Patellofemoral pressure after TKA in vitro: highly conforming vs. posterior stabilized inlays

Abstract

The results of this study suggest that a posterior stabilized prosthesis design reduces the patellofemoral peak and mean pressure in comparison with a high conforming design. The better reproducible femoral rollback with a posterior stabilized model at a tibial ventral shift could serve as a possible explanation.

Functional Outcomes of a New Mobile-Bearing Ultra-Congruent TKA System: Comparison With the Posterior Stabilized System

“…However, its high congruency was ascribed to the restriction of femoral rotation, increased shearing stress on the tibia bone surface, and hence early implant loosening [17][18][19][20]. Furthermore, some kinematic studies revealed nonphysiologic femoral rollback and reduced axial rotation with these inserts [21,22], which may have caused reduced knee flexion.Aiming to overcome these problems of the PS prosthesis and fixedbearing UC prosthesis, a new mobile-bearing UC TKA prosthesis (e.motion Ultra-Congruent; B.Braun-Aesculap, Tuttlingen, Germany) was designed with the intent to improve kinematics and wear characteristics. The prosthesis was designed to avoid contact with stress peaks while providing good stability and mobility on account of its high congruency and better stress distribution.…”

“…However, its high congruency was ascribed to the restriction of femoral rotation, increased shearing stress on the tibia bone surface, and hence early implant loosening [17][18][19][20]. Furthermore, some kinematic studies revealed nonphysiologic femoral rollback and reduced axial rotation with these inserts [21,22], which may have caused reduced knee flexion.…”

Long-term Follow-up of Patellar Nonresurfacing in Total Knee Arthroplasty

“…9) Some studies have reported that an impaired venous drainage induces intraosseous hypertension. 16,17) Schneider et al 16) reported that if the venous pathway of the patella is impaired, patellar drilling leads to the immediate reduction of intraosseous pressure and pain relief.…”

Use of Tekscan pressure sensors for measuring contact pressures in the human knee joint

“…To measure the patellofemoral contact pressure distribution during in vitro tests with native knees, the Tekscan sensor is mostly fixed to the patella (see Figure 2) [17][18][19], only one experiment in which the sensor was fixed to the trochlea of the femur was reported [20]. If the tibiofemoral contact pressure has to be measured, the sensor can be fixed on the femoral plateau underneath [21][22][23][24][25] or on top of the menisci [26].…”

“…Also complete removal of the menisci to install the sensors has been reported [27]. The sensor can be fixed by the use of sutures (see Figure 2) [17,18,23,[27][28][29] or by metal pins [30,31]. Alternatively, the use of a suture-glue combination has been reported [4].…”