Escalating Leg Pain After Tibial Nailing: Block, Compartment, or Both?
Mr. R, 38, is 18 hours post intramedullary nailing of a closed tibial shaft fracture after a motorcycle crash. He has an adductor canal block infusing ropivacaine 0.2% at 8 mL/h plus an IV hydromorphone PCA. He rates incisional pain 5/10 but describes a deep, escalating ache in the anterior leg that "feels different." The anterior compartment is firm, and passive great-toe extension reproduces severe pain. First web space sensation is diminished compared with the left foot; the dorsalis pedis pulse is 2+ and capillary refill is 2 seconds. Urine output is 60 mL/h, and he received 4 L of crystalloid in the OR. Compartment pressure has not yet been measured.
1. Which findings most strongly suggest acute compartment syndrome, which findings are falsely reassuring, and what will you do in the next 30 minutes?
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Findings that support compartment syndrome
- Pain with passive stretch of the toes is the most sensitive early sign and is present here.
- Escalating, deep pain that feels qualitatively different from incisional pain, even though the numeric score is only 5/10.
- Firm compartment and decreased first web space sensation (deep peroneal nerve distribution), indicating early neurologic compromise.
Falsely reassuring findings
- A 2+ pulse and 2-second capillary refill reflect large-vessel flow; compartment syndrome occurs in a closed fascial space and can exist with normal pulses.
- The 5/10 pain score is blunted by the local anesthetic; a low score does not exclude the diagnosis.
- Good urine output rules out neither compartment syndrome nor rhabdomyolysis. It should still be monitored.
Actions within 30 minutes
- Notify the surgeon now, describing the trend, not just the number.
- Remove or loosen circumferential dressings and any elastic wrap; keep the leg at heart level, not elevated above it.
- Obtain a compartment pressure measurement; correlate with diastolic pressure (within about 30 mmHg of diastolic is concerning) and with the clinical exam.
- Continue serial neurovascular checks and prepare for possible fasciotomy; do not wait for pulselessness or paralysis, which are late signs.
2. The patient asks why his pulse is strong if the leg is 'at risk.' How do you explain this, and what must your documentation capture?
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Explanation in plain language
- The pulse you feel is in a major artery outside the tight muscle compartments. The pressure problem is inside a compartment that cannot expand, so the muscle and nerve can be injured while the artery still transmits a pulse.
- This is why the nurse checks pain with movement, sensation, and the firmness of the leg, not only the pulse.
Documentation must capture
- Serial, time-stamped neurovascular assessments (sensation, motor, pain with passive stretch, compartment firmness, pulses, capillary refill).
- The trend: what changed from the last check and by how much.
- The exact time the surgeon was notified, the message given, and the response or orders received.
- Interventions performed (dressing released, position changed) and the patient's response.
- That the patient's question was answered and his understanding was confirmed. This supports continuity of care and protects against a delayed diagnosis.
3. How does the continuous nerve block change your monitoring plan? Would you request that it be stopped?
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Effect of the block
- A continuous block can mask the pain that would otherwise be the earliest warning sign, and it can also mask motor and sensory findings in its distribution.
- That does not make the block wrong, but it lowers the reliability of the pain score and requires reliance on other indicators.
Adjusted monitoring
- Assess pain with passive stretch and compartment firmness at every check.
- Test sensation and motor function outside the blocked distribution where possible, and compare with the documented baseline.
- Use compartment pressure measurement earlier when the clinical picture is ambiguous.
- Watch for breakthrough pain, a change in the character of pain, or a rising analgesic requirement as a warning sign.
Should it be stopped?
- That is a prescriber decision, not a nursing unilateral one. The appropriate action is to report the concerning findings and ask the surgical and anesthesia teams whether to decrease or stop the infusion so that the exam becomes interpretable.
- If the team elects to continue it, document the rationale and increase the frequency and objectivity of assessments.