Greater Tuberosity Fractures: Does Fracture Assessment and Treatment Recommendation Vary Based on Imaging Modality?

Background: For greater tuberosity fractures, 5-mm displacement is a commonly used threshold for recommending surgery; however, it is unclear if displacement can be assessed with this degree of precision and reliability using plain radiographs. It also is unclear if CT images provide additional information that might change decision making.
Question/purposes: We asked: (1) Does interobserver agreement for assessment of the amount and direction of fracture-fragment displacement vary based on imaging modality (radiographs only; 2-dimensional [2-D] CT images and radiographs; and 3-dimensional [3-D] and 2-D CT images and radiographs)? (2) Does the likelihood of recommending surgery vary based on imaging modality? (3) Does the level of confidence regarding the decision for treatment vary based on imaging modality?
Methods: We invited 791 orthopaedic surgeons to complete a survey on greater tuberosity fractures. One hundred eighty (23%) responded and were randomized on a 1:1:1 basis in one of the three imaging modality groups and evaluated the same set of 22 fractures. We described age, sex, mechanism of injury, days between injury and imaging, and that patients had no comorbidities or signs of neurovascular damage for every case. One hundred sixty-four of the 180 respondents completed the study and there was an imbalance in noncompletion between the three groups (two of 67 [3.0%] in the radiograph only group; nine of 57 [16%] in the 2-D CT and radiograph group; and five of 56 [8.9%] in the 3-D CT, 2-D CT, and radiograph group; p = 0.043 by Fisher's exact test). Participants assessed amount (in millimeters) and direction (posterosuperior/posteroinferior/anterosuperior/anteroinferior/no displacement) of displacement; recommended treatment (surgical or nonoperative); and indicated their level of confidence regarding the recommended treatment on a scale from 0 to 10 for every case. Overall recommendation for treatment was expressed as a surgery score per surgeon by dividing the amount of cases they would operate on by the total number of cases (n = 22) and presented as a percentage. Confidence regarding the decision for treatment was calculated by averaging the confidence score per surgeon, ranging from 0 to 10. We compared interobserver agreement using kappa for categorical variables and intraclass correlation (ICC) for continuous variables. We used multivariable linear regression to assess difference in surgery score and confidence level between imaging groups, controlling for surgeon characteristics.
Results: Interobserver agreement for assessment of amount (radiographs: ICC, 0.55, 2-D CT + radiographs ICC, 0.53, 3-D CT + 2-D CT + radiographs ICC, 0.57; p values on all comparisons >0.7) and direction (radiographs: kappa, 0.30, 2-D CT + radiographs kappa, 0.43, 3-D CT + 2-D CT + radiographs kappa, 0.40; p values for all comparisons >0.096) of displacement did not vary by imaging modality. 2-D CT and radiographs (β regression coefficient [β], 3.1; p = 0.253) and 3-D CT, 2-D CT and radiographs (β, 1.6; p = 0.561) did not result in a difference in recommendation for surgery compared with radiographs alone. 2-D CT and radiographs (β, 0.40; p = 0.021) and 3-D CT, 2-D CT and radiographs (β, 0.44; p = 0.011) were associated with slightly higher levels of confidence compared with radiographs alone.
Conclusions: Imaging modality, with the numbers evaluated, does not influence interobserver agreement of greater tuberosity fracture assessment, nor did it influence the recommendation for surgical treatment. However, surgeons did feel slightly more confident about their treatment recommendation when assessing CT images with radiographs compared with radiographs alone. Our results therefore suggest no additional value of CT scans for assessment of greater tuberosity fractures when displacement seems to be minimal on plain radiographs. CT scans could be helpful in borderline cases, or in case other fractures can be expected (eg, an occult surgical neck fracture).
Level of Evidence: Level III, diagnostic study.