Stress Fractures

Stress fractures occur when repetitive submaximal loading causes fatigue failure of bone at a rate exceeding the bone's ability to remodel. They are divided into low-risk fractures (tibia posteromedial, metatarsal shaft, fibula, iliac crest) that reliably heal with activity modification; and high-risk fractures (anterior tibial cortex, navicular, fifth metatarsal Jones zone, femoral neck, medial malleolus, patella, sesamoids) that have high nonunion or displacement risk and often require surgical fixation, particularly in athletes.

Female Athlete Triad (disordered eating, amenorrhea, osteoporosis) substantially increases stress fracture risk and should be screened in women with recurrent stress fractures.

Plain X-rays are insensitive early (2–3 weeks). MRI is the most sensitive test and defines fracture grading (Fredericson MRI grading I–IV). Bone scan is an alternative. CT is used for high-risk sites to assess cortical breach and displacement. DEXA scan for bone density in recurrent or atypical presentations.

High-risk stress fractures (especially navicular, femoral neck tension-side, anterior tibia "dreaded black line") and fractures with cortical breakthrough are managed operatively in active patients.

External patient-education references and related OSI pages for additional background:

• Britannica — Bone disease (fractures)
• Britannica — Human skeleton
• AAOS OrthoInfo — patient education library
• OSI glossary — orthopedic terminology in plain language