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Posterior tilting of the tibial component decreases femoral rollback in posterior‐substituting knee replacement: A computer simulation study
Author(s) -
Piazza Stephen J.,
Delp Scott L.,
Stulberg S. David,
Stern Steven H.
Publication year - 1998
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.1100160214
Subject(s) - sagittal plane , condyle , knee replacement , total knee replacement , range of motion , implant , orthodontics , medicine , posterior cruciate ligament , tilt (camera) , orthopedic surgery , anatomy , surgery , mathematics , geometry , anterior cruciate ligament
Posterior tilting of the tibial component is thought to increase the range of motion in posterior cruciate‐retaining total knee replacement, but its effect on implant motion in posterior cruciate‐substituting total knee replacement is unknown. This issue has become of interest recently because manufacturers have introduced instrumentation that produces a posteriorly tilted tibial cut for both implant types. The purpose of this study was to investigate how motion of posterior cruciate‐substituting total knee replacement is affected when the tibial component is installed with posterior tilt. Sagittal plane implant motions were predicted from prosthesis geometry with use of a computer simulation in which the femoral condyles were assumed to sit in the bottoms of the tibial condylar wells when the knee was in extension. Rollback of the femoral component was produced by a cam‐spine mechanism at higher angles of flexion. The simulations revealed that even small degrees of posterior tilt reduced rollback by limiting the interaction between the cam and spine. Tilting the component posteriorly by 5° caused the cam to contact the spine at a knee flexion angle that was 18° higher than with the untilted component. The results suggest that posterior tilting of the tibial component in posterior cruciate‐substituting knee replacement may not produce the same beneficial effects that have been reported for the tilting of tibial components in posterior cruciate‐retaining knee replacement.