Arthroscopic Rotator Cuff Surgery

Rotator Cuff Disease

Introduction

The rotator cuff is the group of muscles and their tendons that act to stabilize the shoulder. The four muscles of the rotator cuff, along with the teres major and the deltoid, make up the six scapulohumeral (those that connect to the humerus and scapula and act on the glenohumeral joint) muscles of the human body.

 

Function

The rotator cuff muscles are important in shoulder movement and in maintaining glenohumeral joint (shoulder joint) stability. These muscles arise from the scapula and connect to the head of the humerus forming a cuff at the shoulder joint. They hold the head of the humerus in the small and shallow glenoid fossa of the scapula. The glenohumeral joint is often likened to a golf ball (head of the humerus) sitting on a golf tee (glenoid fossa). During abduction of the arm, the rotator cuff compresses the glenohumeral joint, a term known as concavity compression, in order to allow the large deltoid muscle to further elevate the arm. In other words, without the rotator cuff, the humeral head would ride up partially out of the glenoid fossa, lessening the efficiency of the deltoid muscle. The anterior and posterior directions of the glenoid fossa are more susceptible to shear force perturbations as the glenoid fossa is not as deep relative to the superior and inferior directions. The rotator cuff's contributions to concavity compression and stability vary according to their stiffness and the direction of the force they apply upon the joint.

Rotator Cuff Tear

The tendons at the ends of the rotator cuff muscles can tear, leading to pain and restricted movement of the arm. A torn rotator cuff can occur following a trauma to the shoulder or it can occur through the "wear and tear" of tendons, most commonly that of the supraspinatus under the acromion. It is an injury frequently sustained by athletes whose duties involve making repetitive throws, such as baseball pitchers, volleyball players (due to their swinging motions), water polo players, shotput throwers (due to using poor technique), swimmers, boxers, kayakers, fast bowlers in cricket, tennis players (due to their service motion), and Wii players. This type of injury also commonly affects conductors due to the swinging motions and other movements used to lead their ensemble. It is commonly associated with motions that require repeated overhead motions or forceful pulling motions.

It commonly occurs due to "impingement" - where the tendons rub against the overlying acromion bone.

Long Term Issues

The tear most often increases in size over time. Although the pain may improve, longer term functional problems usually develop.

Pain is often intermittent but deteriorates over time.

With severe and long standing tears, the humerus migrates skyward causing severe arthritis.

Treatment

1. Non-Operative

Although the tear will most likely increase with time, in the older age groups (suffering from other medical conditions) simple therapeutic modalities may be used to help symptoms.

These include rest, avoidance of aggravating factors (eg. Lifting overhead), and simple analgesics.

Non-steroidal anti-inflammatory drugs can be used with caution. Injection into the area may help the pain temporarily but do not help the tendon repair. Excessive use of steroid injections may be detrimental.

2. Operative

The operation is performed arthroscopically (key-hole).

A general anaesthetic is usually used with or without a shoulder block (local anesthetic) 3 small stab incisions (8mm) are usually required.

The first stage of the procedure involves inspecting the shoulder joint. There is often other pathology in this area which is addressed at this stage. This may include bicep tendon tears, joint inflammation, labral (cartilage) tears and loose bodies.

The arthroscope (telescope) is then placed into the subacromial (rotator cuff area) space.
The inflamed tissue (bursa) is removed. The acromion (overlying bone) is then resected to stop impingement (rubbing of the tendon)
The AC Joint is commonly involved and may be treated.

The tear is then inspected. A number of bone anchors are placed in the humerus bone with stitches (ropes) attached. These are then threaded through the tear so that the tendon is lying against the humerus bone. The bone will need to be roughened to help with the healing.

The Keyhole approach is used to provide better patient outcomes.
It provides better pain relief, higher functional shoulder scores and similar tendon healing rates. The rates of stiffness following surgery are reduced, and most patients will stay in hospital for 1 day, although 50% will be day-patients only.

Post-Operative

The dressings will be bulky, but can be removed at day 3. Under these bulky dressings, there will be smaller rectangular dressing which need to be left intact until review.

Wound ooze is common and expected. The operation is performed "under water" using a pressure unit designed to increase the "space" to provide safe instrument insertion. The body will resorb most of this fluid, but the wounds will ooze for the first few days.

The wounds should be kept dry otherwise.

The swelling will resolve over the first few days. A shoulder protocol will outline all the post-operative instructions and limitation.

You will be placed in a sling for 4 weeks.
A full copy of the shoulder protocol is available on this website.

Risks and Complications

All surgery carries risk. Although the operation is minimally invasive and using only 8mm incisions, there are some risks to consider.

  1. Infection: The true infection rate is unknown following this surgery but is not common. Symptoms to consider are feeling unwell, fevers, intense pain and pus from the wound. If this occurs please contact the Rooms or the nearest Emergency Department.
  2. Stiffness: All surgery carries a risk of stiffness. This may also be related to the type and extent of the rotator cuff tear. It is important to carefully follow the shoulder guidelines.
  3. Nerve/Artery Damage: Rare, but reported in the literature. If the patient develops tingling, numbness, lack of movement in the hand of change of colour in the limb, immediately contact the Rooms or the emergency department. NOTE: Some patients are given an anaesthetic block which will cause numbness but should wear off by 12 hours.
  4. Re-tear and pain: The re-tear rates are related to the size of the tear and patient factors. Smoking, diabetes, general medical condition such as cardiovascular and respiratory disease and patients who have an active Workcover or TAC claim are at increased risk.
  5. Blood Clots: This is uncommon