What is the subacromial impingement syndrome and how is it treated?

Subacromial syndrome is a common shoulder disorder characterized by compression of structures within the subacromial space, causing pain and functional impairment.


Diagnosis:

Clinical evaluation is crucial and includes a thorough history to understand the onset, duration, and factors that exacerbate symptoms.

The physical examination focuses on evaluating the range of motion, strength, stability, and provocative maneuvers of the shoulder. Common tests include the Neer test, the Hawkins-Kennedy test, and the painful arch test.


Imaging studies:

X-rays may reveal signs of bone abnormalities, such as acromial spurs or osteoarthritis.

Ultrasound provides real-time imaging and may be useful for dynamic assessments of impingement during shoulder motion.

Magnetic resonance imaging is useful in evaluating soft tissue structures, including the rotator cuff tendons, subacromial bursa, and possible tears.


Phenotypes:

External impingement: mechanical compression of the rotator cuff tendons and subacromial bursa between the acromion and the humeral head during arm elevation.

Internal impingement: compression of the rotator cuff tendons, particularly the posterior aspect, between the humeral head and the glenoid during certain positions.

Primary impingement: Structural factors that contribute to impingement, such as variations in acromial shape or osteophytes.

Secondary impingement: related to factors such as shoulder instability, muscle imbalances or scapular dyskinesia that alter the normal biomechanics of the shoulder.


Treatment:

Conservative treatment:

Temporary avoidance of activities that cause symptoms is important for timely recovery.

Physical therapy emphasizes strengthening the rotator cuff and scapular stabilizers, stretching, and correcting faulty movement patterns. Biomechanical interventions to address muscle imbalances and optimize shoulder mechanics often aid recovery.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to relieve pain and reduce inflammation.

Corticosteroid injections may be considered (intra-articular or subacromial) for short-term pain relief and reduction of inflammation.

Acromioplasty (surgery) may be considered for subacromial decompression in refractory cases to create more space and relieve impingement.


Forecast:

Many patients with subacromial syndrome respond well to conservative treatments, especially when started early.

Prognosis may be influenced by factors such as the severity of impingement, the presence of structural abnormalities, the patient's compliance with rehabilitation, and the effectiveness of biomechanical interventions.

Surgical results are generally positive, with improvement in symptoms and function. However, success may vary and a thorough preoperative evaluation is crucial to identifying suitable candidates.