Ankle injuries - Injury Patterns to Ligaments

Lateral collateral ligaments
Medial collateral ligaments
Syndesmotic ligaments
Tendons

Lateral Collateral Ligaments 

• Injuries to the lateral collateral ligaments are responsible for 85% of acute ankle sprains, particularly in sports. 
• This ligament complex limits inversion (adduction) of the talus and prevents its anterior and lateral subluxation. 
• Injury typically occurs during forceful inversion, which stretches the individual 
• ligaments to the point of complete or partial rupture. 
• The anterior talarfibular ligament or ATFL for short is the most commonly injured ligament. Always check the medial side for fractures when there is a lateral ankle sprain or tear. 

Medial Collateral Ligaments 

• The deltoid (medial) ligament is a primary stabilizer of the ankle joint. 
• This group of ligaments is 20%-50% stronger than the lateral group and is rarely injured in isolation its main function is to limits eversion (abduction) and external rotation, and it prevents talar subluxation. 
• Injury typically occurs through a mechanism of forced eversion. 
• Deltoid ligament tears occur concomitantly with medial malleolar fractures, fibular fractures, and sprains of the lateral ligaments or syndesmosis. 
• When the deltoid ligament is damaged, the emergency physician should search carefully for other injuries. 

Syndesmotic Ligaments

The ankle syndesmosis, or distal tibiofibular joint, is comprised of several ligaments that limit displacement of the fibula relative to the tibia and preserve the correct anatomic and functional relationship of the talar dome within the mortise. 

A mechanism of forceful dorsiflexion or external rotation of the ankle is responsible for the majority of these injuries. 

Tendons

The peroneal muscles of the lateral crural compartment contribute to foot eversion and plantar flexion and give rise to the longus and brevis tendons just above the ankle. Sudden forced dorsiflexion of the foot typically produces injuries to the peroneal tendons or their bony attachments. Pain over the proximal part of the 5th metatarsal should alert the clinician to investigate for possible avulsion fractures due to pernoneus brevis implantation. 

The Achilles tendon, arises from the gastrocnemius and soleus muscles of the calf and inserts on the calcaneus. It is the main plantar flexor of the foot. The Achilles tendon can rupture when abrupt dorsiflexion overstretches the tendon, as often happens during sports. Spontaneous rupture may occur in older patients with underlying medical conditions (rheumatoid arthritis, gout, or hyperparathyroidism), those taking fluoroquinolones, or individuals who have had prior steroid injections around the tendon.