Frozen Shoulder (Adhesive Capsulitis)

Overview

Adhesive capsulitis, often known as frozen shoulder, is an inflammatory disorder characterized by stiffness, discomfort, and severe loss of passive range of motion in the shoulder. Long-term impairment has been recorded in individuals at ten to twenty percent, with symptoms persisting at thirty to sixty percent.

This inflammatory disorder develops fibrosis of the glenohumeral joint capsule and is characterized by gradually growing stiffness and substantial range of motion limitation (typically external rotation). Patients, on the other hand, may have abrupt onset of symptoms and a lengthy recovery period. In most situations, recuperation is satisfactory, even if it might take up to two to three years.

Frozen Shoulder definition

Adhesive capsulitis is defined by the American Academy of Orthopedic Surgeons as "a disorder of various severity characterized by the progressive development of global restriction of active and passive shoulder mobility in the absence of radiographic abnormalities other than osteopenia."

The majority of patients exhibit considerable loss of passive range of motion, which is critical for diagnosis.

When you do not undergo exercise treatment after tendinitis or an accident, and you wear a sling for more than a few days without periodic stretching, you increase your chances of developing a frozen shoulder. Frozen shoulder affects around 10% of persons with rotator cuff problems. A frozen shoulder can occur as a result of forced immobility caused by a stroke, heart condition, or surgery. Thyroid diseases and Parkinson's disease are two more factors that increase the likelihood of a frozen shoulder.

Epidemiology

In the general population, the prevalence of adhesive capsulitis is between two and five percent. The average age of onset is 55 years old. Females have a somewhat higher prevalence (1.4:1). Typically, the afflicted hand is the non-dominant hand. Interestingly, various autoimmune comorbid diseases, including thyroid disorders and diabetes mellitus, have been proven to predispose people to this syndrome. Furthermore, depending on the duration of their diabetes, people with diabetes often have poorer treatment results.

Etiology 

Primary capsulitis and secondary capsulitis are the two types of adhesive capsulitis. The main condition has an insidious beginning, is idiopathic, and is frequently linked with other disorders such as diabetes, thyroid disease, medications, hypertriglyceridemia, or cervical spondylosis.

Trauma or injuries to the shoulder are common causes of subsequent illness. Rotator cuff tears, fractures, surgery, or immobilization are all common ailments.

Pathophysiology

Adhesive capsulitis' precise pathogenesis is uncertain. According to the most widely recognized theory, inflammation begins in the joint capsule and synovial fluid. The inflammation is followed by reactive fibrosis and adhesions of the joint's synovial lining. Pain is caused by the initial inflammation of the capsule, and capsular fibrosis and adhesions cause a reduction in range of motion.

Frozen shoulder is often defined as fibrotic, inflammatory contracture of the rotator cuff, capsule, and ligaments. However, the evolution of AC is still not entirely understood. Based on arthroscopic studies, the most known pathophysiology is cytokine-mediated synovial inflammation with fibroblastic growth. Adhesions surrounding the rotator interval induced by increased collagen, as well as nodular band development, were also discovered.

The coracohumeral ligament, which forms the roof of the rotator cuff interval, is frequently the first component to be impacted. Contraction of the coracohumeral ligament restricts external rotation of the arm, which is often impacted initially in early AC. In later phases, the glenohumeral joint capsule thickens and contracts, significantly reducing range of motion in both directions.

Symptoms of Adhesive capsulitis 

Early AC patients typically appear with a rapid onset of unilateral anterior shoulder discomfort. The usual symptoms include passive and active range of motion restrictions, affecting external rotation first and then abduction of the shoulder later. In general, depending on the stage and severity of the ailment, it is self-limiting, interfering with everyday routines, jobs, and leisure activities.

Limited reaching is one of the functional deficits produced by frozen shoulder, notably when overhead (e.g., hanging clothing) or to-the-side (e.g., fastening one's seat belt) tasks. Patients often have limited shoulder rotations, which makes personal hygiene, clothes, and hair brushing problematic. Another typical complication of frozen shoulder is neck discomfort, which is caused by overuse of the cervical muscles to compensate for the lack of shoulder mobility.

Although discomfort and stiffness make it difficult for patients to comply with a full set of physical examinations, they are necessary for a frozen shoulder diagnosis. Two physical exams, including tests of combined mobility, such as feeling the scapula from behind the neck and behind the back, are usually used to diagnose AC.

The most pathognomonic aspect of AC, however, is a lack of passive ROM. In practice, an evaluation of active motion can be avoided in situations of considerable limitation of passive ROM. Nonetheless, because an undetected limitation of shoulder mobility may exist in the early stage, AC should be revisited in patients who present with a progressive reduction of range of motion at follow-ups.

Patients with frozen shoulder typically have considerable restrictions in both active and passive range of motion, notably in external rotation and abduction movement. Restricted mobility in all directions not only signals the existence of a frozen shoulder, but it may also be a "red flag" indicating an underlying malignancy or fracture.

