Locked plating of periprosthetic femur fractures above total knee arthroplasty.

BACKGROUND

Fractures of the femur above a total knee arthroplasty (TKA) are becoming increasingly common in the osteoporotic, aging populations of developed countries. Treatment of these fractures is complicated by the presence of a knee prosthesis, frequently limiting the bone available for distal fracture fixation. The recent application of minimally invasive surgical techniques and locked plate technology to this problem offers the promise of stable, fixed-angle fixation of small distal fracture fragments with limited surgical exposure. The purpose of this study is to report the clinical and radiographic outcomes of fracture fixation using this technique in patients with periprosthetic femur fractures above TKA.

METHODS

Fifty-three patients presenting with periprosthetic femur fractures above a TKA were treated with osteosynthesis. One patient was lost to follow-up resulting in 52 patients with complete data. Thirty-four patients were treated with plate fixation and 18 patients underwent retrograde intramedullary nail fixation (RIMN). Using a comprehensive electronic medical record, we recorded data regarding patient-related demographics, nature of the fractures, the operative treatment, and clinical and radiographic outcomes for all patients treated with osteosynthesis.

RESULTS

Successful fracture healing occurred in 75% of patients (39 of 52). Mean operating time was 91.6 ± 6.8 minutes in the RIMN group and 87.4 ± 6.4 minutes in the locked plating (LP) group (P = 0.46). Mean intraoperative blood loss was 182 ± 31.6 mL in the RIMN group and 177.5 ± 23.4 mL in the LP group (P = 0.91). The mean time to bone union was 3.7 ± 0.30 months in the RIMN group and 4.0 ± 0.27 months in the LP group (P = 0.95). The most common cause of treatment failure was patient death within 6 months (9 patients [17%]); three of 18 were treated with a nail and 6 of 34 with a plate (P = 1.0). In the LP group, three (9%) sustained fracture nonunions, three (9%) sustained fracture malunions, and two (6%) sustained surgical site infections. In the RIMN group, one (6%) failed to unite as a result of infection and two (11%) developed fracture malunions. There were no significant differences between patients treated with LP and those treated with RIMN.

CONCLUSIONS

Despite significant advances in surgical technique and implant design, the treatment of periprosthetic femur fractures above a TKA remains a challenge. LP using an indirect reduction technique is applicable to most patients and prosthetic designs and can provide similar favorable results as compared with treatment with a RIMN in periprosthetic femoral fractures.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.