Minimally invasive surgery has recently been introduced in TKA surgery. The purpose of this study was to evaluate the effect of eversion of the patella, on safety and functional result after TKA. In a prospective, randomised, double blinded trial, 60 patients were divided in two groups: group A underwent TKA through a standard medial parapatellar arthrotomy, with patellar eversion. Group B underwent the same exposure, except for the fact that the patella was subluxed laterally. All other treatment protocols were identical. Outcomes were measured until 1 year postoperatively. Radiographic evaluation included AP, lateral, skyline and full leg standing radiographs. VAS, WOMAC score, Knee Society Knee and Function score were performed. Active and passive range of motion (ROM) and knee proprioception was measured. All patients underwent isokinetic strength testing. The mean passive ROM changed from 121 degrees preoperatively to 121 degrees postoperatively in group A, compared to 118 degrees -131 degrees respectively in group B at 1 year (P = 0.003). The mean active ROM changed from 112 degrees to 115 degrees in group A, and from 108 degrees to 125 degrees in group B (P = 0.005). All other parameters were not significantly different. Patellar dislocation without eversion for exposing the knee during TKA is a safe procedure and improves ROM at 1 year postoperatively.

To describe the status of the intermediate femur and its medullary canal encumbrance, we propose adding a category D to the SoFCOT and Vancouver classifications, corresponding to interprosthetic fracture on TKR with diaphyseal extension stem. Interprosthetic fracture internal fixation should begin with long devices bridging the two prostheses. When the implant is loose, it may be replaced; in case of diaphyseal extension, however, the residual femur between the two extensions should be protected against peak stress by a plate extending upward and downward. In case of limited bone stock, due to osteolysis or initial femoral medullary canal compromise, especially if one or both implants are loose, TFR may be indicated as consolidation, is jeopardized by the uncertain mechanical situation.

No abstract

Level IV, retrospective study.