No difference in patellar tracking between symmetrical and asymmetrical femoral component designs in TKA

作者：Stoddard J E; Deehan D J; Bull A M J; McCaskie A W; Amis A A^*

来源：Knee Surgery, Sports Traumatology, Arthroscopy, 2014, 22(3): 534-542.

DOI：10.1007/s00167-013-2534-8

• Total knee arthroplasty (TKA)
• Patellofemoral joint
• Stability
• Kinematics
• Trochlear groove

Purpose Poor knee extension function after total knee arthroplasty (TKA) is associated with factors including articular geometry and alignment. Femoral trochlear geometry has evolved from symmetrical to become more prominent proximal-laterally, with the groove aligned proximal-lateral to distal-medial. This study in vitro tested the hypothesis that a modern asymmetrical prosthesis would restore patellar tracking and stability to more natural behaviour than an older symmetrical prosthesis.
Methods Six knees had their patellar tracking measured optically during active knee extension. Medial-lateral force versus displacement stability was measured at fixed angles of knee flexion. The measurements were repeated after inserting each of the symmetrical and asymmetrical TKAs.
Results Significant differences of patellar lateral displacement stability, compared to normal, were not found at any angle of knee flexion. The patella tracked medial-laterally within 2.5 mm of the natural path with both TKAs. However, for both TKAs near knee extension, the patella was tilted laterally by approximately 6 degrees and was also flexed approximately 8 degrees more than in the natural knee.
Conclusion The hypothesis was not supported: The more anatomical component design did not provide more anatomical patellar kinematics and stability.

• 出版日期2014-3