A 19-year-old athlete has sudden severe ankle pain after being tackled. X-ray shows a spiral fracture of the distal fibula at the level of the ankle mortise with medial clear space widening on the stress view. This corresponds to which Weber/AO classification and what does medial clear space widening indicate?
- A Weber B fracture at the level of the syndesmosis with likely deltoid ligament tear or medial malleolus fracture causing mortise instability ✓
- B Weber A fracture below the syndesmosis, an isolated avulsion with stable mortise
- C Weber C fracture above the syndesmosis with intact deltoid ligament
- D Pilon fracture with articular comminution requiring staged treatment
Correct answer: A. Weber B fracture at the level of the syndesmosis with likely deltoid ligament tear or medial malleolus fracture causing mortise instability
Explanation
A fibula fracture at the level of the ankle joint (syndesmosis) is Weber B (AO 44-B). Medial clear space widening greater than 4 mm (or exceeding the superior joint space) indicates rupture of the deltoid ligament or an occult medial malleolus fracture, creating an unstable mortise. These injuries require operative fixation (fibula plate ± syndesmotic screw) to restore the mortise and prevent post-traumatic arthritis.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.