Impingement Syndrome

Neer first introduced the concept of rotator cuff impingement to the literature in 1972, stating that it results from mechanical impingement of the rotator cuff tendon beneath the antero-inferior portion of the acromion, especially when the shoulder is placed in the forward-flexed and internally rotated position.
Occurs against the anterior edge and undersurface of the anterior 1/3 of the acromion, the coraco- acromial ligament and at times the acromio-clavicular joint arthritis may centred on the supraspinatus.
Neer describes the following 3 stages in the spectrum of rotator cuff impingement:

Stage 1
commonly affecting patients younger than 25 years, is depicted by acute inflammation, edema, and hemorrhage in the rotator cuff. This stage usually is reversible with nonoperative treatment.

Stage 2
usually affects patients aged 25-40 years, resulting as a continuum of stage 1. The rotator cuff tendon progresses to fibrosis and tendonitis, which commonly does not respond to conservative treatment and requires operative intervention.

Stage 3
commonly affects patients older than 40 years. As this condition progresses, it may lead to mechanical disruption of the rotator cuff tendon and to changes in the coracoacromial arch with osteophytosis along the anterior acromion. Surgical l anterior acromioplasty and rotator cuff repair is commonly required.

In all Neer stages, etiology is impingement of the rotator cuff tendons under the acromion and a rigid coracoacromial arch, eventually leading to degeneration and tearing of the rotator cuff tendon.

Although rotator cuff tears are more common in the older population, impingement and rotator cuff disease are frequently seen in the repetitive overhead athlete. The increased forces and repetitive overhead motions can cause attritional changes in the distal part of the rotator cuff tendon, which is at risk due to poor blood supply. Impingement syndrome and rotator cuff disease affect athletes at a younger age compared with the general population.
Bigliani and associates described 3 variations in acromion morphology

Type 1 – Flat
Type 2 -Curved
Type 3 -Hooked

Although the curved configuration was the most common (43% prevalence, compared to 17% flat and 40% hooked), the hooked configuration most strongly was associated with full-thickness rotator cuff tears.

Management

Clinical examination is the main stay diagnosis

Near impingement test
Hawken Kenedy sign

X-Rays

findings Anterior acromial spur may be evident due to traction by the coraco- acromial ligament
May be prominence of the greater tuberosity due to impingement of the facet for supraspinatus against the acromion
Advanced cases eburnation and wear of the anterior 1/3 of the acromion and AC joint, also rounding off of the greater tuberosity and finally cuff arthropathy

Treatment

Non-operative

In the acute phase treatment is conservative (~ 50% satisfactory outcome)

Anti-inflammatory medications are helpful
Rest
Non-narcotic analgesics
Heat
Passive stretching and muscle strengthening exercises
Steroid injection (limited) Corticosteroid injection into the sub-acromial space especially in the throwing athlete and in elderly people should not be used more than three times over an extended period

Surgery

Anterior acromioplasty:
1. When repairing a tear of the rotator cuff
2. To relieve pain when there has been persistent disability for one year with a positive impingement test
3. Impingement with secondary cuff or biceps ruptures

Resection of AC ligament
Resection of distal clavicle if symptomatic AC jt OA