SLR - June 2021 - Anna Kakizaki

Identifying Common Peroneal Neuropathy before Foot Drop 

Reference: Lu JC, Dengler J, Poppler LH, Van Handel A, Linkugel A, Jacobson L, Mackinnon SE. Identifying Common Peroneal Neuropathy before Foot Drop. Plast Reconstr Surg. 2020 Sep;146(3):664-675. doi: 10.1097/PRS.0000000000007096. PMID: 32459730.

Level of Evidence: II 

Scientific Literature Review 

Reviewed By: Anna Kakizaki, DPM 
Residency Program: Cambridge Health Alliance, Cambridge, MA

Podiatric Relevance: Common peroneal neuropathy symptomatology associated with foot and ankle conditions is often recognized and treated late as compared with other more common neuropathic conditions. It is important for one treating the lower extremity to be well educated of possible related symptoms that may correlate with common peroneal nerve compression. In this retrospective cohort study, the authors elucidate a range of symptoms associated with this process while identifying variables predictive of successful outcomes of surgical decompression.

Methods: Patient data, demographics, and clinical evaluation was collected from a single tertiary medical center from 2011 to 2017. Patient groups were divided into two groups: Overt foot drop (OFD) and Prefoot droop (PFD) groups. In the OFD group, patients exhibit foot drop or weakness of ankle dorsiflexion. In the Prefoot drop (PFD) group, patients exhibited a positive provocative test (tinels or sensory collapse test) with at least one other symptom. Surgical decompression of common peroneal nerve performed for both groups and results were collected.  

Results: One hundred eighty-five patient meeting inclusion criteria were studied, 54 percent overt drop foot and 46 percent pre foot drop. Average follow up was 249 days. Obesity was the most prevalent comorbidity (38 percent), common cause was iatrogenic (49 percent). For patient with OFD, 84 percent had acute symptoms onset, less than a year. Symptoms most commonly reported were affecting dorsal foot 57 percent, lateral leg 46 percent lateral ankle, followed by knee and fibular neck. Reported symptoms being numbness or tingling. For patient with PDF, onset of symptoms noted to be more gradual, more than a year. Presenting with more frequent pain, described by tingling aching shooting burning numbing and throbbing. 

Outcomes of surgical decompression was assessed. Most notable finding was the improvement in quality of life on a visual analog scale score in both groups. In the PDF, great decrease in pain score and in OFD, great improvement in motor function. No significant differences of post-operative complications between the two groups were noted.  

Conclusions: In this article, authors conclude that milder forms of peroneal neuropathy should be clinically recognized even when foot drop is not present. The authors apply the Seddon classification with symptoms noted in this study. PFD group fall in neuropraxia and axonotmesis stages, while OFD group falling in neurotmesis. Authors discuss that decompression of nerve will prevent complete damage, and earlier intervention is recommended. There are limitations to this study, and a more definitive way of diagnosing this disease pattern in earlier stages is needed. 

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