Adhesive capsulitis of the shoulder

Adhesive capsulitis, also known as frozen shoulder, is a condition associated with shoulder pain and stiffness.<ref name="Ram2019">Template:Cite journal</ref> It is a common shoulder ailment that is marked by pain and a loss of range of motion, particularly in external rotation.<ref name="Chiang_2106">Template:Cite journal</ref> There is a loss of the ability to move the shoulder, both voluntarily and by others, in multiple directions.<ref name="Ram2019" /><ref name="Stat2019" /> The shoulder itself, however, does not generally hurt significantly when touched.<ref name="Ram2019" /> Muscle loss around the shoulder may also occur.<ref name="Ram2019" /> Onset is gradual over weeks to months.<ref name="Stat2019">Template:Cite book</ref> Complications can include fracture of the humerus or biceps tendon rupture.<ref name="Stat2019" />

The cause in most cases is unknown.<ref name=Ram2019/> The condition can also occur after injury or surgery to the shoulder.<ref name=Stat2019/> Risk factors include diabetes and thyroid disease.<ref name=Ram2019/><ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

The underlying mechanism involves inflammation and scarring.<ref name="Stat2019" /><ref name="Red2019">Template:Cite journal</ref> The diagnosis is generally based on a person's symptoms and a physical exam.<ref name="Ram2019" /> The diagnosis may be supported by an MRI.<ref name="Ram2019" /> Adhesive capsulitis has been linked to diabetes and hypothyroidism, according to research. Adhesive capsulitis was five times more common in diabetic patients than in the control group, according to a meta-analysis published in 2016.<ref name="Chiang_2106" />

The condition often resolves itself over time without intervention but this may take several years.<ref name=Ram2019/> While a number of treatments, such as nonsteroidal anti-inflammatory drugs, physical therapy, steroids, and injecting the shoulder at high pressure, may be tried, it is unclear what is best.<ref name=Ram2019/> Surgery may be suggested for those who do not get better after a few months.<ref name=Ram2019/> The prevalence of adhesive capsulitis is estimated at 2% to 5% of the general population.<ref name=Ram2019/> It is more common in people 40–60 years of age and in women.<ref name=Ram2019/>

Signs and symptoms

Symptoms include shoulder pain and limited range of motion although these symptoms are common in many shoulder conditions. An important symptom of adhesive capsulitis is the severity of stiffness that often makes it nearly impossible to carry out simple arm movements. Pain due to frozen shoulder is usually dull or aching and may be worse at night and with any motion.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

The symptoms of primary frozen shoulder have been described as having three<ref name="titleYour Orthopaedic Connection: Frozen Shoulder">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> or four stages.<ref name = "Kelley_2013">Template:Cite journal</ref> Sometimes a prodromal stage is described that can be present up to three months prior to the shoulder freezing. During this stage people describe sharp pain at end ranges of motion, achy pain at rest, and sleep disturbances.

• Stage one: The "freezing" or painful stage, which may last from six weeks to nine months, and in which the patient has a slow onset of pain. As the pain worsens, the shoulder loses motion.
• Stage two: The "frozen" or adhesive stage is marked by a slow improvement in pain but the stiffness remains. This stage generally lasts from four to twelve<ref name="Comparison of Treatments for Frozen">Template:Cite journal</ref> months.
• Stage three: The "thawing" or recovery, when shoulder motion slowly returns toward normal. This generally lasts from 5 to 26 months.<ref name="pthealth.ca">{{#invoke:citation/CS1|citation

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Physical exam findings include restricted range of motion in all planes of movement in both active and passive range of motion.<ref>Template:Cite journal</ref> This contrasts with conditions such as shoulder impingement syndrome or rotator cuff tendinitis in which the active range of motion is restricted but passive range of motion is normal. Some exam maneuvers of the shoulder may be impossible due to pain.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Causes

The causes of adhesive capsulitis are incompletely understood; however, there are several factors associated with higher risk. Risk factors for secondary adhesive capsulitis include injury or surgery leading to prolonged immobility. Risk factors for primary, or idiopathic adhesive capsulitis include many systemic diseases, such as diabetes mellitus, stroke, lung disease, connective tissue diseases, thyroid disease, heart disease, autoimmune disease, and Dupuytren's contracture.<ref name="Le_2017">Template:Cite journal</ref> Both type 1 diabetes and type 2 diabetes are risk factors for the condition.<ref name="Le_2017" />

