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


CONCLUSIONS
Restoring normal kinematics may improve function and patient satisfaction after total knee arthroplasty.
Shantanu
S
Patil
Adam
A
Bunn
William D
WD
Bugbee
Clifford W
CW
Colwell
Darryl D
DD
D'Lima
D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology / Q000601:surgery; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery*; D007720:Knee Prosthesis; D009989:Orthotic Devices; D011474:Prosthesis Design; D016059:Range of Motion, Articular / Q000502:physiology*