The value of clinical tests in acute full-thickness tears of the supraspinatus tendon: does a subacromial lidocaine injection help in the clinical diagnosis? A prospective study.

PURPOSE: Early repair of rotator cuff tears leads to superior results. To detect symptomatic full-thickness tears of the supraspinatus tendon at an early stage, we conducted a prospective study to evaluate the value of clinical examination with and without subacromial lidocaine within the first weeks after an acute injury to the shoulder.

METHODS: Of 104 patients included in a prospective investigation, 52 patients were selected to evaluate the diagnostic accuracy of clinical tests in acute full-thickness tears of the supraspinatus tendon. Clinical tests and ultrasound examination were performed at a median of 13 days (range, 3 to 49 days) after the initial injury. The study group consisted of 29 patients (median age, 56 years [range, 39 to 75 years]) who all had an acute complete tear of the supraspinatus tendon verified by ultrasound and arthroscopy. The control group consisted of 23 patients who all had an intact tendon confirmed by ultrasound (median age, 38 years [range, 19 to 73 years]).

RESULTS: The Hawkins sign (0.83) and the painful arc test (0.97) had high sensitivity but low specificity (0.23 and 0.05, respectively). The external rotation lag sign (ERLS) and the drop-arm test (DAT) had a sensitivity of 0.39 and 0.37, respectively, and specificity of 0.91 and 0.86, respectively, in diagnosing acute full-thickness tears of the rotator cuff. After a subacromial lidocaine injection, sensitivity of all lag sign tests was reduced, whereas specificity and likelihood ratios of the Jobe test, the ERLS, and the DAT improved. Active abduction was significantly reduced in the full-thickness tear group.

CONCLUSIONS: A positive lag sign (ERLS or DAT) is indicative of a full-thickness supraspinatus tear, but a negative lag sign does not preclude a tear. After a subacromial injection of lidocaine, the specificity improves whereas the sensitivity is reduced. Overall, in patients with suspected acute rotator cuff tear, clinical tests cannot stand alone in the evaluation the first weeks after an acute injury.

LEVEL OF EVIDENCE: Level I, diagnostic study-testing of previously developed criteria in a series of consecutive patients (by use of arthroscopy and ultrasound as the gold standard).