Impingement Syndrome and Rotator Cuff Disease

The rotator cuff is an encapsulating sleeve of a group of tendons that surround the shoulder joint. These tendons are connected to four muscles that act to stabilize the shoulder joint in its socket and to lift and rotate the arm. The tendons run in spaces (subacromial and subcoracoid), beneath the shoulder blade, coracoid process and under the coraco-acromial ligament where they are vulnerable to injury.

Impingement Syndrome

Impingement syndrome, is a clinical syndrome which occurs when the tendons of the rotator cuff muscles become irritated and inflamed as they pass through the subacromial space. Pain is the primary symptom of impingement syndrome and rotator cuff disease. The pain can be of gradual, insidious onset, or can be directly correlated with a single traumatic or an overuse event (e.g. a day spent trimming hedges). This pain is poorly localised over the deltoid area of the shoulder girdle and can occasionally travel down to the elbow. The pain is increased when the shoulder is moved away from the side of the body and patients’have what is called a “painful arc”. The pain is often worse at night and aggravated by lying on the affected shoulder.

Impingement can be caused by extrinsic mechanical factors , where the space for the tendon is too narrow, e.g. bony spurs, thickened ligaments, swollen tendons, or by is intrinsic factors where the musculo-tendon unit is weak and unbalanced. Often the cause is a combination of both.

Impingement is described as occurring in three stages:

Stage 1:
- reversible oedema and hemorrhage,
- usually in patients aged 20 – 30 years,
- painful arc of abduction between 60 and 120 degrees.

Stage 2:
- chronic inflammation leading to fibrosis & thickening of supraspinatus, biceps, & subacromion bursa,
- patients are usually between 25-40 years,
- symptoms consist of an aching discomfort, often interfering with sleep & work, and may progress to interfere
with activities of daily living.

Stage 3:
- rotator cuff tears, biceps ruptures, and bone changes,
- significant tendon degeneration,
- patients are usually in the 5th or 6th decade, and often admit to prolonged
periods of pain, particularly at night;

Other potential causes for similar shoulder pain are:

- Bursitis
- Calcific tendonitis
- Rotator cuff tear
- Biceps tendinopathy
- AC Joint arthropathy

Treatment of Impingement Syndrome:

The goal of treatment is to reduce pain and restore function.

Nonsurgical Treatment

The vast majority of Stage I and II impingment syndrome responds well to conservative measures. Nonsurgical treatment may take several weeks to months for patients to experience full resolution of their symptoms.
1. Rest and activity avoidance
2. Non-steroidal anti-inflammatory medicines.
3. Physical therapy. Therapy is initially focused on restoration of normal range of motion in the shoulder joint.

Once achieved, the therapist will begin a program of improving core stability, scapular stability, cuff strengthening and improved proprioreceptive feedback.
4. Injection. A combination of local anaesthetic and steroid is injected into the subacromial space. This has the immediate effect of giving temporary pain relief. The longer term therapeutic effect of the steroid may take 2 -3 weeks to become apparent. Rarely, patients can experience a temporary pro-inflammatory response.

Surgical Treatment

If non- operative treatment does not provide long-term relief or if the rotator cuff is at risk of tear, surgical decompression may be beneficial.

Arthroscopic Subacromial Decompression

This is a procedure where bony spurs and the anterior edge of the undersurface of the acromion are removed via keyhole surgery. This operation has a threefold effect of:
1. improving the physical space available to the tendon,
2. removing any inflamed bursal tissue,
3. blood products released from the raw undersurface of the acromion contain a variety of growth factors and chemicals that may promote tendon healing.

The Procedure

Most operations are performed as daycase surgery.
Prior to surgery I recommend that you stop aspirin or similar medications 7 days prior to surgery, if it is safe to do so.

I perform the procedure under general anaesthesia. Before starting surgery I give a suprascapular nerve block and infiltrate the subacromial bursa with local anaesthetic. This is very effective at minimizing post-operative pain.

The operation itself is performed through two 5mm incisions, one posterior and one lateral. An arthroscope ( a lens about the size and shape of a pencil) with camera attached is inserted through the posterior incision. First of all, the
interior of the shoulder joint is inspected for other pathology, e.g. synovitis, cuff tears, biceps and labral problems, articular surfaces. The arthroscope is then inserted into the subacromial space (above the shoulder joint). A radiofrequency probe and an electric shaver are inserted through the lateral portal (incision). The bursa is excised, the coraco-acromial ligament is often resected. The bony spur and 4mm of bone are resected from the anterior acromion , the acromioclavicular joint is not violated.

Any other pathology found at time of surgery is also treated. Skin sutures are not necessary. Simple adhesive plasters cover the wound.

Post-operative Care

Immediately following your surgery:
- you will have an absorbent dressing covering you shoulder for 24 hours to absorb the arthroscopic fluid that was pumped through your shoulder during the procedure.
- you will have an icepack to help reduce post op inflammation. I recommend it is applied for 30 -45 minutes and then removed for 2 hours before being re-applied. This has been shown to be effective for up to 72 hours post surgery.
- your arm will be supported in a sling. This is for comfort and pain relief. It is possible that you will need to wear this for 1 – 2 weeks.
- Physiotherapy can commence when the post-operative pain begins to settle. It is important to be guided by your therapist and not to overdo your exercises.

Post-operative physiotherapy program

Following discharge from hospital you will have regular outpatient review until your symptoms are significantly resolved.

Outcome

The pain of impingement syndrome mostly comes from the rotator cuff tendon. Arthroscopic SubAcromial Decompression is effective at improving symptoms in about 85% of cases . Whilst the operation increases the mechanical space available for the rotator cuff, it also functions to promote your body’s own healing response. This response can take 9 – 12 months to attain maximum benefit. A general rule of thumb is that you can expect to get better at a rate of 10% reduction in pain levels per month.

Complications of surgery

Complications following arthroscopic subacromial decompression are rare but can include:

Post operative stiffness – usually temporary
Infection
Nerve irritability
ACJ pain – occasionally pre-existing but asymptomatic problems with the AC joint can be unmasked once subacromial symptoms are alleviated.