Finite element simulations of a hip joint with femoroacetabular impingement

Abstract

In this study, a three-dimensional finite element (FE) model based on the specific anatomy of a patient presenting a femoroacetabular impingement of the 'cam'-type is developed. The FE meshes of the structures of interest are obtained from arthrographic magnetic resonance images. All soft tissues are considered linear elastic and isotropic, and the bones were assumed rigid. A compression of the femur on the acetabular cavity as well as flexural movements and internal rotations are applied. Stresses and contact pressures are evaluated in this patient-specific model in order to better interpret the mechanism of aggression of the femoral and acetabular cartilages. The corresponding results are presented and discussed. The values obtained for the contact pressures are similar to those reported by other models based on idealised geometries. An FE analysis of a non-cam hip is also performed for comparison with the pathological case.

Hip kinematics and kinetics in persons with and without cam femoroacetabular impingement during a deep squat task

“…This seems logical given previous reports of a relationship between cam morphology and diminishing passive hip internal rotation range of motion (Audenaert et al, 2012;Notzli et al, 2002;Wyss et al, 2007). Additionally, a previous finite element modeling study by Jorge et al (2014) demonstrated the extent to which cam morphology can limit hip internal rotation. These authors found that at 90°of hip flexion, internal rotation was limited to 2.8°in the presence of a large cam deformity (alpha angle 98°) (Jorge et al, 2014).…”

“…Additionally, a previous finite element modeling study by Jorge et al (2014) demonstrated the extent to which cam morphology can limit hip internal rotation. These authors found that at 90°of hip flexion, internal rotation was limited to 2.8°in the presence of a large cam deformity (alpha angle 98°) (Jorge et al, 2014). A post-hoc analysis of the data obtained in the current study revealed that the degree of cam morphology and peak hip internal rotation during the deep squat task were inversely correlated (R = 0.48; P = 0.04).…”

Increased Hip Stresses Resulting From a Cam Deformity and Decreased Femoral Neck-Shaft Angle During Level Walking

“…The current study considered hip contact forces as opposed to intersegmental forces from inverse dynamics, thus improving the representation of hip contact stresses. Jorge and associates [18] found much higher cartilage contact pressures at higher amplitudes of hip motion. However, their study was limited to one male subject with a severe cam deformity (age = 27 years, alpha angle = 98°) matched with one healthy female control subject (age = 50 years, alpha angle = 48°).…”

“…It has also been demonstrated that subchondral bone density is higher in individuals with a symptomatic or asymptomatic cam morphology [52,53]; however, previous finite element simulations neglected subject-specific bone material properties. Previous finite element studies also attempted to delineate pathomechanics of cam FAI using hip reaction loads from instrumented hip prostheses [8,15,18] or from inverse dynamics [37], which is typically limited to external and inertial forces and neglects muscle activity [26,54]. Because muscles contribute greatly to hip contact forces, it may be more appropriate to implement rigid body dynamics and musculoskeletal modeling (including gravitational, inertial, and muscle forces) to calculate joint contact loads.…”

Sagittal plane pelvis motion influences transverse plane motion of the femur: Kinematic coupling at the hip joint

“…In persons with femoroacetabular impingement, for example, anterior pelvis tilt and femur internal rotation increase approximation of the femoral head-neck junction with the acetabulum [14,15]. Such abutment is hypothesized to contribute to A c c e p t e d M a n u s c r i p t 9 labral damage [16][17][18], chondral damage [16,17,19], and hip osteoarthritis [20,21].…”