Can Bilateral Pes Planus Cause Peripheral Neuropathy?
No, bilateral pes planus (flat feet) does not cause peripheral neuropathy in the traditional sense, but it can cause localized nerve compression syndromes affecting specific nerves in the foot, which is mechanically distinct from systemic peripheral neuropathy.
Understanding the Relationship
The relationship between pes planus and nerve problems is one of mechanical compression, not causation of true peripheral neuropathy. Here's the critical distinction:
What Pes Planus Actually Causes
Pes planus creates altered foot biomechanics that can lead to:
Compression neuropathies of specific plantar nerves - Research demonstrates that pes planus subjects show electrodiagnostic abnormalities including mild prolongation of distal latency in medial and lateral plantar sensory nerves and delayed sensory conduction velocity of the medial plantar nerve 1. This substantiates the presence of compression neuropathy of these specific nerves.
Baxter's neuropathy (inferior calcaneal nerve entrapment) - Altered foot biomechanics such as flatfoot is a recognized cause of this specific nerve entrapment syndrome 2.
What It Does NOT Cause
Pes planus does not cause:
- Systemic peripheral neuropathy affecting multiple limbs
- Diabetic peripheral neuropathy
- Length-dependent polyneuropathy
- Chemotherapy-induced peripheral neuropathy
Clinical Context from Guidelines
The diabetes care guidelines 3, 4, 3, 5, 6 consistently identify the reverse relationship: peripheral neuropathy (particularly diabetic neuropathy) leads to altered biomechanics and bony deformities including pes planus, NOT the other way around. Specifically, these guidelines note that "altered biomechanics in the presence of neuropathy" is a risk factor for foot complications 3, 4.
Key Clinical Pitfalls to Avoid
Don't confuse localized nerve compression with peripheral neuropathy - If a patient with pes planus has foot numbness or pain, consider focal nerve entrapment (medial/lateral plantar nerves, Baxter's nerve) rather than systemic neuropathy.
Look for the actual cause of neuropathy - If true peripheral neuropathy is present with pes planus, investigate standard causes: diabetes, alcohol, vitamin B12 deficiency, hypothyroidism, renal disease, neurotoxic medications, or inherited neuropathies 5, 6.
Recognize the temporal sequence - In diabetic patients, neuropathy develops first and then contributes to foot deformities including pes planus through altered biomechanics and muscle imbalances 3, 4.
Practical Assessment Approach
When evaluating a patient with pes planus and sensory complaints:
Examine the distribution: Localized plantar foot symptoms suggest compression neuropathy from pes planus; bilateral symmetric stocking-glove distribution suggests systemic peripheral neuropathy from another cause.
Check for systemic neuropathy signs: Test with 10-g monofilament, assess vibration sense with 128-Hz tuning fork, check pinprick and temperature sensation 6.
Consider nerve conduction studies: These can differentiate between focal plantar nerve compression (which pes planus can cause) versus diffuse polyneuropathy (which it cannot) 1.
Bottom Line
Pes planus causes focal mechanical nerve compression of plantar nerves, not generalized peripheral neuropathy. If a patient presents with both conditions, they are either coincidental or the neuropathy preceded and contributed to the pes planus development (as seen in diabetes). Always investigate standard causes of peripheral neuropathy rather than attributing it to the foot deformity 5, 6.