Abstract
It is well recognized that following excision of bone tumours around the knee, which often requires excision of the joint, cemented fixed hinged endoprosthetic replacements can give excellent results in terms of function (87%). However, for patients under 20 years of age the overall survivorship of distal femoral replacements in this age group is less than 45% at 10 years. To try and address this we have used HA ingrowth collars since 1989 and introduced the Smiles rotating hinge in 1991. In the younger patients we have also used uncemented prostheses using HA.
The HA collars at 70mm thickness are now standard protocol on all extremeity endoprosthetic replacements. We will present the results of retrieval specimens. We have also undertaken a study to determine the effect that HA collars and roating hinges have on enhancement of implant fixation. A survivorship and radiographic analysis has been carried out with three groups of patients: 1. Fixed hinge no collar. 2. Rotating hinge no collar. 3. Rotating hinge with HA collar
The selection criteria were all distal femoral replacements of patients who were over 16 years of age and had a cemented intramedullary stem. The study groups were consistent for age and amount of bone resected and all patients have been followed up.
The abstracts were prepared by Nico Verdonschot. Correspondence should be addressed to him at Orthopaedic Research Laboratory, University Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
