Proximal Biceps Tenodesis An Anatomic Study and Comparison of the Accuracy of Arthroscopic and Open Techniques Using Interference Screws

Purpose: To (1) better define the anatomy of the proximal shoulder in relation to the long head of the biceps tendon, (2) compare the length-tension relationship of the biceps tendon in the native shoulder with that after arthroscopic and open tenodesis techniques using interference screws, and (3) provide surgical recommendations for both procedures based on study findings. Study Design: Descriptive laboratory study. Methods: Twenty fresh-frozen cadaveric shoulders were dissected for analysis. Initial anatomic measurements involving the proximal long head of the biceps tendon (BT) were made, which included: the labral origin to the superior bicipital groove (LO-SBG), the total tendon length (TTL), the musculotendinous junction (MTJ) to the inferior pectoralis major tendon border, the MTJ to the superior pectoralis major tendon border, and the biceps tendon diameter (BTD) at 2 different tenodesis locations. These same measurements were made again after completing a simulated suprapectoral arthroscopic and open subpectoral tenodesis, both with interference screw fixation. Statistical comparisons were then made between the native anatomy and that after tenodesis, with the goal of assessing the accuracy of re-establishing the normal length-tension relationship of the long head of the BT after simulated arthroscopic suprapectoral and open subpectoral tenodesis with tenodesis screws. Results: For all cadavers, the mean TTL was 104.1 mm. For the arthroscopic suprapectoral technique, the mean LO-SBG was 33.6 mm, and the mean tendon resection length was 12.8 mm in males and 5.0 mm in females. The mean BTD was 6.35 mm at the arthroscopic suprapectoral tenodesis site and 5.75 mm at the open subpectoral tenodesis site. Males were found to have statistically longer TTL and LO-SBG measurements (111.6 vs 96.5 mm [P = .027] and 37.2 vs 30.0 mm [P = .009], respectively). In the native shoulder, the mean distances from the MTJ to the superior and inferior borders of the pectoralis major tendon were 23.8 and 31.7 mm, respectively. No statistically significant differences were found in the location of the MTJ after simulated arthroscopic or open tenodesis with tenodesis screws as compared with the native shoulder. Mean hole depth in the open subpectoralis tenodesis was 22.4 mm (males) and 18.6 mm (females), with a mean of 20.5 mm for both sexes. Conclusion: This study better defines the anatomy of the proximal shoulder in relationship to the long head of the BT. Using our surgical techniques and recommendations, both arthroscopic and open tenodesis procedures adequately restored the native length-tension relationship of the long head of the biceps. Surgical recommendations are as follows: For arthroscopic suprapectoral tenodesis with tenodesis screws, the anatomic landmark of the SBG should be used. The tendon resection length should be approximately 1 cm in males and 5 mm in females when using a 25-mm tunnel. For subpectoral tenodesis, the site of tenodesis should be placed approximately 3 cm above the inferior border of the pectoralis major tendon in the bicipital groove; whipstitching and preserving approximately 2 cm of the biceps tendon above the MTJ is also recommended. The diameter of the screws in either location should be based on patient anatomy. However, this study shows the need for slightly longer screws for the subpectoral tenodesis, as the average hole depth was 20.5 mm. The system used in this study has 7 x 10-mm and 8 x 12-mm screws available. Based on study findings, a screw length of 15 to 18 mm may be needed.