Pelvic tilt (PT) can significantly change the functional orientation of the acetabular component and may differ markedly between patients undergoing total hip arthroplasty (THA). Patients with stiff spines who have little change in PT are considered at high risk for instability following THA. Femoral component position also contributes to the limits of impingement-free range of motion (ROM), but has been less studied. Little is known about the impact of combined anteversion on risk of impingement with changing pelvic position. We used a virtual hip ROM (vROM) tool to investigate whether there is an ideal functional combined anteversion for reduced risk of hip impingement. We collected PT information from functional lateral radiographs (standing and sitting) and a supine CT scan, which was then input into the vROM tool. We developed a novel vROM scoring system, considering both seated flexion and standing extension manoeuvres, to quantify whether hips had limited ROM and then correlated the vROM score to component position.Aims
Methods
DDH These methods have been applied to examine systematic variations in the shape and dimensions of the dysplastic femur through reference to data from 171 dysplastic and 84 skeletally normal patients. Of the 171 dysplastic femora, 74 (43%) were graded as Crowe I, 82 (48%) as Crowe stages II or III, and 15 (9%) as Crowe IV. The change in femoral morphology was quantified as a function of the grade of deformity in comparison with normal controls. The principal sources of deformity were also identified. FAI We examined the hypothesis that the femur of patients with femoro-acetbular impingement has multiple morphologic characteristics leading to reduced range of motion. Sixty-six cadaveric femora (30 male and 36 female, average age: 76 years) were selected from a large osteologic collection. Thirteen femora were morphologically normal and 53 were abnormal. Standard morphologic parameters were calculated and normalized with respect to the femoral head diameter. Additional parameters were determined to quantify the head/neck relationship. These included the I angle, the. angle, the anterior offset ratio (OSR), the anterior head-neck ratio, the posterior ‘slip’ of the femoral head, the neck shaft angle and the femoral neck anteversion.
