The shoulder joint is a remarkably complex structure that allows a wide range of arm motion and power when it is functioning properly. Due to the joint's elegant structure and the stresses often placed on it, the muscles and tendons of the shoulder are highly vulnerable to injury.

One of the most common injuries occurs to the rotator cuff muscles. The rotator cuff muscles are important in keeping the shoulder joint stable and allowing flexibility of the arm and shoulder.

The rotator cuff is composed of four tendons that connect the muscles of the shoulder blade (scapula) to the upper arm bone (humerus). The rotator cuff tendons form a band that attaches to and surrounds the top of the humerus.

Rotator cuff tears cause shoulder weakness and pain, and immobility in severe cases.

Tears can occur in tendons weakened by age, inflammation, disease, trauma, bone spur, and repetitive strain injury. Rotator cuff tears can occur in younger people, especially following sudden and major trauma. In older patients, tear can result more insidiously from attrition wear. Tears most commonly occur at the "insertion", where the tendon joins the muscle to the bone. A tear is unlikely to heal by itself because:

• this area of the tendon has a low blood supply,
• daily movement of the muscles constantly pull on the tendon, pulling the edges of the tear further apart and limiting the amount of healing that can occur.

Tears range from a partial tear in one tendon to complete tears of one or more tendons. In a partial tear, only some tendon fibres are torn. This weakens the tendon and causes significant discomfort, but the arm can still move relatively normally.

Partial tears usually occur as a result of overuse but can occur due to injury.

Over time, a partial tear can worsen and go through all the layers of the tendon to become a full-thickness tear. A larger tear causes more weakness and pain. Depending on its location, a full thickness tear can lead to a complete rupture of the tendon, and the tendon completely tears off the bone.

If the tendons completely rupture, the person is unable to move the arm normally. A complete tear will not heal by itself. In these cases, surgery is the only means of repairing a tear.

The goal of surgery is to restore shoulder function and comfort by repairing tears in the tendon and reattaching the tendon to bone.

However, in some patients, rotator cuff tears cannot be repaired. Success of surgical treatment depends on:

• the size, thickness and location of the tear
• the quality and amount of tendon tissue still remaining
• the length of time the tendon has been torn
• the patient's capacity to heal.

Rotator cuff repairs restore reasonable movement and relief of discomfort in most patients.

The Surgical Procedure

Arthroscopy with small incisions: This is done through several small incisions, each less than one centimetre long. The arthroscope is a thin instrument containing a miniature video camera and light source. It allows the surgeon to see inside of the shoulder joint and perform the procedure while watching a video monitor.

The arthroscope is inserted through a small incision in the shoulder. Working through another small incision, the surgeon uses tiny cutting instruments to trim the edges of the tendon and then removes fragments of torn cuff tendon. Small grinding instruments may be used to remove a bone spur from the acromion and prevent further damage to a tendon. Small tears in the tendon are then repaired. Arthroscopy incisions are closed with one or two stitches or small adhesive strips.

Arthroscopy plus a four to five centimetre incision: Arthroscopy may be combined with a four to five centimetre incision in the shoulder. The arthroscope is used to locate the tear. The incision is then made through the skin and underlying tissues, directly above the tear.

Open surgery: In cases of rotator cuff tear where open surgery is necessary, the surgeon makes a 10 to 12 centimetre incision in the side of the shoulder. The surgeon reaches the rotator cuff by dissecting through muscle and other tissues. Unhealthy tendon tissue is trimmed and removed, and a clean area of bone is created.

The tendon is anchored to the bone in one of two ways:

1. small holes are drilled in the prepared area of bone. Strong stitches are placed in the end of the torn tendon and then looped through the holes to anchor the tendon to the bone.
2. small, strong suture anchors, with stitches attached, are fixed into the bone. These suture anchors are made of metal, plastic or a synthetic material that is eventually absorbed by the body. The stitches are then passed through the torn end of the tendon and tied down to the anchors

Skin incisions are closed with stitches and dressings applied.

Recovery After Rotator Cuff Repair Surgery

Immediately after surgery, you will be transferred from the operating theatre to the recovery room. Nursing staff will monitor your recovery and give you a painkiller if needed.

Incisions are covered with a dressing, and your arm may be in a sling or shoulder immobiliser. This is to protect the shoulder and keep it in the correct position.

After arthroscopy, you can probably go home the same day but some may have to stay in hospital overnight.

You will have a follow-up visit with your orthopaedic surgeon in 7 to 10 days.

While the shoulder is healing, pain and discomfort are normal. You may need to use pain-relieving medication for a few weeks, as prescribed by your surgeon.

Depending on the size of the tear and the quality of the cuff muscle, you may have difficulty with day-to-day activities for two to three months.

An exercise program is important to your recovery and begins soon after surgery. Your physiotherapist will design a program for you.

Generally you will need to be in a sling for 2 to 6 weeks. Gentle pendulum exercises are usually started immediately after operation. Exercises to increase the range of motion are then started either the 3rd or the 6th week depending on the size of tear and the quality of the muscle.

Your surgeon will advise you about a return to work and normal activities. Recovery takes time and depends on the type of surgical repair. It usually take several months (possibly up to a year) for strength and comfort of your shoulder to return.

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