Although the reasons for onset of Frozen Shoulder remain unclear to the medical profession, the physiological process and symptoms experienced are quite predictable.
Most patients present with a general stiffness, restricted movement and some associated pain in the shoulder that radiates down the upper arm. In some cases the pain is slight and in others extreme.
Ultrasounds and MRIs can detect many subtle abnormalities of joints and surrounding muscle and tissue but Frozen Shoulder is largely diagnosed by the physician based on movement dysfunction and associated pain, especially when elongated timeframes are involved e.g. 6 months plus.
It might sound a bit hit and miss but Frozen Shoulder is quite common – in fact 2% of the population suffer it with the vast majority of patients in their 50s. If you have diabetic issues then the chances of it developing are even greater.
And ‘Developing’ is the only way to describe it. Frozen Shoulder mainly occurs from no obvious associated injury to the shoulder. In fact it can just develop for no apparent reason, though it will often accompany a recent traumatic incident – though again not necessarily to the shoulder. A patient presented recently who had had a car accident, suffering whiplash and three weeks later developed a frozen shoulder.
What happens is that the body ‘believes’ the main shoulder joint is damaged and therefore triggers an inflammatory response in order to heal it. This involves streams of white blood cells, platelets and fibroplasts being sent to the joint lining and surrounding joint capsule and ligaments which causes inflammation and subsequent shrinkage which in turn restricts movement.
Left: Normal capsule allows generous movement Right: Frozen capsule shrinkage restricts movement
This process is like a ‘domino effect’, once started it naturally continues with no known way of stopping it – even though there is no original injury that triggered it.
It is as if the immune system makes an error of judgement. In fact it is a natural hormonal change that instigates this ‘Inflammatory Cascade’ in the first place, which is why it affects women in their early 50s and men in their late 50s who are experiencing natural hormonal life changes at this time.
Eventually, after many months (usually around 5-7 months) the ‘dominoes’ run out and the inflammatory cascade stops, at which point Myofibroplasts are then sent in to smooth out the scar tissue. This is exactly what happens with external injuries where the initial ugly scar tissue will soften and decrease until it eventually all but disappears.
Pain starts to decrease and mobility return, but this is often a very slow process taking up to two years (and sometimes more) to complete and cannot be hurried along.
The most common treatment that can be effective during this ‘post freeze’ time is a cortisone injection into the glenohumeral (shoulder) joint which reduces the inflammation making it less painful and debilitating to everyday activities for around 3-4 weeks. The injection can be repeated if needed.
It is a popular treatment that has much success but doesn’t always have optimum effect and in some cases can be relatively ineffective.
There are other methods for severe cases including arthroscopic capsular release, which is a key-hole, day-surgery procedure.
Physiotherapy may exacerbate the pain in the first few months following the onset of symptoms in the ‘freezing’ phase or the inflammatory phase. But in the ‘thawing’ phase when the inflammation has settled, then physiotherapy and stretch exercises will help accelerate recovery in range of motion.
Due to the restrictions on movement inflicted by the Frozen Shoulder, all the other muscles surrounding the shoulder area will weaken and ligaments shrink, so a gradual stretching and re-building of muscle tone will be required over at least 6 months, sometimes longer.
Your physiotherapist is best to advise on exercise and stretching regimes, while taking care not to impinge the recovering joint.
Author: This is a shortened version of an in-depth article by Mark Haber, specialist orthopaedic surgeon, M.B. B.S. F.R.A.C.S. (Ortho). All illustrations copyright Mark Haber. See full length article here.
Mark Haber conducts consultations at Warringah Medical Centre, Dale Street, Brookvale on referral from your GP.