Stress fractures

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A stress fracture is a fracture of structurally normal bone due to the coalescence of microfractures caused by repetitive activity. Risk factors include female sex, calcium deficiency, and highly repetitive activity. Clinical manifestations include pain that worsens with activity and improves with rest and tenderness over the affected bone. High-risk stress fractures are stress fractures in locations (e.g., lateral femoral neck, anterior tibia, 5^th metatarsal) that are prone to complications (e.g., fracture progression, nonunion). Stress fractures may be managed based on a clinical diagnosis, but x-rays are typically obtained for confirmation. Because x-rays are often normal, an MRI is indicated if there is a concern for a high-risk stress fracture. Treatment is mainly conservative and focuses on cessation of the inciting activity, but high-risk stress fractures are managed as acute fractures, with immobilization, avoidance of weight-bearing activities, and referral to orthopedics.

• Common injury in athletes; accounts for ∼ 10% of all sports-related overuse injuries ^[2]
• Most commonly affected regions in both children and adults: ^[2][3]
  • Lower extremity (most commonly the tibia and tarsal bones) ^[4]
  • Foot (most commonly the metatarsals)

Epidemiological data refers to the US, unless otherwise specified.

Mechanism

Normal bone develops a fracture as a result of bone remodeling due to repetitive microtrauma. ^[5][6]

Risk factors ^[6][7]

• Participation in repetitive high-intensity physical activity: often seen in athletes and military recruits, and children and adolescents participating in year-round sports ^[3][8]
• Improper technique during physical activity
• Ill-fitting footwear
• Poor nutrition and/or low calorie intake (e.g., in anorexia nervosa)
• Low bone mineral density
• Calcium and/or vitamin D deficiency
• Female sex ^[9]
• Previous stress fracture ^[2]

The female athlete triad syndrome is associated with an increased risk of stress fractures. ^[2]

Stress fractures are classified based on the risk of stress fracture complications. ^[2][6][7]

Low-risk stress fractures

• Posteromedial tibia ^[4]
• 1^st–4^th metatarsal shaft ^[4]
• Fibula and lateral malleolus
• Medial femoral neck
• Cuneiform, cuboid
• Calcaneal stress fractures

High-risk stress fractures

• Anterior tibia ^[4]
• Proximal 5^th metatarsal shaft ^[2]
• 1^st metatarsal sesamoid bones ^[2]
• Talus, tarsal navicular
• Medial malleolus
• Superolateral femoral neck
• Patella

• Location ^[10]
  • Lower extremities (most common): tibia, tarsal navicular, metatarsals (march fracture), femur, fibula, pelvis
  • Upper extremities (least common): humerus, scapula, ribs
• Symptoms ^[6][7]
  • Pain that worsens with activity and resolves with rest
    • Typically begins several weeks after an increase in exercise intensity
    • Usually well localized
  • Fractures may be asymptomatic (incidental finding). ^[11]
• Signs ^[2][7]
  • Focal bone tenderness, erythema, and/or soft tissue swelling
  • Provocation test reproduces pain
    • Rotation of the hip exacerbates pain from a proximal femur stress fracture.
    • Hop test exacerbates pain from a lower extremity stress fracture.
    • Foot inversion exacerbates pain in metatarsal stress fracture.

Imaging

A preliminary clinical diagnosis guides early management, but imaging of the affected region is indicated for confirmation. ^[2][12]

• X-ray: recommended initial imaging study ^[5]
  • Radiographic features of stress fractures include: ^[7]
    • Fracture line: line of faint lucency
    • Indirect features: periosteal thickening, increased cortical density, formation of a callus, endosteal thickening and/or sclerosis
  • Often normal in the first 2–3 weeks of disease onset ^[7][12]
  • If the initial radiograph is negative: ^[5]
    • Suspected low-risk stress fractures: Repeat in 10–14 days.
    • Suspected stress fractures of the pelvis, hip, or lower extremity: Obtain early MRI.
    • Other suspected high-risk stress fractures: Consider MRI.
    • For athletes with any stress fracture: Obtain an MRI.
• MRI without contrast
  • High sensitivity and specificity
  • Indications ^[4][5]
    • Early definitive diagnosis required (gold standard)
    • Diagnostic uncertainty
    • Assessment for return to play required
  • Findings include: ^[13][14]
    • Fracture line: line of low signal intensity
    • Bone marrow and/or periosseous soft tissue edema
• Other imaging modalities: Consider if there is diagnostic uncertainty in patients with contraindications to MRI. ^[5]
  • Bone scan
  • CT
  • Ultrasound

Stress fractures may often not be visible on plain films, particularly during the first 2–3 weeks of disease onset. Repeat x-ray and/or MRI is often required. ^[12]

Laboratory studies ^[15]

• Usually not required
• Consider if there is diagnostic uncertainty or to exclude serious differential diagnoses of stress fractures (e.g., osteomyelitis, malignancy).
• Recommended studies include:
  • CMP
  • CBC
  • ESR

• Soft tissue injury ^[4]
• Tendinopathy ^[7]
• Entrapment neuropathy
• Pathologic fracture
• Peripheral arterial disease ^[16]
• Exertional compartment syndrome ^[2]
• Malignant bone tumors ^[7]

The differential diagnoses listed here are not exhaustive.

