From the Guidelines
To assess for clavicle union after fracture, a non-contrast CT scan with thin-slice multiplanar reconstructions is recommended. This type of CT scan provides detailed visualization of the fracture site and allows for accurate assessment of bone healing and union status, which is crucial for determining the effectiveness of treatment and preventing complications such as nonunion or malunion, as highlighted in the American Academy of Orthopaedic Surgeons clinical practice guideline summary on the treatment of clavicle fractures 1. The scan should include axial images with coronal and sagittal reconstructions at 1-2mm slice thickness to optimize visualization of the clavicle's complex anatomy.
When ordering this study, it's essential to specifically request that the radiologist evaluate for fracture union, as this will ensure appropriate attention to cortical bridging and callus formation. CT is superior to plain radiographs for this purpose because it eliminates overlapping structures and provides three-dimensional information about the healing process, which is particularly valuable for clavicle fractures where radiographs may be limited by overlapping shoulder structures and the curved nature of the clavicle, as noted in the ACR Appropriateness Criteria for shoulder pain-traumatic 1. CT can detect early signs of union before they become apparent on plain films, and can also identify complications such as nonunion, malunion, or hardware complications if the fracture was surgically repaired.
Key considerations for the CT scan include:
- Non-contrast to avoid unnecessary radiation exposure and potential allergic reactions
- Thin-slice multiplanar reconstructions to provide detailed visualization of the fracture site
- Axial images with coronal and sagittal reconstructions at 1-2mm slice thickness to optimize visualization of the clavicle's complex anatomy
- Specific request for the radiologist to evaluate for fracture union to ensure appropriate attention to cortical bridging and callus formation.
From the Research
CT Scan for Clavicle Union Assessment
- A CT scan can be used to assess clavicle union after a fracture, with a study finding that CT is 100% sensitive and 81.7% specific for non-union diagnosis 2.
- The accuracy of CT scanning for clavicle non-union evaluation can be influenced by scan timing, callus, and patient characteristics 2.
- A retrospective review of CT scans found that atrophic callus was associated with a confirmed non-union, while hypertrophic callus was associated with delayed union in approximately half of the cases 2.
Predicting Clavicle Union
- A prospective cohort study found that a delayed assessment at 6 weeks following injury can accurately predict fracture-healing, with factors such as QuickDASH score, radiographic callus, and fracture movement on examination being significant predictors of nonunion 3.
- The study found that patients with a QuickDASH score of ≥40 points, no callus on radiographs, and fracture movement on examination were at a higher risk of nonunion 3.
Imaging Evaluation
- Clavicle fractures are typically diagnosed and followed with plain radiography, but CT scans can provide more accurate information on union and non-union 4.
- A review of current concepts in clavicle fracture treatment found that operative treatment is being considered more frequently, especially in young and active patients with displaced fractures 5.