Internal femoral component malrotation in TKA significantly alters tibiofemoral kinematics

Abstract

tibia in lexion (squat 33-111°, p < 0.05), an elevated (squat 43-111°, p < 0.05) and more anterior (passive 61-126°, p < 0.05) located medial femoral condyle and a lateral femoral condyle located more posterior and inferior (squat 73-111°, p < 0.05) than in the neutrally aligned TKA. External component malrotation caused only little changes under passive motion. Under a squat there was less internal rotation and more adduction to the tibia (33-111°, p < 0.05). The medial femoral condyle was moved more posterior (squat 59-97°, p < 0.05), the lateral femoral condyle more superior (squat 54-105°, p < 0.05) than in the neutrally aligned TKA. Conclusion The greatest diferences to the native tibiofemoral kinematics were introduced by internal rotation of the femoral component. Also neutrally and externally rotated femoral components introduce kinematic changes, but to a lesser extent. With respect to the alterations introduced to kinematics internal malrotation should be avoided when performing PS TKA.

Lift-off reduction and patella tracking in Total Knee Arthroplasty (TKA) using a 3D printed patient-specific knee model

“…Lateral lift-off was also observed more often than medial lift-off in a study by Key et al 30 using fluoroscopy on patients after total knee arthroplasty while performing activity. More specifically, two studies by Scuderi 31 and Heyse 32 , show a similar reduction in lift-off when the femoral component is externally rotated. However, despite the general improvement in stability with improved prosthesis positioning, studies show that there is no direct correlation between femoral component rotation and postoperative patient satisfaction, as observed by Corona et al 33 .…”

Preoperative Virtual Total Knee Arthroplasty Surgery Using a Computed Tomography-based 3-dimensional Model With Variation in Reference Points and Target Alignment to Predict Femoral Component Sizing

“…In addition, there is a risk of internal rotation of the femoral component when using 2D measurement including CT slice planning, even with a precise bone cutting technique [ 29 ]. Many papers have reported problems with internal rotation placement [ [29] , [30] , [31] ]. When the femoral component is placed in internal rotation, the quadriceps force and the effect on the collateral ligaments are increased, and maltracking of the patella, increased peak contact force in the medial compartment, and paradoxical anterior position of the medial femoral condyle are observed [ 30 , 31 ].…”

“…Many papers have reported problems with internal rotation placement [ [29] , [30] , [31] ]. When the femoral component is placed in internal rotation, the quadriceps force and the effect on the collateral ligaments are increased, and maltracking of the patella, increased peak contact force in the medial compartment, and paradoxical anterior position of the medial femoral condyle are observed [ 30 , 31 ]. Based on the results of this study, we believe that if we can predict the size of components through accurate planning, we can suspect the possibility of internal rotation placement when the size is smaller than the planned size.…”

Is standard total knee arthroplasty with lateral femoral overhanging a cause of anterior knee pain? A randomized controlled trial

“…The reported incidence of AKP after TKA is 3-30% [6][7][8][9]. The causes of AKP after TKA were divided as follows: surgical technique factors such as instability, malalignment of the prosthesis, patellar maltracking, and overhang of implant [10][11][12][13][14]; implant factors such as posterior stabilized TKA with high intercondylar box, too large and thick of anterior condyle, shallow trochlea groove [3][4][5]; and patient factors such as female, obesity, and high Q-angle [15][16][17][18][19][20][21]. Females tended to develop AKP even when they had good TKA, because females have greater anteroposterior (AP)/mediolateral (ML) ratios and smaller anterior condyles.…”