Muscle guarding has a role in restricted range of motion loss in patients with frozen shoulder

Frozen shoulder, also called adhesive capsulitis, is a common shoulder condition characterized by loss of range of motion (ROM) in the shoulder (glenohumeral) joint. Pain and the feeling of stiffness often also occur. The average length of symptoms is 30 months. Spontaneous recovery sometimes occurs, but the condition may become chronic. It has been classically stated that the cause of frozen shoulder is chronic capsule inflammation and fibrotic adhesion of connective tissues surrounding the glenohumeral joint. However, the pathomechanics of this condition are not yet fully understood.

Researchers from Australia recently conducted a preliminary cross-sectional observation study to investigate the feasibility of a muscle guarding component to movement restriction in patients with idiopathic frozen shoulder.

Five patients with painful, global restriction of passive shoulder movement volunteered for this study. The patients were scheduled for capsular release surgery for frozen shoulder. Passive shoulder abduction and external rotation range of motion (ROM) were measured before and after the administration of general anaesthesia.

The results showed that passive abduction ROM increased following anaesthesia in all participants, with increases ranging from approximately 55°–110° of pre-anaesthetic ROM. Three of these participants also demonstrated substantial increases in passive external rotation ROM following anaesthesia ranging from approximately 15°–40° of pre-anaesthetic ROM.

See the video here https://twitter.com/LuiseHollmann/status/1017339041803481088

This case series of five patients with frozen shoulder demonstrates that active muscle guarding, and not capsular contracture, may be a major contributing factor to movement restriction in some patients who exhibit the classical clinical features of idiopathic frozen shoulder. These findings highlight the need to reconsider our understanding of the pathoanatomy of frozen shoulder.

Note:

Robert Schleip conducted a similar observational study about 20 years ago, which he described in his article:

We did a small ‘experiment’ at a surgery room in Adelaide on three patients undergoing orthopaedic knee surgery. I was given a consent to do some passive joint range of motion testing with the 3 patients before and during anaesthesia. With the patient in a supine position I elevated the arms superiorly above the head and noticed the freedom of movement in this direction. With one of the patients, the elbow dropped all the way to the table above the head before the anaesthesia, and this was no different after he lost consciousness. However, with the other 2 patients I could not elevate their elbows all the way in their normal state, i.e. their elbows kept hanging somewhere in the air above the head. Five minutes later, when they had lost consciousness I again elevated their arms above the head and to my surprise, their elbows dropped all the way down to the table – no restrictions whatsoever, they just dropped! Additionally, I dorsiflexed the feet of all 3 patients. Here I could not detect any increased joint mobility during anaesthesia. (I used my subjective comparison only, without any measuring devices).

Comment by Joe Muscolino:

That muscle guarding / muscle tightness / muscle hypertonicity / overly facilitated musculature should be able to restrict joint range of motion, including in patients/clients with frozen shoulder should suddenly become a relevant finding is quite interesting to me.

I learned 35 years ago that frozen shoulder would usually have two stages. Stage 1, called Neurogenic Frozen Shoulder, would be due to muscle hypertonicity (caused, as its name implies by the nervous system facilitating / tightening musculature). Then because the joint had not moved for some time, Stage 2 called Adhesive Capsulitis, would then be caused by the accumulation of fascial adhesions (as the “adhesive” implies). Muscle guarding for any joint that the nervous system perceives as fragile / vulnerable / injured is a well-recognized and well understood concept. Fascial adhesions occurring in any tissue that does not have movement is also a well-recognized and well understood concept (please see Gil Hedley’s Fuzz Speech video for a better appreciation of this). I am very happy that a new research study bears out these concepts, but slightly disappointed that it requires an evidence-based research study for us to apply fundamental principles of neuromyofascial tissue mechanics and pathomechanics to frozen shoulder.