- The rotator cuff is comprised of four musculotendinous units. The muscles help stabilize and move the shoulder joint.
- Damage to any (or all) of the four muscles (alongside the ligaments that attach the muscles to the bones) can be attributed to chronic overuse, gradual ageing, or acute weakness
- The damage can result in -pain, decreased motion range (and use of the shoulder joint), weakness in raising the arm and in some instances, disability.
The shoulder is a ball and socket joint. It makes moving the arm in several directions possible. It is made up of the upper end of the upper arm’s bone (humeral head) fitting into the shoulder blade’s (scapula) glenoid fossa. The labrum and the joint capsule keeps the humeral head in place. The rotator cuff muscles are considered the movers and the dynamic stabilizers of the shoulder joint. It also adjusts the scapula and humeral head’s position during shoulder movement.
The four rotator cuff muscles are:
- Teres minor
Other muscles that help stabilize and move the shoulder include:
- The long head of the biceps tendon
- Teres major
- Pectoralis major
- Latissimus dorsi
Injuries to muscle and tendons are called strains. Strains are classified based on the damage to the tendon or muscle fibers. For instance:
- Grade I – the fibers are stretched but there are no tears.
- Grade II – injury resulted in partial tendon or muscle tearing.
- Grade III – injury resulted in complete muscle or tendon tear.
The tendons and muscles in the rotator cuff can become damaged in several ways. Damage can be a result of acute injury (i.e. from accidents or falls), gradual degeneration of the muscle and tendon secondary to ageing, or chronic overuse (i.e. lifting or throwing a ball).
1. Acute Rotator Cuff Tear – Injury can be from an attempt to cushion a fall (for instance, a fall on the shoulder) or from a drastic and powerful raising of the arm against resistance. This type of injury will often require a significant amount of force. This is especially the case for people that are below 30 years of age.
2. Chronic Tear – This injury is common among people engaged in sports or jobs that require an excessive amount of overhead activity (i.e. tennis and badminton players, baseball pitchers, and painters). Chronic injuries can also be traced to previous acute injuries that have caused structural issues within the shoulder and has also affected the rotator cuff function or anatomy (i.e. bone spurs that impinge upon a tendon or muscle, causing inflammation).
3. Tendinitis – Tendinitis can result from wearing out of the tendons and muscles (degeneration) secondary to age. When the rotator cuff is damaged, several issues may arise as a result:
- Spasm and pain will limit the shoulder’s range of motion significantly.
- The muscles will not make the small adjustments within the joint that will make the smooth movement of the humeral head possible.
- Inflammation may cause fluid accumulation within the joint that can limit movement.
- Calcium deposit and arthritis that can develop over time may also result in limited movement.
Injury severity can range from inflammation of the tendon or mild strain (no permanent damage) to partial or complete muscle tears that might require surgery to repair.
1. Acute Rotator Cuff Tear
- Sudden tearing sensation.
- Severe pain coming from the upper shoulder area (both in the back and front) down to the arm toward the elbow.
- Decreased motion range secondary to muscle spasm and pain.
- Acute pain from muscle spasm and bleeding (may be resolved within a few days).
- Large tears may result in an inability to elevate the arm or raise it away from the body’s side (abduction).
2. Chronic Rotator Cuff Tear
- Pain that is often worse at night and may interfere with sleep.
- Reduced shoulder motion and gradual weakness.
- Reduced ability to abduct the arm.
3. Rotator Cuff Tendinitis
- Deep ache in the shoulder and the outside upper arm (over the deltoid muscle).
- Tenderness in the area injured.
- Gradual pain that can become worse during abduction or internal rotation.
In the absence of tendon tears, pain medications, physical therapy, and range of motion exercises are recommended. In certain cases, steroid injections into the shoulder joint can help, especially the elderly with chronic tears not suitable for repair. However, in the event of tears and severe pain, checking with an orthopaedic surgeon to discuss surgical repairs might be necessary. Surgical intervention is often an option in the following scenarios:
- There is a complete rotator cuff tear.
- The patient is below 60 years old.
- The injury does not respond to conservative treatments (rest, anti-inflammatory medications, physical therapy) after 6 to 8 weeks.
Arthroscopic Rotator Cuff Repair
Traditionally, surgery to repair the rotator cuff is carried out through a medium incision in the shoulder (about 5 to 7 cm long). However, newer and more advanced surgical techniques may now be used to help minimize pain and reduce recovery time.
Arthroscopic rotator cuff repair is a minimally invasive procedure performed through tiny incisions (about 1 cm each) using an arthroscope. The arthroscope is a thin fiber-optic viewing instrument comprised of a video camera, light source, and tiny lens. Surgical instruments utilized are often only around 3 to 5 mm in diameter but will appear much larger viewed through the arthroscope. The television camera that is attached to the arthroscope will display the image of the joint on a television screen so the surgeon can look throughout the shoulder—cartilage, ligaments, and the rotator cuff.
From there, the surgeon can also determine the type and severity of the damage and repair and correct the problem. It is more useful for acute tears in sporting individuals but may not be applicable to chronic tears in older patients. Unlike before, arthroscopic rotator cuff repair is now the preferred option of many instead of the traditional open shoulder surgery because of benefits which include:
- Minimal trauma to the soft tissues
- Less pain
- Smaller incisions
- Quicker healing time
- Less scarring
- Lower infection rate
- Earlier mobilization in some cases