Kinematics of a cementless mobile bearing posterior cruciate ligament-retaining total knee arthroplasty.
Mobile bearing (MB) total knee arthroplasty (TKA) was developed to provide low contact stress and unconstrained joint motion. We studied a consecutive series of 41 knees with mobile-bearing, posterior cruciate-retaining (CR) TKAs to determine if kinematics resembled normal knees or if kinematics changed over time. Patients were studied at 3 and 21 months average follow-up with weight-bearing radiographs at full extension, 30 degrees flexion and maximum flexion. Shape-matching techniques were used to measure TKA kinematics. Implant hyperextension, maximum flexion and total ROM increased with follow-up. Tibial rotation and condylar translations did not change with time. The medial condyle did not translate from extension to 30 degrees, but translated 5 mm anteriorly from 30 degrees to maximum flexion. Lateral condylar translation was 3 mm posterior from extension to 30 degrees, with no translation from 30 degrees to maximum flexion. Tibiofemoral kinematics in CR-MB-TKAs were stable over time, but did not replicate motions observed in healthy knees. The mobile tibial insert showed rotation and translation at both follow-up examinations, but the patterns of translation were not predictable.
Chouteau
J
J
Service de chirurgie orthopédique, de traumatologie et de médecine du sport, Centre Hospitalier Lyon-Sud, Chemin du Grand Revoyet, 69495 Pierre Bénite, Cedex, France. juchout@club-internet.fr
Lerat
J L
JL
Testa
R
R
Moyen
B
B
Fessy
M H
MH
Banks
S A
SA
D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D002484:Cementation; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery; D010329:Patella / Q000601:surgery; D016119:Posterior Cruciate Ligament; D011859:Radiography; D016059:Range of Motion, Articular; D016474:Weight-Bearing