Significant influence of rotational limb alignment parameters on patellar kinematics: an in vitro study.
OBJECTIVE
Component malrotation has a major impact on patellar kinematics in total knee arthroplasty. The influence of natural rotational limb alignment on patellar kinematics is unclear so far. Based on recent clinical investigations, we hypothesized that rotational limb alignment significantly influences patellar kinematics.


METHODS
Patellar kinematics of ten cadaveric knees was measured using computer navigation during passive motion. Data were correlated with different rotational limb alignment parameters of preoperative CT scans.


RESULTS
Femoral antetorsion showed a significant influence on patellar rotation, while tibial tubercle-posterior cruciate ligament distance additionally displayed a significant influence on patellar mediolateral shift (p < 0.05). Femoral posterior condylar angle was sensitive to patellar epicondylar distance, rotation and tilt (p < 0.05). Patellar rotation was influenced by five out of eight rotational limb alignment parameters (p < 0.05).


CONCLUSIONS
Rotational limb alignment should be paid more attention in terms of clinical evaluation of patellar tracking and future biomechanical and clinical investigations.
Department of Orthopaedic Surgery, University of Regensburg, Kaiser-Karl-V Allee 3, 93077, Bad Abbach, Germany. keshmiri_armin@yahoo.de.
Armin
A
Keshmiri
Department of Orthopaedic Surgery, University of Regensburg, Kaiser-Karl-V Allee 3, 93077, Bad Abbach, Germany.
Günther
G
Maderbacher
Department of Orthopaedic Surgery, University of Regensburg, Kaiser-Karl-V Allee 3, 93077, Bad Abbach, Germany.
Clemens
C
Baier
Centre for Clinical Studies, Franz-Josef-Strauß-Allee 11, 93053, Regensburg, Germany.
Florian
F
Zeman
Department of Orthopaedic Surgery, University of Regensburg, Kaiser-Karl-V Allee 3, 93077, Bad Abbach, Germany.
Joachim
J
Grifka
Department of Orthopaedic Surgery, University of Regensburg, Kaiser-Karl-V Allee 3, 93077, Bad Abbach, Germany.
Hans Robert
HR
Springorum
D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D017760:Bone Malalignment; D005260:Female; D005269:Femur / Q000601:surgery; D006801:Humans; D066298:In Vitro Techniques; D007717:Knee / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery; D010329:Patella / Q000502:physiology* / Q000601:surgery; D016119:Posterior Cruciate Ligament / Q000601:surgery; D016059:Range of Motion, Articular; D012399:Rotation; D013977:Tibia / Q000601:surgery; D014057:Tomography, X-Ray Computed
CT measurement; Computer navigation; Patellar kinematics; Patellar tracking; Rotational limb alignment