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Femoral reconstruction can be challenging during revision hip arthroplasty. Aseptic loosening and osteolysis can prevent secure fixation of revision femoral components if stability is solely based on the proximal femoral bone. The surgeon must find the best method to secure the implant in a femur with deficient bone stock proximally that will provide stability for load bearing. In revision surgery, the environment for proximal bone ingrowth usually is unfavorable as the proximal femoral bone stock often is deficient, weak, poorly vascularized, and sclerotic.
Efforts to obtain diaphyseal fit, fill, and biologic fixation have led to the development of the fully coated cementless femoral implant This technique permits reliable biologic fixation at intermediate- and long-term follow up.1,2 Over the past several years, a femoral bone loss classification system has been developed. The use of an extensively porous-coated stem during femoral reconstruction is becoming the gold standard in revision surgery.
This article presents a femoral defect classification system and assesses the outcome of fully-coated cementless femoral revision components at minimum 11 -year follow-up.
MATERIALS AND METHODS
Between 1984 and 1989, a total of 188 consecutive cementless femoral revision surgeries were performed. Eighteen patients died or were lost to follow-up. The remaining 170 patients underwent follow-up for an average of 14.2 years (range: 11-16 years). Mean patient age was 61 .2 years. Reasons for revision included aseptic loosening (82%), septic loosening (8%), periprosthetic fractures (6%), and improper component position (4%).
The femoral bone loss classification system is based on the location and extent of the bone loss. There are four categories of bone loss, type I through type IV (Figure 1 ).3 Type I defects are minimal. The femur does not differ significantly from that encountered in the primary total hip. Type U defects reveal mostly metaphyseal damage with minimal diaphyseal damage. Type III defects are characterized by metadiaphyseal bone loss. These defects are subdivided into femurs in which a minimum...