The project goals are to improve combat readiness of U.S. Soldiers and sustain the availability of the military to deploy by, 1) decreasing the number of days not physically ready for duty after diagnosis of a diaphyseal tibial stress fracture, 2) decreasing the need for a physical profile or medical discharge board after bone stress injury, and 3) decreasing the recurrence rates of bone stress injuries.

The study will examine the utility of a novel, non-operative, anabolic bone agent in the treatment of diaphyseal tibial stress fractures (DTSF). Teriparatide has been well studied in basic science and clinical studies to conclude its positive effects on building bone mass and preventing fractures in post-menopausal women. This allowed the medication to gain it an FDA indication for treatment in these groups. The investigators seek to explore additional uses for this anabolic agent in an at risk study population that has an imbalance of bone stress and bone formation resulting in a bone stress injury (BSI).

The only prior study to examine the effect of teriparatide on fracture healing demonstrated an absolute difference in the time to heal a fracture in the treatment groups, but was under powered to detect a difference. Given these positive results members of the research team have used these findings to administer teriparatide at the 20mg dose to young adult NCAA collegiate athletes who have DTSFs and other BSIs. The promising preliminary clinical observations have led the investigators to hypothesize that teriparatide will have a positive effect on bone healing and return to duty among service members with DTSFs.

A powered, prospective, controlled randomized study design will be utilized. Study subjects are to be recruited from the basic training corps at Fort Jackson via convenience sample. Soldiers who experience pain in the mid-shaft of the tibia during basic training will be evaluated and diagnosed according to the standard of care. Based on direct discussions with physical therapists stationed at Fort Jackson this diagnosis is often made by using a combination of bone scan and plain radiographs. After diagnosis, soldiers with a DTSF present to the physical therapy department for treatment and guidance for their progression of activities.

Inclusion Criteria:

• Soldiers actively enlisted in the U.S. Army attached to basic training unit at Fort Jackson
• Soldiers diagnosed with a tibial diaphyseal BSI requiring convalescent leave
• Skeletally mature
• Willing to self-administer study medication
• Desire to continue their military commitment

Exclusion Criteria:

• History of any form of cancer
• Currently pregnant
• Paget's disease of bone
• Unexplained elevations of alkaline phosphatase (elevations in alkaline phosphatase may signal undiagnosed Paget's disease of bone)
• Pediatric and young adult patients with open epiphyses
• Prior external beam or implant radiation therapy involving the skeleton
• Recent (within the last 6 months) urolithiasis (kidney stones)
• Elevated serum calcium, alkaline phosphatase or uric acid
• Orthostatic hypotension

The case records from this study will be available for review by members of the Institutional Review Board (IRB) at Eisenhower Army Medical Center, Fort Gordon, GA, by representatives of the Food and Drug Administration (FDA) and other governmental agencies as part of their normal duties. This study is being conducted in conjunction with faculty in the Department of Orthopedics, School of Medicine, and the Department of Exercise Science, Arnold School of Public Health at the University of South Carolina, who will also have access to the testing outcomes. All records will be kept in a confidential form. Otherwise, only the Physical Therapists and Physicians conducting this study will have access to the records from this study.

This will be a double-blinded study. All investigators will have access to the subjects results/outcomes, but will not know which randomization group the subject is in.