Initial management of stress fractures is typically conservative. Surgical management is reserved for refractory cases and high-risk stress fractures (e.g. anterior tibia, proximal 5^th metatarsal, patella, talus, superolateral femoral neck), which are prone to fracture progression, delayed union, or nonunion.

Low-risk stress fractures ^[10][12]

• Cease inciting activity for 4–6 weeks.
• Continue weight-bearing as tolerated.
• Consider splinting or a short walking boot in case of severe symptoms.
• Pain control (e.g., acetaminophen, ice packs) ^[6]
• Risk factor modification (e.g., improved nutrition, calcium and vitamin D supplementation)
• Screen female patients for female athlete triad. ^[2]

Up to one-third of low-risk stress fractures do not heal with conservative management. Refer patients with refractory fractures to orthopedic surgery. ^[6]

High-risk stress fractures ^[2][12]

• Manage like an acute fracture: See “General principles of fracture management.”
  • Immobilize the affected extremity (e.g., cast, splint).
  • Advise avoidance of weight-bearing activities.
  • Risk factor modification (e.g., improved nutrition, calcium and vitamin D supplementation)
• Refer to orthopedic surgery.

High-risk stress fractures should be managed like acute fractures. ^[2]

• Progression to complete fracture ^[2][7]
• Avascular necrosis
• Delayed healing
• Nonunion

We list the most important complications. The selection is not exhaustive.

Calcaneal stress fractures are most commonly found in individuals who run, jump, and/or march for extended periods of time (e.g., athletes, dancers, soldiers). For acute fractures of the calcaneus, see “Calcaneal fractures.” ^[17]

Etiology ^[17]

• Repetitive microstress to the calcaneus (e.g., weight overload, increase in physical activity)
• Inadequate footwear and activity on hard surfaces increase risk.
• See also “Etiology of stress fractures.”

Clinical features ^[17]

• Heel pain on activity (e.g., weight-bearing activities, walking on hard surfaces)
• Point tenderness on palpation of the posterior calcaneus
• Swelling, warmth, and/or ecchymosis of the heel (uncommon)
• Positive calcaneal squeeze test: pain elicited by mediolateral compression of the heel between thumb and index finger

Diagnostics

• X-ray: foot series with Harris axial view ^[10]
  • Fractures may not be visible until 2–3 weeks after onset of clinical features.
  • Findings: focal sclerosis in posterior calcaneus (most common) ^[17]
• MRI
  • Indicated if clinical features and x-rays are equivocal
  • Findings: sclerosis, soft tissue changes
• See also “Diagnostics for stress fractures.”

Differential diagnosis of chronic heel pain

• Calcaneal stress fracture
• Plantar fasciitis
• Achilles tendinopathy
• Heel pad syndrome
• Tarsal tunnel syndrome
• Calcaneal spur (heel spur)
• Peripheral neuropathy
• Lumbosacral radiculopathy

Treatment ^[17][18]

Calcaneal stress fractures are considered low-risk and can usually be managed conservatively.

• Activity modification with reduced weight bearing
• Heel pad inserts
• Consider a walking boot and/or shock-absorbing orthotic.
• Routine orthopedic follow up
• See also “Treatment of stress fractures.”

Calcaneal stress fractures are often misdiagnosed as soft-tissue injuries and undertreated. ^[17]

Tibial stress fractures result from activities that put excessive force through the tibia and are classified as either low-risk or high-risk for complications depending on the location of injury. For acute fractures of the tibia, see “Tibial fracture” and “Fractures.” ^[2][4]

Etiology ^[2][4][7]

• Excessive repetitive force through the tibia (e.g., from running, jumping, dancing) ^[10]
• Specific risk factors include: ^[2]
  • Anatomical features such as pes cavus and high arched feet ^[19]
  • Poor running technique (e.g., inadequate pronation of the foot)
  • Physical activity performed on hard or steep surfaces
• See also “Risk factors for stress fractures.”

Clinical features

• Pain with weight-bearing activities ^[4]
• Location of pain ^[4][7]
  • Knee: for injuries to the proximal tibia ^[15]
  • Tibial shaft (shin): for injuries to the anterior and medial tibia
• Signs
  • Limping with ambulation ^[15]
  • Positive hop test ^[4][7]
• See also “Clinical features of stress fractures.”

