ABSTRACT
To study the direction and biomechanical consequences of hip center of rotation (HCOR) migration in Crowe type III and VI hips after total hip arthroplasty, post-operative radiographs and CT scans of several unilaterally affected hips were evaluated. Using a three-dimensional model of the human hip, the HCOR was moved in all directions, and joint reaction force (JRF) and abductor muscle force (AMF) were calculated for single-leg stance configuration. Comparing to the normal side, HCOR had displaced medially and inferiorly by an average of 23.4% and 20.8%, respectively, of the normal femoral head diameter. Significant decreases in JRF (13%) and AMF (46.13%) were observed in a presumptive case with that amount of displacement. Isolated inferior displacement had a small, increasing effect on these forces. In Crowe type III and IV hips, the HCOR migrates inferiorly and medially after THA, resulting in a decrease in JRF, AMF, and abductor muscle contraction force.
Subject(s)
Arthroplasty, Replacement, Hip , Hip Dislocation, Congenital/diagnostic imaging , Hip Dislocation, Congenital/physiopathology , Biomechanical Phenomena , Computer Simulation , Hip Dislocation, Congenital/surgery , Humans , Radiography , RotationABSTRACT
Fresh osteochondral allografts were used for post-traumatic knee defects >3 cm in diameter and 1 cm in depth. Harvesting of the grafts was carried out within 24 hours of the death of the donor, and implantation into the recipient was carried out within 72 hours. The grafts were unipolar, fixed by screws, and combined with realignment osteotomy if a deformity existed. Meniscal transplantation also was performed if indicated. The survivorship of all grafts (plateaus and condyles) at 7.5 years was 85%. The survivorship of femoral condyle grafts at 10 years was 85%. Viable hyaline cartilage has been confirmed at 17 years.
