Prevalence of Incidental Benign and Malignant Lesions on Radiographs Ordered by Orthopaedic Surgeons

Radiographs are the most commonly available diagnostic imaging modalities used to evaluate orthopaedic conditions. In addition to suspected findings based on the initial indication to obtain radiographic images, incidental findings may be observed as well, some of which may have notable medical and legal ramifications. This study evaluates the number of incidental findings reported from orthopaedic radiographs ordered in an academic orthopaedic multispecialty group over 1 year.

A retrospective review was conducted of 13,948 eligible radiographs recorded at our institution over a 12-month period. Reports were categorized based on examination type. Incidental findings were categorized as having concern for possible malignancy versus likely benign conditions. The possibly malignant findings were then further subdivided into either bone or lung malignancies. The benign findings were subcategorized by etiology and anatomic location.

Thirteen thousand nine hundred forty-eight radiographs were evaluated, and 289 (2.07%) incidental findings were identified. The three study categories with the highest prevalence of incidental findings were spine (3.96%), leg length alignment (3.94%), and pelvic and hip (2.81%) radiographs. The three most common types of incidental findings identified were for possible malignancy or metastases in bone (30.1%), benign bone disease (24.9%), and gastrointestinal conditions (6.57%). Follow-up was recommended for 122 (42.2%) incidental findings.

This study describes the prevalence of incidental findings on orthopaedic radiographs in adults. Axial radiographs such as of the spine and pelvis are more likely to report an incidental finding as opposed to appendicular radiographs of distal extremities. The exception is leg alignment radiographs that include the entire lower extremity and pelvis and image a larger area of the body. Nearly one-third of incidental findings were suspicious for possible malignancy or metastases. Additional diagnostic workup with focused imaging is often recommended. This information is useful to orthopaedic surgeons who read their own radiographs (without formal radiologist interpretation) to increase awareness of common, concerning incidental findings that may be missed and warrant additional follow-up.

Level III.