title: Osteogenesis imperfecta in childhood: impairment and disability.
abstract: OBJECTIVE
  To determine clinical characteristics in children with osteogenesis imperfecta (OI) regarding impairment (range of joint motion and muscle strength) and disability (functional skills) in relation to the different types of the disease, and to study the correlation between characteristics of impairment and disability.
  
  
  METHODS
  In a cross-sectional study 54 children with OI (OI type I: 24; OI type III: 15; OI type IV: 15), the range of joint motion, muscle strength, and functional ability were measured in a standardized way and analyzed statistically.
  
  
  RESULTS
  The range of joint motion in almost all joints differed significantly with respect to the different disease types. In OI type I patients, generalized hypermobility of the joints was present, without decrease in joint motion. In OI type III the extremities were severely maligned, especially the lower limbs. In type IV the upper and lower extremities were equally maligned. Muscle strength differed significantly with respect to the different types of OI. In type I patients, muscle strength was normal except for the periarticular hip muscles. In type III, especially in the lower extremities, muscle strength was severely decreased, with a muscular imbalance around the hip joint. In type IV, muscle strength was mainly decreased in the proximal muscles of the upper and lower extremities. In children </=7.5 years of age, significant differences existed among the different disease types in functional skills regarding mobility. No significant difference was observed in self-care and social function, although the most severely affected children showed a tendency to score better with social function. Older children differed significantly concerning mobility and self-care items. In children </=7.5 years old, a correlation was sometimes observed between impairment and disability items, although in older children a moderate to good correlation was always present (r > .6).
  
  
  CONCLUSIONS
  In OI, severity-related profiles exist, within the different subtypes of the disease, regarding range of joint motion, muscle strength, and functional skills. In younger children, impairment parameters do not sufficiently correlate for disability. Rehabilitation strategies in younger children should therefore focus on improvement of functional skills and not only on impairment parameters.
authors.affiliation: Department of Pediatric Physical Therapy, University Hospital for Children and Youth, "Wilhelmina Children's Hospital", Utrecht, The Netherlands.
authors.forename: R H
authors.initials: RH
authors.lastname: Engelbert
authors.forename: Y
authors.initials: Y
authors.lastname: van der Graaf
authors.forename: R
authors.initials: R
authors.lastname: van Empelen
authors.forename: F A
authors.initials: FA
authors.lastname: Beemer
authors.forename: P J
authors.initials: PJ
authors.lastname: Helders
mesh_terms: D000203:Activities of Daily Living; D001696:Biomechanical Phenomena; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D019988:Children with Disabilities; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D018482:Muscle, Skeletal; D010013:Osteogenesis Imperfecta / Q000145:classification / Q000503:physiopathology*; D016059:Range of Motion, Articular