Anatomy and Function:
- Medial side of ankle joint is stabilized by deltoid ligament, which has two major components.
- Originates from anterior and inferior aspects of the medial malleolus fanning out and sending 3 bands to the navicular and along the plantar calcaneonavicular (spring) ligament, to sustenaculum tali of the calcaneus and to the medial tubercle.
- Superficial deltoid ligament primarily resists eversion of the hindfoot.
- Tibionavicular portion suspends spring ligament and prevents inward displacement of the head of the talus, while tibiocalcaneal portion prevents valgus displacement.
- Superficial deltoid is also partially covered by the tendon sheaths and crural fascia.
Deep Deltoid Ligament:
- Originates on the posterior border of the anterior colliculus, intercollicular groove and posterior colliculus.
- It is oriented transversely inserts into the entire nonarticular surface of the medial talus.
- Deep deltoid extends function of the medial malleolus and prevents lateral displacement of the talus and prevents external rotation of the talus.
- Latter effect is pronounced in plantarflexion when the deep deltoid tends to pull the talus into internal rotation.
- Originates from inferior and posterior aspects of the medial malleolus and inserts on the medial and posteromedial aspects of the talus.
- Eversion test.
- In neutral evaluates the superficial deltoid ligament complex..
- External rotation stress test to evaluate syndesmotic ligaments and additionally - the deep deltoid ligament.
Fractures with Deloid Injury:
- In the absence of a medial malleolar fracture the deltoid ligament may be stretched or torn in all oblique fractures of the fibula.
- This ligament prevents the PT tendon from slipping into the ankle joint.
- Ligament ultimately heals in a lengthened position.
- These patients are often diagnosed as having chronic deltoid sprains.
- The main problem, however, is lateral talar shift resulting from malunited fracture of the lateral malleolus or a syndesmotic ligament injury, which widens the mortise and produces chronic ankle instability.
Radiographic Diagnosis of Injury:
- Deltoid is usually avulsed from the tibial attachment, frequently with a small flake of bone visible on x-rays.
- Disruption of the deltoid ligament can be diagnosed with relative confidence when the medial clear space between the talus and the medial malleolus is increased.
- There is usually associated lateral shift of the talus, with incr medial joint space ( > 3 mm), but this may be apparent only on stress view or in postcasting films, after the swelling has subsided.
- Presence of medial tenderness and > 5 mm of space is seen when there is substantial injury of deltoid ligament.
Treatment of Deltoid Tear:
- Such injuries should be treated as bimalleolar fracture with ORIF of lateral malleolus.
- Routine exploration of the medial side of the ankle is not necessary unless there is evidence that a portion of the deltoid ligament has entered the joint and is blocking reduction of the talus.
BiMalleolar Equivalent Fracture With Displaced Fibula Fracture and Deltoid Rupture treated with ORIF Fibula with 2 Arthrex Syndesmotic Tightropes.