Abstract
Introduction: To evaluate the medium-term outcome of patients undergoing revision knee arthroplasty with structural allograft for uncontained defects.
Methods: We followed prospectively 50 patients undergoing 52 revision knee replacements with 66 structural grafts in three institutions. An independent investigator reviewed twenty-nine knees in 27 patients after a mean of 96.9 months.
Results: Twelve knees were re-revised at a mean of 70.7 months. Two of these patients retained their allografts. Eleven patients died with their structural allograft and implants intact and were not awaiting revision at a mean of 93 months.
Failure was defined as an increase of less than 20 points in the modified HSS knee score at the time of the review or the need for an additional operation related to the allograft. Thirteen knees were deemed to be failures giving a 75% success rate. Graft resorption occurred in five patients resulting in implant loosening. Four failed due to infection and non-union between the host bone and allograft was present in two. One patient with both knees grafted failed to gain a 20-point improvement. Survival analysis showed a 72% survival at 10 years. Clinically, the modified HSS score improved from a mean of 32.5 pre-operatively to 75.6 at the time of the review. Radiographic analysis of the surviving grafts showed no severe resorption, one moderate and two mild cases of resorption. Evaluation for loosening revealed one patient with a loose tibial component, while three patients had non-progressive tibial radiolucent lines. All four patients were asymptomatic.
Conclusions: Our results demonstrated encouraging medium-term survival of allografts utilised for revision knee replacement in a group of difficult patients with massive bone loss.
The abstracts were prepared by Professor A. J. Thurston. Correspondence should be addressed to him at the Department of Surgery, Wellington School of Medicine, PO Box 7343, Wellington South, New Zealand
