Are radiologists superior to orthopaedic surgeons in diagnosing instability-related shoulder lesions on magnetic resonance arthrography? A multicenter reproducibility and accuracy study.

Background: We compared the diagnostic reproducibility and accuracy of musculoskeletal radiologists with orthopaedic shoulder surgeons in 2 large medical centers in assessing magnetic resonance arthrograms (MRAs) of patients with traumatic anterior shoulder instability.

Methods: Forty-five surgically confirmed MRAs were assessed by 4 radiologists, 4 orthopaedic surgeons, 2 radiologic teams, and 2 orthopaedic teams. During MRA assessment and surgery, the same 7-lesion scoring form was used. κ Coefficients, sensitivity, specificity, and differences in percentage of agreement or correct diagnosis (P < .05, McNemar test) were calculated per lesion and overall per the 7 lesion types.

Results: The overall κ between the individual radiologists (κ = 0.51, κ = 0.46) and orthopaedic surgeons (κ = 0.46, κ = 0.41) was moderate. Although the overall percentage of agreement between the radiologists was slightly higher than that between the orthopaedic surgeons in both centers (80.0% vs 77.5% and 75.2% vs 73.7%), there was no significant difference. In each medical center, however, the most experienced orthopaedic surgeon was exceedingly more accurate than both radiologists per the 7 lesion types (81.9% vs 72.4%/74.6% and 76.5% vs 67.3%/73.7%). In 3 of 4 cases, this difference was significant. Overall accuracy improvement through consensus assessment was merely established for the weakest member of each team.

Conclusion: Experienced orthopaedic surgeons are more accurate than radiologists in assessing traumatic anterior shoulder instability-related lesions on MRA. In case of diagnosis disagreement, these orthopaedic surgeons should base their treatment decision on their own MRA interpretation.