Osteogenesis imperfecta in childhood: impairment and disability.

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 .6). CONCLUSION 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.