What causes a Superior Labrum Anterior to Posterior (SLAP) lesion?

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Last updated: February 21, 2025View editorial policy

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From the Guidelines

A SLAP lesion is typically caused by acute trauma or repetitive overhead motions that stress the shoulder joint, with the most common causes including sudden trauma, repetitive overhead activities, forceful pulling on the arm, and age-related degeneration. The etiology of traumatic shoulder pain, including SLAP lesions, can often be determined on the basis of clinical examination, radiography, and mechanism of injury 1. Common causes of SLAP lesions include:

  • Sudden trauma: Falls onto an outstretched arm or direct blows to the shoulder
  • Repetitive overhead activities: Common in athletes who throw (baseball pitchers, tennis players) or workers who frequently reach overhead
  • Forceful pulling on the arm: Such as when trying to catch oneself during a fall
  • Age-related degeneration: Natural wear and tear of the labrum over time The mechanism of injury often involves a combination of compression and traction forces on the shoulder joint, which can cause the labrum to tear, as noted in the evaluation of shoulder pain-traumatic 1. Understanding these causes is crucial for prevention and treatment, and athletes and workers in high-risk occupations should focus on proper technique, strength training, and adequate rest to reduce the risk of SLAP lesions, with treatment typically involving rest, physical therapy, and in some cases, surgical repair, depending on the severity of the tear and the individual's activity level. According to the most recent study on shoulder pain-traumatic 1, traumatic shoulder injuries can generally be separated into injuries requiring acute surgical management and injuries in which conservative management can be attempted before considering surgical treatment.

From the Research

Causes of SLAP Lesions

  • Repetitive overhead motion is a common cause of SLAP lesions, particularly in overhead athletes 2, 3
  • Falls on an outstretched arm can also lead to SLAP lesions, as the compression force to the shoulder can cause injury to the superior labrum 3, 4, 5
  • Overuse, such as from repetitive baseball pitching, can result in SLAP lesions in throwing athletes 6

Mechanisms of Injury

  • Compression force to the shoulder, usually as a result of a fall onto an outstretched arm, with the shoulder positioned in abduction and slight forward flexion at the time of the impact 4, 5
  • Repetitive overhead motion can cause wear and tear on the superior labrum, leading to SLAP lesions 2, 3

Risk Factors

  • Age: older athletes may be more prone to SLAP lesions due to decreased flexibility and increased wear and tear on the joint 2, 6
  • Playing position: pitchers and other overhead athletes may be at higher risk for SLAP lesions due to the repetitive nature of their sport 2, 6
  • Duration of baseball experience: athletes with longer careers may be more prone to SLAP lesions due to cumulative wear and tear on the joint 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

SLAP Tears: Treatment Algorithm.

Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association, 2022

Research

Arthroscopy classics. SLAP lesions of the shoulder.

Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association, 2010

Research

SLAP lesions of the shoulder.

Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association, 1990

Research

Factors influencing outcomes of nonsurgical treatment for baseball players with SLAP lesion.

Asia-Pacific journal of sports medicine, arthroscopy, rehabilitation and technology, 2018

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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