Anatomy Msk · Year 1 · from Anatomy Msk
Case 3: Stress Fracture Evaluation with Multi-Modality Imaging
Clinical Image
Source: Wikimedia Commons - Bone Scan - Public Domain
Case Presentation
A 22-year-old female cross-country runner presents with 3 weeks of progressive left anterior shin pain. The pain started after she increased her weekly mileage for an upcoming race. It initially occurred only during running but now hurts with walking and at rest. She reports her menstrual periods have been irregular. Physical examination reveals point tenderness over the anterior tibia at the junction of the middle and distal thirds. There is no swelling, warmth, or erythema. Single-leg hop test reproduces her pain. Initial radiographs of the tibia are normal with no visible fracture line or periosteal reaction. Given the high clinical suspicion, MRI is obtained which demonstrates bone marrow edema in the anterior tibial cortex with a focal linear hypointensity consistent with a stress fracture. There is no evidence of a complete fracture. She is diagnosed with a tibial stress fracture, placed in a walking boot, and her training is modified. Laboratory evaluation reveals low vitamin D and relative energy deficiency (RED-S) is suspected. She is counseled on proper nutrition and referred to sports medicine for comprehensive management.
Key Learning Points
- Stress fractures occur from repetitive loading; radiographs are often negative early (2-4 weeks to show changes)
- MRI is most sensitive for early stress fractures, showing bone marrow edema before cortical changes are visible
- Bone scintigraphy (bone scan) is highly sensitive but less specific; shows increased uptake at sites of bone remodeling
- Female athlete triad/RED-S (relative energy deficiency in sport) predisposes to stress fractures
- Radiograph findings of stress fracture (when visible): periosteal reaction, cortical thickening, fracture line