Shoulder impingement syndrome is the most frequent cause of shoulder pain in sport and the average population.
The term impingement is used to describe the pain and inflammation (tendonitis in shoulder) as a result of the frequent friction between the rotator cuff and the bony-ligamentous arch above the rotator cuff which is formed by the acromion and the Coraco- acromial ligament. This is what is called a primary impingement syndrome.
The rotator cuff is a compound of muscles and tendons which form a cover around the humoural head and connect it to the scapula. The function of the rotator cuff is to keep the shoulder joint in place and to help with movement of the shoulder in abduction and external rotation.
There is a lubricating membrane which is called Bursa which separate the rotator cuff from the acromion which is the bone on top of the rotator cuff allowing no direct contact.
Impingement syndrome pain can be related to either tendinitis of the rotator cuff or bursitis or both. The tendinitis or Bursitis can arise as a result of excessive over head activities or due to a bony spur from the anterior part of the acromion catching against the rotator cuff or the bursa, or as a result of an osteophyte from the acromioclavicular joint which can also cause the same.
Frequent impingement of the rotator cuff will lead gradually to a tear in the cuff which can be catastrophic on the long-term leading to progressive arthritis of the shoulder joint. Therefore we recommend adequate treatment of impingement syndrome at early stages to prevent any long-term complications.
The patient describes pain in the anterior aspect of the shoulder and upper part of the arm particularly with overhead activities. They also describes pain at night, weakness in shoulder function, and difficulties placing the arm behind the back particularly ladies trying to deal with their bra.
The clinical examination will help to identify the source of the pain and the painful arc related to impingement syndrome and also to identify if there is any particular tear in the rotator cuff leading to weakness particularly in external rotation movements.
The clinical examination is augmented by radiological investigation including simple x-ray to identify the anatomical shape of the acromion and if there is any particular bony spurs causing the impingement and also to assess the acromioclavicular joint. Shoulder MRI scan have an advantage of identifying the integrity of the rotator cuff and to also identify the area of inflammation around the rotator cuff and the fluid retention in the bursa.
Most of the impingement syndrome cases are treated primarily with conservative management using non-steroidal anti-inflammatory medication and physiotherapy to increase the range of motion and muscles strength. Some cases may require a steroid injection in the subacromial space to deal with the significant inflammation. The patient is also advised to avoid excessive overhead activities during the treatment period to avoid any recurrence of his condition.
If the Conservative management fail, the surgeon would have to recommended surgical treatment in the form of arthroscopy of the shoulder to perform anterior acromioplasty to remove a piece of bone which is interfering with the rotator cuff. This is usually done by the help of the arthroscopic technique. During arthroscopy, the surgeon will remove the inflamed bursa and inspect the rotator cuff for any tear, which may require repair on the same time. The surgeon would also inspect the acromioclavicular joint and check if there is any particular impingement caused by AC joint by a bony growth from the undersurface of the joint.
Most of the cases settle fully after the arthroscopic procedure which is usually followed by physiotherapy and rehabilitation programme. It takes approximately 6 to 8 weeks for most of sport players to return to almost full activity after simple subacromial decompression particularly if no rotator cuff repair was carried out.