BACKGROUND: Previous studies have demonstrated that the humerus slides along the long head of the biceps tendon (LHBT). Blocking this motion may result in decreased glenohumeral (GH) range of motion (ROM). The goal of the study was to characterize the excursion of the LHBT and measure the effect of biceps adhesions on GH ROM. MATERIALS AND METHODS: A custom biomechanical testing setup was used to measure the excursion of the LHBT and rotation of the humerus at 0°, 15°, 30°, 60°, and 90° of GH abduction in the scapular plane. An in situ biceps tenodesis with the biceps anchor still intact, thus simulating biceps adhesions, was sequentially performed in 2 positions: 0° abduction and maximum external rotation, followed by 0° abduction and maximum internal rotation. The effect of tenodesis on ROM was measured. RESULTS: There was an average excursion of 19.4 ± 5.4 mm of the LHBT as the humerus was taken through ROM in the scapular plane. Tenodesis in 0° abduction and maximum internal rotation resulted in a significant decrease in GH external rotation of 47.3° ± 12.2° (P = .007) with the arm in 0° abduction. CONCLUSIONS: Tenodesis in maximum internal rotation limited rotation significantly, such that in situ tenodesis without proximal tenotomy should not be performed. Furthermore, in situations where the biceps is at risk for scarring, such as proximal humeral fractures, shoulder arthroplasty, and the stiff shoulder, the biomechanical consequence of biceps adhesions may be similar to in situ tenodesis and may limit ROM and clinical outcomes.
BACKGROUND: Previous studies have demonstrated that the humerus slides along the long head of the biceps tendon (LHBT). Blocking this motion may result in decreased glenohumeral (GH) range of motion (ROM). The goal of the study was to characterize the excursion of the LHBT and measure the effect of biceps adhesions on GH ROM. MATERIALS AND METHODS: A custom biomechanical testing setup was used to measure the excursion of the LHBT and rotation of the humerus at 0°, 15°, 30°, 60°, and 90° of GH abduction in the scapular plane. An in situ biceps tenodesis with the biceps anchor still intact, thus simulating biceps adhesions, was sequentially performed in 2 positions: 0° abduction and maximum external rotation, followed by 0° abduction and maximum internal rotation. The effect of tenodesis on ROM was measured. RESULTS: There was an average excursion of 19.4 ± 5.4 mm of the LHBT as the humerus was taken through ROM in the scapular plane. Tenodesis in 0° abduction and maximum internal rotation resulted in a significant decrease in GH external rotation of 47.3° ± 12.2° (P = .007) with the arm in 0° abduction. CONCLUSIONS: Tenodesis in maximum internal rotation limited rotation significantly, such that in situ tenodesis without proximal tenotomy should not be performed. Furthermore, in situations where the biceps is at risk for scarring, such as proximal humeral fractures, shoulder arthroplasty, and the stiff shoulder, the biomechanical consequence of biceps adhesions may be similar to in situ tenodesis and may limit ROM and clinical outcomes.