Impingement is one of the most common causes of pain in the adult shoulder. It results from pressure on the rotator cuff from part of the shoulder blade (scapula) as the arm is lifted. Except in a throwing athlete, impingement syndrome is a disease of a middle age. Most often patient do not relate a history of a specific injury, but instead complain of an insidious onset of pain with overhead activities.

Lateral anatomic view of the shoulder.  Above the humerus is acromion, the roof of the shoulder joint.

Schematic view of acromion.  The drawing place is the main cause for subacromial impingement.

Shoulder impingement mechanism.


Patient with impingement typically presents with pain, difficulty with overhead activities, stiffness, and weakness. Night pain, particularly when rolling onto the affected side is commonly found in patients with rotator cuff disease. From the functional standpoint patients often report having difficulty with those activities that require reaching overhead or behind the back. Women for example often describe an inability to fasten their brasserie. Local or referred pain, usually to the deltoid insertion or to the lateral side of the upper arm, is common.

Diagnosis and Diagnostic Imaging

The diagnosis of impingement syndrome is based primarily on a careful history and physical examination.

Plain films can often be helpful. Calcification or bony changes may be seen as evidence of chronic impingement. Thus radiographs may show anatomic variants, sclerotic changes, spurring on the undersurface of the acromion.

Ultrasound is the modality for investigating changes in the rotator cuff and subacromial bursa. Additionally, can define the contour of the humeral head and structural changes in the deltoid muscle.

MRI is the modality of choice especially if a soft tissue lesion is presumed but cannot be demonstrated with other techniques.

Calcific tendinitis of the supraspinatus tendon is the cause of shoulder impingement

Calcific tendinitis of the right shoulder in a woman 26 years old. The patient reports intense pain symptomatology reason for the accumulation of calcium  in the tendon of the supraspinatus

Ultrasonography of the shoulder: Calcific tendonitis (red circle) is a common cause of severe pain in shoulder

Ultrasound shoulder. Highlighting sizable calcium carbonate scale build mass in the tendon of the supraspinatus

MRI:  the arrows shows the inflammation of the subacromial bursa and the traumatic condition of the tendons. The spur from undersurface of the acromion is the cause of the disease. 

MRI:  the inflammation of the subacromial bursa and the traumatic condition of the tendons due to spur from undersurface of the acromion (red circle).




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Conservative treatment

Most patients with primary impingement can be successfully treated without surgery. Conservative treatment should be tried first in cases where significant mechanical causes, such as large osteophytes have been excluded. Rest from those activities that exacerbates the symptoms, nonsteroidal anti-inflammatory medications, physical therapy and judicious use of cortisone injections is the plan of conservative treatment.  The PRP (Platelet Rich Plasma) local injection is the new promising therapeutic method for inflammation and pain releif.


Surgical Treatment

When nonsurgical treatment does not relieve pain following at least 6 month trial, the doctor may recommend surgery. The goal of surgery is to remove the impingement and create more space for the rotator cuff. This allows the humeral head to move freely in the subacromial space and to lift the arm without pain.
The most common surgical treatment is subacromial decompression or anterior acromioplasty. This may be performed by arthroscopic technique.

In an arthroscopic procedure, two or three small puncture wounds are made. The joint is examined through a fiberoptic scope connected to a television camera. Small instruments are used to remove bone and soft tissue.

Shoulder arthoscopy - Acromioplasty

Acromioplasty.  The special shaver cut the acromion osteophyte which produced the impingement syndrome


After surgery, the arm may be placed in a sling for a short period of time. This allows for early healing. As soon as comfort allows, the sling may be removed to begin exercise and use of the arm.

The surgeon will provide a rehabilitation program based on the patient's needs and the findings at surgery. This will include exercises to regain range of motion of the shoulder and strength of the arm. It typically takes two to four months to achieve complete relief of pain, and may take up to a year.