Review Question - QID 219762

Z-type fracture pattern, comminution, shortening greater than 2 cm, and 100% displacement are all risk factors for developing nonunion for patients with midshaft clavicle fractures.

Midshaft clavicle fractures are a common injury, and large prospective studies have helped guide treatment paradigms. Historically, even displaced fractures were treated nonoperatively. However, contemporary literature reports unacceptably high nonunion rates with nonoperative management for certain fracture patterns, spurring further investigation toward identifying possible risk factors for this complication. Although variation in practice exists, fracture morphology has been found to serve as the most impactful risk factor for nonunion. Specifically, shortening greater than 2 cm, displacement greater than 100%, significant comminution, or a Z-type fracture pattern all increase the risk for nonunion. These serve as indications for operative fixation to minimize the risk of nonunion.

Jørgensen et al. performed a system review of midshaft clavicle fractures to determine predictors of nonunion and symptomatic malunion. They report 13 risk factors associated with nonunion and identify six predictors (displacement, comminution, shortening, age, female gender, and smoking). The authors concluded that, despite varied evidence, the degree of displacement is the strongest predictor of nonunion.

Wiesel et al. reviewed midshaft clavicle fractures in adults. They report outcomes comparing non-surgical and surgical techniques, as well as several studies that investigate fixation strategy, including plate number, location, and use of intramedullary nailing. The authors conclude that nonunion rates with nonsurgical treatment are higher than historical reports, and surgical intervention should be strongly considered in the setting of Z-type fracture pattern, comminution, shortening greater than 2 cm, and 100% displacement.

Figure A is an AP radiograph of the left shoulder showing a midshaft clavicle fracture with Z-type deformity and shortening.

Incorrect answers:
Answer 2: Female sex has been shown to increase the risk of nonunion.
Answer 3: Ipsilateral handedness has not been shown to increase the risk of nonunion when treated non-operatively.
Answer 4: Shortening >2 cm is associated with risk of nonunion.
Answer 5: Greater than 100% displacement increases the risk of nonunion.