What is Tarsal Tunnel Syndrome

WHAT IS INVOLVED

Posterior Tibial Nerve

LOCATION

Posterior Tibial nerve entrapment at the Tarsal Tunnel in the foot at the level of the medial malleolus

COMMON SYMPTOMS

– Foot, Ankle, Sole pain/burning and aching
– Worse at night
– Occasional numbness/tingling sole of foot
– No muscle weakness
– Usually unilateral
– Difficulty walking because of pain and discomfort with shoes
– Positive Tinel (tingling upon tapping nerve) sign behind the medial malleolus

ONSET

– May be Sudden in trauma, injury
– Usually Gradual, weeks, months

RISK FACTORS

– No gender preference
– Diabetes or family history of Diabetes, Alcoholism or other occupational or nutritional causes of Neuropathies, HIV infection
– Usually post-traumatic
– Can be aggravated with joint inflammation from tenosynovitis, phlebitis

EXAM

– Very positive and tender Tinel (tingling upon tapping nerve) sign behind the medial malleolus
– Usually ankle swelling, tenderness
– No weakness or atrophy
– May have decreased sensation over the sole of the foot
– Patient quite uncomfortable with standing, walking

LOCALIZATION

The Posterior Tibial nerve inside the Tarsal Tunnel affecting both Medial and Lateral Plantar nerves of the foot

EMG

– Prolonged Posterior Tibial distal latency to the Abductor Hallucis or Abductor Digiti Quinti Pedis
– May be accompanied by low motor amplitude or absent responses in either of these muscles
– Medial and/or Lateral plantar sensory action potentials may be affected early on with prolonged latency, slowed velocity and decreased amplitude
– Sensory Action potentials unobtainable in advanced cases
– Needle exam of Abductor Hallucis and/or Abductor Digiti Quinti Pedis may show denervation, active and/or chronic
– Check non-Posterior Tibial muscles (Extensor Digitorum Brevis) or Posterior Tibial muscles above the Tarsal Tunnel (Posterior Tibialis) are spared and Lumbo-Sacral paraspinals are intact to ensure this is not an S1 root lesion

RECOMMENDATIONS

– Symptomatic treatment by relieving cause and treating local trauma
– Foot brace and arch support
– Anti inflammatory medications
– Surgery in advanced cases
– In complicated and post-operative ankle injuries, surgery may actually worsen the symptoms

WHAT ELSE COULD IT BE?

– Could be ankle joint pain without involvement of the Posterior Tibial nerve
– If bilateral, suspect Diabetes, Small Fiber Neuropathy (symptoms not just limited to the foot), but more importantly, bilateral S1 root lesions