INJURIES AROUND THE ANKLE (Pott’s Fracture)
- Injuries around the ankle fall into two groups:
- Ligament injuries
- Bony injuries
- Common ligaments injured are:
- the lateral ligament
- the medial or the deltoid ligament
- the syndesmotic ligament (ligament binding lower tibia and fibula, i.e. inferior tibiofibular syndesmosis).
- These injuries are classified into three grades.
• Grade 1—Stretching of the ligaments
• Grade 2—Partial tear of the ligaments
• Grade 3—Complete tear of the ligaments
- Complete and severe tears require surgical repair.
- Less severe, strains and sprains heal well with adequate immobilization.
- Physiotherapy and gradual mobilization is always essential for a good recovery.
- All bony injuries of the ankle are grouped under one eponym, i.e. ‘Pott’s fracture’.
- Pott’s fracture is defined as a uni, bi or trimalleolar fracture with or without subluxation or dislocation of the ankle joint.
- Ankle joint is a hinge joint.
- Allows only the movement of dorsiflexion and plantar flexion.
- This movement takes place in a mortise known as ankle mortise.
- Formed by medial, lateral and posterior malleolus.
- Any other movement occurring in the ankle joint other than dorsiflexion and plantar flexion, is abnormal
- Tends to injure the supporting bony and ligamentous structures, leading to deformation of the joint.
- Abduction injuries (pronation abduction)
- Adduction injuries (supination-adduction)
- Pronation external rotation injuries
- Supination external rotation injuries
- Vertical compression injuries
- The talus abducts in the ankle mortise.
- Abduction occurs in the vertical axis of the talus.
- The foot is in pronation when this occurs.
- Hence, the term pronation-abduction injury is used.
2. Adduction injuries:
- Talus adducts in the ankle mortise.
- Adduction occurs in the vertical axis of the talus.
- The foot is in supination when this occurs.
- Hence, the term supination-adduction injury is used.
- Foot is in pronation while the talus rotates externally.
- Complete failure pattern in pronation external rotation injury is either Maisonneuve or Dupuytren’s fracture-dislocation.
- Foot is in supination while the talus rotates externally.
- When talus supinates and rotates externally, it springs backwards and out of the ankle mortise.
- Hence, the failure sequence that occurs is as follows:
- First structure to fail is the lateral malleolus— Stage 1
- Next is the posterior malleolus—Stage 2
- Last is the medial malleolus—Stage 3.
- The fracture is known as a trimalleolar fracture or a ‘Cotton’s fracture’.
5. Vertical compression injuries:
- Occurs when a person falls from a height.
- The talus is violently pushed upwards into the inferior articular surface of the tibia, shattering the articular surface.
- Nature of injury is so severe that the mechanism is unclassifiable.
- These injuries are always compound/open injuries resulting in severe morbidity.
- Undisplaced and incomplete fractures:
- Managed with immobilization in plaster/fiber,
- below knee or above knee cast as per indication for a period of 4–6 weeks.
- Displaced fractures:
- Managed by open reduction and internal fixation
- With emphasis on restoration of articular surface congruity.
- Commonest ligament injured in ankle injury is Anterior talofibular ligament.
- Injury around the ankle joint occur at Inversion of foot.
- Ankle sprain is due to Rupture of anterior talo-fibular ligament.
- Cottons fracture is fracture of Ankle.
- Cotton’s Fracture involves Ankle.
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