Archives of Medical Science vol:11 issue:2 pages:311-318
Introduction: Correct restoration of the joint line is generally considered as crucial when performing total knee arthroplasty. During revision knee arthroplasty however, elevation of the joint line occurs frequently. The general belief is that this negatively affects clinical outcome, but reasons are still not well understood.
Materials and Methods: In this cadaveric in vitro study the biomechanical consequences of joint line elevation were investigated using a previously validated cadaver model simulating active deep knee squats and passive flexion-extension cycles. Knee specimens were sequentially tested after total knee arthroplasty with joint line restoration and after 4 mm joint line elevation.
Results: Results show that no significantly negative effects of 4 mm joint line elevation were observed on tibio-femoral kinematics, collateral ligaments lengths, tibio-femoral contact pressures or quadriceps forces after TKA.
Discussion and Conclusion: Our study suggests that joint line elevation by 4 mm in revision total knee arthroplasty does not cause significant kinematic and kinetic differences during passive flexion/extension movement and squatting in the tibio-femoral joint, nor does it affect the elongation patterns of collateral ligaments. Therefore, clinical problems after joint line elevation are probably situated in the patello-femoral joint or caused by joint line elevation of more than 4 mm.