Computational modelling of hip resurfacing arthroplasty investigating the effect of femoral version on hip biomechanics

Abstract

Aim How reduced femoral neck anteversion alters the distribution of pressure and contact area in Hip Resurfacing Arthroplasty (HRA) remains unclear. The purpose of this study was to quantitatively describe the biomechanical implication of different femoral neck version angles on HRA using a finite element analysis. Materials and methods A total of sixty models were constructed to assess the effect of different femoral neck version angles on three different functional loads: 0°of hip flexion, 45°of hip flexion, and 90° of hip flexion. Femoral version was varied between 30° of anteversion to 30° of retroversion. All models were tested with the acetabular cup in four different positions: (1) 40°/15° (inclination/version), (2) 40°/25°, (3) 50°/15°, and (4) 50°/25°. Differences in range of motion due to presence of impingement, joint contact pressure, and joint contact area with different femoral versions and acetabular cup positions were calculated. Results Impingement was found to be most significant with the femur in 30° of retroversion, regardless of acetabular cup position. Anterior hip impingement occurred earlier during hip flexion as the femur was progressively retroverted. Impingement was reduced in all models by increasing acetabular cup inclination and anteversion, yet this consequentially led to higher contact pressures. At 90° of hip flexion, contact pressures and contact areas were inversely related and showed most notable change with 30° of femoral retroversion. In this model, the contact area migrated towards the anterior implant-bone interface along the femoral neck. Conclusion Femoral retroversion in HRA influences impingement and increases joint contact pressure most when the hip is loaded in flexion. Increasing acetabular inclination decreases the area of impingement but doing so causes a reciprocal increase in joint contact pressure. It may be advisable to study femoral neck version pre-operatively to better choose hip resurfacing arthroplasty candidates.

Abnormal Spinopelvic Motion and Spine Deformity are Associated With Native Femoral Retroversion in the Setting of Total Hip Arthroplasty

“…Furthermore, femoral retroversion carries the risk of impingement of the femoral neck and acetabular rim and should be especially considered in THA patients with histories of femoroacetabular impingement, slipped capital femoral epiphysis, and malunited fracture [ 22 ]. Compensatory increases in acetabular anteversion in arthroplasty decrease impingement risk at the cost of increased joint contact forces [ 23 ]. Subsequently risk of instability, wear, and dislocation is increased [ 7 ].…”

Analysis of contact pressure in a 3D model of dual-mobility hip joint prosthesis under a gait cycle

“…2. Based on the literature 32 , the inclination angle applied on the acetabular cup component would lead to different resulting contact pressure values on the bearing of the hip joint prosthesis. The inner liner and outer liner have the same ideal inclination on all variations of the acetabular cup inclination angle applied.…”