Shoulder impingement syndrome
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Synopsis
Causes / typical injury mechanism: Shoulder impingement syndrome, or subacromial impingement, occurs when soft tissue inside the shoulder joint is ensnared and irritated. It is often a result of rotator cuff degeneration due to age, overuse, microtrauma, and hypoxia. However, it can also be caused by subacromial bursitis, tendinosis, calcific tendonitis, os acromiale, coracoacromial ligament (CAL) ossification, anterior acromial osteophytes, acromioclavicular (AC) joint arthritis with inferior osteophytes, or a type III acromion morphology.Classic history and presentation: Patients with the syndrome usually report experiencing pain when raising the arm between 70 and 120 degrees, when lying on the injured shoulder, and with forced movement of the arm overhead. Patients typically present with lateral and posterior shoulder pain.
Prevalence:
- Age – More common in those older than 40 years.
- Sex / gender – Equal prevalence.
- A reported 44%-65% of shoulder pain complaints are attributed to shoulder impingement syndrome.
- Older age
- Sports participation
- Occupations with repetitive overhead arm movement
- Individual shoulder anatomy variants (eg, hooked acromion, excessive coverage of the shoulder joint by the acromion)
Codes
ICD10CM:M75.40 – Impingement syndrome of unspecified shoulder
SNOMEDCT:
239960007 – Impingement syndrome of shoulder region
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Rotator cuff tear
- AC joint arthritis
- AC joint sprain
- Biceps tendonitis
- Proximal biceps tendon rupture
- Trapezius muscle spasm
- Calcific tendonitis
- Distal clavicle osteolysis
- Glenohumeral arthritis
- Thoracic outlet syndrome
- Cervical radiculopathy
- Deltoid strain
- Pectoralis major tear
- Proximal humerus fracture
- Greater tuberosity fracture
- Shoulder instability (see anterior, posterior, multidirectional)
- Internal impingement syndrome
- Cervical radiculopathy
- Thoracic outlet syndrome
- Rotator cuff tear
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Therapy
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References
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Last Reviewed:01/05/2022
Last Updated:01/12/2023
Last Updated:01/12/2023
Shoulder impingement syndrome