Revision of the failed distal femoral replacement to allograft prosthetic composite.

Orthopaedic oncologists often prefer a modular prosthetic cemented prosthesis for reconstruction after tumor excision in the distal femur. However, these frequently young patients face the prospect of either mechanical failure or loosening during their lifetime. Between 1993 and 2000, 41 patients (18 males, 23 females) with a malignancy of the distal femur had distal femoral replacement. Eight revisions and one amputation were required. Of these, four patients had revision to an allograft-prosthetic composite because of prosthetic fracture or loosening. These patients comprise the study population. Revisions were required at an average of 4 years after distal femoral replacement and the average age of the patients at revision was 17 years. The average time to achieve healing at the allograft-host junction was approximately 3 months and patients were fully weightbearing by that time. Followup from revision surgery to the last visit averaged 59 months, with average Musculoskeletal Tumor Society and Hospital for Special Surgery scores of 62% and 72%, respectively. There have been no mechanical problems, fractures, or osteolysis to signify loosening in the allograft or host bone. It is anticipated that this type of revision will survive longer than a conventional cemented revision and obviate the need for multiple reoperations in young patients who have difficulty with the biologic features of a cemented prosthesis construct.