Structural proximal femoral allografts for failed total hip replacements -A minimum review of five years

There are few medium- and long-term data on the I outcome of the use of pro ximal femoral structural allografts in revision hip arthroplasty. This is a study of a consecutive series of 40 proximal femoral allografts performed for failed total hip replacements using the same technique with a minimum f ollow-up of five years (mean 8.8 gears; range 5 to 11.5 years), In all case s the stem was cemented into both the allograft and the host femur. The pro ximal femur of the host was resected in 37 cases. There were four early revisions (10%), tno for infection, one for nonunion of the allograft-host junction, and one for allograft resorption noted at t he time of revision of a failed acetabular reconstruction. Junctional nonun ion was seen in three patients (8%) two of whom were managed successfully b y bone grafting, and bone grafting and plating respectively Instability was observed in four (10%). Trochanteric nonunion was seen in 18 patients (46% ) and trochanteric escape in ten of these (27%). The mean Harris hip score improved from 39 to 79, Severe resorption involving the full thickness of t he allograft was seen in seven patients (17.5%). This progressed rapidly an d silently, but has yet to cause failure of any of the reconstructions. Profound resorption of the allograft may be related to a combination of fac tors, including a slow form of immune rejection, stress shielding and resor ption due to mechanical disuse with solid cemented distal fixation, and the absence of any masking or protective effect which may be provided by the r etention of the bivalved host bone as a vascularised onlay autograft, Altho ugh continued surveillance is warranted, the very good medium-term clinical results justify the continued use of structural allografts for failed tota l hip replacements with severe loss of proximal femoral bone.