Contact pressure and three-dimensional tracking of unresurfaced patella in total knee arthroplasty

The Measurement of Patellar Alignment in Patellofemoral Pain Syndrome: Are We Confusing Assumptions With Evidence?

“…3,4,11,34,61,63,95 Other studies have found no initial medial movement. 31,76,77 Of the former group, the point at which the medial displacement becomes maximal and the lateral movement begins is highly variable and ranges from 15° to 40° of knee flexion.…”

“…3,4,11,23,30,34,61,63,77,95 Most studies agree that this initial medial tilt is then followed by a lateral tilt as knee flexion continues past 30° to 50°, but the amount of this lateral tilt ranges from 0.7° to 8.2°. 11,30 One study, Goh et al, 25 described the opposite pattern of an initial lateral tilt followed by a medial tilt at 60° to 90° of knee flexion, although they did not measure the first 20° of knee flexion.…”

Dynamic in vitro measurement of patellar movement after total knee arthroplasty: an in vitro study

“…Other devices had a metal-backed baseplate with a rotating, asymmetrical high-conforming polyethylene prosthesis [14]. In-vitro studies utilizing pressure-sensitive films showed significantly higher stresses in these designs which exceeded the yield strength on the polyethylene (>12 MPa) [9,14-17]. Furthermore, 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].…”

In Vivo Kinematics of the Extensor Mechanism of the Knee During Deep Flexion

“…In contemporary TKA components, while the patellofemoral contact locations have been measured using various techniques [31,32], the effect of the TKA on the function of the quadriceps-patellar tendon-patella complex has not been reported. Further, the patellofemoral contact biomechanics of the knee were not reproduced by the TKAs during flexion [20,[33][34][35]. It is unknown if a physiological quadriceps and patellar tendon ratio could be reproduced in the knee after a TKA implantation.…”