Painful Clicking, Snapping and Popping of the Shoulder

 1. Glenohumeral Joint

 The glenohumeral joint is a common source of painful clicking of the shoulder.

Causes can be classified according to age:

1.1 Young adults (approximately <30 years)

Glenohumeral instability is the commonest cause of clicking in the young. This may be atraumatic and associated with hyerlaxity of the shoulder. Patients may not recognise true apprehension or instability but may simply report painful clicking. This is predominantly posterior.
In cases where trauma has been involved, often sporting trauma, an injury to the labrum or capsule is sustained and this ‘subclinical instability’ can be associated with painful clicking. Large labral tears can lead to painful clicking without instability in a similar way to meniscal injuries of the knee.
Clinical identification of the causes in the young is by assessing generalised ligamentus laxity, shoulder laxity and apprehension tests. The apprehension tests may not or only subtly be positive in a patient with sub-clinical instability with painful clicking therefore more dynamic assessments are beneficial.
The radiological investigation of choice is an MR-Arthrogram (MRA), to assess the capsule-labral structures.

Treatment is non-operative in the absence of a tear, but surgical repair where there is a tear.

1.2 Older adults (approximately >30 years)

Clicking is often related to degenerative pathologies. These being either degenerate chondral lesions and/or degenerate labral tears - particularly in the older athlete. Clinical identification of glenohumeral joint pathology is to distinguish this from subacromial pathology by passive rotation of the arm in neutral reproducing the pain and possibly clicking. The Kibler Clunk test is a useful test for identifying glenohumeral clicking, very similar to the McMurray’s test of the knee.

Investigations include plain radiographs for glenohumeral arthritis and a plain MRI scan, if required.

Treatment depends on the severity of symptoms and range from GHJ injections to surgical arthroscopic treatment or shoulder replacement.

2. Subacromial

2.1. Young adult

In the young subacromial clicking is rare. The commonest cause is an impinging subacromial bursal plica. This is a synovial fold of the bursa that may cause clicking and subacromial impingement pain with bursitis. The clicking is usually directly palpable over the subacromial bursa anterolateral to the acromion. The clicking can usually be reproduced by passive rotation of the shoulder in abduction. A targeted subacromial bursal injection is useful to identify the source of the painful clicking and may relieve the symptoms in many patients. This is combined with scapula, postural and rotator cuff rehabilitation. Should this fail, an arthroscopic subacromial decompression with resection of the bursal plica is indicated.

2.2. Older adult

In older patients with bursal clicking the most likely is a rotator cuff tear. However painful clicking is a very rare symptom of rotator cuff tears. An ultrasound scan or MRI scan are the most appropriate investigations of choice and management would be targeted to the rotator cuff tear.

3. Long head of biceps

The long head of biceps (LHB) is an inherently unstable structure due to its tortuous course over the proximal humerus. It is stabilised by the transverse humeral ligament and the biceps pulley, which comprises stabilising tissues from the subscapularis and supraspinatus tendons.

Painful clicking of the LHB tendon is usually due to a significant pulley lesion or rupture of the transverse humeral ligament (THL), leading to instability of the LHB.

Pulley and THL injuries are associated with partial or full thickness subscapularis tendon tears. They tend to occur in young athletes as a result of explosive overhead movements, contact injuries. In older patients it is part of rotator cuff pathology.

Clinical diagnosis is by direct palpation over the biceps groove whilst rotating the arm and feeling for a reproducible click. A positive Speed’s test may be present. There may be tenderness over the LHB at the biceps groove. Subscapularis and supraspinatus strength should be carefully assessed.

Dynamic ultrasound scanning is the most useful investigation for an unstable LHB tendon, but a dislocated tendon will also be seen on static MRI scanning. MRI is more sensitive than ultrasound in detecting an associated subscapularis injury.

Treatment depends on the severity of associated lesions. Should there be a traumatic subscapularis tear then surgical treatment in the form of repair of the subscapularis tear and tenodesis of the long head of biceps tendon would be appropriate. Should there not be a significant subscapularis tear then ultrasound guided injections of the biceps tendon can be attempted and if this fails a biceps tenotomy or Tenodesis. Management does often depend on the age and functional demands of the patient, along with surgeon preference.

4. Acromioclavicular joint

4.1. Young adult

A painful clicking acromioclavicular joint (ACJ) may be due to a single traumatic event, or chronic repetitive loading. In a single injury the ACJ ligaments are torn, along with rupture of the ACJ meniscus. Repetitive trauma in overhead and power athletes leads to lateral clavicle osteolysis and may cause painful clicking.

4.2. Older adult

In older patients the cause is almost certainly ACJ osteoarthritis.

Clinical diagnosis is by direct palpation over the ACJ. Other signs include reproduction of the clicking on high arc movements, positive Scarf test and positive Paxinos test. ACJ excess mobility can be demonstrated on dynamic ultrasound scanning. X-rays are beneficial for ACJ arthritis, however they may not demonstrate tan ACJ subluxation without identical comparative Zanca views of the opposite side. Therefore, we prefer ultrasound and MR scanning in younger patients.

Treatment involves steroid injections initially. If this fails ACJ excision is indicated in young patients. It is essential to assess the ACJ stability at the time of surgery as a common cause of ongoing symptoms is continued ACJ instability after excision. In these cases the ACJ should be stabilised/reconstructed.

5. Sternoclavicular joint

The sternoclavicular joint causes are almost identical to the AC joint and treatment options in the same.

6. Scapulothoracic

The scapulothoracic articulation is a rare, but significant cause of painful clicking of the shoulder. It is generally always in younger patients. The most common cause is due to an inflamed scapulothoracic bursa. The causes of this are either muscular or bony.

Muscular causes are complex and usually related to scapular dysrhythmia. This may be secondary to primary glenohumeral joint pathology or due to a primary scapular dysrhythmia either muscular or neurogenic in origin.

Investigations should involve an MR scan specifically of the scapulothoracic articulation. Treatment is targeted to the root cause. This can often be quite complex and in my opinion best managed in a multi-disciplinary specialist shoulder unit. Bursal injections with the rehab is often useful. If this fails a bursectomy and resection of the superomedial border of the scapular might be beneficial.

Osteochondromas are rare but a significant cause and should be sought on the MR scan.

Summary

Painless clicking of the shoulder is not abnormal, but where it is associated with pain and/or instability it is pathological. Using the algorithms above accurate diagnosis is possible and treatment targeted accordingly.