Department of Orthopaedic Surgery University of California, Davis

Department of Orthopaedic Surgery University of California, Davis Lloyd W. Taylor Resident Award: Diagnostic Accuracy of MRI in SLAP Tears: A Retrospective Review of 444 Patients Utilizing Musculoskeletal Fellowship Trained Radiologists Kent Sheridan, MD Financial Disclosures: None

Introduction Clinical examination of SLAP lesions has relatively poor diagnostic value. MRI is relied upon heavily, but its validity has wide variability reported in the literature. Sensitivities 67%-98% Specificities 72%-99% Accuracies 27%-95% The diagnosis of a SLAP tear remains challenging. The repair of arthroscopic SLAP lesions has significant geographic variability.

Hypothesis The purpose of this study was to evaluate the accuracy of MRI and MRA in diagnosing SLAP lesions utilizing fellowship trained musculoskeletal radiologists. We hypothesize that the accuracy of MRI, with or without arthrography, is lower than previously reported.

Inclusion Criteria: -Suspected SLAP tears based on history and clinical exam Methods All patients who had shoulder arthroscopy (n=734) Patients with MRI (1.5 Tesla) and arthroscopy at our institution (n=454) Exclusion Criteria: -Physical exams consistent with instability. -No preoperative MRI within 6 months or MRI at a different institution. -History of previous SLAP repair -Lack of definitive diagnosis, i.e. equivocal SLAP Included in this study (n=444) MRI reading lacking definitive diagnosis of SLAP(n=10) Contrast use? Yes: (n=210) Contrast use? No: (n=234)

Results Contrast in MRI Total Used (n=210) Not used (n=234) (n=444) Overall Accuracy* 69% (63-75) 82% (77-87) 76% (72-80) Sensitivity 80% (61-92) 36% (14-64) 66% (50-79) Specificity* 67% (60-74) 85% (79-89) 77% (73-81) Positive predictive value Negative predictive value 29% (20-40) 13% (5-29) 24% (17-33) 95% (90-98) 95% (91-98) 95% (92-97) Numbers in parenthesis are 95% confidence intervals. An asterisk denotes non-overlapping 95% confidence intervals suggesting statistical difference (p < 0.05).

Results + SLAP Arthroscopy - SLAP Arthroscopy Total Combined MRI reading Positive 29 (True positive) 92 (False positive) 121 Negative 15 (False negative) 308(True negative) 323 Total 44 400 444 + SLAP Arthroscopy - SLAP Arthroscopy Total Contrast MRI Reading Positive 24 (True positive) 59 (False positive) 83 Negative 6 (False negative) 121(True negative) 127 Total 30 180 210 + SLAP Arthroscopy - SLAP Arthroscopy Total Noncontrast MRI Reading Positive 5 (True positive) 33 (False positive) 38 Negative 9 (False negative) 187 (True negative) 196 Total 14 220 234

Discussion Noncontrast MRI was more specific. Contrast MRI was more sensitive. The combined accuracy of noncontrast MRI was superior to contrast MRI. Our study underscores the importance of carefully integrating clinical information with diagnostic imaging prior to indicating patients for SLAP repair. Study Limitations Retrospective design may introduce bias. Higher field strength scanners may yield improved results. Arthroscopy as a gold standard has limitations.

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Thanks! Christopher Kreulen, MD Sunny Kim, Ph.D. Walter Mak, MD Kirk Lewis, MD Richard Marder, MD