The Effect on External Rotation of an Anchor Placed Anterior to the Biceps in Type 2 SLAP Repairs in a Cadaveric Throwing Model

Purpose This study examined whether there is a difference in external rotation (ER) between type 2 SLAP repairs consisting of anchors placed only posterior to the biceps insertion compared with repairs with an additional anchor placed anterior to the biceps. Methods Seven cadaveric shoulders from donors with a mean age of 39.4 years were tested. Type 2 SLAP lesions were created, followed by a 3-anchor repair: a standard repair with 2 anchors posterior to the biceps plus an additional anchor anterior to the biceps. The specimens were placed on a material testing system machine and rotation was measured under a constant torque. The sutures were then removed sequentially from anterior to posterior during testing. Results The average ER of the intact shoulder was 115.7° ± 2.6°. After SLAP tear creation and cyclic loading, the ER was 118.5° ± 2.6°, which decreased to 116.5° ± 2.6° after repair. This corresponds to a reduction of 2.0° of ER ( P < .0001) with the repair. After release of the anterior anchor, the ER increased to 117.9° ± 2.6°, which corresponds to an increase in shoulder motion of 1.4° of ER ( P = .0011). Additional release of the middle anchor, leaving only the posterior anchor intact, resulted in 118.0° ± 2.7° of ER, which corresponds to an increase of only 0.1° of ER ( P = .7667). Conclusions Following type 2 SLAP repair in the cadaveric shoulder, removing the effect of the anchor anterior to the biceps resulted in a small but statistically significant increase in ER. The anterior anchor had the greatest effect on ER. The presence of 1 or 2 anchors posterior to the biceps did not have a significant effect on rotation. Clinical Relevance When performing SLAP repairs on those in whom even a small loss of ER would be detrimental, such as baseball pitchers, avoidance of the use of an anchor anterior to the biceps should be considered.