Bone, 2015; 79(): 52-57, PMID: 26004918

The functional muscle-bone unit in patients with osteogenesis imperfecta type I.

Year: 2015

Veilleux LN, Pouliot-Laforte A, Lemay M, Cheung MS, Glorieux FH, Rauch F
Shriners Hospital for Children, 1529 Cedar Avenue, Montreal, Quebec H3G 1A6, Canada; Department of Pediatrics, McGill University, 1529 Cedar Avenue, Montreal, Quebec H3G 1A6, Canada; Centre de Readaptation Marie-Enfant, Research Center, Hopital Sainte-Jus

Abstract

CONTEXT: Osteogenesis imperfecta (OI) type I is a heritable bone fragility disorder that is caused by mutations affecting collagen type I. We recently showed that patients with OI type I frequently have muscle weakness. As muscle force and bone mass are usually closely related, we hypothesized that muscle weakness in OI type I could contribute to increase bone mass deficit in the lower extremities. OBJECTIVE: To assess the muscle-bone relationship in the lower extremities of children and adolescents with OI type I. SETTING: The study was carried out in the outpatients department of a pediatric orthopedic hospital. Patients and other participants Thirty children and adolescents with OI type I (20 females; mean age [SD]: 11.2years [3.9]) were compared with 30 healthy age- and sex-matched controls (mean age [SD]: 11.1years [4.5]). MAIN OUTCOME MEASURES: Tibia bone mineral content (BMC; mg/mm) was measured by peripheral quantitative computed tomography to estimate bone strength at the 4% and 14% sites. Lower extremity peak force (kN) was measured by mechanography using the multiple two-legged hopping test. RESULTS: Compared with age- and sex-matched controls, patients with OI type I had 17% lower peak force (1.3kN vs. 1.7kN; p=0.002) as well as a 22% lower BMC (128mg/mm vs. 165mg/mm; p<0.001). Stepwise regression analysis showed that muscle force and tibia length were positively related to bone strength (r2=0.90, p<0.001) whereas there was no effect of the disease status (OI vs. control). CONCLUSIONS: These results suggest that the muscle-bone relationship is similar between children and adolescents with OI type I and healthy age and sex-matched controls. It also suggests that muscle weakness may contribute to decreased bone strength in individuals with OI type I.

GID: 3925; Last update: 17.06.2015