Quantifying the extent of a type II SLAP lesion required to cause peel-back of the glenoid labrum--a cadaveric study.
PURPOSE: To quantify the extent of labral disruption required to cause it to peel back when the peel-back test is performed. METHODS: Ten cadaveric shoulders were prepared by removal of the deltoid and rotator cuff muscles. The glenohumeral joint was concentrically reduced and brought into 90 degrees abduction and maximal external rotation. The peel-back of the labrum was graded 0, 1, or 2. The labrum was sequentially detached from the glenoid in the following order: biceps anchor only, 1 o'clock, 2 o'clock, 11 o'clock, and 3 o'clock positions. After each labral cut, the peel-back test was performed. Labral repair was performed with a single suture anchor placed at the 12:30 o'clock position; labral peel-back was reassessed. RESULTS: A progressive increase was noted in peel-back grade with sequential cutting of the labrum posteriorly. However, disruption of the anchor alone did not lead to a positive peel-back sign. Disruption to the 2 o'clock position resulted in a positive peel-back sign overall in 9 of 10 shoulders (5 were grade 1, and 4 were grade 2). No increase was seen in peel-back grade with anterior extension of the labral detachment. Labral repair with a single anchor placed at the 12:30 o'clock position eliminated labral peel-back in 100% of shoulders. CONCLUSIONS: Detachment of the biceps anchor alone does not cause peel-back. The labrum must be disrupted to at least the 2 o'clock position before overt (grade 2) peel-back is observed. A single suture anchor placed at 12:30 o'clock eliminated peel-back of the labrum. CLINICAL RELEVANCE: Validation of the peel-back test as an important diagnostic tool during shoulder arthroscopy.