Andrews and colleagues described where glenoid labrum tears occur in the throwing shoulder and examined whether the long head of the biceps could be causing them.
73 throwing athletes, including 35 baseball pitchers, with arthroscopy of the dominant shoulder. Biceps stimulation was done in 5 of them, and motion analysis in 2 pitchers.
Methods
Design
Arthroscopic examination of the dominant shoulder
Electrical stimulation of the biceps at arthroscopy in 5 patients
3D high‑speed cinematography of 2 baseball pitchers
Patients
73 throwing athletes
35 baseball pitchers among them
Outcomes
Location of labral tears
Associated rotator cuff and biceps tendon tears
Elbow motion and moments during throwing
Key Findings
83% of the throwers had a tear somewhere in the anterosuperior labrum, where the biceps tendon joins it.
Electrical stimulation tightened the biceps tendon and raised the superior labrum off the glenoid in all 5 patients tested.
In the 2 filmed pitchers, the elbow extended from 80° to 30° of flexion in 25 milliseconds, with moments of up to 600 inch‑pounds.
Among the arm muscles that slow the elbow in follow‑through, the biceps is the only one that crosses both the elbow and the shoulder.
Partial supraspinatus tears were present in 45% of all throwers, and partial rotator cuff tears in 25 of the 35 pitchers (73%).
In the published discussion, the authors reported anteroinferior labral tears in 11.1% of the group and 2 frank anterior dislocations after debridement.
Board pearl
Andrews proposed that eccentric biceps contraction during follow‑through may pull the anterosuperior labrum off the glenoid at the biceps origin, a tear to be distinguished from the Bankart lesion of structural instability.
Authors' conclusion
we believe that the tendon of the long head of the biceps may be a cause of tearing of the glenoid labrum in the throwing athlete.
Andrews and colleagues described where glenoid labrum tears occur in the throwing shoulder and examined whether the long head of the biceps could be causing them.
73 throwing athletes, including 35 baseball pitchers, with arthroscopy of the dominant shoulder. Biceps stimulation was done in 5 of them, and motion analysis in 2 pitchers.
Methods
Design
Arthroscopic examination of the dominant shoulder
Electrical stimulation of the biceps at arthroscopy in 5 patients
3D high‑speed cinematography of 2 baseball pitchers
Patients
73 throwing athletes
35 baseball pitchers among them
Outcomes
Location of labral tears
Associated rotator cuff and biceps tendon tears
Elbow motion and moments during throwing
Key Findings
83% of the throwers had a tear somewhere in the anterosuperior labrum, where the biceps tendon joins it.
Electrical stimulation tightened the biceps tendon and raised the superior labrum off the glenoid in all 5 patients tested.
In the 2 filmed pitchers, the elbow extended from 80° to 30° of flexion in 25 milliseconds, with moments of up to 600 inch‑pounds.
Among the arm muscles that slow the elbow in follow‑through, the biceps is the only one that crosses both the elbow and the shoulder.
Partial supraspinatus tears were present in 45% of all throwers, and partial rotator cuff tears in 25 of the 35 pitchers (73%).
In the published discussion, the authors reported anteroinferior labral tears in 11.1% of the group and 2 frank anterior dislocations after debridement.
Board pearl
Andrews proposed that eccentric biceps contraction during follow‑through may pull the anterosuperior labrum off the glenoid at the biceps origin, a tear to be distinguished from the Bankart lesion of structural instability.
Authors' conclusion
we believe that the tendon of the long head of the biceps may be a cause of tearing of the glenoid labrum in the throwing athlete.