Abstract
BackgroundChanging the kinematic behaviour of patellar movement could be one of the reasons for anterior knee pain after implantation of a total knee arthroplasty (TKA). The aim of the current study was to measure the potential influence on patellar kinematics of patellar resurfacing during TKA.MethodsPatellar movement before and after TKA with and without patellar resurfacing was measured under dynamic conditions in an in vitro cadaver simulation. Physiologic Musculus quadriceps forces were applied to five physiologic human knee specimens undergoing simulated isokinetic extension motions, patellar movement was measured using an ultrasonic measurement system. Thereafter, the Interax® I.S.A.-prosthesis system was implanted without and with resurfacing the patella, and patellar movement was again measured.ResultsThe physiologic patella center moved on a semilunar path up to 6.4 mm (SD 6.4 mm) medially during extension. After TKA, the unresurfaced patella showed significantly less medial translation (p = 0.04) than the resurfaced patella. Subsequent resurfacing of the patella then resulted in a return to mediolateral positioning of the patella similar to the physiological case, whereas the resurfaced patella tilted up to twice as much as physiologic.ConclusionThe results of this study suggest that resurfacing of the patella during TKA can result in a restoration of the physiologic mediolateral shift of the patellofemoral joint while angulation of the patella remains unphysiologic.
Highlights
Changing the kinematic behaviour of patellar movement could be one of the reasons for anterior knee pain after implantation of a total knee arthroplasty (TKA)
Patellofemoral or anterior knee pain represents one of the most common problems during rehabilitation after total knee arthroplasty (TKA), with postoperative problems reported in 0,5–12% of patients [1,2,3,4,5,6]
Other studies showed substantial changes in movement of the patella after TKA: An unresurfaced patella moved along a different path in the groove of the femoral component compared to the physiological motion [1]
Summary
Changing the kinematic behaviour of patellar movement could be one of the reasons for anterior knee pain after implantation of a total knee arthroplasty (TKA). IFmigpularnete1d components with attached marker triangles Implanted components with attached marker triangles correctly implanted patella inlay it is possible to avoid changing patellar tracking in the femoral groove and with it the associated potential malalignment of the degenerated patella [1,11,12,13]. Several types of retropatellar resurfacing devices have been developed These included symmetrical, dome shaped, and non anatomic all polyethylene components [3]. Other studies showed substantial changes in movement of the patella after TKA: An unresurfaced patella moved along a different path in the groove of the femoral component compared to the physiological motion [1]. While demonstrating the same amount of flexion around the horizontal axis and rotation around the sagittal axis, the resurfaced patella moved on the same path as a physiologic patella, while at the same time exhibiting a significantly greater lateral tilt around the frontal axis [11,12,13]
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