Retrospective Analysis of Fractures and Factors Causing Ambulation Loss After Lower Limb Fractures in Duchenne Muscular Dystrophy

Objective: Prevalence and characteristics of fractures and factors related to loss of ambulation after lower limb fractures were investigated. Design: Chart review included height, weight, dual-energy x-ray absorptiometry, corticosteroid use, vitamin D, fracture history, muscle strength, range of motion, and timed performance tests (10 meter walk/run, Gowers, and four steps). Patients were grouped by fracture location and ambulation loss after fracture. Results: Two hundred eighty-seven patients with Duchenne muscular dystrophy were identified, 53 of these had experienced fracture. Eighty-one percent were older than 9 yrs at first fracture and 36.4% became nonambulatory after fracture. Dorsiflexion range of motion (fracture side,P= 0.021), quadriceps strength (right side,P= 0.025), and shoulder abduction strength (right, left, and fracture side;P= 0.028,P= 0.027, andP= 0.016) were significantly different within the groups. Patients who became nonambulatory after fracture initially had less dorsiflexion (right, left, fracture side; 2.25(0)vs. -7.29(0),P= 0.004; 2.67(0)vs. -12(0),P= 0.001; and 2.41(0)vs. -7.42(0),P= 0.002) and slower 10-meter walk/run times (7.43 secs vs. 14.7 secs,P= 0.005). Conclusions: Fracture represents a significant risk in patients with Duchenne muscular dystrophy; both slower walking speed and ankle contracture confer an increased risk of ambulation loss after fracture.