cartilage contact visualization postview

While the labrum might become inverted with large amounts of traction, the amount of traction used herein aimed only to separate the acetabular and femoral cartilage surfaces and does not appear to have deformed the labrum ( Fig 1). However, as the labrum is marginal to the hip capsule, the increased tension on the capsule may have altered the morphology of the labrum and influenced the observed results. A related concern is that of the morphology of the labrum to provide clear visualization of the labrum and separate cartilage layers of the femur and acetabulum, traction was applied during image acquisition. Our study is also unable to quantify the amount of motion that would occur due to conformation of the labrum to the femur nor the amount of motion that would eventually lead to labral tears or chondral pathology. Similarly, external rotation angles greater than 60° were considered to be non-physiological and no result was recorded for these cases. In these cases, no result was recorded for the simulation position for the subject. Due to the morphology of the femur, acetabulum, and labrum (i.e., femoral neck shaft angle, femoral version, and morphology of the anterior inferior iliac spine), a femur position that did not overlap with the pelvis or labrum could not always be found using this simulation protocol. For larger flexion or adduction angles, the femur may have been in contact with the acetabulum or labrum before any internal rotation in this scenario, the femur was externally rotated, resulting in a negative internal rotation angle. For the simulation, the pelvis was fixed and the femur rotated internally in increments of 1°. Before the start of the simulation, the pelvis was transformed to represent femoral flexion and adduction while maintaining the femoral coordinate system. The ROM simulation was completed using custom MATLAB scripts, which evaluated surface-based overlap relative to vectors normal to the bone surface. All rotations were applied about the FHC. All landmarks were defined using surface-based curvature in PostView (2.4.1 University of Utah, Salt Lake City, UT) and custom scripts in MATLAB (9.3.0 MathWorks, Natick, MA). The neutral position of the hip was deﬁned as the position at which both the pelvic and femoral coordinate systems were aligned rotationally, and the femoral and acetabular centers were aligned. The lateral axis of the femur connected the 2 posterior landmarks of the femoral condyles, whereas the vertical axis connected the FHC and the knee center. The femoral coordinate system was constructed from the posterior aspects of the 2 femoral condyles, the knee center, and the femoral head center (FHC) ( Fig 2C). The lateral axis of the pelvis connected the 2 ASIS landmarks ( Fig 2A), whereas the vertical axis connected the midpoints of the 2 ASIS and the 2 pubic tubercle landmarks ( Fig 2B). The pelvic coordinate system was constructed using bilateral landmarks of the anterior superior iliac spine (ASIS) and the midpoint of the pubic tubercles to generate the anterior–pelvic plane.

Cartilage contact visualization postview