Bone Stress Injury Recovery and Return to Sport: A Natural History Study

Lower extremity bone stress injury (BSI) is a common overuse injury in athletes and typically requires 4-12 weeks rehabilitation time, provided the injury does not require surgery. Current BSI treatment strategies include cessation of load-bearing sporting activities, consideration for crutches and/or immobilization, pain management, and a gradual return to activities until symptoms resolve. Premature return to sport can result in risk of complications and reinjury of the healing BSI. Moreover, our prior work reported that 1/3 of women with a tibial BSI will sustain at least one additional BSI within one year, indicating that current return to sport guidelines may be inadequate. However, there are no gold standard or validated clinical, functional or imaging outcomes that are consistently used to assess BSI healing and guide return to sport. In this prospective observational study, the investigators will enroll male and female athletes with a diagnosed BSI. The investigators will utilize diagnostic imaging, blood samples, and questionnaires to identify primary and secondary outcomes for assessing BSI healing in runners. Our long-term goal is to identify whether biomarkers, health and lifestyle factors, and training patterns associated with future BSI have the potential to inform and improve BSI treatment.

Inclusion Criteria: * Diagnosed BSI of the tibia, metatarsal two, three, or four, femoral neck or femoral shaft by MRI, grade two or higher on the Fredericson grading scale7 * Age 16-35 years * Body Mass Index 17.5-30 kg/m2 * Self-reported minimum of three hours per week of endurance exercise that includes running at least fifteen miles per week during three months prior to injury * Study enrollment within three weeks of MRI Exclusion Criteria: * Self-reported history of endocrine disorder that impacts bone health (e.g., diabetes, hyperthyroidism, or primary hyperparathyroidism) * Self-reported history of bone disease or other bone disorder (e.g., osteopetrosis, osteogenesis imperfecta, osteomalacia, rickets, Paget's disease, or multiple myeloma) * Use of thyroid hormone replacement at suppressive doses for a history of thyroid cancer * History of chemotherapy or radiation treatment for cancer in the past 5 years * Currently taking or have taken oral glucocorticoids for greater than three months (e.g., prednisone or hydrocortisone) * Current or prior use of osteoporosis medications (e.g., bisphosphonates, teriparatide) * Current use of anti-seizure medications (e.g. Phenytoin (Dilantin), Carbamazepine (Tegretol), Phenobarbitol) * Currently pregnant * Currently lactating * Contraindications to MRI * BSI is planned to be managed operatively * Tibial BSI on the anterior aspect of the bone * Participants that are non-English speaking