The shoulder is a complex area which allows significant mobility of the upper limb. This is important for completion of activities of daily living as well as participation in several types of sporting activities.
The shoulder consists of two separate joints- the acromioclavicular (AC) joint and the glenohumeral (GH) joint. Shoulder motion occurs at the GH joint in multiple directions; this great mobility comes at the price of decreased stability of the glenohumeral joint when compared to some other joints in the body such as the knee or hip.
Multiple ligaments and the joint capsules act as static (stationary) stabilizers of the joints of the shoulder while the four rotator cuff muscles act as dynamic (moving) stabilizers of the GH joint.
The scapulothoracic joint is the position of the scapula (shoulder blade) on the back of the rib cage. Movement at this joint is important for normal shoulder movement and it is stabilized in a good position by several muscles.
There are multiple possible causes of shoulder pain. The likely cause of a person’s shoulder pain can be influenced by age, medical conditions, trauma to the shoulder and a history of repetitive upper limb use for work-related or sporting activities. Today we will discuss three of the most common conditions:
1) Rotator cuff disorders,
2) Adhesive capsulitis (frozen shoulder)
The rotator cuff consists of four muscles which originate on the scapula and attach to the head of the humerus (arm bone) and help maintain its position in the glenoid fossa (shoulder socket). These muscles are the supraspinatus, infraspinatus, teres minor and subscapularis.
The tendon of the supraspinatus is the most common part of the rotator cuff that is injured. Tendinopathy (tendon disease) can involve inflammation, a chronic degenerative process or a tear of the tendon. Tendinopathy can result from trauma to the shoulder (such as a fall) or from chronic impingement (compression) of the tendon between two bony parts.
Rotator cuff disorders are most common after 40 years of age but can occur in younger sportspersons who have chronic impingement. In many cases of tendinopathy, there is an associated inflammation of the subacromial-subdeltoid bursa. Symptoms include pain on the side of the shoulder, decreased range of motion, trouble sleeping on the affected shoulder and weakness of shoulder movement.
Adhesive capsulitis is a condition in which the synovial tissue of the capsule of the GH joint becomes adherent to itself as a result of the development of adhesions within the joint. This leads to progressive loss of range of motion of the shoulder.
Symptoms include shoulder pain with significantly reduced range of motion. There is usually a progression from a painful stage to a stage of freezing/stiffening and then to the thawing stage. It can last up to two years without treatment. This disorder is associated with several conditions:
· Parkinson’s disease
Osteoarthritis of the shoulder can affect either the AC or GH joint. The cause of the arthritis may be unknown or it may occur after trauma, infection or inflammatory disorders. Symptoms include shoulder pain, decreased range of motion, crepitus (creaking or cracking) when moving the shoulder. Examination may show obvious deformity if the AC joint is affected and tenderness over the affected joint.
The rehabilitation specialist can play a very important role in the management of shoulder pain. Taking a thorough history and performing a good physical examination will provide the physician with the correct diagnosis in most cases.
When necessary, imaging studies such as x-rays, musculoskeletal ultrasound or MRI will be ordered to help make the diagnosis. An appropriate treatment plan can then be designed for each patient. The treatment plan will include a corticosteroid injection or oral medications for pain control and physical therapy followed by a home exercise programme.
In some cases of rotator cuff tendinopathy and osteoarthritis, surgery may be needed and adhesive capsulitis may require manipulation under anesthesia. In these cases, the patient would be referred to an orthopaedic surgeon for treatment.
If you have shoulder pain which has not responded to treatment after 1-2 weeks, an adequate evaluation is the first step towards regaining optimal physical function.
Dr Shane Drakes is a Specialist in Physical Medicine and Rehabilitation and Sports Medicine. He can be contacted at firstname.lastname@example.org.