bereduced to avoid increasing forces on the hip.