Locked plates combined with minimally invasive insertion technique for the treatment of periprosthetic supracondylar femur fractures above a total knee arthroplasty.

Objective: New locked plate devices offer theoretical advantages for the treatment of supracondylar femur fractures associated with a total knee arthroplasty (TKA). These devices also can be inserted with relative ease by using minimally invasive techniques, provide a fixed angle construct, and improve fixation in osteoporotic bone. The purpose of this study was to evaluate the results and complications of treating periprosthetic supracondylar femur fractures above a TKA with a locked plate designed for the distal femur.

Design: Prospective, consecutive case series.

Setting: Level I trauma center.

Patients/participants: Twenty-two consecutive adult patients with 24 (2 bilateral) supracondylar femur fractures (OTA 33A) above a well-fixed non-stemmed TKA were treated with the Locking Condylar Plate. One patient who died before fracture healing and 1 who was lost to follow-up were excluded from analysis. All remaining patients (5 males, 15 females, average age, 73 (range, 50-95) years) were available for follow-up at an average of 15 (range, 6-45) months. According to the OTA classification, there were three 33A1, eight 33A2, and eleven 33A3 fractures. All fractures were closed. Indirect reduction methods without bone graft were used in all cases.

Results: Nineteen of 22 fractures healed after the index procedure (86%). All 3 patients with healing complications were insulin-dependent patients with diabetes who also were obese (body mass index >30). Two developed infected nonunions and 1 an aseptic nonunion. Postoperative alignment was satisfactory (within 5 degrees ) for 20 of 22 fractures. Fracture of screws in the proximal fragment occurred in 4 patients. In 3 of these cases, there was progressive coronal plane deformity. There was no change in alignment in any other patient. Fifteen of 17 patients who healed returned to their baseline ambulatory status, with 5 requiring additional ambulatory support compared with baseline.

Conclusions: Fixation of periprosthetic supracondylar femur fractures with a locking plate provided satisfactory results in nondiabetic patients. Diabetic patients seem to be at high risk for healing complications and infection.