Skip to content

Unraveling the Mystery of Frozen Shoulder: Causes and Risk Factors

Frozen shoulder, medically known as adhesive capsulitis, is a condition that can significantly limit shoulder movement and cause persistent pain. Understanding why it occurs and identifying who is most susceptible to this condition is crucial for effective prevention and management.

What is Frozen Shoulder?

Frozen shoulder is a debilitating condition characterised by stiffness, pain, and a limited range of motion in the shoulder joint. The shoulder joint is known as a synovial joint, meaning it has synovial fluid enclosed by a capsule of connective tissue. The fluid allows for an extremely large level of smooth movement.

The shoulder is one of the most mobile joints in the body. The fluid is there to keep the connective tissue of the capsule healthy, as well as to provide lubrication. In frozen shoulder, this fluid becomes more sticky, hence the term “adhesive capsulitis” and this, in turn, causes the capsule to become thickened and tight, leading to reduced joint mobility and pain.

Causes of Frozen Shoulder

So, what causes this condition in the first place? The precise causes remain elusive, but several factors contribute to its development. The primary factors include:

  1. Inflammation and Immune Response:
    Inflammation plays a key role in the development of frozen shoulder. The body’s immune response triggers the release of inflammatory chemicals, leading to the thickening and tightening of the shoulder capsule. This inflammatory process can result from various factors, including injury, surgery, or other underlying conditions. Technically this condition isn’t an injury, it is an auto immune condition where the body starts to attack itself and this is why steroid injections can be useful, if they are administered before the joint fully seizes up.
  2. Age and Gender:
    Frozen shoulder is more common in people aged between 40 and 60 and is often seen in women more than men. Hormonal changes or differences in collagen composition between genders, may contribute to this difference, though this has yet to be fully proven.
  3. Diabetes Connection:
    Individuals with diabetes are at an increased risk of developing this condition. The exact relationship between diabetes and frozen shoulder is not fully understood, but it is believed that elevated blood sugar levels may contribute to inflammation and collagen changes in the shoulder joint.
  4. Immobilisation:
    Prolonged immobilisation of the shoulder, such as after surgery or after an injury, can contribute to the development of frozen shoulder. Lack of movement may lead to the formation of adhesions within the joint capsule, restricting its flexibility.
  5. Injury:
    It is not uncommon for someone to go on to develop Frozen shoulder after an injury. The person concerned usually approaches us with an injury that won’t go away and is getting worse showing a very stiff shoulder with restricted movement that is getting worse. They have often had a legitimate injury, and it is possible that the inflammation process, which started after the injury, may have got out of control leading, to the Frozen condition.
  6. Systemic Diseases:
    Certain systemic conditions, such as cardiovascular disease, thyroid disorders, and autoimmune diseases, have been linked to an increased risk of this condition. The interplay between these diseases and the body’s inflammatory response may contribute to the development of the condition.

Risk factors for Frozen Shoulder?

While frozen shoulder can affect anyone, certain people may be more predisposed to developing this condition. The following groups are considered higher-risk:

  1. Middle-Aged Individuals:
    As mentioned before, Frozen Shoulder most commonly occurs in individuals between the ages of 40 and 60. There is a theory that the aging process may contribute to changes in joint structures and the body’s inflammatory response, making this age group more susceptible. It is important to ensure you stay fit and strong in middle age, by using weights and physical movement to keep the joints strong, healthy and in a good bio-mechanical position.
  2. Women:
    Again, studies have shown that being a woman incurs a higher risk factor than being a man. Given the age at which this condition tends to appear, it is a logical conclusion that the cause of this is the menopause or peri-menopause. However, to date there is no evidence of this, though research continues in this area.
  3. Diabetic Patients:
    People with diabetes have a significantly higher risk of developing frozen shoulder. The prevalence of frozen shoulder in diabetic individuals is estimated to be two to four times higher than in the general population. Tight glycemic control and early intervention may help mitigate this risk and it is hypothesised that the high blood sugars may affect the immune system, leading to this condition .
  4. Those with Prolonged Immobilisation:
    If you have recently had surgery and are in one of the other higher risk groups, it may not be a slow recovery to the surgery that is slowing you down. It is possible that the lack of movement over the post surgical period, along with other risk factors, have combined to create a Frozen Shoulder. This slows your recovery which can be hugely frustrating. Once you have the go ahead from you surgeon it is important to get the joint moving again, slowly building up both the movement and the strength of the shoulder.
  5. Patients with Systemic Diseases:
    Those with underlying systemic diseases and autoimmune conditions such as Arthritis, can have more issues with a frozen shoulder. It is thought the higher levels of inflammation circulating in these conditions increases the risk of getting this shoulder problem. It is important to ensure inflammation is under control and joint health is protected with targeted and appropriate strength work to minimise these risks.

If you suspect a Frozen Shoulder it is important to get your shoulder joint fully assessed as many shoulder conditions can mimic a Frozen shoulder. The only true way to know is to have an ultrasound or MRI scan but the good news is that most shoulder conditions, including Frozen Shoulder can improve with targeted strength and muscle loosening techniques. To understand how we approach Frozen Shoulder, take a look here.

For more information on Frozen Shoulder and the treatments available, visit the NHS website.