FEVER: The Flexed Elbow Valgus External Rotation View for MRI Evaluation of the Ulnar Collateral Ligament in Throwing...

BACKGROUND. Ulnar collateral ligament (UCL) injuries are common in throwing athletes owing to repetitive extreme valgus stress during overhead throwing maneuvers. Conventional positioning for elbow MRI provides suboptimal rendering of the UCL. OBJECTIVE. The purpose of this prospective pilot study was to assess the effect of flexed elbow valgus external rotation (FEVER) on ulnotrochlear joint space measurement and reader evaluation of the UCL when the FEVER view is incorporated into standard elbow MRI of throwing athletes. METHODS. A total of 44 Major League Baseball pitchers underwent elbow MRI including standard sequences and a coronal fat-saturated proton density-weighted sequence in the FEVER view. To achieve the FEVER view, specific positioning maneuvers are performed, and sandbags are placed to immobilize the elbow in valgus stress so that the UCL can be visualized parallel to its long axis. Patients recorded pain during FEVER on a scale of 0 (none) to 10 (maximal). Two radiologists independently evaluated standard and FEVER images to measure the ulnotrochlear joint space, assess confidence in UCL-related findings, and assess the UCL as normal or abnormal. RESULTS. Pain during FEVER was rated 0 by 29 patients, 1-3 by 11 patients, 4-7 by four patients, and 8-10 by no patients. Intrareader agreement on ulnotrochlear joint space measurement was higher for FEVER (intraclass correlation coefficient [ICC], 0.92) than standard (ICC, 0.54) views. Averaged between readers, the mean increase in ulnotrochlear joint space in the FEVER compared with the standard view was 1.80 mm (95% CI, 1.58-2.03). Confidence was higher for the FEVER than for the standard view for reader 1 in assessment of the UCL as normal versus abnormal (mean increase in confidence, 0.40), intensity of abnormal signal (0.39), injury grade (1.04), and retraction (0.25) and for reader 2 in assessment of the UCL as normal versus abnormal (0.50), location of abnormal signal (0.46), intensity of abnormal signal (0.51), injury grade (0.96), and retraction (0.53). Readers 1 and 2 classified three and two additional UCLs as abnormal on FEVER view compared with standard view images; neither reader classified any UCL as abnormal on standard view but normal on FEVER view images. CONCLUSION. The increased joint space width confirmed elbow valgus stress in the FEVER view. Diagnostic confidence increased, and additional UCLs were identified as abnormal. CLINICAL IMPACT. Use of the FEVER view may improve MRI evaluation of the UCL in throwing athletes.