Objective:
To assess whether finite element modeling of the lower extremities of patients with OI during gait , when used with clinical assessment, will allow more accurate prediction of fracture risk.

Methods:
Surgical bone samples will be collected from 34 patients with OI who have routine surgery for fracture repair. Criteria for selection will include interested patients five to 18 years of age with moderate to severe OI who has chosen to undergo elective reconstructive surgery of the tibia or femur and has been scheduled for surgical repair of fractures.

As a second, separate initiative, 24 patients with OI will be receive the following tests during four repeat visits at six-month intervals:

• routine gait analysis
• physical exam and routine clinical x-rays
• an activity diary to complete at home
• an upper extremity evaluation (range of motion and strength),
• a lower extremity evaluation (range of motion and strength)
• Pediatric Evaluation of Disability Inventory (PEDI)
• Pain assessment (using the International Pain Scale Assessment)
• a neurodevelopmental evaluation with the Wong-Baker scale
• Dexa Scan

Results from the two studies will be analyzed and used to develop the finite element models for fracture prediction. Predictive results from the finite element model will be compared to those from the gait and clinical tests.