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Differences in patellar tracking and knee kinematics among three different total knee designs.
Clin Orthop Relat Res. 1997 DecCO

Abstract

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 tibiofemoral 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 degrees knee flexion, the normal patella was tilted laterally to 0.44 degree +/- 2.15 degrees as compared with the Genesis II patella at 4.75 degrees +/- 4.81 degrees, the NexGen patella at 4.85 degrees +/- 4.81 degrees, and the P.F.C. Sigma patella at 4.89 degrees +/- 3.79 degrees 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.

Authors+Show Affiliations

Chew JT
Orthopaedics Biomechanics Laboratory, Mayo Clinic, Rochester, MN 55905, USA.
Stewart NJ
No affiliation info available
Hanssen AD
No affiliation info available
Luo ZP
No affiliation info available
Rand JA
No affiliation info available
An KN
No affiliation info available

MeSH

Arthroplasty, Replacement, KneeFemurHumansKnee JointKnee ProsthesisMovementMuscle, SkeletalPatellaProsthesis DesignRange of Motion, ArticularReoperationRotationStress, MechanicalSurface PropertiesTendonsTibia

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

9418625

Citation

Chew, J T., et al. "Differences in Patellar Tracking and Knee Kinematics Among Three Different Total Knee Designs." Clinical Orthopaedics and Related Research, 1997, pp. 87-98.
Chew JT, Stewart NJ, Hanssen AD, et al. Differences in patellar tracking and knee kinematics among three different total knee designs. Clin Orthop Relat Res. 1997.
Chew, J. T., Stewart, N. J., Hanssen, A. D., Luo, Z. P., Rand, J. A., & An, K. N. (1997). Differences in patellar tracking and knee kinematics among three different total knee designs. Clinical Orthopaedics and Related Research, (345), 87-98.
Chew JT, et al. Differences in Patellar Tracking and Knee Kinematics Among Three Different Total Knee Designs. Clin Orthop Relat Res. 1997;(345)87-98. PubMed PMID: 9418625.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Differences in patellar tracking and knee kinematics among three different total knee designs. AU - Chew,J T, AU - Stewart,N J, AU - Hanssen,A D, AU - Luo,Z P, AU - Rand,J A, AU - An,K N, PY - 1998/1/7/pubmed PY - 1998/1/7/medline PY - 1998/1/7/entrez SP - 87 EP - 98 JF - Clinical orthopaedics and related research JO - Clin Orthop Relat Res IS - 345 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 tibiofemoral 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 degrees knee flexion, the normal patella was tilted laterally to 0.44 degree +/- 2.15 degrees as compared with the Genesis II patella at 4.75 degrees +/- 4.81 degrees, the NexGen patella at 4.85 degrees +/- 4.81 degrees, and the P.F.C. Sigma patella at 4.89 degrees +/- 3.79 degrees 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. SN - 0009-921X UR - https://www.unboundmedicine.com/medline/citation/9418625/Differences_in_patellar_tracking_and_knee_kinematics_among_three_different_total_knee_designs_ DB - PRIME DP - Unbound Medicine ER -