56-year-old male with osteoarthritis and instability

EXPLORE MORE CASES EXPLORE MORE CASES Watch Video Watch Video Review Stacks Review Stacks

Posttraumatic osteoarthritis peroneal tendinitis short Achilles tendon or Achilles tendon contracture posterior tibial tendon disease instability.

Long- and short-axis fat- and water-weighted images were performed. 

  • Tenosynovitis with tendon sheath septations and haustra are noted involving the flexor hallucis longus. Above the ankle within the distended tendon sheath numerous joint mice or synovial osteochondromas are noted (see CT study or plain radiographs).
  • At the lowest portion of the retromalleolar groove complete tear with distal retraction of the posterior tibial tendon. No tendon is seen on subsequent images till the navicular tuberosity where a thickened 1.0×1.5cm tendon stump with mucoid degeneration is noted.
  • Tenosynovitis with fluid tracks deep into the plantar portions of the flexor hallucis and digitorum. The flexor hallucis tendon has the fibrous bands and haustral markings characteristic for tenosynovitis.
  • Peroneal longus and brevis tendons demonstrate tenosynovitis from their retrofibular segments till their plantar segments. 1 to 2cm of split brevis tear noted behind the fibular groove. 
  • Extensor tendons appear normal. The Achilles tendon appears intact. 
  • Adventitial bursa noted between the distal Achilles tendon and proximal plantar fascia.
  • Normal plantar fascia.
  • End-stage changes are noted related to chronic posterior tibial tendon failure within the spectrum of extraarticular hindfoot impingement and hindfoot valgus. The hindfoot valgus angle exceeds 50 degrees and extraarticular impingement is noted between the fibula and calcaneus and impingement is noted between the lateral tibial plafond and lateral talar dome with high-grade tibiotalar arthrosis bone-on-bone and penetrating chondromalacic changes within tibia and talus. 
  • No acute macrofracture or microtrabecular injury. 
  • Fluid collection in the retrocalcaneal bursa appears continuous with fluid within the posterior recess of the subtalar joint. 
  • Normal tarsal sinus. Aside from tenosynovitis tarsal tunnel is normal. 
  • Normal Chopart joints and no Lisfranc injury. 
  • The plantar musculature appears intact. 
  • No soft tissue masses are noted.
  • Long segment complete tear of the posterior tibial tendon from the tip of the fibula till the navicular tuberosity.
  • Endstage changes of hindfoot valgus manifest as fibular calcaneal impaction and tibiotalar impaction (along the lateral talar dome) with hindfoot valgus angle above 50 degrees all of which represent endstage sequela of chronic posterior tibial tendon failure. 
  • Tenosynovitis involving the medial and lateral flexor tendons with marked distention of the flexor hallucis tendon sheath above and below the ankle with characteristic haustrations and joint mice or synovial osteochondromas. More joint mice or osteochondromas along the anterolateral gutter.
  • Adventitial bursitis in the heel soft tissues between the end of the Achilles tendon and beginning of the plantar fascia. 
  • May see above for additional findings and pertinent negative findings.

Case-based learning.

Try MRI Online Premium for free.



Mastery Series video courses


High-yield cases


Expert case reviews


CME & SA-CME credits

Learn from world renowned radiologists anytime,
actice on real, high-yield cases with MRI Online Premium.