Purpose of the study: We report a prospective consecutive series of femoral fractures on prosthesis. The goal was to evaluate mid-term outcome of treatment with a locking plate.

Material and methods: From June 2002 to December 2007, we treated 35 patients (1 bilateral), 28 female and 7 male, with a fracture around their total hip arthroplasty (n=21), total knee arthroplasty n=7), unicompartmental knee prosthesis (n=1), between a THA and a TKA (n=2), or between a trochanteric osteosynthesis and a TKA (n=5). Mean age was 76 years (39–93). For the majority, osteosynthesis was achieved via a mini-invasive incision, using a locking plat (Synthes^®) bridging the implant in situ. The rehabilitation protocol consisted in immediate weight-bearing for most of the cases.

Results: At revision, one patient was lost to follow-up, one was an early failure, and seven patients had died, including four which were retained for the analysis because data was available for 24, 40, 43 and 67 months respectively. The analysis thus included 30 patients with 31 fractures and mean 26 months follow-up (range 6 – 67 months). The following results were obtained for the initial series: mini-invasive surgery (n=26), access to fracture focus (n=10), total postoperative weight bearing (n=20), partial weight bearing at 20 kg (n=3), no weight-bearing for six weeks (n=13). Complications were: infection (n=2), general (n=2), disassembly (n=3, one femoral stem replacement and two revision ostheosynthesis). Bone healing was obtained in all cases except one. There was a misalignment > 5 in five cases. At review, there was no implant loosening.

Discussion: This work shows that locking compression plates inserted via a mini-invasive approach followed by weight-bearing is a feasible option. This technique combines the principles of closed osteosynthesis with preservation of the haematoma and stability of osteosynthesis material. The rehabilitation protocol was developed in consideration of the nature of the material. The locked plate acts like an internal fixator, allowing increased implant stability. Screw hold appeared to be sufficient to allow early weight-bearing.

Conclusion: Use of locking compression plates for femoral fractures on osteosynthesis implants is effective. The stability of the assembly allow, despite the age of the patients, early weight-bearing and walking, with a stable outcome over time.