Periprosthetic femur fractures, defined as femur frac- tures occurring around a pre-existing prosthetic hip or knee, are increasing in incidence on par with the number of arthroplasties

INTRODUCTION Periprosthetic femur fractures, defined as femur fractures occurring around a pre-existing prosthetic hip or knee, are increasing in incidence on par with the number of arthroplasties performed in our increasingly aging population. Periprosthetic hip fractures most commonly occur around or just distal to a hip stem prosthesis (Vancouver Type B, 88%) [1], and periprosthetic distal femur fractures proximal to a knee arthroplasty may extend into the bone-prosthetic interface. Patients with unstable implants are treated with prosthetic revision. However, patients with stable implants are treated with open reduction and internal fixation (ORIF) [2]. Traditional ORIF of hip periprosthetic femur fractures has been done using cortical struts, allogenic bone grafting, cerclage wiring, and plating. Surgical approaches for this type of treatment have had a variable rate of success with reports showing high rates of union such as 39 out of 40 patients in one case series [3]. However, others reported non-union rates of 33% and rates of refracture of 34% [1]. ORIF can involve significantly extensive procedures that often result in significant blood loss and patient morbidity. One-year mortality rate across all periprosthetic fractures can be as high as 33% [4]. Recently, the development of locking plates and the increased experience with minimally invasive plate osteosynthesis (MIPO) has provided a new alternative. MIPO preserves soft tissue and bony perfusion, which are critical for successful fracture healing. However, its efficacy on periprosthetic fractures is not well studied. The amount of published data on MIPO applied to the management of hip periprosthetic fractures is limited to only two case series [5, 6]. We present in this report our early experience using MIPO technique in the management of periprosthetic femur fractures. MATERIAL AND METHODS After IRB approval, all patients presenting to the BIDMC orthopedic trauma unit with a periprosthetic femur fractures between 2005 and 2007 were considered. The study identified and enrolled a total of 24 patients with 26 periprosthetic fractures around a hip stem prosthesis or proximal to a total knee component. Medical records, follow up notes and radiographic studies were examined. Periprosthetic fractures associated with a hip stem were classified using the Vancouver system, based on the location of the fracture. Primarily Vancouver B1 and C fractures were treated. The surgical plan was determined by the patient’s attending orthopedic surgeon after radiographic assessment of the stability of the prosthetic stem. The MIPO procedure uses a single lateral long locking plate (LCP or LISS) to stabilize the periprosthetic fracture without bone allograft. Patients were operated in a lateral position if the fracture was a Vancouver B1 or in the supine position if the fracture either was a Vancouver C or was proximal to a knee component. For Vancouver B1 fractures, the entry point of the plate was identified lateral to the distal femur where a 4 cm incision was placed (Figure 1). A second small incision was placed at the level of the greater trochanter to control the plate position proximally. Accessory percutaneous incisions were made as needed for screw and cerclage placement (Figure 2). The use of cerclage was kept to a minimum in order to limit circumferential stripping. Stability was achieved primarily using screws, and radiography was used to visualize proper reduction and MiniMally invaSive plaTe OSTeOSynTheSiS Of periprOSTheTic feMur fracTureS aSSOciaTed WiTh TOTal hip replaceMenT: a caSe SerieS