# Traumatic Versus Atraumatic Causes of Shoulder Impingement Syndrome: A Systematic Review of Pathophysiology and Outcomes

## TL;DR

This review compares traumatic and atraumatic causes of shoulder impingement syndrome, highlighting their distinct pathophysiology and treatment approaches.

## Contribution

The study systematically differentiates traumatic and atraumatic shoulder impingement syndrome based on pathophysiology and outcomes.

## Key findings

- Traumatic SIS is linked to acute injuries and requires surgical intervention.
- Atraumatic SIS results from repetitive microtrauma and is managed with rehabilitation.
- Both types share inflammation but differ in anatomical changes and treatment needs.

## Abstract

Shoulder impingement syndrome (SIS) is a common musculoskeletal disorder caused by traumatic or atraumatic factors, resulting in pain, functional limitation, and reduced quality of life. This systematic review aimed to summarize the pathophysiology, anatomical changes, and functional outcomes of traumatic versus atraumatic SIS. A comprehensive search of PubMed, Embase, Scopus, and the Cochrane Library up to 2025 was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines, including studies reporting clinical outcomes and pathophysiological findings in humans. Five studies comprising 467 participants were included. Traumatic SIS, often following acute injuries or post-acromioclavicular (AC) joint fixation, was associated with rotator cuff tears, labral lesions, and anatomical changes, leading to pain, limited range of motion, and delayed recovery. Atraumatic SIS, common in overhead athletes, resulted from repetitive microtrauma, causing tendon degeneration, subacromial narrowing, and deficits in strength, motion, and dynamic balance. Both etiologies shared rotator cuff and bursal inflammation. Traumatic SIS frequently requires surgical intervention, whereas atraumatic SIS is managed conservatively with structured rehabilitation. Differentiating etiologies is essential to optimize outcomes, prevent recurrence, and guide treatment strategies, and further long-term studies are warranted to evaluate functional recovery and intervention effectiveness.