Primary

Primary adhesive capsulitis, also known as idiopathic adhesive capsulitis, occurs with no known trigger. It is more likely to develop in the non-dominant arm.Template:Citation needed

Secondary

Adhesive capsulitis is called secondary when it develops after an injury or surgery to the shoulder.Template:Citation needed

Pathophysiology

The underlying pathophysiology is incompletely understood, but is generally accepted to have both inflammatory and fibrotic components. The hardening of the shoulder joint capsule is central to the disease process. This is the result of scar tissue (adhesions) around the joint capsule.<ref name="Le_2017" /> There also may be a reduction in synovial fluid, which normally helps the shoulder joint, a ball and socket joint, move by lubricating the gap between the humerus and the socket in the shoulder blade. In the painful stage (stage I), there is evidence of inflammatory cytokines in the joint fluid.<ref name="Le_2017" />

The main limiting factor in external rotation is due to the thickening of the coracohumeral ligament, which forms the roof of the rotator cuff and is a primary symptom of adhesive capsulitis. In addition, the coracohumeral ligament attributes to the limitation of internal rotation considering its connection to the supraspinatus and subscapular tendons. As the phases of adhesive capsulitis progress, the glenohumeral (GH) capsule begins to thicken and as a result the contraction of the capsule itself becomes the main reason as to why range of motion will be restricted in all planes of motion.<ref>Template:Cite journal</ref>

Diagnosis

Adhesive capsulitis can be diagnosed by history and physical exam. It is often a diagnosis of exclusion, as other causes of shoulder pain and stiffness must first be ruled out. On physical exam, adhesive capsulitis can be diagnosed if limits of the active range of motion are the same or similar to the limits to the passive range of motion. The movement that is most severely inhibited is external rotation of the shoulder.Template:Citation needed

Imaging studies are not required for diagnosis, but may be used to rule out other causes of pain. Radiographs will often be normal, but imaging features of adhesive capsulitis can be seen on ultrasound or non-contrast MRI. Ultrasound and MRI can help in diagnosis by assessing the coracohumeral ligament, with a width of greater than 3 mm being 60% sensitive and 95% specific for the diagnosis. Shoulders with adhesive capsulitis also characteristically fibrose and thicken at the axillary pouch and "rotator interval", best seen as a dark signal on T1 sequences with edema and inflammation on T2 sequences.<ref>Template:Cite journal</ref> A finding on ultrasound associated with adhesive capsulitis is hypoechoic material surrounding the long head of the biceps tendon at the rotator interval, reflecting fibrosis. In the painful stage, such hypoechoic material may demonstrate increased vascularity with Doppler ultrasound.<ref>Arend CF. Ultrasound of the Shoulder. Master Medical Books, 2013. Chapter on ultrasound findings of adhesive capsulitis available at ShoulderUS.com</ref>

Grey-scale ultrasound can play a key role in timely diagnosis of adhesive capsulitis due to its high sensitivity and specificity. It is also widely available, convenient, and cost efficient. Thickening in the coracohumeral ligament, inferior capsule/ axillary recess capsule, and rotator interval abnormality, as well as restriction in range of motion in the shoulder can be detected using ultrasound. The range of motion is prohibited due to scapulohumeral rhythm changes occurring in the shoulder joint. The altered scapular kinematics can restrict anterior and posterior tilting, downward rotation and depression as well as external rotation. All of these restrictions lead the scapula to be excessively upwardly rotated. The restriction of the scapular posterior tilt is due to tightness in the lower serratus anterior, anterior capsule and the pectoralis minor. Downward rotation and depression are restricted due to the tightness of the rhomboids, upper trapezius and the superior capsule.<ref>Template:Cite journal</ref> Respective sensitivity values were 64.4, 82.1, 82.6, and 94.3, and respective specificity levels were 88.9, 95.7, 93.9, and 90.9.<ref>Template:Cite journal</ref>

Treatment

There is consensus that non-surgical management is the initial treatment of choice for frozen shoulder.<ref name="Millar2022">Template:Cite journal</ref> There is no strong evidence to favor any particular approach; in fact, some reviews suggest that multi-modal approaches combining several treatments are better.<ref name="Mertens"/> Research in the UK showed that there were three typical approaches to treatment (physiotherapy, manipulation of the shoulder under general anaesthesia, and surgery (arthroscopic capsular release)). All three treatments were deemed effective but they had different benefits and drawbacks, suggesting clinicians and patients should decide together on the most appropriate treatment.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>Template:Cite journal</ref>

