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December Image Quiz

Lateral Clavicle Fractures

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A 64-year-old woman presents to your office with right shoulder pain 3 weeks after falling out of bed while sleeping and landing directly on the lateral aspect of the shoulder. She was originally seen in the emergency room, where anteroposterior and Zanca view radiographs were obtained (Figs. 1 and 2) and she was diagnosed with a lateral clavicle fracture. A sling was applied, and she was instructed to be seen at an orthopaedic practice for follow-up. She used the sling for approximately 2 weeks before removing it because her strength had seemed to return. However, she continued to have shoulder pain when using the arm with overhead activities and when sleeping on the shoulder at night. She had had a rotator cuff repair 10 years previously and had been doing very well until this most recent injury.

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What is the best next step in treatment?

  1. Ordering a magnetic resonance imaging (MRI) scan to evaluate the coracoclavicular ligaments
  2. Open reduction and internal fixation with a locking plate
  3. Continuing the treatment with the simple sling until the pain with overhead activities resolves
  4. Transacromial wire fixation

Clavicle fractures are commonly seen in orthopaedic practice as they represent 4% of all fractures. The most common mechanism for this injury is a fall directly on the shoulder with the arm at the side. The majority of clavicle fractures (approximately 80%) occur at the middle one-third of the clavicle. Fractures of the lateral one-third are less common, and it is important to recognize them as their prognosis is less predictable than that of fractures of the middle one-third. Anteroposterior radiographs including a standing Zanca view are recommended to establish the diagnosis and determine fracture stability.

Stability of clavicle fractures is largely dependent on an intact acromioclavicular (AC) joint capsule, AC joint ligaments, and coracoclavicular (CC) ligaments. The CC ligaments are the primary vertical stabilizers of the clavicle and include the medial conoid and lateral trapezoid ligaments. The Neer classification, based on the location of the fracture in relation to the AC joint and CC ligaments, is the gold standard for describing stability of lateral clavicle fractures. The Neer classification consists of 5 types. Type-I fractures, the most common, occur lateral to or between the CC ligaments but spare the AC joint. Type-I fractures remain stable as the intact CC ligaments support the medial fragment, preventing superior migration. Type-II fractures occur when the CC ligaments detach from the medial fragment, with type IIA occurring medial to the conoid and trapezoid ligaments and type IIB occurring between the torn conoid ligament and the intact trapezoid ligament. Type-II fractures are unstable and have a high nonunion rate. Displacing forces from the weight of the arm and muscular attachments make it difficult for the fracture to heal when the CC ligaments are detached. Type-III fractures occur lateral to the CC ligaments and extend into the AC joint. Type IV, which is rare, is a periosteal sleeve fracture of the lateral part of the clavicle that occurs in the pediatric population. The CC ligaments remain intact in types III and IV and therefore these are stable fracture patterns. Type-V fractures include comminuted fractures of the lateral part of the clavicle with the CC ligaments remaining attached to a small inferior fragment. Type-V fractures are unstable as the CC ligaments are detached from the medial and lateral fragments.

The Neer fracture type along with the size of the lateral fragment are the factors determining which treatment is recommended. Stable lateral clavicle fractures including Neer types I, III, and IV can be successfully treated nonoperatively, with nonunion rates as low as 5%. Sling immobilization for comfort is recommended for 2 to 3 weeks or until pain with shoulder motion subsides. Radiographs may be repeated in 6 weeks to be sure that the fracture healed appropriately.

Treatment of type-II fractures remains controversial. These fractures are inherently unstable, are prone to displacement, and have high rates of delayed union and nonunion. Nonunion rates have been reported to be 28% to 44% with nonoperative treatment, and 45% to 67% of fractures that do heal take >3 months to do so. However, there is no evidence that surgery offers a benefit over nonoperative treatment for displaced fractures. Surgery is generally reserved for patients with soft-tissue compromise or who develop a symptomatic nonunion or AC joint arthritis >6 months after the injury. Age and activity also play a role in the decision regarding whether to perform surgery. Older patients with osteoporotic bone are likely to have more complications with operative fixation, whereas young active patients are less likely to tolerate a long period of nonoperative treatment. Surgical techniques may include transacromial wire fixation, open reduction and internal fixation with locking plates, tension band wiring, and excision of the lateral clavicle fragment. These techniques may be performed with or without CC ligament repair or reconstruction. The size of the lateral fragment often determines the choice of technique, as the fragment should be at least 1 cm long to accommodate screw and plate fixation. If the lateral fragment is too small a plate that hooks under the acromion—i.e., a hooked plate—may be used. However, the hooked plate requires a second procedure as it must be removed once the fracture heals.

Conclusions

The patient presented with a Neer type-I lateral clavicle fracture. The fracture line appears to be between the CC ligaments. There is no superior migration of the medial clavicle fragment, indicating the conoid ligament is likely intact. The fracture pattern also appears stable on the standing Zanca view and therefore surgery is not indicated. As discussed previously, type-I fractures can be treated with a simple sling until the pain subsides. MRI is not routinely ordered to determine stability of the CC ligaments.

Answer: C

The patient was informed that data concerning the case would be submitted for publication, and she provided consent.

 

Suggested Reading
 
 
Robinson CM, Cairns DA. Primary nonoperative treatment of displaced lateral fractures of the clavicle. J Bone Joint Surg Am. 2004 Apr;86(4):778-82.
 
Bishop JY, Jones GL, Lewis B, Pedroza A; MOON Shoulder Group. Intra-and interobserver agreement in the classification and treatment of distal third clavicle fractures. Am J Sports Med. 2015 Apr;43(4):979-84. Epub 2015 Jan 13.
 
Banerjee R, Waterman B, Padalecki J, Robertson W. Management of distal clavicle
fractures. J Am Acad Orthop Surg. 2011 Jul;19(7):392-401.
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