Abstract
This study constitutes the minimum 5-year follow-up (mean 8.8 years; range 5 – 11.5 years) of a consecutive series of 40 proximal femoral allografts performed for failed total hip arthroplasties using the same technique. Nine of these cases had been two stage reconstructions for the management of infected total hip replacements with bone loss. In all these cases the stem was cemented into both the allograft and the host femur. The host bone was resected in 37 cases, and the greater trochanter reattached with a cable grip in 33 cases and with wire and mesh in 3 cases.
The patients were reviewed by an independent observer. There were 4 early revisions (10%): one for infection, one for non-union of the allograft host junction, and two following revision of a failed acetabular reconstruction. Three further acetabular revisions have since also been performed. Junctional nonunion was seen in 3 cases (8%), two of which were managed successfully with bone grafting and bone grafting and plating respectively. Instability was observed in 6 cases (15%). Trochanteric non-union was seen in 17 cases (42.5%) and trochanteric escape in 10 of these (25%). The mean Harris Hip Score improved from 39 to 79. Severe resorption involving the full thickness of the allograft was seen in 7 cases. This progressed rapidly and silently but has yet to lead to the failure of any of the reconstructions.
Although there was a high early complication rate, the medium term survivorship is excellent, and the clinical outcomes highly satisfactory. The striking observation of severe allograft resorption may be related to a combination of factors. These include the absence of any masking or protective effect that the host bone may have proximally, and surface revascularisation with stress shielding secondary to solid cemented distal fixation. Although continued surveillance is warranted, these results justify the use of structural allografts for selected cases.
The abstracts were prepared by Mr Simon Donell. Correspondence should be addressed to him at the Department of Orthopaedics, Norfolk & Norwich Hospital, Level 4, Centre Block, Colney Lane, Norwich NR4 7UY, United Kingdom.
