PERI-PROSTHETIC FRACTURES: IS IT A PROBLEM ON THE RISE?

As the incidence of total hip arthroplasty (THA) rises, an increasing prevalence of peri-prosthetic femur fractures has been reported. This is likely due to the growing population with arthroplasties, increasing patient survival and a more active life-style following arthroplasty. It is the 3rd most common reason for THA reoperation (9.5%) and 5th most common reason for revision (5% with fracture risk after primary THA reported at 0.4%-1.1% and after revision at 2.1%-4%). High quality radiographs are usually sufficient to classify the fracture and plan treatment. Important issues in treatment include stem fixation status and fracture location relative to the stem. Additional comorbidities will also influence treatment choices, of which the most critical is the presence of infection and the quality of bone stock. The most commonly studied, and reported classification system is the Vancouver. Type A are peri-trochanteric fractures with AL at the lesser and AG at the greater trochanter. B fractures are those around the stem with B1 fractures having a well-fixed stem, B2 a loose stem with adequate bone stock, and B3 representing loose stem and inadequate bone stock. C fractures are distal to the stem. Type A) Trochanteric Fractures: These are usually associated with lysis. Displaced fractures can be managed adequately with cerclage fixation and cancellous allograft to fill osteolytic defects. Undisplaced fractures usually heal well with symptomatic treatment. Type B) Fractures Around the Stem: The B1 type has a well-fixed component and is usually treated with extramedullary fixation plus graft. Contemporary plates have been designed specifically for these fractures. Strut allograft may be used to provide a more rigid construct. Spiral and long oblique fractures can be cerclaged while short oblique or transverse fractures require fixation anterior and lateral with cable plates and cortical strut grafts. Screws can be used distal to the implant, and cables used proximally. The B2 type has a loose prosthesis but otherwise good bone stock. In this setting, the fracture line may be extended on the lateral cortex of the femur as an extended osteotomy to provide easy access for cement removal. These fractures can be managed with an extensively coated stem if rotational stability can be obtained in the distal segment. If rotational stability over a 4 cm scratch interference fit of the stem isn9t possible, then a fluted tapered modular stem should be used. Strut allografts improve initial stability. The B3 type has both a loose prosthesis and poor bone stock and in the younger patient restoration of bone stock should be a priority. Bulk femoral grafts may be needed. The elderly or low functional demand patient may be treated with a proximal femoral replacement. Because of soft-tissue deficiencies, a constrained acetabular liner may be needed to prevent instability. Type C) Fractures Distal to the Stem: These usually accompany a stable stem and many fixation devices are available. Locking plates have become most popular and should be secured with cerclage wires proximally around the component with screws distally. Retrograde nails may be employed if there is adequate bone distal to the stem tip and above the fracture.