TY - JOUR
T1 - Differences in patellar tracking and knee kinematics among three different total knee designs
AU - Chew, Jeffrey T.H.
AU - Stewart, Nathaniel J.
AU - Hanssen, Arlen D.
AU - Luo, Zong Ping
AU - Rand, James A.
AU - An, Kai Nan
PY - 1997
Y1 - 1997
N2 - Patellar complications are the primary reason for reoperation of the current condylar type designs. The aim of this study was to compare patellar tracking of various knee implant designs: Genesis II NexGen, and the P.F.C. Sigma Modular Knee System regarding trochlear groove center curvature. Nine unembalmed whole cadaveric lower extremities were used. The quadriceps and hamstrings were dissected into their individual muscles and loads were applied onto the muscles proximally based on the cross sectional area of the muscles. The three-dimensional kinematics of the patellofemoral and fibiofemoral joint of the intact knee were measured using a 3Space tracking system. Three implants (one from each company) were implanted onto the same cadaveric knee in random order consecutively. This was done to ensure consistency of the soft tissue constraints in influencing the amount of patellar tracking. Patellar rotation, patellar tilting, patellar lateral shift and patellar displacement in relation to groove center were measured. There was no significant difference between the intact knee and the various implants regarding patellar rotation and lateral shift. However, all three prosthetic designs showed a significant degree of lateral tilting when compared with the intact knee. At 60°knee flexion, the normal patella was tilted laterally to 0.44°± 2.15°as compared with the Genesis II patella at 4.75°± 4.81°, the NexGen patella at 4.85°± 4.81°, and the P.F.C. Sigma patella at 4.89°± 3.79°lateral tilt. There was no difference between the intact knee compared with the resurfaced patella in patellar displacement in relation to the groove center. This study suggests the relatively similar kinematic behavior between the implant designs as compared with the intact knees. However, additional modification of implant geometry may be required to help decrease the amount of patellar tilt.
AB - Patellar complications are the primary reason for reoperation of the current condylar type designs. The aim of this study was to compare patellar tracking of various knee implant designs: Genesis II NexGen, and the P.F.C. Sigma Modular Knee System regarding trochlear groove center curvature. Nine unembalmed whole cadaveric lower extremities were used. The quadriceps and hamstrings were dissected into their individual muscles and loads were applied onto the muscles proximally based on the cross sectional area of the muscles. The three-dimensional kinematics of the patellofemoral and fibiofemoral joint of the intact knee were measured using a 3Space tracking system. Three implants (one from each company) were implanted onto the same cadaveric knee in random order consecutively. This was done to ensure consistency of the soft tissue constraints in influencing the amount of patellar tracking. Patellar rotation, patellar tilting, patellar lateral shift and patellar displacement in relation to groove center were measured. There was no significant difference between the intact knee and the various implants regarding patellar rotation and lateral shift. However, all three prosthetic designs showed a significant degree of lateral tilting when compared with the intact knee. At 60°knee flexion, the normal patella was tilted laterally to 0.44°± 2.15°as compared with the Genesis II patella at 4.75°± 4.81°, the NexGen patella at 4.85°± 4.81°, and the P.F.C. Sigma patella at 4.89°± 3.79°lateral tilt. There was no difference between the intact knee compared with the resurfaced patella in patellar displacement in relation to the groove center. This study suggests the relatively similar kinematic behavior between the implant designs as compared with the intact knees. However, additional modification of implant geometry may be required to help decrease the amount of patellar tilt.
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U2 - 10.1097/00003086-199712000-00013
DO - 10.1097/00003086-199712000-00013
M3 - Article
C2 - 9418625
AN - SCOPUS:0031468408
SN - 0009-921X
VL - 345
SP - 87
EP - 98
JO - Clinical Orthopaedics and Related Research
JF - Clinical Orthopaedics and Related Research
ER -