Patient History

50-year-old woman with a history of previous left plantar fasciotomy and nerve repair, now complaining of sharp pain in the same foot.

Findings

Skeletal/osseous and articulations:

Mild 1st metatarsophalangeal joint arthrosis, with associated joint space narrowing. No substantial spurring or subchondral fibrovascular reaction.

Mild to moderate degenerative arthrosis of the lateral sesamoid and to a lesser degree medial sesamoid. Lateral sesamoid demonstrates bipartite configuration.

Incidental note is made of a non-shouldered medial talar dome osteochondral lesion/defect measuring 5 x 6 mm. No displaced intra-articular fragment identified.

No substantial arthropathic change involving the visualized midfoot or 2nd to 5th metatarsophalangeal joints.

No micro- or macro-trabecular fracture. No stress related osteoedema. No stress fracture.

Incidental type 1 os navicularis/os tibialis externum. No adjacent posterior tibial tendinopathy.

Lisfranc joint:

Intact.

Tendons:

Intact and unremarkable.

Ligaments:

Intact.

Plantar plates:

Intact.

Soft tissues:

See below.

Other:

Status post previous medial cord plantar fasciotomy and tarsal tunnel surgery with nerve repair. Partially imaged nodular low signal fibrous scar tissue along the flexor retinaculum and throughout the tarsal tunnel, measuring approximately 1.8 x 1.1 cm.  Fibrous pseudomass abuts the adjacent tibial nerve and tibial nerve bifurcation within the tarsal tunnel. Fibrous pseudomass causes nerve compression within the tarsal tunnel. Mild thickening and edema of the plantar nerves within the tarsal tunnel.

Myoedema and mild-to-moderate atrophy of the quadratus plantae muscle, suggesting active lateral plantar nerve entrapment with function denervation.

Impressions

Tarsal tunnel syndrome with the following:

  1. Postsurgical fibrous pseudomass involving the flexor retinaculum and tarsal tunnel, contributing to tibial and calcaneal nerve entrapment/impingement.
  2. Muscle edema and atrophy of the quadratus plantae muscle, consistent with active impingement (Baxter neuropathy/forme fruste tarsal tunnel syndrome).
  3. Incidental small osteochondral lesion of the medial talar dome, lateral sesamoid arthrosis, and mild 1st metatarsophalangeal joint arthrosis.