Two novel musculoskeletal radiology applications came to my attention at a recent conference. The first related to MRI and the second to Ultrasound scanning using Doppler blood flow measurement.
MRI and Subtle Shoulder Pathology
The focus of this discussion was from the perspective of the radiologist diagnosing pathology with imaging and correlating radiological diagnosis with surgical findings.
Discussion was largely focused on differential diagnosis rather than easily definable pathologies such as gross instability, tendon rupture or gross degenerative change.
The first issue of discussion was quantifying the site of a glenoid labral lesion in relation to its position on the glenoid. It appears from a surgical perspective that the reconstructive techniques can vary quite considerably depending on the site of the labral lesion and therefore it is of significant benefit to the surgeon to know in advance of surgical exploration to plan appointment times and surgical lists. What struck me most was a series of five images of subtle shoulder pathology displayed to an audience of 100 sports medicine doctors, physicians, physiotherapists and strength and conditioning coaches. None could identify the subtle image changes at specific sites along the labrum, which correlated with labral pathology involving partial tearing and inflammation at the site. In comparison to more obvious ‘SLAP’ lesions (superior labral antero-posterior) there was obviously a significant visual difference and reliance on a high level of skill in determining radiological abnormality.
We then switched our attention to evaluating rotator cuff tendonopathy where some extremely exciting developments are emerging. It appears that radiologists are now capable of determining whether rotator cuff tendonopathy is evident on the sub-acromial side or the tendon under surface at the humeral head. I had never seen this commented on before clinically, but from a rehabilitation perspective it is extremely exciting, because it help’s to sub-classify patients into primary or secondary impingements and therefore streamline for specific shoulder rehabilitation protocols (we have discussed in the shoulder course on this blog). If this turns out to be incorporated into routine practice I think it will become very beneficial to physiotherapy and provide an excellent opportunity for research into shoulder rehabilitation protocols.
Doppler Ultrasound Imaging
The other interesting radiological investigation discussed was ultrasound scanning of achilles tendonopathies. The cost effectiveness and ease of use of ultrasound coupled with the major improvements in image quality have widely increased its application in musculoskeletal medicine. Most typically in achilles tendonopathy the purpose of the scan is to quantify the integrity of the tendon, but also to investigate more subtle processes where there are visible changes of degenerative change within the tendon, indicated by partial fibre disruption or cysts within the tendon substance – associated with tendonosis. Whilst these applications are relatively well established, the new application of ultrasound scanning is to use the Doppler blood flow measurement to investigate blood flow within the target structure. As we know, tendons have a notoriously poor blood supply and it appears that one marker of an inflammatory response is an increase in vascular proliferation and together with chemical
substraits which precipitate vascular infiltration of the tendon. The colour image quantification of Doppler ultrasound allows what essentially is a “heat map” of a tendon to be reproduced, giving more detailed evaluation of the state of pathophysiology in cases where we were not looking at gross tendon disruption.
An interesting reference to a study of elite marathon runners was made where biochemical markers for vascular proliferation were monitored in achilles tendon’s up to one month post event. It appears that it took this length of time for the vascular proliferation markers to return to pre-running base line levels, which the researchers classified as normal. As one of the current concepts of perpetuating factors in chronic tendonopathy and enthesopathies is vascular proliferation distorting a normal repair process, this now gives us another level of insight into the pathophysiology..
Interestingly sports physiotherapists in elite professional soccer are using Doppler blood flow assessment of low grade tendon strain as a marker of when to increase training load rather than relying on clinical observation and functional loading capacity. This raises some very interesting questions and needs to be subjected to more rigorous research analysis in the future.
The two exciting thoughts to start us off for 2010!
Enjoy the clinical challenge.
Most clinicians involved in treating shoulder impingement syndromes acknowledge the role of scapulo-thoracic joint alignment in impingement patients. The clinical challenges is to determine the relevance of postural symmetries in the shoulder girdle as part of the pathology. Clinicians will be aware of the two broad distinctions in shoulder impingement pathology as being either primary or secondary mechanisms.
Primary mechanisms relate to factors which reduce the subacromial space resulting in encroachment on the intervening tissues.
Secondary impingements do not result from space occupying pathology such as:
AC joint mal-alignment,
Osseous anomalies in the acronimal shape.
These are variable parameters, which a treating therapist must evaluate in order to determine their relevance (or not) in the mechanism of impingement pain.
Understanding patterns of motion is essential if we are trying to determine relevant malalignment. American physiotherapist Shirley Sahrmann in her classic text ‘Movement Impairment Syndromes’ describes a group of scapular mal-alignments associated with impingement together with a description of the functional anatomy and pathophysiology associated.
Superior scapular migration syndrome
Inferior scapular migration syndrome
Downward scapular rotation syndrome
Winging scapular syndrome
The net result of variations in scapular position as outlined above alter the alignment of the Humerus relative to the Glenoid or perhaps more correctly, the Glenoid relative to the Humerus. This altered mechanical relationship produces changes in the length- tension characteristics of the relevant muscles of the scapular thoracic and rotator cuff complexes. Such malalignments may alter either the antero-posterior force couple across the Gleno-humeral joint, or as is more traditionally perceived alter the superior inferior force couple across the joint with a potential for superior Humeral migration.
The challenge for the therapist in clinical practice is to….
1. Determine the existence of the mal-alignment
2. Identify the predominant mechanism behind this malalignment.
Having determined the existence of one or both of these features, then the key issue is to determine its relevance.
The relevance can be ascertained by passively correcting the perceived / hypothesised mal-alignment or facilitating movement with the mal-alignment corrected.
Changes in the objective clinical signs confirm or refute the clinical hypothesis of “scapular contribution” to shoulder impingement
This is part 1 of a 2 part audio from a talk I gave on shoulder impingement rehabilitation.
As I mentioned after my presentation I have now made the Audio of this lecture available as a free MP3 download for attendees.
Many thanks to Garrett Coughlan and his team at Sports Managment Ireland for organising the event and inviting me to speak. I hope you got some useful clinical information – the ultimate objective of the day!!
I will post the slides I used on the day shortly but in the meantime you can listen/download the audio to playback on your PC or iPod as you prefer.
- Mechanisms of Impingement
- Clinical Algorithm’s
- Differential Diagnosis
- Treatment Selection
Shoulder impingement represents a clincal challenge because patients present with similar complaints which can be cause by a variety of pathologies.
Furthurmore, the mechanism of pathology is of prime importance for physiotherapists and rehabilitation professionals who provide care. Distinction between a tendonitis, a partial cuff tear or a mechanical impingment can be very challenging but has profound implications on the treatment strategy.
In addition mechanical impingement can be either primary or secondary with a multitude of different contributary factors.
Rotator cuff strengthening progressing through range ie into the impingment zone is highly unlikely to be beneficial in the presence of underlying capsular restriction. Failure to identify this component is a common reason for poor treatment outcomes.
It is therefore critical that therapists identify disturbance of the key accessory joint motion in the GH joint if they are attempting to progress loading in functional positions.
The above illustration highlights only one aspect of the clinical relevance of determining the mechanism of impingement
Instructions for use:
1 Double click on link
2 Slides will play automatically
3. Pause, forward, rewind from the control panel at the bottom of the player screen.
4, Can skip to slides from the left hand side slide menu.
5 Suggestion – if you downloaded the audio previously you can use your MP3 player whilst viewing the slideshow.
Hope you enjoy