Impingement syndrome is characterized by pain in the shoulder due to inflammation of the tendons of the rotator cuff or the bursa (subacromial bursa) that sits between the rotator cuff and the roof of the shoulder (acromion). The rotator cuff is a series of four muscles that surround the ball of the shoulder (humeral head). The subacromial bursa sits over the top of the cuff, allowing the cuff tendons to slide near the roof of the shoulder without undue friction. Normally, the humeral head gets closer to the acromion when the shoulder is moved, particularly as you reach overhead. When the rotator cuff becomes inflamed because of injury or overuse, or when the bursa becomes inflamed, then both the swollen tendon and swollen bursa may become pinched between the humeral head and the acromion.

Impingement syndrome may represent a grade 1 or 2 strain of the tendon. A grade 1 strain is a mild strain. There is a slight pull without obvious tearing (it is microscopic tendon tearing). There is no loss of strength, and the tendon is the correct length. A grade 2 strain is a moderate strain. There is tearing of fibers within the substance of the tendon or where the tendon meets the bone or muscle. The length of the whole muscle-tendon-bone unit is increased, although there usually is decreased strength. A grade 3 strain is a complete rupture of the tendon.

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How does impingement syndrome occur?

• Strain from sudden increase in amount or intensity of activity
• Direct blow or injury to the shoulder
• Aging, degeneration of the tendon with normal use
• Acromial spur

What increases risk?

• Contact sports such as football, wrestling or boxing
• Throwing sports, such as baseball, tennis or volleyball
• Weightlifting and bodybuilding
• Heavy labor
• Previous injury to rotator cuff, including impingement
• Poor physical conditioning (strength and flexibility)
• Inadequate warm-up before practice or play
• Inadequate protective equipment
• Increasing age
• Spurring of the acromion

What are the symptoms of impingement syndrome?

• Pain around the shoulder, often at the outer portion of the upper arm
• Pain that is worse with shoulder function, especially when reaching overhead or lifting
• Occasionally, aching when not using the arm
• Often, pain that awakens you at night
• Occasionally, tenderness, swelling, warmth or redness over the other aspect of the shoulder
• Loss of strength
• Limited motion of the shoulder, especially reaching behind (such as to back pocket or to unhook bra) or across your body
• Crepitation (a crackling sound) when moving the arm
• Biceps tendon pain and inflammation (in the front of the shoulder); worse when bending the elbow or lifting

How is impingement syndrome treated?

Non-operative treatment: Initial treatment consists of medication and ice to relieve the pain, stretching and strengthening exercises and modification of the activity that initially caused the problem. These all can be carried out at home, although referral to a physical therapist or athletic trainer may be recommended. An injection of cortisone to the area around the tendon (within the bursa) may be recommended.

Operative treatment: Surgery for rotator cuff tendonitis, subacromial bursitis or impingement is reserved for people who have continued shoulder pain that affects activities of daily living or sports activities despite completing an appropriate rehabilitation program for at least 3 months. Persons with an acromion (roof of the shoulder) that has a curve, hook or spur and those with partial thickness rotator cuff tears are most likely to benefit from this surgery. The goal of surgery is to eliminate the shoulder pain by removing the thickened and chronically inflamed bursa, removing the curve, hook or spur from the acromion, and cutting the cora-coacromial ligament to increase the space under the acromion so that the rotator cuff is less likely to be pinched between the acromion and humeral head.

Different techniques are in use at this time. The overall goal is to remove the chronically inflamed and scarred bursa and remove the acromial curve, hook, or bone spur. This can be done arthroscopically or with an open incision. Arthroscopic techniques involve using small incisions (arthroscopy portals) to look in the shoulder joint; then electricity is used to cauterize small capillaries. Electricity or a motorized shaver is used to remove the bursa. The cora-coacromial ligament is usually removed. Next a power burr is used to remove the bony curve, hook, or spur from the acromion.

Open decompression involves detaching the large deltoid muscle from the acromion, as well as cutting the coracoacro-mial ligament. Next, the acromial curve, hook, or spur is removed using a saw or osteotome (chisel). A rasp is often used to smooth the cut bone edges. The bursa is then removed with scissors. The deltoid muscle is sewn back onto the acromion.

What are the complications of treatment?

Possible complications of operative treatment include:

• Surgical complications not specifically associated with rotator cuff repair, such as pain, bleeding (uncommon), infection (<1percent), nerve injury (uncommon), stiffness, problems with anesthesia, and inability to return to previous level of pre-injury activity.

When can you return to your sport/activity?

This condition is usually curable within six weeks if treated appropriately with conservative treatment and resting of the affected area. Healing is usually quicker if injury is caused by a direct blow (versus overuse). If surgery is performed, keep the shoulder in a sling, brace or immobilizer for as long as your surgeon tells you; this is usually a couple of days if done arthroscopically or up to six to eight weeks if done as an open procedure, after which the deltoid needs to heal to the acromion. Return to full activity is usually possible in 3 months. Return to sports depends on the type of sport and the position played, and full shoulder motion and strength are necessary before returning to sports.

How can impingement syndrome be prevented?

• Appropriately warm up and stretch before practice or competition
• Allow time for adequate rest and recovery between practices and competition
• Maintain appropriate conditioning:
  • Cardiovascular fitness
  • Shoulder flexibility
  • Muscle strength and endurance
• Use proper technique