Thursday, December 4, 2008

The Shoulder and Physiotherapy

By Jonathan Blood Smyth

The function of the human arm is to allow placement of the hand in useful positions so the hands can perform activities where the eyes can see them. Because of the huge range of positions required the shoulder is very flexible with a large motion range, but this is at the expense of some reduced strength and greatly reduced stability. A "soft tissue joint" is often a description of the shoulder, indicating it is the tendons, muscles and ligaments which are important to the joint's function. Shoulder treatment and rehabilitation is a core physiotherapy skill.

The shoulder joint is constructed from the socket of the scapula and the humeral head, the ball at the top of the upper arm bone. The head of the upper arm is a large ball and important tendons insert onto it to move and stabilise the shoulder, but the shoulder socket, the glenoid, is small in comparison and very shallow. A cartilage rim, the labrum of the glenoid, deepens the socket and adds to stability. The acromio-clavicular joint lies above the shoulder joint proper and provides dynamic stability during arm movements, being made up from part of the scapula and the outer end of the clavicle.

The glenohumeral and scapulothoracic joints of the upper limb are acted on by large, strong, prime mover muscles as well as smaller stabilisers. The major back and hip muscles keep the shoulder stable to allow strong movements, the thoracic stabilisers keep the scapula stable so that the rotator cuff can act on a stable humeral head. The deltoid can then perform shoulder movements on the background of a solid base and allow precise placement and control of the arm for hand function to be optimal.

Around the shoulder all the muscles narrow down into flat, fibrous tendons, some larger and stronger, some thinner and weaker. All these tendons are anchoring themselves to the humeral head, allowing their muscles to act on the shoulder. The rotator cuff includes a group of relatively small shoulder muscles, the subscapularis, the supraspinatus, the infraspinatus and the teres minor. The tendons form a wide sheet over the ball, allowing muscle forces to act on it. The rotator cuff, despite its name, acts to hold the humeral head down on the socket and allow the more powerful muscles to perform shoulder movements.

The rotator cuff degenerates with age, small tears appearing across its substance which can progress to massive tears, completely interfering with muscular function of the shoulder. Rotator cuff tears are often painful but it is not clear exactly why, as many older people have tears and do not have pain. Physiotherapists work to strengthen the rotator cuff or by exercising the main shoulder muscles without gravity resistance and gradually increasing the effort. Physios also work on rehabilitation after rotator cuff surgery for rotator cuff tears, following the detailed protocols for small, medium, large or massive rotator cuff tears.

Osteoarthritis (OA) more commonly affects the hips and the knees, however the shoulder can be severely affected in which cases physiotherapy can help with advice, mobilisation of the joints and work on strength and joint motion. Once physiotherapy treatment has been tried then total shoulder replacement is the only remaining treatment option, surgical replacement occurring of the head of the arm bone and the socket of the shoulder blade. As the shoulder is referred to as a "soft-tissue joint" it is the balance and strength of the tendons, muscles and ligaments that determines a good outcome for the replacement. Physiotherapists closely follow the surgical protocols to get the optimal results.

Physiotherapy treatments include the assessment and management of many different shoulder pathologies such as shoulder fractures and dislocations, sub-acromial impingement, tendinitis, abnormal patterning and hypermobility. Physio treatment for fractures and dislocations depends on the severity and type of injury and follows the physiotherapy and surgical protocols. Patient education and muscle stabilising work is used for hypermobility, while biofeedback and correct muscle activity teaching is the treatment for abnormal patterning. Impingement physio is cuff strengthening and joint mobilisation, with joint injections and surgical acromioplasty if physiotherapy is not successful. - 14130

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