A 20-year-old female cross-country runner comes to the clinic complaining of aching pain in her right forefoot that has progressively worsened over the last 3 weeks. There is no history of trauma. She recently increased her weekly mileage in preparation for a marathon. Initially, the pain only occurred at the end of her runs, but now it persists during daily walking. Past medical history is unremarkable. On physical examination, there is localized point tenderness and mild swelling over the dorsal aspect of the second metatarsal shaft. There is no bruising, warmth, or erythema. Plain radiographs of the foot are negative for fracture or cortical thickening.
Which of the following is the most appropriate next step in management?
The correct answer is:
E) Rest and activity modification
The patient has a metatarsal stress fracture, a common overuse injury in athletes, especially runners and military recruits (historically called a "march fracture"). It results from repetitive submaximal loading that outpaces the bone's ability to remodel.The second metatarsal is the most common site because it is the longest and least mobile of the metatarsals. The clinical diagnosis is based on localized point tenderness over the bone. In the acute phase (first 2–3 weeks), plain X-rays are notoriously insensitive and often appear completely normal. Evidence of healing, such as a periosteal reaction or callus formation, only appears later. Therefore, if the clinical suspicion is high, the management is started immediately despite negative X-rays.
Answer choice A: Bone biopsy, is incorrect. Bone biopsy is used when a bone tumor like Ewing sarcoma is suspected. While tumors can cause localized pain, the history of increased athletic training makes a stress fracture far more likely.
Answer choice B: MRI of the foot, is incorrect. While MRI is the most sensitive test for detecting early stress reactions and marrow edema before they become frank fractures, it is usually unnecessary if the clinical history and exam are classic. Treatment with rest remains the same. MRI is reserved for elite athletes needing an accelerated timeline or when the diagnosis is unclear.
Answer choice C: Measurement of compartment pressures, is incorrect. This is the diagnostic test for acute compartment syndrome (an emergency usually following major trauma) or chronic exertional compartment syndrome (which presents as diffuse exercise-induced muscle pain/tightness, not localized bone tenderness).
Answer choice D: Open reduction and internal fixation, is incorrect. Most metatarsal stress fractures, especially the 2nd, 3rd, and 4th, are managed conservatively. Surgery is typically reserved for high-risk stress fractures, such as those at the base of the 5th metatarsal (Jones fracture) or the navicular bone, due to their poor blood supply and high risk of non-union.
Key Learning Point
Metatarsal stress fractures present with localized point tenderness in athletes who have recently increased their activity level. X-rays are often negative in the first few weeks. The mainstay of treatment for low-risk fractures (2nd–4th metatarsals) is rest, activity modification (using a stiff-soled shoe or walking boot), and gradual return to activity once pain-free.
