Intra-Articular Shoulder Pain – Diagnostic Accuracy and Clinical Relevance

The broad classification of intra-articular shoulder pain as an “impingement syndrome” is highly prevalent in clinical practice.  As we have previously discussed classification of impingement into primary and secondary sub-groups provides a useful clinical framework in order to direct treatment.  The recognition of the potential for subtle glenohumeral instabilities to contribute to a similar type of symptom pattern has also received significant attention in the literature in recent years.  Some specific tests have been devised to evaluate this and perhaps the best known of them is the Kinetic Shoulder Test.

If we take a step back from considering the mechanism of tendon injury to considering whether all tendon irritation can be truly considered as a tendonitis / tendonosis in the true sense.  This is not simply an academic debate because it profoundly influences the direction in which therapeutic interventions are conducted.  Take for example a common clinical scenario of applying resisted tests to the rotator cuff in a neutral anatomical positions. The clinical interpretation of a negative response is that a tendonitis or partial tear can be excluded.  Similarly, of the multitude of orthopaedic tests which have been devised to test for impingement (with varying diagnostic sensitivity) it raises the issue of whether clinical treatment is directed towards reducing the sensitivity of the irritated tendon or focusing on the patho-mechanics as a primary treatment strategy.

When we consider our normal treatment strategies for tendonitis in other anatomical regions the currently accepted protocols are to apply selectively graded loading sufficient to produce a positive physiological response and staying short of inducing overload.  Obviously this is not an exact science and it is a fairly common clinical experience for increased pain levels of post treatment soreness to dictate a modification of loading.

A particularly useful classification of tendon irritation has been presented by Craig Allingham, Australian Physiotherapist, and discussed in an excellent text called “Sports Physiotherapy”.

He presented the argument that tendonitis should be classified as either:

1. Compressive tendonitis

2. Tensile tendonitis.

For the biomechanists amongst you, you will recall that the tensile load placed upon a structure is the force which tends to increase tension through it. When tendons have a limited capacity to tolerate tensile load the clinical management is usually to partially unload allowing healing to occur and then gradually increase graded loading within tolerance. In the lower limb, specifically in the case of Achilles and Patellar tendonopathies the concept on eccentric training programmes have been popularised originally by Kirwan and Stanish in the 1980′s and these principals hold true in cases of tensile tendonitis in the shoulder region.

Specifically with regard to functional impairment different components of the cuff maybe overloaded at different phases e.g. an overhead athlete in the terminal phase of a tennis serve, known as late cocking, requires deceleration by strong eccentric activity of the internal humeral rotators.  Patients who complain of symptoms at this phase of the movement may have a tensile overload phenomenon of the anterior shoulder structures.  Alternatively, patients who complain of symptoms at the end of follow through, when the ball has been struck or an implement thrown, place high eccentric load on the posterior cuff in order to decelerate the arm and thus may expose the posterior cuff elements to an excessive tensile load.  This conceptual framework allows the clinician to be more selective in identifying the mechanism of breakdown and implementing specifically relevant treatment programmes.

Therefore clinically we are looking at differentiating positive resisted tests in non-impinged positions and applying graded loading as tolerated from tendon sensitivity which is only elicited in positions of compression – “impingement”.

Enjoy the clinical challenge.

David.