Foot

Os Trigonum Syndrome

Os Trigonum Syndrome, Accessory Bone Pain, Painful Accessory Bones, Os Trigonum, Accessory Tarsal Navicular

Anatomy of variably present accessory bones (result from incomplete fusion of the talus)
1. Os Trigonum (Variant present in 14-25%)
  1. Adjacent to the Talus posterior margin
2. Accessory Tarsal Navicular (Variant present in 4-14%)
  1. Adjacent to medial and posterior Tarsal Navicular margin
Os Trigonum Syndrome
1. Pain at the Os Trigonum provoked by high impact sports

Stieda's process
Pain on extreme plantar flexion
Heel thrust maneuver
1. Patient lies prone with foot in dorsiflexion
2. Examiner
  1. Palm of one hand on the patient's heel
  2. Holds the patient's posterior distal calf with the other hand
3. Maneuver
  1. Patient's heel is pushed toward the head (cranially)
  2. Posterior ankle pain is a positive test
Passive plantar hyperflexion
1. Patient lies prone
2. Examiner passively plantar flexes the ankle to >50 degrees
3. Posterior ankle pain with passive plantar flexion is positive test for posterior ankle impingement

Ankle XRay
1. Lateral Ankle XRay with with a well-corticated ossicle posterior to the talus
2. Compare with XRay of opposite foot

Conservative measures to reduce pain on plantar flexion
1. Modify activity to reduce provocative measures
2. NSAIDs
3. Consider taping and bracing
Ultrasound guided Corticosteroid Injection
1. May allow for earlier return to sport (within 3-4 weeks)
Surgery may be considered in refractory course
1. May be needed in up to 15% of patients
2. Expect return to full activity in 70-80% of patients at 13-18 weeks