The effects of most treatments are primarily short-term, focusing on alleviating symptoms such as shoulder pain and reduced joint movement. Common treatments include exercise, physical therapy, oral analgesics such as paracetamol and nonsteroidal anti-inflammatory drugs, and intra-articular corticosteroid injections. Non-surgical treatment may continue for months, with more complex treatments such as extracorporeal shock wave therapy, movement under analgesia, and hydrodilatation. It is unclear if these treatments lead to a quicker resolution of the disorder, or only manage chronic symptoms. The condition generally resolves itself with or without treatment. If conservative measures have no effect and the condition is long-lasting, or if evidence suggests surgical intervention, there are also several surgical procedures that may alleviate the disorder.<ref name="Millar2022" />

Medication

Medications such as nonsteroidal anti-inflammatory drugs can be used for pain control. Oral steroids may provide short-term benefits in range of movement and pain but have side effects such as hyperglycemia. Corticosteroids may also be used by local injection. In the short and medium term, intra-articular corticosteroid injections appear most effective in pain alleviation and increase in range of motion, although the injection does carry complications.<ref name="Challoumas2020">Template:Cite journal</ref> Unfortunately, the effects of medication are not long-lasting. Oral corticosteroids in particular should not be used consistently to treat adhesive capsulitis, because of the dangers associated with long-term use and the lack of long-term benefit.Template:Citation needed

Exercise and physical therapy

Shoulder stretching and strengthening exercises improve shoulder function and decrease pain. When using intra-articular corticosteroid injections, the effects of exercise on short-term relief were not significant, although individual studies found some benefits.<ref name="Challoumas2020"/> Concerning techniques, posterior glenohumeral mobilization had a large effect; mirror therapy, rotator cuff strengthening, spray & stretch, and end range mobilization had moderate results; continuous passive motion, scapular recognition, scapulothoracic exercises, yijin jing, and lower trapezius strengthening had small effects; and electromagnetic therapy, Kaltenborn mobilization, and instrument assisted soft tissue mobilization had insignificant effects compared to control kinesthetic exercises.<ref name="Mertens">Template:Cite journal</ref> It has been found that performing exercises under supervision is more effective than unsupervised exercise at home.<ref name="Millar2022"/>

Extracorporeal shock wave therapy has been strongly recommended as a way of reducing pain levels and improving range of motion and functioning in people with Stage 2 and 3 adhesive capsulitis of the shoulder. Laser therapy was also found to have these similar effects for people dealing with Stage 2 adhesive capsulitis. Moderate evidence points to improvements in pain management, range of motion and functional status for interventions such as PNF techniques (stretching), continuous passive motion, dynamic scapular stability exercises, and conventional physiotherapy. Low evidence exists for manual muscle release.<ref>Template:Cite journal</ref>

Hydrodilatation or distension arthrography is controversial. However, some studies show that arthrographic distension may play a positive role in reducing pain and improve range of movement and function.<ref>Template:Cite journal</ref>

Manipulation of the shoulder under general anesthesia to break up the adhesions is sometimes used.

Because adhesive capsulitis is a condition that produces stiffness and causes the capsule of the glenohumeral joint to become thickened and progressively contract, it is important to exercise regularly to increase the range of motion and decrease the pain. Physical therapy is recommended to provide a treatment for the condition. The three stages to adhesive capsulitis are freezing, frozen, and thawing. During the freezing stage, there is a significant increase in pain in the night hours. The Frozen stage is where the shoulder loses its range of motion and becomes stiff. Lastly, the thawing stage is where pain becomes minimal, and range of motion is restored. Exercise increases blood flow to the muscles affected which enhances blood flow.

