[Plate osteosynthesis in vancouver type b1 and b2 periprosthetic fractures].

PURPOSE OF THE STUDY: In a retrospective study we evaluated the results of plate osteosynthesis for treatment of periprosthetic femoral fractures classified as Vancouver types B1 and B2.

MATERIAL AND METHODS: The group comprised 19 patients with post-operative periprosthetic fractures treated by open reduction and internal fixation with plate osteosynthesis at our department between the beginning of 2004 and June 2007. Perioperative fractures were not included. The average age of the patients was 72.0 (range, 53 to 88) years. A locking compression plate (PCL) was used in 16 patients. The average follow-up was 21 months, with 6 months at least.We evaluated radiographs of the fracture and, in the majority of cases, also those before a periprosthetic fracture occurred. We focussed on the signs of potential femoral component loosening and the course of fracture line; fractures were classified according to the Vancouver classification system. Follow-up included both clinical and radiographic examination.

RESULTS: Thirteen patients showed bone union and a good functional outcome. One patient was present at follow-up only once and was not included in the final evaluation. Non-union was recorded in five patients (27.7 %), marked implant migration occurred in three (all had type B2 fracture) and osteosynthesis failed in two patients.

DISCUSSION: We consider the Vancouver classification to be the most suitable classification system. The relatively high proportion of non-union fractures can be accounted for by an inappropriate indication for osteosynthesis in fractures with stem loosening.The assessment of stem stability based on a radiograph only may, in some cases, be questionable; therefore, if doubtful, we prefer an intra-operative evaluation of implant stability.We also discuss a contribution of angle-stable plates to the osteosynthesis of periprosthetic fractures as well as their bone fixation technique.

CONCLUSIONS: Plate osteosynthesis is a suitable method for treatment of periprosthetic fractures if there is a stable femoral component. LPC implants are not discriminative enough in the range of indications for plate osteosynthesis.The use of plate osteosynthesis in a total hip arthroplasty with signs of loosening is bound to lead to acceleration of loosening and stem migration, and may even result in plate breakage or its expulsion. This implies that, in such THAs, plate osteosynthesis can only be carried out as a palliative procedure in immobile and severely ill old patients. Key words: periprosthetic fractures, total hip arthroplasty, revision total hip arthroplasty, plate fixation, LCP, Vancouver classification.