Review Question - QID 214157

This patient has sustained a Hawkins II talar injury (displaced talar neck fracture with subtalar dislocation). The most common long-term complication of his injury is degenerative changes in the subtalar joint, as described by answer choice 1.

The management of displaced talar neck fractures is difficult owing to the unique osseous and vascular anatomy of the talus, resulting in poor outcomes and a high incidence of complications. Urgent open reduction and internal fixation of talar neck fracture-dislocations is recommended to minimize soft tissue complications and increase the chances of revascularization, with nonoperative treatment or percutaneous fixation reserved for nondisplaced talar neck fractures. While varus malunion, nonunion, avascular necrosis are all potential complications, the leading complication is post-traumatic arthritis, with the subtalar joint being most common location.

Jordan et al. reviewed the complications of talar neck fractures by the Hawkins classification. They reported that avascular necrosis was observed in 0.00% of type I fractures, 15.91% of type II fractures, 38.89% of type III fractures, 55.00% of type IV fractures, and 26.47% of all fractures. As for subtalar arthritis, it was present in 0.00% of type I fractures, 54.29% of type II fractures, 46.43% of type III fractures, 45.45% of type IV fractures, and 44.97% of all fractures. They concluded that patients sustaining talar neck fractures should be prepared for the greater likelihood of long-term complications and should maintain contact with their orthopedist.

Maceroli et al. investigated the healing and radiographic outcomes of displaced and comminuted talar neck fractures treated with medial position screws augmented with lateral minifragment plate fixation. They reported an 11.5% rate of nonunion, 0% malunion, 27% avascular necrosis, and 38% post-traumatic arthritis, predominantly in the subtalar joint. They concluded that lateral mini fragment plate fixation with medial augments and sagittal plane position screws provides a length stable construct that prevents talar neck shortening and malunion.

Clare et al. reviewed the prevention of avascular necrosis with talar neck fractures. They reported that the timing of definitive surgery no longer has a bearing on the risk of osteonecrosis, and that the amount of initial fracture displacement is best predictor of osteonecrosis. They highlighted that markedly displaced fractures or fracture-dislocations should be provisionally reduced, with or without temporary external fixation. They concluded that rigid internal fixation with solid cortical screws countersunk within the talar head and applied below the "equator" of the talar head is important for optimum stability.

Figures A and B depict a Hawkins II talar injury (displaced talar neck fracture with subtalar dislocation). Figures C and D are representative normal radiographs with labels A-D identifying the subtalar joint, ankle joint, talonavicular joint, and talar body, respectively.

Incorrect Answers:
Answer 2: While osteonecrosis of the talar body is not uncommon, it is not the most common long-term complication.
Answer 3: Subchondral lucency (i.e. Hawkins sign) would not be considered a complication, as it represents good vascularity.
Answer 4: Hawkins II injuries do not involve the talonavicular joint and would be rare to find degenerative changes here as a result.
Answer 5: In the long-term, subtalar arthritis is more common than ankle arthritis.