The Role of the Superior Labrum Following Biceps Tenodesis in Glenohumeral Kinematics and Stability (SS-07)

Abstract

Introduction At the present time, little is known about the role a torn superior labrum plays in glenohumeral (GH) kinematics and stability following biceps tenodesis (BT). The current biomechanical study evaluated the contribution a type II SLAP lesion has on GH translation in the presence of a BT, asking two questions: Does a type II SLAP tear require fixation following BT, and if so, which of two repair techniques is superior? Methods Baseline GH translation data was collected from 15 intact cadaveric shoulders using a custom shoulder testing apparatus. Anterior (n=5) and posterior (n=10) type II SLAP tears were created, and translation testing was repeated. BT was then performed for each specimen, with re-evaluation of translation post-procedure. Finally, repair of the type II SLAP lesion was performed utilizing one of two suture anchor constructs for the posterior SLAP (two single-loaded vs. one double-loaded anchor) and one suture anchor construct for the anterior SLAP (two single-loaded anchors), followed by repeat translation testing. Comparisons were made between the translation data for each group. Results Both anterior and posterior type II SLAP lesions led to increases in anterior and posterior GH translation compared to baseline. In the presence of a posterior SLAP lesion, anterior and posterior translation increased significantly to 85.7% (5.2mm to 9.6mm) and 54.8% (5.4mm to 8.4mm), respectively. Anterior SLAP lesions led to a significant increase in anterior translation of 72.8% (4.3mm to 7.5mm) and a 37.8% non-significant increase in posterior translation (7.1mm to 9.8mm). BT for both types of SLAP improved translation stability, reducing anterior translation in the presence of a posterior tear from 9.6mm to 7.7mm and posterior translation in the presence of an anterior tear from 9.8mm to 8.0mm, although these values were not significant. For anatomic repair with either 2 single-loaded anchors or 1 double-loaded anchor, posterior SLAP repair improved anterior translation to 0.0% and 22.1% of baseline, respectively. For anterior tears, anatomic repair led to a posterior translation 11.6% of baseline. All repairs did not differ significantly from baseline. Conclusion Biceps tenodesis shows no deleterious effect on glenohumeral kinematics and stability in the presence of a SLAP lesion. Thus, BT can be a useful revision procedure for patients with persistent pain following SLAP repair. Additionally, no significance was found between the two repair constructs. At the present time, little is known about the role a torn superior labrum plays in glenohumeral (GH) kinematics and stability following biceps tenodesis (BT). The current biomechanical study evaluated the contribution a type II SLAP lesion has on GH translation in the presence of a BT, asking two questions: Does a type II SLAP tear require fixation following BT, and if so, which of two repair techniques is superior? Baseline GH translation data was collected from 15 intact cadaveric shoulders using a custom shoulder testing apparatus. Anterior (n=5) and posterior (n=10) type II SLAP tears were created, and translation testing was repeated. BT was then performed for each specimen, with re-evaluation of translation post-procedure. Finally, repair of the type II SLAP lesion was performed utilizing one of two suture anchor constructs for the posterior SLAP (two single-loaded vs. one double-loaded anchor) and one suture anchor construct for the anterior SLAP (two single-loaded anchors), followed by repeat translation testing. Comparisons were made between the translation data for each group. Both anterior and posterior type II SLAP lesions led to increases in anterior and posterior GH translation compared to baseline. In the presence of a posterior SLAP lesion, anterior and posterior translation increased significantly to 85.7% (5.2mm to 9.6mm) and 54.8% (5.4mm to 8.4mm), respectively. Anterior SLAP lesions led to a significant increase in anterior translation of 72.8% (4.3mm to 7.5mm) and a 37.8% non-significant increase in posterior translation (7.1mm to 9.8mm). BT for both types of SLAP improved translation stability, reducing anterior translation in the presence of a posterior tear from 9.6mm to 7.7mm and posterior translation in the presence of an anterior tear from 9.8mm to 8.0mm, although these values were not significant. For anatomic repair with either 2 single-loaded anchors or 1 double-loaded anchor, posterior SLAP repair improved anterior translation to 0.0% and 22.1% of baseline, respectively. For anterior tears, anatomic repair led to a posterior translation 11.6% of baseline. All repairs did not differ significantly from baseline. Biceps tenodesis shows no deleterious effect on glenohumeral kinematics and stability in the presence of a SLAP lesion. Thus, BT can be a useful revision procedure for patients with persistent pain following SLAP repair. Additionally, no significance was found between the two repair constructs.