What is the workup for nonunion of a clavicle (collarbone) fracture?

From the Guidelines

The workup for nonunion of a clavicle fracture should include a comprehensive clinical evaluation, appropriate imaging studies, and assessment of risk factors that contribute to nonunion, as outlined in the most recent clinical practice guideline summary from the American Academy of Orthopaedic Surgeons 1. The initial step in the workup involves a detailed history focusing on the initial injury, previous treatments, functional limitations, and pain assessment.

• A physical examination should evaluate shoulder range of motion, strength, neurovascular status, and any visible deformity, such as the "Z" deformity often resulting from the pull of the pectoralis major and the weight of the arm 1.
• Radiographic assessment is essential, including standard anteroposterior and 45-degree cephalic tilt views of the clavicle to visualize the fracture site, gap distance, and any hardware if present.
• CT scanning provides more detailed information about bone stock, fracture pattern, and the degree of displacement, which is particularly valuable for surgical planning, as surgical treatment of displaced clavicle fractures results in equivalent or improved short-term patient-reported outcomes and reduced rates of nonunion or symptomatic malunion when compared with nonsurgical treatment 1.
• Laboratory studies including complete blood count, erythrocyte sedimentation rate, C-reactive protein, and cultures (if infection is suspected) should be obtained to rule out underlying infection.
• Additional workup may include evaluation for risk factors that contribute to nonunion such as smoking status, nutritional deficiencies (vitamin D, calcium levels), metabolic disorders, and medication use that might impair bone healing, as these factors can significantly impact the success of treatment, whether conservative management or surgical intervention is ultimately required for the nonunion 1.
• Electromyography and nerve conduction studies may be warranted if there are concerns about brachial plexus involvement. This comprehensive approach allows for accurate diagnosis and appropriate treatment planning, taking into consideration the increasing evidence that nonsurgical management of widely displaced fractures often results in malunions, which may have adverse effects on strength and function of the shoulder, in addition to being cosmetically unacceptable 1.

From the Research

Evaluation and Etiology of Clavicle Nonunion

• Clavicle nonunion is a rare complication of clavicle fractures, with a reported rate of 0.1% to 15% 2
• Contributing factors to nonunion include severe initial trauma, marked initial displacement and shortening, soft tissue interposition, primary open reduction and internal fixation, refracture, open fracture, polytrauma, and inadequate initial immobilization 2
• Clavicle nonunion can result in disability from pain at the site of nonunion, altered shoulder mechanics, or a compression lesion involving the underlying brachial plexus or vascular structures 2

Treatment Options for Clavicle Nonunion

• Treatment options for clavicle nonunion include nonsurgical management, salvage procedures, and reconstructive procedures 2
• Reconstructive procedures aim to obtain union and restore the clavicle to its normal length, with fixation methods ranging from external fixation to plate and screw osteosynthesis 2
• Open reduction and internal fixation with plates and screws, and with intercalary tricorticocancellous grafts, is a preferred method for obtaining union and restoring the clavicle to its normal length 2
• Plating and bone grafting of the clavicle is an effective method of management of painful nonunion, with minimal complications 3

Surgical Intervention for Clavicle Nonunion

• Surgical repair of clavicle fractures is being employed more frequently, although most fractures are still treated conservatively 4
• Current treatments for clavicle nonunion include open reduction with internal fixation (ORIF) plating without bone graft, ORIF plating with bone graft, and intramedullary pin fixation 4
• A systematic review of 53 studies found that 95% of patients achieved union after primary nonunion surgery, with an overall complication rate of 17% 4
• Single-plating fixation had significantly faster union time, lower reoperation rate, and hardware removal rate than intramedullary pin fixation 4
• Bone graft had significantly lower rates of delayed union but higher complication and reoperation rates than the other groups 4

Use of Bone Graft in Clavicle Nonunion

• Autologous bone graft is not a necessary augment to internal fixation for clavicle nonunion, with a series of 15 patients achieving clinical and radiological union without the use of distant bone graft 5
• The use of bone graft in clavicle nonunion requires further study to determine its value and risk/benefit ratio 4
• A study found that a risk factor for plate breakage was the increased stress in free hole area around the fracture zone, and recommended the use of monocortical screws or simple obturators for the holes around the fracture zone to protect the comminuted fragment for further damage and enhance plate strength 6