title: A comparison of function after limb salvage with   non-invasive expandable or modular prostheses in children.
abstract: BACKGROUND
  Modular and non-invasive expandable prostheses have been developed to provide a functional knee joint that allows future expansion as growth occurs in the contralateral extremity in children with bone sarcomas that require removal of the growth plate. This study aimed to evaluate the functional outcomes of paediatric patients who received either a non-invasive expandable or modular prosthesis for bone sarcomas arising around the knee.
  
  
  METHODS
  We evaluated clinician-reported, patient-reported and measured function in 42 paediatric patients at least one year (median age at assessment 19.1 years) after limb salvage surgery, and compared patients who received modular system prostheses (N = 29, median age 15.5), who did not require lengthening procedures to those who received non-invasive expandable prostheses (N = 13, median age 11.1) requiring lengthening procedures (median 5).
  
  
  RESULTS
  The number of revisions and time to first revision did not differ between the two groups. There were no differences between the two groups in total scores on the Enneking Musculoskeletal Tumor Society Scale, the Toronto Extremity Salvage Scale, and the Functional Mobility Assessment. Children with non-invasive expandable prostheses climbed stairs (11.93 ± 4.83 versus 16.73 ± 7.24 s, p = 0.02) in less time than those with modular prostheses.
  
  
  CONCLUSIONS
  Our results suggest that the non-invasive expandable prosthesis produces similar functional results to the more traditional modular prosthesis.
authors.forename: Kirsten K
authors.initials: KK
authors.lastname: Ness
authors.forename: Michael D
authors.initials: MD
authors.lastname: Neel
authors.forename: Sue C
authors.initials: SC
authors.lastname: Kaste
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Billups
authors.forename: Victoria G
authors.initials: VG
authors.lastname: Marchese
authors.forename: Bhaskar N
authors.initials: BN
authors.lastname: Rao
authors.forename: Najat C
authors.initials: NC
authors.lastname: Daw
mesh_terms: D000293:Adolescent; D001186:Artificial Limbs; D001852:Bone Lengthening / Q000295:instrumentation; D001859:Bone Neoplasms / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D007870:Leg Length Inequality / Q000601:surgery; D023821:Limb Salvage / Q000379:methods*; D008297:Male; D012516:Osteosarcoma / Q000503:physiopathology / Q000601:surgery*; D019736:Prostheses and Implants; D011474:Prosthesis Design; D016059:Range of Motion, Articular / Q000502:physiology; D016896:Treatment Outcome