Extensor mechanism problems following total knee replacement.

Despite advances in TKR, a number of complications related to the extensor mechanism still exist. The vast majority of these are preventable with good surgical technique and attention to detail. Proper component positioning, adequate soft-tissue balancing and dissection, and gentle retraction are imperative. Proper resection and resurfacing of the patella, central tracking of the implant, maintenance of the patella vascularity, and use of an implant with a well designed patellofemoral joint help minimize complications of TKR.