Articular cartilage contact pressure after tibial tuberosity transfer - A cadaveric study

Medial transfer of the tibial tuberosity has been commonly used for treatme nt of recurrent dislocation of the patella and patellofemoral malalignment. In this study; six fresh human cadaveric knees were used. Static intrajoin t loads were recorded using Fuji Prescale pressure-sensitive film for conta ct pressure and contact area determination in a closed kinetic chain knee t esting protocol. Peak pressures, average contact pressures, and contact are as of the patellofemoral and tibiofemoral joints were calculated on native intact knee specimens and after tibial tuberosity transfer. All native inta ct knee specimens had a normal Q angle. Medialization of the tibial tuberos ity significantly increased the patellofemoral contact pressure. Medial dis placement of the tibial tuberosity also significantly increased the average contact pressure of the medial tibiofemoral compartment and changed the ba lance of tibiofemoral joint loading. The results of our study suggest that caution should be used when transferring a patellar tendon in the face of a preexisting normal Q angle as this will result in abnormally high peak pre ssure within the tibiofemoral joint. Overmedialization of the tibial tubero sity should be avoided in the varus knee, the knee after medial meniscectom y, and the knee with preexisting degenerative arthritis of the medial compa rtment.