Shoulder pain is one of the commoner complaints seen by GPs. The shoulder girdle itself comprises five separate joints: the sternoclavicular, acromioclavicular, subacromial, glenohumeral and scapulothoracic joints. Problems in any of these can cause shoulder pain.
Patients may also experience shoulder pain referred from distant areas such as the cervical spine, thoracic inlet, mediastinum and lungs, the diaphragm and even sub-diaphragmatic problems such as hepatic problems. So the clinician needs to keep an open mind as to the cause of shoulder symptoms, although here l will focus on problems within the shoulder girdle.
The sternoclavicular joint
This is a synovial joint with a small meniscus, and is between the manubrium of the sternum and the medial end of the clavicle. Problems with this joint are rare, which is just as well because solutions for sternoclavicular pain tend not to be effective. Degenerative change in this joint is usually post-traumatic and can be treated usually by a series of up to three hydrocortisone injections into the sternoclavicular joint. An excision arthroplasty of the joint can be done in severe cases. Sternoclavicular dislocations are rare and are usually treated conservatively with the patients being managed symptomatically.
If the patient continues to have pain and instability from a long-standing sternoclavicular dislocation or subluxation surgical options include either stabilising the dislocated joint or an excision arthroplasty, but only about half the patients see a significant improvement.
Problems affecting the glenohumeral joint
The glenohumeral joint is the main joint of the shoulder girdle and can be involved in a number of problems.
This presents with a painful, stiff shoulder and is confirmed radiologically with the expected signs of loss of joint space, subchondral sclerosis, cysts and osteophyte formation. Management is usually conservative with analgesics, NSAIDs and intra-articular steroid injections. Joint replacement is rarely required.
This is a poorly understood condition, presenting with spontaneous onset of increasing pain and stiffness in the shoulder girdle. The condition affects the normally lax lining of the glenohumeral joint.
Marked inflammation of the lining of the joint leads to the joint capsule tending to glue itself together, producing a marked, restriction in range of movement at the glenohumeral joint. Patients have restricted internal and external rotation compared with the normal side, with a lesser degree of restricted elevation.
The natural history is typically eight months of pain, followed by eight months of pain and stiffness, followed by eight months of stiffness before resolution. Therefore after 24 months, the majority of patients with this condition will settle. The diagnosis is made from the history, examination and normal X-rays.
Management consists of informing the patient about the natural history of the condition, and ,symptoms are managed according to their severity. A few patients are so disabled by this condition that they need a manipulation under anaesthetic and intra-articular steroids.
The extreme mobility of the glenohumeral joint is achieved because the socket is only one-third of the area of the ball of the humeral head. This architectural arrangement allows great mobility at the expense of stability. Shoulder instability is a therefore a frequent problem.
In 90 to 95 per cent of cases there is an anteroinferior dislocation. Patients who suffer three or more dislocations, that is have become recurrent dislocators, should be referred for consideration of surgical repair. This usually means a Bankart repair, in which the glenoid Iabrum is reattached to the anterior aspect of the glenoid.
An arthroscopic approach is replacing open surgery, although patients should be aware that success rates for arthroscopic surgery are about 70 per cent, whereas open surgery is up to 95 per cent successful. Arthroscopic repair rates continue to improve, however. Patients are managed postoperatively in a sling for six weeks, and this is followed by a six-week rehabilitation programme.
Problems with the subacromial joint
The subacromial joint is the articulation between the top surface of the rotator cuff and the under surface of the acromion, and presents two main problems.
Subacromial impingement syndrome
This is probably the commonest problem affecting the shoulder. Patients report pain in the rcgion of the lateral deltoid or deltoid insertion. It can disturb sleep, be aggravated by lying on the affected shoulder, and typically causes pain whenever the arm is used at or around shoulder height.The patient usually points vaguely to the latcral deltoid area as being the source of the pain. There is often evidence of wasting of supraspinatus and secondary wasting of the deltoid muscle. There are usually no particular tender areas.
Positive findings are of a mid-range painful arc when the arm is elevated through abduction and flexion.The patient may also show an abnormal rhythm of movement when the arm is raised and lowered. This trick is subconsciously learnt by the patient and takes the traumatised part of the rotator cuff away from the under surface of the acromion. A specific test consists of asking the patient to abduct the arm to 30¡ while resisting the movement. This should cause a reproduction of the pain.
Treating impingement syndrome
Conservative treatments include physiotherapy to strengthen the subscapularis and infraspinatus muscles, thereby pulling the inflamed and irritated top surface of the rotator cuff away from the undersurface of the acrimony. Other conservative measures include steroid injections into the subacromial joint. A diagnostic local anaesthetic injection is made into the subacromial joint to help confirm the diagnosis, and this is effective at relieving pain. Up to three hydrocortisone injections can be given at four- to six-week intervals. A combination of physiotherapy and a series of steroid injections will resolve symptoms in about 80 per cent of cases.
