title: The medium-term results of the Stanmore non-invasive extendible endoprosthesis in the treatment of paediatric bone tumours.
abstract: In skeletally immature patients, resection of bone tumours and reconstruction of the lower limb often results in leg-length discrepancy. The Stanmore non-invasive extendible endoprosthesis, which uses electromagnetic induction, allows post-operative lengthening without anaesthesia. Between 2002 and 2009, 55 children with a mean age of 11.4 years (5 to 16) underwent reconstruction with this prosthesis; ten patients (18.2%) died of disseminated disease and one child underwent amputation due to infection. We reviewed 44 patients after a mean follow-up of 41.2 months (22 to 104). The mean Musculoskeletal Tumor Society score was 24.7 (8 to 30) and the Toronto Extremity Salvage score was 92.3% (55.2% to 99.0%). There was no local recurrence of tumour. Complications developed in 16 patients (29.1%) and ten (18.2%) underwent revision. The mean length gained per patient was 38.6 mm (3.5 to 161.5), requiring a mean of 11.3 extensions (1 to 40), and ten component exchanges were performed in nine patients (16.4%) after attaining the maximum lengthening capacity of the implant. There were 11 patients (20%) who were skeletally mature at follow-up, ten of whom had equal leg lengths and nine had a full range of movement of the hip and knee. This is the largest reported series using non-invasive extendible endoprostheses after excision of primary bone tumours in skeletally immature patients. The technique produces a good functional outcome, with prevention of limb-length discrepancy at skeletal maturity.
authors.affiliation: Royal National Orthopaedic Hospital, Bone Tumour Unit, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK. emmapicardo@yahoo.co.uk
authors.forename: N E
authors.initials: NE
authors.lastname: Picardo
authors.forename: G W
authors.initials: GW
authors.lastname: Blunn
authors.forename: A S
authors.initials: AS
authors.lastname: Shekkeris
authors.forename: J
authors.initials: J
authors.lastname: Meswania
authors.forename: W J
authors.initials: WJ
authors.lastname: Aston
authors.forename: R C
authors.initials: RC
authors.lastname: Pollock
authors.forename: J A
authors.initials: JA
authors.lastname: Skinner
authors.forename: S R
authors.initials: SR
authors.lastname: Cannon
authors.forename: T W
authors.initials: TW
authors.lastname: Briggs
mesh_terms: D000293:Adolescent; D001852:Bone Lengthening / Q000295:instrumentation* / Q000379:methods; D001859:Bone Neoplasms / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery; D005500:Follow-Up Studies; D006128:Growth; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D007870:Leg Length Inequality / Q000209:etiology / Q000517:prevention & control; D023821:Limb Salvage / Q000379:methods; D035002:Lower Extremity / Q000601:surgery*; D008297:Male; D019736:Prostheses and Implants; D011474:Prosthesis Design; D019919:Prosthesis Implantation / Q000009:adverse effects / Q000379:methods; D011859:Radiography; D016059:Range of Motion, Articular; D012086:Reoperation / Q000379:methods; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery; D016896:Treatment Outcome