What causes a painful and bruised limb on the tibia?

Painful and Bruised Tibia: Differential Diagnosis and Evaluation

A painful, bruised tibial area most commonly results from direct trauma causing contusion or hematoma, but requires systematic evaluation to exclude fracture (including occult toddler's fracture), compartment syndrome, deep vein thrombosis, or infection.

Primary Diagnostic Considerations

Trauma-Related Causes

• Soft tissue contusion/hematoma is the most frequent cause when there is visible bruising over the tibia following known or suspected trauma 1
• Occult tibial fracture must be excluded, as initial radiographs may be negative in up to 41% of cases, particularly with nondisplaced oblique fractures (toddler's fractures in young children) 2
• Compartment syndrome requires immediate assessment if pain is out of proportion to examination findings, with associated paresthesias, paralysis, or pulselessness—this constitutes a surgical emergency requiring fasciotomy 1

Vascular Causes

• Superficial vein thrombosis presents as a tender, red, palpable cord under the skin and affects 64-131 per 100,000 person-years 3
• Deep vein thrombosis (DVT) should be considered, though it typically causes diffuse leg swelling rather than localized tibial pain with bruising 4, 5
• Note that approximately 25% of patients with superficial vein thrombosis have concomitant DVT 3

Infectious Causes

• Osteomyelitis or soft tissue infection may present with pain and swelling, though bruising is less typical unless there is associated trauma 2
• Early acute osteomyelitis (<14 days) may show only mild soft tissue swelling on radiographs 2

Initial Diagnostic Approach

Immediate Clinical Assessment

• Evaluate for compartment syndrome by assessing pain severity, passive stretch pain, paresthesias, and pulses—do not delay surgical consultation if suspected 1
• Assess hemodynamic stability if the hematoma is large, as significant blood loss may require fluid resuscitation 1
• Examine for signs of infection including fever, warmth, erythema beyond the bruised area, and systemic symptoms 2

First-Line Imaging

• Radiographs of the affected tibial region are mandatory as initial imaging to exclude fracture, even when clinical suspicion is low 2
• Radiographs provide excellent anatomic overview and exclude tumors, though they may miss nondisplaced fractures initially 2
• Follow-up radiographs at 7-10 days should be obtained if symptoms persist despite negative initial films, as fracture lines become visible with resorption 2

Advanced Imaging When Indicated

• Ultrasound can evaluate for DVT or superficial vein thrombosis if vascular etiology is suspected, and can detect joint effusions or soft tissue fluid collections 2, 3
• MRI has 93% sensitivity for detecting occult fractures, stress reactions, and soft tissue pathology when radiographs are negative and symptoms persist 2, 6
• D-dimer testing has poor sensitivity (48-74%) for superficial vein thrombosis and should not be relied upon to exclude it 3

Management Based on Etiology

For Traumatic Hematoma/Contusion

• Apply cold compresses in the first 24-48 hours to limit expansion and reduce swelling 1
• Elevation and compression facilitate progressive size reduction, typically occurring between weeks 2-6 1
• Expected healing time: Complete resorption of large hematomas typically requires 2-3 months, with functional recovery in 3-4 weeks for uncomplicated cases 1
• Anticoagulation management: Consider discontinuing or reversing anticoagulation after weighing thrombotic risks if the patient is on blood thinners 1

For Confirmed or Suspected Fracture

• Immobilization is essential to prevent nerve damage and promote healing 6
• Avoid tight compression that could compromise circulation or cause nerve compression 6
• Monitor for complications including neuroma formation, which presents as persistent burning or shooting pain after fracture healing 6

For Vascular Thrombosis

• Superficial vein thrombosis ≥5 cm: Treat with fondaparinux 2.5 mg or rivaroxaban 10 mg once daily, plus elastic compression stockings 3
• Superficial vein thrombosis within 3 cm of deep vein: Requires therapeutic-dose anticoagulation with direct oral anticoagulants 3
• Deep vein thrombosis: Requires full anticoagulation with low-molecular-weight heparin followed by vitamin K antagonists or direct oral anticoagulants 4, 5, 7

For Suspected Infection

• Obtain radiographs first to evaluate for soft tissue swelling, gas, foreign bodies, or bony changes 2
• Image-guided aspiration may be necessary for culture if fluid collection is present, as imaging alone cannot distinguish infected from noninfected collections 2
• MRI or CT can help differentiate cellulitis from deeper infections like myositis or osteomyelitis if radiographs are inconclusive 2

Critical Pitfalls to Avoid

• Do not dismiss persistent pain after negative radiographs—up to 41% of toddler's fractures are missed initially and require follow-up imaging 2
• Do not delay compartment syndrome evaluation—this is a surgical emergency that cannot wait for imaging 1
• Do not rely on D-dimer to exclude superficial vein thrombosis—its sensitivity is inadequate for this purpose 3
• Do not assume all bruising is benign—elderly patients and those on anticoagulation have impaired healing and higher complication risks 1
• Consider referred pain—hip pathology commonly presents as knee or thigh pain, so evaluate proximal joints if tibial imaging is negative 2