Contact pressures in the flexed hip joint during lateral trochanteric loading

Abstract

Acetabular fractures are an especially problematic outcome of motor vehicle side impacts. While fracture type has been correlated with impact direction and femoral orientation, actual contact pressures in the hip joint have not been quantified for lateral loading conditions. In the present study, we used pressure sensitive film to measure contact areas and pressures in seven hip joints from four cadavers under quasi-static lateral loading through the greater trochanter. The aim was to quantify the interactions of the femoral head with the acetabulum associated with variations in femoral orientation. Three angles of hip flexion (80°, 90°, 100") and hip abduction (-loo, 0", 10') were tested, producing nine test orientations for each joint. We observed that contact areas, pressures, and forces varied significantly with femoral orientation for the adducted hip. The principal locations of load transmission were in the anterior and posterior regions of the acetabulum. For the abducted femur, contact pressures were concentrated anteriorly, and with increased adduction, anterior contact pressures diminished while posterior and superior pressures increased. The movement of pressure sites was consistent with mechanisms of acetabular fractures described by Letournel and Judet and provides new data for validation of finite element models of the pelvis in side impact.

Impact induced failure of cartilage-on-bone following creep loading: A microstructural and fracture mechanics study

“…In vivo studies show that the hip and knee joint experience significant contact forces of between 1 and 2 times bodyweight even in seemingly relaxed positions such as sitting and standing (Bergmann et al, 2001;Varadarajan et al, 2008). Further, equivalent contact stresses in these same joints have been estimated to be as much as 3-8 MPa (Thambyah et al, 2005;Sparks et al, 2005;Yoshida et al, 2006). In view of such physiological levels of stress we might ask whether such large and sustained contact stresses might make the joint tissues more susceptible to subsequent injury following a more dynamic or transient mode of loading.…”

Deformation and recovery of cartilage in the intact hip under physiological loads using 7T MRI

“…However, the natural incongruity of the femoral head with the acetabulum is lost and the cartilage-cartilage interface is replaced by a cartilage-synthetic interface, which limits extrapolation of these results to the natural hip (Hodge et al, 1986;Krebs et al, 1991;Macirowski et al, 1994). Pressure sensitive film has been used ex vivo (Afoke et al, 1987;Sparks et al, 2005), but it has a limited resolution and interferes substantially with contact mechanics because of its thickness (Wu et al, 1998).…”

Is quality of life following hip arthroscopy in patients with chondrolabral pathology associated with impairments in hip strength or range of motion?

“…No other measures of hip joint ROM were associated with PROs. Hip flexion ROM beyond 80° is considered to increase load at the anterior aspect of the acetabulum [31]. As the majority of chondrolabral lesions occur in the anterior acetabulum [22], greater flexion ROM may increase load on damaged articular surfaces.…”