Frozen shoulder, or adhesive capsulitis, is a reasonably common condition that we really should know more about. The more we know, the greater chance we have of avoiding it altogether. It also may help us help others a little more.
Adhesive Capsulitis can be a bit tricky to define because there’s still a lot we don’t know about WHY it happens. It’s characterized by non-specific pain in the shoulder that typically changes throughout the progression of the condition and varying degrees of restricted mobility in the glenohumeral (GH) joint, for which we do have some standardized “rules”.
There are many elements to the anatomy of the shoulder girdle, but we’re going to focus on the glenohumeral joint and the surrounding structures involved in adhesive capsulitis.
Key general anatomy:On the scapula we need to know about the glenoid fossa (the round flat surface that the upper arm bone articulates with – unlisted in this picture, but it is where the ball of the upper arm bone glides up against), the coracoid process (bit that sticks out at the front of the scapula), and the acromion process (bit that sticks out to the back and side of the scapula). There are many more details to each of these structures, but for now just keep these in mind.
This is the bony anatomy – the next image lays some ligaments, tendons and a couple of muscles over this. Just keep in mind that this again, is a few extra components and that there’s more to learn here.
Zooming in for frozen shoulder:The dotted line here demarks what is call the “rotator interval“. It is comprised of the superior and middle glenohumeral ligaments (which connect the glenoid fossa to the humeral head), the coracohumeral ligament (connecting the coracoid process to the humerus), the long head of the biceps, and a thin layer of the joint capsule.
So keep this in mind – there are some specific ligaments, and then some tendons (which stem from muscles) directly involved in this rotator interval, and then we also have the rotator cuff muscles that comprise the joint capsule and stabilize the glenohumeral joint. The muscles that comprise the rotator cuff are the subscapularis, infraspinatus, supraspinatus and the teres minor.
So, how does movement get restricted?
The mechanisms involved in creating the restriction in the GH joint happens are still somewhat of a mystery. We do know that the volume of synovial fluid in the joint goes from about 30mL in a healthy glenohumeral joint to about 10mL in frozen shoulder (reference). Synovial fluid is crucial to ensuring smooth movement at the joint.
In addition to reduced lubrication and joint volume, contracture and fibrosis of the connective tissue that forms the joint capsule occurs. The joint capsule and the synovial membrane thicken (with scar tissue), which restricts the joint further and can lead to inflammation and more pain. Interestingly as well, low-grade inflammation may not only be a symptom it may actually also be a contributing factor in the development of this thickening response of the connective tissues and the resultant contracture. (reference).
Typically, the most restricted movement is lateral (external) rotation of the humerus, however frozen shoulder also usually involves a significantly reduced range of motion in all planes and with all other movements. This is one of the diagnostic features of adhesive capsulitis biomechanics – a reduction in range of motion of equal to or greater than 50% of external rotation when compared with the other side of the body, or a measure of less than 30 degrees of external rotation. On top of external rotation restriction, we also need to see a loss of range of motion of at least 25% in two other planes of movement.
How does this happen?
You are more likely to get frozen shoulder in a variety of different scenarios, including (but not limited to) injury, lack of movement in daily activities, diabetes mellitus, upper crossed syndrome (and associated kyphosis), changes in weather and psychological stress. But like I mentioned above, there’s no fixed or set formula (at least that we know of yet) that causes adhesive capsulitis.
Can it be treated?
Yes and no.
Because we don’t have clearly defined pathways of pathophysiology, it’s difficult to qualify and standardize effective therapeutic treatment options. Many different methods of management have been identified (including massage) that show some degree of therapeutic value.
The combination of massage, acupuncture and a home-exercise program has shown to be a consistently more effective treatment regimen than individual treatments.
We’ve seen and been a part of the resolution of frozen shoulder through the application of massage. This is of course, anecdotal evidence and personal experience, however it’s promising and gives cause for greater investigation of the role of massage in the management of adhesive capsulitis.
As a therapist, the first thing that needs to happen is identifying which structures are primarily involved. This is where our list of rotator cuff muscles and our list of structures in the rotator interval come in handy. Manual technique application to these structures can prove fruitful, and especially if you back that up with active inputs such as the exercises found in this video.
What happens if massage and homework don’t work?
My suggestion would be to try out another therapist who has previous experience, and good results working with adhesive capsulitis.
But if that also does not work, frozen shoulder may resolve itself spontaneously within an average of 26 months (long time). It can become chronic and last beyond this time frame, and it has a greater likelihood of doing so without exercises and massage. Alternate and more drastic interventions exist in the case of a chronically frozen shoulder.