Adhesive capsulitis or frozen shoulder (ข้อ ไหล่ ติด which is the term in Thai) has always been described as a self-limiting disease. However, there are no studies of its true natural history, as some treatment is carried out in all published articles. It is known that most patients have satisfactory shoulder function after two years of illness, as reported by some older scientific studies.
However, this does not mean that all patients show spontaneous improvement, nor is it indicated to what degree this function is satisfactory, especially according to the demand of each age group.
Some studies show that 30% of patients cannot perform a more intense function after an extended follow-up, such as placing an object on a shelf or carrying a 10kg object with the affected arm. Other studies also show that up to 50% of patients followed for a long time (4 to 7 years) have some residual limitation of movement or mild pain.
What Conditions Can Cause Shoulder Movement Limitation?
It is important to remember that adhesive capsulitis is not the only cause of limited shoulder movement. Several other diseases can cause shoulder stiffness, such as:
- Shoulder arthrosis: pain usually progresses slowly over the years;
- Osteonecrosis is more common after a proximal humerus fracture or in patients with diseases such as lupus, sickle cell anemia, or in patients with very high triglycerides. It also occurs in drinkers;
- Stiffness after surgeries: Shoulder surgeries can cause stiffness for several reasons. It is a different limitation as it is not always self-limiting like adhesive capsulitis.
- Calcareous tendinitis: this type of tendonitis can generate a clinical picture that is very similar to adhesive capsulitis. Straightforward exams such as radiography can make this difference.
How Is Adhesive Capsulitis Or Frozen Shoulder Diagnosed?
Diagnosis is made late in many cases. It is common for the patient to be diagnosed with bursitis, tendonitis, or impingement syndrome, but in fact to be in an early stage of adhesive capsulitis, as the pain symptom is similar to these diseases. A physical examination is essential for an early diagnosis, which can already demonstrate a loss of movement and detailed clinical history, evaluating the main risk factors.
Imaging tests such as radiography (xr) or ultrasonography (usg) will not demonstrate changes in adhesive capsulitis but may be helpful to differentiate from other causes of stiffness. There is no need for further tests in the presence of a characteristic clinical picture, and it is possible to rule out other causes. In doubtful cases or where other diseases are suspected, magnetic resonance imaging may be indicated.