Identifying Common Peroneal Neuropathy before Foot Drop

Abstract

Background: Common peroneal neuropathy shares the same pathophysiology as carpal tunnel syndrome. However, management is often delayed because of the traditional misconception of recognizing foot drop as the defining symptom for diagnosis. The authors believe recognizing common peroneal neuropathy before foot drop can relieve pain and help improve quality of life. Methods: One hundred eighty-five patients who underwent surgical common peroneal neuropathy decompression between 2011 and 2017 were included. The mean follow-up time was 249 ± 28 days. Patients were classified into two stages of severity based on clinical presentation: pre–foot drop and overt foot drop. Demographics, presenting symptoms, clinical signs, electrodiagnostic studies and response to surgery were compared between these two groups. Multivariate regression analysis was used to identify variables that predicted outcome following surgery. Results: Overt foot drop patients presented with significantly lower preoperative motor function (percentage of patients with Medical Research Council grade ≤ 1: overt foot drop, 90 percent; pre–foot drop, 0 percent; p < 0.001). Pre–foot drop patients presented with a significantly higher preoperative pain visual analogue scale score (pre–foot drop, 6.2 ± 0.2; overt foot drop, 4.6 ± 0.3; p < 0.001) and normal electrodiagnostic studies (pre–foot drop, 31.4 percent; overt foot drop, 0.1 percent). Postoperatively, both groups of patients showed significant improvement in quality-of-life score (pre–foot drop, 2.6 ± 0.3; overt foot drop, 2.7 ± 0.3). Patients with obesity or a traumatic cause for common peroneal neuropathy were less likely to have improvements in quality of life after surgical decompression. Conclusion: Increased recognition of common peroneal neuropathy can aid early management, relieve pain, and improve quality of life. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

Complete Foot Drop With Normal Electrodiagnostic Studies

“…16 By contrast, there is little in the literature for making the diagnosis of peroneal neuropathy based on clinical presentation alone. 17,18 Physicians and surgeons typically rely on the presence of a foot drop in addition to electrodiagnostic abnormalities to confirm the diagnosis and offer surgical treatment. 15 Electrodiagnostic abnormalities used to confirm the diagnosis of a motor deficit are a decrease in nerve conduction velocity across the fibular neck, a conduction block across the fibular neck, or evidence of muscle denervation (fibrillations, positive sharp waves, increased insertional activity, multiphase motor unit potentials, and decreased compound muscle action potentials [CMAPs] of the tibialis anterior).…”

“…Pain is occasionally present along this sensory distribution but other than when in association with a ganglion, it is not a common complaint in patients presenting clinically with a complete foot drop 2 . Our extensive experience treating peroneal neuropathy led us to observe that patients typically present in a motor dominant or sensory dominant fashion with either a complete foot drop with a paucity of pain symptoms or as a prefoot drop peroneal neuropathy with a higher incidence of pain symptoms and sensory disturbances, respectively 17–23 . Our group recently published a large series of patients with common peroneal neuropathy 17 .…”

“…2 Our extensive experience treating peroneal neuropathy led us to observe that patients typically present in a motor dominant or sensory dominant fashion with either a complete foot drop with a paucity of pain symptoms or as a prefoot drop peroneal neuropathy with a higher incidence of pain symptoms and sensory disturbances, respectively. [17][18][19][20][21][22][23] Our group recently published a large series of patients with common peroneal neuropathy. 17 It was shown that patients with a prefoot drop common peroneal neuropathy typically presented with a higher severity of pain symptoms and a higher frequency of normal electrodiagnostic studies.…”

Evidence in peroneal nerve entrapment: A scoping review

“…Fabre et al advocate decompressing the nerve if there is no recovery after a period of 2–4 months [58]. Considering surgery only after failure of months of conservative therapy is supported by several authors (who did not meet the inclusion criteria for this scoping review) [1,72–76]. Wilson et al [54] performed a meta‐analysis to identify predictors of outcome for their dataset and an additional 115 patients with peroneal neuropathy (idiopathic and nonidiopathic) from previous papers.…”

An overview of common peroneal nerve dysfunction and systematic assessment of its relation to falls

“…The diagnostic testing can comprise an electrodiagnostic evaluation, which is more useful in diagnosing a neuropathy with axonal deficits and can help localize a more severe peroneal neuropathy [ 20 ]. In milder cases, nerve conduction studies of the peroneal nerve are often normal, limiting the usefulness of electrodiagnostic testing [ 21 ]. Imaging, in the form of ultrasound and magnetic resonance neurography, is emerging as an additional tool to identify a swollen peroneal nerve [ 22 ].…”