title: Custom rotating hinge total knee arthroplasty in patients with poliomyelitis affected limbs.
abstract: OBJECTIVE
  Total knee arthroplasty (TKA) in limbs affected by poliomyelitis is a technically challenging procedure. These patients often demonstrate acquired articular and metaphyseal angular deformities, bone loss, narrowness of the intramedullary canals, impaired quadriceps strength, flexion contractures and ligamentous laxity producing painful hyperextension. Thus, using condylar knee designs in these patients will likely result in early failure because of instability and abnormal load distribution. The aim of this study was to assess the outcomes associated with use of the customised (SMILES) rotating-hinge knee system at our institution for TKA in poliomyelitis-affected limbs.
  
  
  METHODS
  We retrospectively reviewed the outcome of 14 TKAs using the (SMILES) prosthesis in 13 patients with limbs affected by poliomyelitis. All patients had painful unstable knees with hyperextension. There were ten females and three males with a mean age of 66 years (range 51-84) at time of surgery. Patients were followed up clinically, radiologically and functionally with the Oxford knee score (OKS). Mean follow-up was 72 months (16-156).
  
  
  RESULTS
  There were no immediate or early complications. One patient fell and sustained a peri-prosthetic fracture at seven months requiring revision to a longer stem. Radiological evaluation showed satisfactory alignment with no signs of loosening in all cases. Mean OKS improved from 11.6 (4-18) to 31.5 (18-40) postoperatively (p < 0.001).
  
  
  CONCLUSIONS
  The rotating hinge (SMILES) prosthesis is effective at relieving pain and improving function in patients with poliomyelitis. The device compensates well for ligamentous insufficiency as well as for any associated bony deformity.
authors.affiliation: Joint Reconstruction Unit, Royal National Orthopaedic Hospital, Stanmore, UK.
authors.forename: Jeeshan
authors.initials: J
authors.lastname: Rahman
authors.forename: Sammy A
authors.initials: SA
authors.lastname: Hanna
authors.forename: Babar
authors.initials: B
authors.lastname: Kayani
authors.forename: Jonathan
authors.initials: J
authors.lastname: Miles
authors.forename: Robin C
authors.initials: RC
authors.lastname: Pollock
authors.forename: John A
authors.initials: JA
authors.lastname: Skinner
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Briggs
authors.forename: Richard W
authors.initials: RW
authors.lastname: Carrington
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000601:surgery; D007719:Knee Joint / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000453:epidemiology* / Q000503:physiopathology / Q000601:surgery; D011051:Poliomyelitis / Q000453:epidemiology*; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D012189:Retrospective Studies