title: Foot and ankle abnormalities in the Hurler syndrome: additions to the phenotype.
abstract: BACKGROUND
  After successful hematopoietic stem cell transplantation maintaining function and mobility has become the key goal in the management of patients with mucopolysaccharoidosis type 1 (MPS-1). We detail the foot and ankle pathology in 18 patients with MPS-1 managed in our unit.
  
  
  METHODS
  Functional assessment was performed using the Oxford Foot and Ankle Questionnaire for children (OxAFQ-C). Morphologic assessment was performed by means of a mirrored foot photograph box, the Foot Posture Index (FPI), and clinical photography. Standardized radiologic investigations were sought when clinically warranted. Average lateral talus-first metatarsal angle, anteroposterior and lateral talocalcaneal angles, and lateral distal tibial angle (LDTA) were determined.
  
  
  RESULTS
  The average patient-reported OxAFQ-C score was 44.7 (range, 10 to 60). The average proxy-reported OxAFQ-C score was 45.7 (range, 11 to 60). Ten of the 18 patients wore customized footwear. Of the 36 feet examined 11 were found scored as "highly pronated" (FPI>+9), 12 feet had a "pronated posture" (FPI +6 to +9), and 13 feet were found to have a "normal posture" (FPI 0 to +5). Thirteen of the 18 (72%) patients studied had curly toes. The average talus-first metatarsal angle recorded was 10.7 degrees (range, -7 to 30 degrees). The average lateral and anteroposterior talocalcaneal angles were 45.8 degrees (range, 16 to 62 degrees) and 31 degrees (range, 1 to 51 degrees), respectively. The average LDTA was found to be 70.6 degrees (range, 48 to 82 degrees). A single-sample Student t test shows significant divergence of measured LDTA, OxAFQ-C, and FPI from normal populations (P<0.005).
  
  
  CONCLUSIONS
  MPS-1 is associated with a significant degree of foot and ankle pathology that has not been previously described. We found a high incidence of curly toes, ankle valgus, functional foot, and ankle disability and a requirement for customized footwear among our cohort. We recommend that careful assessment of foot and ankle pathology should be routine in the interdisciplinary management of patients with MPS-1.
  
  
  METHODS
  Level III.
authors.affiliation: Our Lady's Children's Hospital, Crumlin, Dublin, Ireland. getjimkennedy@gmail.com
authors.forename: Jim
authors.initials: J
authors.lastname: Kennedy
authors.forename: Jacque
authors.initials: J
authors.lastname: Noel
authors.forename: Anne
authors.initials: A
authors.lastname: O'Meara
authors.forename: Paula
authors.initials: P
authors.lastname: Kelly
mesh_terms: D000293:Adolescent; D000842:Ankle / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005528:Foot / Q000473:pathology*; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006801:Humans; D008297:Male; D008059:Mucopolysaccharidosis I / Q000503:physiopathology* / Q000628:therapy; D010641:Phenotype; D011446:Prospective Studies; D012775:Shoes; D055815:Young Adult