Tibial shaft fracture is one of the most common fractures in children and adolescents. It encompasses approximately 15 % of all long-bone fractures and is third behind only fractures of the femur and both bones of the forearm. (2). Although most authorities agree that closed tibial shaft fractures are best treated by immobilization in a long-leg cast, there is no clear consensus as to when to allow weight bearing on the injured extremity. While most recent articles have recommended long-leg casts with the knee bent in flexion of 30-60 degrees to preclude weight-bearing(1,2,3,4), other authors have recommended much less flexion, 0-5 degrees, to encourage early weight bearing.(5).

The purpose of this randomized controlled prospective study is to determine if the position of immobilization of the knee influences the rate of healing, delayed union, and nonunion As well, we will assess if the type of immobilization affects the function of the patient during the period of treatment using the Activities Scale for Kids - Performance (ASK-P) child self-report musculoskeletal outcome measure . A minimum of 36 patients in each group for a total of 72 patients between 4 and 14 years of age (open physis) with closed fractures of the tibia, with or without fracture of the fibula, will be included in the study

Inclusion Criteria:

• Patients between 4 and 14 years of age (open physis)
• Patients seen at the Los Angeles Orthopaedic Medical center within 7 days of the original injury
• All closed tibia and tibia and fibula shaft fractures regardless of fracture pattern

Exclusion Criteria:

• Fractures with greater than 2 cm of initial shortening
• Open fractures
• Patients that have other orthopaedic medical issues such as hemophilia