From the Guidelines
A SLAP lesion is typically caused by acute trauma or repetitive overhead motions that stress the shoulder joint, with the primary causes including acute trauma, repetitive overhead motions, lifting heavy objects, and rapid deceleration, as supported by the most recent study 1. The primary causes of a SLAP lesion include:
- Acute trauma: A sudden force to the shoulder, such as falling on an outstretched arm or a direct blow to the shoulder.
- Repetitive overhead motions: Common in athletes who participate in throwing sports (baseball, football), swimming, or volleyball.
- Lifting heavy objects: Especially when done with the arm extended.
- Rapid deceleration: Such as when trying to stop a fall with an outstretched arm. These mechanisms can cause the labrum (a ring of cartilage surrounding the shoulder socket) to tear or separate from the bone, particularly at the top (superior) part where the biceps tendon attaches, as described in the study 1. The injury occurs because these actions place excessive stress on the biceps tendon attachment, which can pull the labrum away from the glenoid (shoulder socket), leading to a SLAP lesion, which is a significant cause of shoulder pain and instability, as noted in the study 1. Understanding these causes is crucial for prevention, especially for athletes and workers who frequently perform overhead activities, and proper technique, strength training, and avoiding overuse can help reduce the risk of developing a SLAP lesion, as implied by the study 1. In clinical practice, it is essential to consider the mechanism of injury and the patient's history to diagnose and manage SLAP lesions effectively, and the use of imaging studies such as MRI or MR arthrography can aid in diagnosis, as recommended in the study 1.
From the Research
Causes of SLAP Lesions
- Repetitive overhead motion is a common cause of SLAP lesions, particularly in overhead athletes 2, 3, 4
- Falls on an outstretched arm can also lead to SLAP lesions 3, 5, 4
- Compression forces to the shoulder, such as those experienced in a fall, can cause SLAP lesions 5
- Overuse, such as from repetitive baseball pitching, can also contribute to the development of SLAP lesions 6
Mechanisms of Injury
- The mechanism of injury for SLAP lesions often involves a combination of factors, including repetitive motion, trauma, and compression forces 2, 3, 5
- The injury typically occurs when the shoulder is positioned in abduction and slight forward flexion, such as when throwing or falling onto an outstretched arm 5