Diagnostics

• X-ray: preferred initial imaging study ^[5]
  • Obtain multiple views (e.g., anteroposterior and lateral). ^[5][20]
  • Findings
    • Radiographic features of stress fractures
    • Anterior fracture: thickened anterior cortex with a lucent fracture line ^[2][8]
• If the x-ray is normal, consider repeat x-ray or MRI.
• For further information, see “Diagnostics for stress fractures.”

Differential diagnoses ^[4]

Depends on the location of the pain, e.g.:

• Anterior lower extremity
  • Sports injuries (e.g., tendinopathy)
  • Osgood-Schlatter disease ^[3]
  • Compartment syndrome
• Medial lower extremity
  • Sports injuries (e.g., medial tibial stress syndrome) ^[7]
  • Tumors: See also “Benign bone tumors” and “Malignant bone tumors.” ^[15]

Management

See also “Treatment of stress fractures.”

Initial management ^[4][7][15]

• Provide pain management as needed.
• Determine whether the fracture is high-risk or low-risk for complications. ^[2]
  • Low-risk location: posteromedial aspect (most common)
  • High-risk location: anterior or medial malleolus
• Refer patients with a high-risk stress fracture to orthopedics or sports medicine.
• Address any underlying etiologies.

Activity modifications for athletes and optimal time to return to play should be determined in consultation with a specialist, as these decisions can affect recovery time and the need for surgery. ^[7]

Low-risk stress fractures of the tibia ^[7]

• Reduce the level of weight-bearing activities until pain-free.
• Consider immobilization, e.g., with a splint or walking boot.
• Refer to physical therapy.
• Evaluate patients every 2–3 weeks to assess response. ^[7]
• Recommend cautious reintroduction of weight-bearing activities from 2–12 weeks based on the level of pain experienced.
• Return to sports is only recommended when patients are pain-free. ^[4][15]

High-risk stress fractures of the tibia ^[2]

• Recommend non-weight-bearing for at least 6–8 weeks. ^[4]
• Consider immobilization. ^[4]
• Refer to orthopedics or sports medicine for further management. ^[2]
  • Conservative management may be trialed for 3–6 months.
  • Surgical management may include: ^[2]
    • Intramedullary nailing
    • Excision and bone grafting
    • Anterior tension band plating

Metatarsal stress fractures are common with repetitive load bearing, hence they are also known as march fractures. For tuberosity avulsion fracture and Jones fracture of the 5^th metatarsal shaft, see “Fractures.” ^[2]

Etiology

• Excessive repetitive force through the foot from:
  • General exercise (e.g., running, walking, dancing) ^[7]
  • Sports that cause tension on the plantar-lateral side of the foot (e.g., soccer, basketball, football) ^[2]
• Specific risk factors include:
  • Anatomical features of the foot or leg such as tibia vara and low arched feet ^[2][19]
  • Fatigued muscles during long, intense physical activity ^[4]
  • Change in terrain or physical training routine ^[4]
  • History of recent trauma ^[4]
• See also “Risk factors for stress fractures.”

Clinical features

• Pain with weight-bearing activities ^[4]
• Location of pain ^[7]
  • Focal tenderness over the fracture site
  • Lateral pain suggests 5^th metatarsal injury. ^[2]
  • May be referred to the ankle
• Signs: In patients with 5^th metatarsal injury, inversion of the foot may provoke pain. ^[2]
• See also “Clinical features of stress fractures.”

Diagnostics ^[5][15]

• X-ray: Preferred initial imaging study
  • Obtain multiple views (anteroposterior, lateral, and oblique). ^[20]
  • Findings: radiographic features of stress fractures
• If the x-ray is normal, consider repeat X-ray or MRI.
• For further information, see “Diagnostics for stress fractures.”

Differential diagnoses ^[4][7]

• Muscle strain
• Interdigital neuroma
• Metatarsalgia
• Plantar fasciitis

Management ^[2][4][7]

See also “Treatment of stress fractures.”

Initial management ^[4][7][15]

• Provide pain management as needed.
• Determine whether the fracture is high-risk or low-risk. ^[2]
  • Low-risk locations: 1^st–4^th metatarsal shaft ^[4]
  • High-risk locations
    • Proximal 5^th metatarsal shaft ^[2]
    • 1^st metatarsal sesamoid bones ^[2]
• Refer patients with a high-risk stress fracture to orthopedics or sports medicine.
• Address underlying etiologies.

Low-risk stress fractures of the metatarsal shaft

• Low risk fracture are typically managed conservatively. ^[2][15]
• Recommend rest and avoidance of weight-bearing activities for 6 weeks. ^[4]
• Refer to physical therapy.
• Evaluate patients every 2–3 weeks to assess response. ^[7]

Sports and physical activity can generally be resumed when weight-bearing activities are no longer painful. ^[4]

High-risk stress fractures of the metatarsal shaft

Refer to a specialist (orthopedic surgeon or sports medicine) for consideration of surgical management (e.g., with intramedullary fixation). ^[2][15]