A posterior-stabilized total knee arthroplasty shows condylar lift-off during deep knee bends
Lee, S.Yang.; Matsui, N.; Kurosaka, M.; Komistek, R.D.; Mahfouz, M.; Dennis, D.A.; Yoshiya, S.
Clinical Orthopaedics and Related Research 2005(435): 181-184
2005
ISSN/ISBN: 0009-921X PMID: 15930936 Document Number: 594279
This prospective randomized study was done to examine whether any difference in presentation of condyler lift-off exists between posterior cruciate-retaining and posterior-stabilized total knee arthroplasties. Fluoroscopic analysis of flexion kinematics under weightbearing condition was done for 18 patients who had bilateral paired total knee arthroplasties. The posterior cruciate-retaining and posterior-stabilized prostheses were from the same total knee arthroplasty series with comparable surface geometries and were implanted by one surgeon. At evaluation, five of 18 patients (28%) with posterior cruciate-retaining total knee arthroplasties had condylar lift-off, compared with 12 of 18 patients (67%) with posterior-stabilized total knee arthroplasties. Consequently, a significant difference in its incidence was seen between the groups. Condylar lift-off in posterior-stabilized knees was observed at various flexion angles, and one knee in this group had lift-off laterally and medially at different flexion angles. These findings raise concern that the higher incidence of condylar lift-off in posterior-stabilized total knee arthroplasty may lead to an increased wear rate of polyethylene associated with long-term prosthetic loosening.