Session X - Geriatrics
Sun., 10/10/04 Geriatrics, Paper #61, 8:47 am
Use of the LISS to Treat Periprosthetic Femur Fractures below Hip or above Knee Arthroplasty or Both
Purpose: Postoperative fractures of the femur after knee or hip arthroplasty present a significant technical challenge. Although these fractures are relatively rare, their incidence appears to be increasing. The fractures typically affect an older population with osteoporotic bone. The treatment of these fractures has historically been complicated by malunion and hardware failure. Our study evaluated the efficacy of a locking-plate system, the Less Invasive Stabilization System (LISS, Synthes, Inc., Paoli, Pennsylvania), to treat these challenging fractures.
Methods: In an Institutional Review Board-approved study, all patients treated with a LISS at our institutions (two level I trauma centers) between July 1, 2001 and July 1, 2003, were prospectively enrolled in a custom trauma database. A subgroup of patients with periprosthetic fractures was identified. Inclusion criteria for the study group included an acute fracture of the femur and an ipsilateral total knee replacement (TKR) or hip prosthesis (either total hip replacement or hemiarthroplasty) or both. Patients were observed until fracture union or failure and for a minimum of 6 months. Patients were evaluated radiographically, clinically, and with use of questionnaires.
Results: The study group consisted of 24 patients with 24 femur fractures; 10 patients had an ipsilateral hip arthroplasty, 9 patients had an ipsilateral total knee replacement, and 5 patients had both knee and hip prostheses. The average age at injury was 80.2 years (range, 58 to 93). All 24 patients were female and had closed fractures caused by low-energy falls from standing. One patient had an ipsilateral olecranon fracture that required operative treatment, but all other fractures were isolated injuries. All of the fractures in the study group had stable prostheses that did not need revision. The average delay between injury and operative date was 3.0 days (range, 0 to 15). The average operative time was 109.8 minutes (range, 66 to 178). The LISS plate always overlapped the TKR and overlapped the hip prosthesis for 12 of the 15 patients with hip prostheses. Freeze-dried bone graft was used in one patient. Four patients died during the study (on postoperative day 6 and 18 and in postoperative month 5 and 8), and one was lost to follow-up. None of the patients that died had known hardware complications. Of the remaining 19 patients, the average follow-up was 10.2 months. All but one of the 19 fractures healed uneventfully. One fracture (below a hemiarthroplasty) was complicated by hardware pullout. It was revised to a longer LISS and healed uneventfully. Otherwise, there were no infections, no hardware failures, and no other complications.
Conclusions/Significance: The study provided data indicating that the LISS may be efficacious for the treatment of periprosthetic femur fractures. This is the first report to our knowledge specifically on the use of the LISS to treat femur fractures below hip arthroplasty as well as femur fractures between TKR and hip prostheses. These results provide clinicians with encouragement that the LISS may have utility in the treatment of periprosthetic femur fractures.