Interprosthetic femoral fractures: Treatment with a lateral angular-stable plate.

Objective: To study the causes and outcomes of patients with interprosthetic femoral fractures.

Material And Methods: A retrospective review conducted on 7 patients treated between 2010 and 2013. The knee arthroplasties had been implanted for at least 5 years, and those of the hip less than a year. They were bipolar cemented in 6 patients and totally non-cemented in one patient, all of them implanted due to a displaced femoral neck fracture. They were treated using osteosynthesis with angular stability plate covering the whole interprosthetic femoral segment. Except for one patient, all have been reviewed at least 12 months.

Results: The patients included 6 women and one man, with a mean age of 84.7. The fracture, always by low energy, occurred between 2 and 8 months after that of the hip without the implants being mobilized. Four of them were located at diaphyseal level, and 3 at supracondylar level, and unrelated to the type of knee implant. There was consolidation in all patients at a mean of 4.5 months, without a re-operation in any of them, and with no mortality during the follow-up period. All patients walked independently at the time of the fracture, and all of them have managed to return to walking independently, having lost as average 20° of knee flexion in cases of supracondylar fracture.

Conclusions: The most important factors in our patients regarding the producing of the fracture have been the changes in the ability to walk after knee replacement and bone fragility. Angular stability plates give good results in the treatment of interprosthetic femoral fractures.