Urgent Evaluation for Compartment Syndrome and Nerve Injury
This patient requires immediate evaluation for compartment syndrome and deep peroneal nerve injury—measure intracompartment pressures urgently and perform emergency fasciotomy if pressures are elevated (>30 mmHg or within 30 mmHg of diastolic pressure).
Clinical Presentation Analysis
The continuous plantar flexion with inability to walk after a posterior leg hematoma strongly suggests:
- Deep peroneal nerve injury (causing foot drop with unopposed plantar flexion from intact posterior compartment muscles)
- Evolving or established compartment syndrome in the anterior and/or lateral compartments
- Possible gastrocnemius/soleus hematoma with mass effect
The two-week duration is concerning—this represents a delayed presentation that significantly increases risk of permanent neurovascular damage.
Immediate Diagnostic Steps
1. Clinical Assessment for Compartment Syndrome
Look specifically for:
- Pain with passive toe dorsiflexion (most sensitive early sign)
- Tense, swollen compartments on palpation
- Sensory deficits in the first web space (deep peroneal nerve distribution)
- Motor weakness of ankle/toe dorsiflexion
- Diminished pulses (late finding—do NOT wait for this) 1
Critical pitfall: Normal pulses do NOT exclude compartment syndrome. The diagnosis is clinical, and waiting for vascular compromise leads to irreversible damage 1, 2.
2. Intracompartment Pressure Measurement
- Measure all four compartments (anterior, lateral, superficial posterior, deep posterior)
- Diagnostic threshold: Absolute pressure >30 mmHg OR delta pressure <30 mmHg (diastolic BP minus compartment pressure) 1
- Document pressures immediately—this is both diagnostic and medicolegal
3. Imaging
- Ultrasound or CT scan to characterize hematoma size, location, and extent 3, 4
- Rule out deep vein thrombosis (can mimic this presentation) 4
- Do NOT delay fasciotomy for imaging if clinical diagnosis is clear
Management Algorithm
If Compartment Syndrome Confirmed:
Emergency four-compartment fasciotomy within hours 1, 3, 2:
- Evacuate any intramuscular hematoma found during fasciotomy 1, 3
- Expect staged wound closure over 1-2 weeks 1
- The 2-week delay makes this even more urgent—muscle necrosis begins at 6-8 hours, and nerve damage becomes irreversible after 12-24 hours
If Large Hematoma Without Compartment Syndrome:
- Operative evacuation under local or general anesthesia 5
- Rationale: Large hematomas cause tissue ischemia through pressure and biochemical changes, leading to skin necrosis even without frank compartment syndrome 5
- Can be performed in wound clinic setting for accessible hematomas 5
Special Considerations:
Check coagulation status immediately 1, 3, 2:
- This patient may have underlying coagulopathy or be on anticoagulation
- Compartment syndrome after minor trauma in anticoagulated patients is well-documented 1, 3, 2, 4
- If anticoagulated: reverse coagulation AND perform fasciotomy—do not delay surgery 2
- May require prothrombin complex concentrate and blood transfusion 2
Post-Operative Management
- Vacuum-assisted closure dressing for open fasciotomy wounds 2
- Monitor for continued bleeding if coagulopathic 2
- Delayed skin closure or grafting at 1-2 weeks 1
- Physical therapy for nerve recovery (can take months)
Prognosis
With prompt fasciotomy at 2 weeks:
- Nerve recovery is possible but uncertain—the deep peroneal nerve injury may be from direct compression or ischemia 1
- Expect 6-10 weeks for return to activities if treated appropriately 1
- Without intervention: permanent foot drop, chronic pain, and potential limb loss
Critical Warning
Do not mistake this for simple "tennis leg" or muscle strain 4. The continuous plantar flexion indicates significant pathology requiring urgent intervention. The minor trauma history combined with a 2-week progressive course suggests either underlying coagulopathy or evolving compartment syndrome that was initially subclinical 1, 3, 2.