Regular exercise is a crucial part of the healing stages of adhesive capsulitis. Frequency of physical therapy visits can range. It has been shown that attending physical therapy three times a week is most common for treating adhesive capsulitis.<ref name=kk>Template:Cite journal</ref> Specific exercises are highlighted to enhance recovery. Another useful tool can be anti-inflammatory medications. These provide temporary relief which aid in exercise exertion. The combination of these techniques allow for the most successful healing process. Combination of manual therapy and exercises while in physical therapy has also shown significant effects in decreasing pain, disability, and increasing range of motion of the affected shoulder.<ref name=kk/>

Types of Exercise

Various types of exercise go into improving function in the shoulder. Specifically, stretches and strengthening exercises are the most beneficial for treating adhesive capsulitis. Rotator cuff stretches are preferred when constructing an exercise treatment plan. Some specific stretches for the rotator cuff include, the wall press, shoulder roll, retraction of the shoulder blade, etc. Eccentric contraction exercises is proven to be more effective with pain since the muscle is being elongated.

The combination of scapulothoracic exercises and glenohumeral exercises allow for a more effective healing process. Scapulothoracic exercises focus on movements of the scapula relative to the thoracic ribcage. Muscle groups such as serratus anterior, trapezius, and rhomboid major/minor need to be strengthened to allow for shoulder function. By stabilizing these muscles there is more alignment which causes a reduction in strain and protects the joints. Glenohumeral exercises are focused around strengthening the rotator cuff muscles. The rotator cuff consists of subscapularis, infraspinatus, teres minor, and supraspinatus.

Benefits of Exercise

Individuals who suffer from adhesive capsulitis have a higher chance of regaining normal function and stability with the use of exercise. Physical therapy is recommended for those with adhesive capsulitis for quicker regain of function. People who do not exercise with this condition heal slower and are not able to achieve the range of motion or mobility they once had.

Exercise with adhesive capsulitis is beneficial to enhance stability of the joints surrounding the shoulder, a reduction of pain, higher functionality in the shoulders, and an increased range of motion.

Surgery

If conservative measures are unsuccessful, surgery can be trialed. Surgery to cut the adhesions (capsular release) may be indicated in prolonged and severe cases; the procedure is usually performed by arthroscopy. Surgical evaluation of other problems with the shoulder, e.g., subacromial bursitis or rotator cuff tear, may be needed. Resistant adhesive capsulitis may respond to open release surgery. This technique allows the surgeon to find and correct the underlying cause of restricted shoulder movement such as contracture of coracohumeral ligament and rotator interval.

The most common surgical technique is arthroscopic capsular release surgery, and it is beneficial to individuals who do not get better with physical therapy treatment. Because this type of surgery is minimally invasive, it allows a faster healing time since it consists of small incisions and a small camera to surgically remove the tissue that is thickened and contracted. This surgery is very detailed which also provides more range of motion to the shoulder post operation.

Another key aspect to surgery is the post-surgical rehabilitation phase. During this phase, physical therapy is utilized to regain range of motion and prevent stiffness. Starting out with rehabilitation there is an emphasis on range of motion exercises such as passive and active assisted which provides mobility to the joints while preventing further stress/damage to the tissues healing. The strengthening phase is where the muscles are put under stress of exercises to build strength and muscle for support of the shoulder. Once the strengthening phase is complete, the individual gets reintroduced gradually to activities of daily living and prior training goals.

Prognosis

Most cases of adhesive capsulitis are self limiting, but may take 1 to 3 years to fully resolve. Pain and stiffness may not completely resolve in 20 to 50 per cent of affected people.<ref name="Le_2017" />

Epidemiology

Adhesive capsulitis newly affects approximately 0.75% to 5.0% percent of people a year.<ref>Template:Cite journal</ref> Rates are higher in people with diabetes (10–46%).<ref name="Minns Lowe 2019 539–556">Template:Cite journal</ref> Following breast surgery, some known complications include loss of shoulder range of motion and reduced functional mobility in the involved arm.<ref>Template:Cite journal</ref> Occurrence is rare in children and people under 40, with the highest prevalence between 40 and 70 years of age.<ref name="Ewald2011">Template:Cite journal</ref> The condition is more common in women than in men (70% of patients are women aged 40–60). People with diabetes, stroke, lung disease, rheumatoid arthritis, or heart disease are at a higher risk for frozen shoulder. Symptoms in people with diabetes may be more protracted than in the non-diabetic population.<ref name="titleQuestions and Answers about Shoulder Problems">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

See also

• Calcific tendinitis
• Milwaukee shoulder syndrome
• Shoulder injury related to vaccine administration

References

U.S. National Library of Medicine. (n.d.). PubMed. National Center for Biotechnology Information. https://pubmed.ncbi.nlm.nih.gov/ Template:Reflist