1,462
Views
25
CrossRef citations to date
0
Altmetric
Biomedical Paper

In vivo patellar kinematics during total knee arthroplasty

, , , , , & show all
Pages 377-391 | Received 24 Mar 2008, Accepted 24 Oct 2008, Published online: 06 Jan 2010
 

Abstract

Patellar maltracking after total knee arthroplasty often results in complications, including anterior knee pain, instability and impingement, and is therefore better resolved intraoperatively. Many factors can affect patellar kinematics during knee replacement, including component position, implant design, joint alignment, and soft tissue tensions. However, to our knowledge, the impact of arthroplasty on patellar kinematics has not been previously reported in vivo. A computer-assisted surgery (CAS) system was developed to measure the pre-arthroplasty patellar kinematics, display the distance between this path and the surface of the planned femoral component, and compare the post-arthroplasty path to the pre-arthroplasty path. Three surgeons from three centers used this CAS system to measure the in vivo pre- and post-arthroplasty kinematics of 18 patients. There was a small, but consistent, proximal shift in the tibial joint lines (mean: 4.2 mm), resulting in pseudo patella-baja, i.e., relatively more distal contact of the patella on the femoral component. This led to significant changes in proximodistal and anteroposterior patellar positioning as well as patellar flexion following arthroplasty (p < 0.008). Mediolateral shift, tilt and internal/external spin had the greatest magnitudes of change (mean: 4.1 mm, 4.6° and 4.6°, respectively) relative to their mean pre-arthroplasty ranges (averaging 2.1 mm, 5.8° and 5.8°, respectively); however, these changes were distributed almost equally medially and laterally, indicating no surgical bias in any one direction. Female patients had more lateral tilt on average than male patients throughout flexion (p < 0.004 post-arthroplasty, p < 0.03 pre-arthroplasty, in later flexion), as well as other kinematic differences; there may therefore be potential for improving overall kinematic results by focusing on gender differences during research, design and surgery. This study demonstrated the feasibility of using a CAS system to measure patellofemoral kinematics. Intraoperative awareness of patellar tracking, including knowledge of the tibiofemoral joint line, could have an impact on the surgical plan and thereby improve the postoperative outcome.

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.