What is the guideline for management of postoperative common peroneal nerve (CPN) palsy after open reduction internal fixation (ORIF) of the proximal tibia?

Management of Postoperative Common Peroneal Nerve Palsy After ORIF Proximal Tibia

Perform early postoperative assessment within 24 hours to detect CPN palsy, initiate immediate conservative management with specific padding and positioning, and if no recovery occurs within 2-4 months, proceed with surgical decompression or nerve repair to optimize functional outcomes.

Immediate Postoperative Assessment

• Conduct a simple postoperative assessment of lower extremity nerve function in the PACU and within 24 hours postoperatively to enable early recognition of CPN palsy 1.
• Document the presence or absence of ankle dorsiflexion, ankle eversion, and sensory deficits in the distribution of the common peroneal nerve 1.
• Early detection allows for prompt intervention and may reduce the severity of long-term complications 1.

Conservative Management (First 2-4 Months)

Positioning and Padding Strategies

• Use specific padding (foam or gel pads) to prevent direct pressure on the fibular head where the peroneal nerve is most vulnerable 1, 2, 3.
• Avoid contact with hard surfaces or supports that apply direct pressure on the fibular head or lateral tibia 1.
• Ensure padding is not excessively tight or restrictive, as inappropriate padding may paradoxically increase the risk of worsening neuropathy 1, 2, 3.
• Position the lower extremity to avoid prolonged pressure on the peroneal nerve at both hip and knee joints 2, 3.

Pharmacological Management for Neuropathic Pain

• Initiate duloxetine as first-line treatment if the patient develops painful neuropathy, based on evidence of efficacy 2.
• Consider tricyclic antidepressants or anticonvulsants (gabapentin, pregabalin) as alternative options for neuropathic pain management, though evidence is more limited 2.
• Venlafaxine may be considered in select cases where other agents are ineffective or contraindicated 2.

Physical Therapy

• Begin exercise therapy focusing on strengthening and sensorimotor functions to maintain muscle tone and prevent contractures 2.
• Implement medical exercise programs that improve muscular strength and coordination of the affected limb 2.
• Provide an ankle-foot orthosis (AFO) to prevent equinus deformity and facilitate ambulation during the recovery period 4.

Surgical Intervention Timing and Indications

When to Operate

• If no spontaneous recovery occurs within 2-4 months after injury, surgical exploration should be strongly considered 5, 4.
• In open wounds where nerve transection is suspected, perform surgical exploration emergently 5.
• The critical window is 2-4 months: waiting beyond this period may compromise outcomes, but operating too early may subject patients with potential for spontaneous recovery to unnecessary surgery 5, 4.

Surgical Options

For Nerve Compression Without Transection:

• Perform surgical decompression of the CPN at the fibular head and proximal origin of the peroneus longus muscle where epineurial fibrosis and constricting fibrous bands are commonly found 4.
• Decompression alone achieved complete recovery in 67% of cases in one series and subjective/functional improvement in 97% of patients at mean 36-month follow-up 4.

For Nerve Transection or Severe Injury:

• Perform nerve repair (direct suture if possible, or nerve grafting if tension-free repair cannot be achieved) combined with tibialis tendon transfer in a single-stage procedure 5.
• The combination of nerve repair with tendon transfer dramatically improves outcomes, with neural regeneration demonstrated in 90% of patients at 2-year follow-up 5.
• The tendon transfer corrects force imbalance between functioning flexors and paralyzed extensors, preventing fixed equinus deformity and facilitating nerve regeneration 5.

Risk Factors and Prevention

Intraoperative Considerations

• Exercise extreme caution when using intraoperative distraction during ORIF, particularly in staged procedures (external fixation followed by definitive ORIF), as this carries a 25% risk of iatrogenic CPN palsy compared to 4% in non-staged procedures 6.
• The overall incidence of iatrogenic peroneal nerve palsy with intraoperative distraction is 16.4%, with only 60% achieving clinical recovery 6.
• Avoid overdistraction, especially in bicondylar tibial plateau fractures that required staged fixation 6.

Documentation

• Document the following on the operative and anesthetic record: overall patient position, position of lower extremities, use of specific padding over the fibular head, and presence or absence of CPN function in the PACU 1.
• This documentation facilitates continuous quality improvement and helps identify modifiable risk factors 1.

Expected Outcomes and Prognostic Factors

• Shorter time to surgery (within 2-4 months) is associated with significantly better outcomes 7.
• Sharp injuries and severe knee dislocations have excellent recovery potential, while crush injuries and gunshot wounds have less favorable outcomes 5.
• There appears to be a bimodal distribution between responders and non-responders to surgical intervention, with 44% achieving MRC grade 4 strength, but 22% remaining at MRC grade 0 7.
• Mean recovery time for those who do recover is approximately 14 weeks 6.
• 40% of patients who develop peroneal nerve palsies do not recover, leading to permanent loss of motor and/or sensory function 6.

Common Pitfalls

• Delaying surgical intervention beyond 4 months significantly compromises outcomes and may result in permanent disability 5, 4.
• Using excessively tight padding in an attempt to protect the nerve may worsen compression 1, 2.
• Failing to perform early postoperative assessment delays recognition and intervention 1.
• Relying solely on nerve repair without addressing the force imbalance through tendon transfer reduces the likelihood of functional recovery 5.