MAGNETIC RESONANCE IMAGING (MRI) VERSUS DIAGNOSTIC ARTHROSCOPY: DOES MRI CHANGE THE INTRA-OPERATIVE DIAGNOSIS? A PROSPECTIVE BLINDED EVALUATION IN PATIENTS WITH SHOULDER IMPINGEMENT SYNDROME.

Abstract

This investigation was performed to determine whether MRI would provide any additional diagnostic information to the clinical evaluation and diagnostic arthroscopy of the shoulder. The study was performed in patients with shoulder impingement syndrome booked for an arthroscopic subacromial decompression. Although there was significant discordance between the MRI and arthroscopic findings, the MRI did not change the diagnosis or treatment plan in a clinically important way.

To determine whether the radiologist’s MRI report provided to an arthroscopist upon completion of a standard diagnostic shoulder arthroscopy would result in changes to the initial arthroscopic findings.

Despite high percentage of discordance between MRI and arthroscopy, the MRI information modified the initial arthroscopic diagnosis in a much smaller percentage of cases. In only one patient, did the change in diagnostic information have an impact on the planned treatment.

MRI adds minimal clinically important information to diagnostic shoulder athroscopy in patients with impingement syndrome.

The percentage discordance between MRI and arthroscopy for each structure of interest was calculated along with the percentage change in diagnosis based upon the arthroscopic re-evaluation and the consequence of the change.

Supraspinatus 55.2% discordance(n=32/58), 18.8% change in diagnosis(n=6/32), in 1 patient a change in the planned operation occurred from subacromial decompression to mini-open rotator cuff repair. Infra-spinatus 44.8% discordance(n=26/58), 3.8% change in diagnosis(n=1/26), and no consequence to planned treatment. Subscapularis 37.9% discordance(n=22/58), no change in diagnosis. Biceps tendon 62.3% discordance(n=33/53; five patients not adequately visualized on MRI), no change in diagnosis.

Fifty-eight patients presenting with shoulder impingement syndrome underwent a standardized MRI prior to planned arthroscopic subacromial decompression. A standard diagnostic arthroscopy was performed. The anatomic and pathologic findings were documented intra-operatively by an independent observer. The arthroscopist was initially blinded to the MRI information. MRI results were then revealed to the surgeon. An arthroscopic re-evaluation was performed to resolve discrepancies between MRI and arthroscopy.