Effects of arm position on maximizing intra-articular visualization of the biceps tendon: a cadaveric study

The purpose of this study was to assess the intra-articular length of the biceps tendon in various shoulder and arm positions and identify the position in which the extra-articular portion of the tendon is maximally visualized within the glenohumeral joint.

We measured 18 positions in 4 fresh-frozen cadaveric shoulders for a total of 72 measurements. In each measurement the position of the proximal biceps tendon was measured relative to a baseline measurement in neutral position (0° shoulder flexion, 0° shoulder abduction, 0° elbow flexion, 0° shoulder rotation). Positions measured ranged between the following: 0° and 30° shoulder flexion; 0° and 40° shoulder abduction; 0° and 90° elbow flexion; and 0° neutral, 30° internal, and 30° external shoulder rotation.

The position creating the greatest increase in intra-articular biceps tendon length from baseline was 30° shoulder flexion, 40° shoulder abduction, 90° elbow flexion, and 0° rotation. On average, 56% of the tendon within the bicipital groove is brought into view by the maximal position relative to baseline. In maximizing intra-articular biceps tendon length, the effect of elbow flexion was highly significant (P < .001) and the combined effect of shoulder flexion-abduction was significant (P = .016).

The position of 30° shoulder flexion, 40° shoulder abduction, and 90° elbow flexion significantly increases the excursion of the proximal biceps tendon relative to a neutral position. Over 50% of the tendon within the bicipital groove at baseline can be pulled out of the groove by placing the extremity in the maximal position and using an arthroscopic probe. Rotation of the humerus does not improve intra-articular excursion.

Maximizing the intra-articular tendon length by arm positional change is likely to be useful for arthroscopic examination of the biceps tendon.