AN UPDATE OF NON-INVASIVE EXPANDABLE ENDOPROSTHESES IN PAEDIATRIC TUMOUR SURGERY – A DUAL CENTRE STUDY

Abstract

Non-invasive expandable prostheses for limb salvage tumour surgery were first used in 2002. These implants allow ongoing lengthening of the operated limb to maintain limb-length equality and function while avoiding unnecessary repeat surgeries and the phenomenon of anniversary operations.

A large series of skeletally immature patients have been treated with these implants at the two leading orthopaedic oncology centres in England (Royal National Orthopaedic Hospital, Stanmore, and Royal Orthopaedic Hospital, Birmingham).

An up to date review of these patients has been made, documenting the relevant diagnoses, sites of tumour and types of implant used. 74 patients were assessed, with an age range of 7 – 16 years and follow up range of 4 – 88 months.

We identified five problems with lengthening. One was due to soft tissue restriction which resolved following excision of the hindering tissue. Another was due to autoclaving of the prosthesis prior to insertion and this patient, along with two others, all had successful further surgery to replace the gearbox. Another six patients required mechanism revision when the prosthesis had reached its maximal length. Complications included one fracture of the prosthesis that was revised successfully and six cases of metalwork infection (two of which were present prior to insertion of the implant and three of which were treated successfully with silver-coated implants). There were no cases of aseptic loosening.

Overall satisfaction was high with the patients avoiding operative lengthening and tolerating the non-invasive lengthenings well. Combined with satisfactory survivorship and functional outcome, we commend its use in the immature population of long bone tumour cases.