The longitudinal anatomy of the long head of the biceps tendon and implications on tenodesis

PURPOSE: Regarding biceps tenodesis, there are no evidence-based recommendations for the ideal level at which to cut and stabilize the tendon. The purpose of this study is to provide information referencing the tendon for potential clinical applications during biceps tenodesis.

METHODS: Forty-three embalmed shoulder specimens were dissected, and markers were placed at four points along each biceps tendon: (1) proximal border of the bicipital groove, (2) distal border of the bicipital groove, (3) proximal edge of the pectoralis major insertion, and (4) musculotendonous junction. Using the origin as the initial point of reference, measurements were made to the four subsequent sites. The humeral length was recorded by measuring the distance between the greater tuberosity and the lateral epicondyle.

RESULTS: Measurements were recorded from the origin of the tendon on the supraglenoid tubercle to each established point along its length, and the mean, minimum, and maximum values (cm) were calculated as follows: origin to the proximal bicipital groove [2.8 (1.9, 4.3)], distal bicipital groove [5.2 (3.8, 7.0)], pectoralis major insertion [8.1 (6.3, 10.4)], and musculotendonous junction [13.8 (7.7, 20.3)], and overall humeral length [29.2 (25.2, 32.7)]. An analysis demonstrated a statistically significant overall increase in tendon length at each anatomic site as the overall humeral length increased (p < 0.05). Utilizing the constant and coefficient data from our regression analysis, a predictive formula was calculated based on humeral length. For example, distance from the origin to each anatomic point was determined by a formula [Tendon length at each anatomic landmark, cm = coefficient (humeral length, cm) + constant] for each respective anatomic landmark along the course of the tendon.

CONCLUSION: This work will allow surgeons who prefer tenodesis to more accurately re-approximate the appropriate length-tension relationship of the biceps when tenodesing the tendon in a variety of locations. This benefit will potentially result in the most efficient biceps muscle-tendon function and improve the results of biceps surgery.IV.