If patients fail to respond, referral is indicated as they may need an arthroscopic subacromial decompression to relieve symptoms and prevent rotator cuff rupture. This generates more space in the subacromial joint to stop the inflamed and swollen tendons from being further rubbed. This 40-minute procedure is successful in about 80 per cent of cases, but full recovery takes about 12 weeks.
Rotator cuff rupture
Rupture of the rotator cuff can be either partial or complete.The rotator cuff is a tube of muscle emanating from the shoulder blade and encircling the humeral head. Its function is to pull the humeral head firmly on to the socket of the glenoid as the arm is elevated. Even with a tear, the rotator cuff may still be able to stabilise the humeral head and the glenoid. In these cases the rotator cuff is defined as functionally intact.
A large rupture will not allow the rotator cuff to stabilise the head of the humerus in its socket, and the patient will be unable to abduct the arm at all. This is because when the deltoid contracts, the humeral head is pulled up through the rent in the rotator cuff. Patients with suspected rotator cuff ruptures require referral to an orthopaedic surgeon with an interest in shoulder problems for investigation and possible repair. Rotator cuff repairs are a major undertaking and require extensive rehabilitation programmes.
The acromioclavicular joint
Problems with the acromioclavicular joint (ACJ) are common, and usually involve osteoarthritis or ACJ dislocation.
Patients localise tile pain extremely well to the area of a degenerate joint, usually pointing with one finger at the ACJ. Using the arm when it is raised typically aggravates the pain. Often there is a history of trauma. When examined, the ACJ is tender and pain is reproduced when stressing the ACJ by fully adducting and internally rotating the shoulder.
The patient also complains of pain when the arm is in full elevation in either flexion or abduction. Physiotherapy or oral anti-inflammatory drugs are used initially, but if there is no response a GP can give a series of up to three hydrocortisone acetate injections to the joint.
Injecting a degenerate ACJ can be quite difficult as the joint space is often narrowed. Infiltration around the joint with local anaesthetic is followed by an injection of I-2m1 of lignocaine into the joint. After a minute or so, test movements to ensure that the local anaesthetic block to the ACJ has resolved the patient’s symptoms. It is then usually fairly easy to inject hydrocortisone into the joint without causing undue discomfort. About 70 to 80 per cent of patients will be cured by a series of up to three such procedures at four- to six-week intervals. If the response is unsatisfactory then refer to an orthopaedic surgeon to consider an arthroscopic ACJ arthroplasty or an open ACJ arthroplasty. I prefer the former operation as this preserves the superior joint capsule and is cosmetically more acceptable.
This is a common injury, particularly on the rugby field when players typically fall onto the point of their shoulder. Most patients will have been seen in a casualty department and may have been referred to a fracture clinic. The jury among orthopaedic surgeons is still out regarding the best treatment for ACJ dislocations.
Most patients can be treated conservatively, because even with a dislocated ACJ most patients are able to compensate well and have a normal range of movement and function of the shoulder. Patients with a marked cosmetic deformity, or those engaged in upper-limb sports or work should be counselled concerning the pros and cons of conservative management versus reconstructive surgery.
An ACJ reconstruction is easy to perform if done in the first few weeks. However, by the time an ACJ dislocation has become chronic – that is, after six weeks – then reconstruction becomes more difficult, requiring ligament or coracoid process transfer. Patients who may justify ACJ reconstruction should therefore be referred to a specialist early.
The scapulothoracic joint
Fortunately, problems in the scapulothoracic joint are rare. The commonest complaint is a painful or snapping scapula. In many of these patients no obvious cause for their symptoms can be found, although a small proportion of patients will have pain arising from the supramedial border of the scapula as it moves over the posterior chest wall.
Usually they are investigated with a CT scan. This investigation can provide a three dimensional picture of the architecture of the shoulder girdle.
A physiotherapy programme is the first route to try and improve their Scapulothoracic control, but if patients fail to respond a small proportion of them may be offered excision of the abnormally angled supra-medial border of their scapula. This procedure may help alleviate their symptoms.
Patients likely to benefit from this operation represent only a small proportion of patients with scapulothoracic pain, however. All patients with scapulothoracic pain and clicking should be referred initially for a physiotherapy programme in the first instance to look at their scapulothoracic control.
Only if this fails to alleviate their symptoms is referral to an orthopaedic surgeon with an interest in shoulder problems recommended.
From an original article published in GP, 18TH MAY 2001