The Knee, ISSN: 1873-5800, Vol: 22, Issue: 6, Page: 624-9

Patient-specific implants with custom cutting blocks better approximate natural knee kinematics than standard TKA without custom cutting blocks

Shantanu Patil; Adam Bunn; William D. Bugbee; Clifford W. Colwell Jr.; Darryl D. D'Lima
Knee

Highlights

  • Patient dissatisfaction after TKA is linked to improper alignment and placement of implants.
  • Restoration of normal kinematics of knee is not achieved using off-the-shelf implants and traditional instruments.
  • A patient-specific implant along with customized instruments recreates kinematics, which is closer to the natural knee.

Abstract

Background

Nearly 14% to 39% TKA patients report dissatisfaction causing incomplete return of function. We proposed that the kinematics of knees implanted with patient-specific prostheses using patient-specific cutting guides would be closer to normal.

 

Methods

Eighteen matched cadaver lower limbs were randomly assigned to two groups: group A was implanted with patient-specific implants using patient-specific cutting guides; group B, the contralateral knee, was implanted with a standard design using intramedullary alignment cutting guides. Knee kinematics were measured on a dynamic closed-kinetic-chain Oxford knee rig, simulating a deep knee bend and in a passive rig testing varus–valgus laxity.

Results

The difference from normal kinematics was lower for group A compared to group B for active femoral rollback, active tibiofemoral adduction, and for passive varus–valgus laxity.

 

Conclusions

Our results support the hypothesis that knees with patient-specific implants generate kinematics more closely resembling normal knee kinematics than standard knee designs.

Clinical Relevance

Restoring normal kinematics may improve function and patient satisfaction after total knee arthroplasty.


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