Definition
Entrapment neuropathy of posterior tibial nerve within the tibial tunnel
Anatomy
Fibro-osseous tunnel
| Roof | Floor | Contents | Tibial nerve |
|---|---|---|---|
|
Flexor Retinaculum - medial malleolus - posterior calcaneum |
Anterior - tibia Posterior - talus Lateral - calcaneum |
Tibialis posterior / FDL / FHL Posterior tibial artery Posterior tibial nerve |
Medial calcaneal branch
Divides in tunnel - medial and lateral plantar |
Etiology
Specific cause identified in 60% cases
| Idiopathic | Post-traumatic | Inflammatory | Space Occupying Lesions | Accessory muscles | Bony |
|---|---|---|---|---|---|
| 40% cases |
Chronic medial instabiliity
Scarring around nerve
|
Tenosynovitis I.e. Rheumatoid arthritis |
Ganglions Lipomas Schwannoma / Neurofibroma
|
Accessory FDL muscle | Medial talocalcaneal bar |
|
Varicose veins Vascular leashes |
Sammarco et al Foot Ankle Int 2003
- surgical release of 62 patients with tarsal tunnel syndrome
- most common finding arterial vascular leashes indenting the nerve and scarring about the nerve
- varcositys and space occupying lesions also common
Symptoms
Paresthesia plantar and medial aspect of foot
Diffuse pain plantar aspect
Aggravated by activity
Examination
Tarsal tunnel
- tenderness
- positive Tinel's sign
- palpable thickening or swelling (cyst, ganglion etc)
Examine plantar sensation
Provocation tests - Dorsi-flexion / eversion test, Plantarflexion / inversion test
Nerve Conduction Studies
Not always helpful
Findings
- sensory amplitude reduced in medial and lateral plantar nerves
- delayed motor latency of the abductor hallucis muscle
MRI
Findings
- space occupying lesions - lipoma / neurofibroma / Schwannoma
- accessory muscle
- varicose veins
- medial talocalcaneal bar
- tenosynovitis
Differential diagnosis
Local - plantar fasciitis / stress fractures
Neurological - neuropathy / Morton's neuroma / vascular claudication
Nonoperative management
Options
Orthotics
Taping
Physiotherapy
NSAIDS
Operative management
Surgical release of flexor retinaculum
Technique
Youtube open tarsal tunnel release video
Posteromedial incision
- proximal to medial malleolus curved distally to TNJ
- release flexor retinaculum
- explore and release tibial nerve
- protect medial calcaneal branch
- remove space occupying lesions
Follow and release both plantar nerves to abductor hallucis fascia
- release lateral plantar tunnel
Results
Gondring et al Foot Ankle Int 2003
- tarsal tunnel release in 68 feet
- 51% subjective symptom relief
Reichert et al Foot Ankle Surg 2015
- tarsal tunnel release in 31 feet
- 93% good/excellent results