Disease progression is described in 3 clinical phases:

• The agonizing stage. The development of widespread and debilitating shoulder discomfort begins at night and escalates to pain during rest. Linked to increased stiffness. It might persist between two and nine months.
• This is the frozen or sticky phase. This stage is distinguished by growing restriction in ROM in all shoulder planes, but with the discomfort gradually diminishing. It might last anywhere from four to twelve months.
• The phase of melting or retreat. The period of recuperation in which the range of motion gradually returns. It takes 12 to 24 months to regain full range of motion (ROM).

Diagnosis

Patients will frequently report a reduced glenohumeral range of motion and concomitant discomfort with testing during a physical exam. A comprehensive and thorough physical exam is sometimes hampered by pain. When compared to the unaffected side, there is usually a considerable loss in the active and passive range of motion in two or more planes of motion.

External rotation, abduction, internal rotation, and forward flexion are the most common ways that range of motion is decreased. The Neer and Hawkins tests for impingement and the Speed's test for biceps tendinopathy are both positive when employing specific shoulder testing. The diagnosis is clinical, based on the above-mentioned history and physical exam findings.

For diagnosis, no laboratory testing is recommended. Test as needed if there is a suspicion of underlying systemic illness. Imaging is not advised. Adhesive capsulitis is generally diagnosed clinically. Imaging, such as a shoulder X-ray, may be beneficial if there is a worry about an alternate diagnosis, such as checking for a fracture.

If a clinician is unsure about the etiology of shoulder discomfort based on the history and exam, the injection test might be used. Anesthetic is injected into the subacromial region, typically 5 ml of 1% lidocaine. The ROM restrictions and pain in patients with adhesive capsulitis will persist after the injection. Patients with subacromial pathology (rotator cuff tendinopathy or subacromial bursitis) will have pain relief and increased range of motion.

The "lidocaine test" is a subacromial injection test that can be used to rule out subacromial conditions in unclear clinical settings. Passive movement limitation continues in AC patients following injection of local anesthetics into the subacromial region. Patients with subacromial impingement syndrome (e.g., rotator cuff or bursa pathology) typically experience increased passive range of motion after injection. The injection is simple to carry out with ultrasound assistance.

Management

Adhesive capsulitis is often a self-limiting condition with a high incidence of spontaneous healing between 18 to 30 months. The treatment focuses on symptom alleviation and increasing range of motion. There have been few studies to guide treatment management. Some feasible therapy options are as follows:

• NSAIDs: During the initial phase NSAIDs can be used to aid with pain control.
• Physical therapy: Although there is limited data to support the effectiveness of therapy, patients in the recovery period may benefit from the modest range of motion exercises, stretching, and graded resistance training. These have been shown to alleviate pain while also improving function. Patients and providers should avoid vigorous rehab because it can worsen symptoms.
• Oral corticosteroids: These provide short-term pain alleviation in exchange for increased ROM and function. The advantages rarely persist more than a few weeks, and the doctor should be aware of the negative effects of oral steroid treatment.
• Intra-articular steroid injection: Injections have been shown to improve function, alleviate pain, and increase range of motion. Steroid injections, like oral steroids, have a limited duration of action since doctors must be aware of negative effects. Patients who receive injections early in the course of their disease are more likely to benefit. To provide symptomatic alleviation, several injections can be administered.
• Hydrosilation: The joint is injected with saline and steroid to widen the glenohumeral capsule in this therapy technique. In the short term, this has been demonstrated to alleviate discomfort and enhance ROM and function. When comparing hydrodilatation to intra-articular steroid injection, current evidence suggests no substantial difference in outcomes.
• Manipulation under anesthesia: thi is reserved for more refractory cases that do not respond to the modalities mentioned above. There is an increased risk of homers fractures.
• Surgical capsular release: This is only used in refractory instances. If symptoms do not improve after 10 to 12 months of conservative treatment, a referral to an orthopedic surgeon is usually recommended.

Indications for Surgery

• The patient fails a trial of prednisone or NSAIDs.
• No response to glenohumeral or subacromial injections
• No response respond to physical therapy

Contraindications for Surgery

• The patient has had an inadequate course of steroids or NSAIDs.
• The patient has not had any attempt at conservative therapy.
• There is an acute infection.
• The patient has a concomitant malignancy in the shoulder.
• The patient has a neurological deficit or nerve complaint originating from the cervical spine.

Early Frozen Shoulder

Subacromial pathology is frequently used to treat an early stage of AC. The above-mentioned early "freezing" AC can be termed inflammatory. In the later stages, however, where ROM restriction is predominate and inflammation-related discomfort is less pronounced, the inflammation becomes less pronounced. In light of the aforementioned distinctions, we must evaluate the illness stage when developing a therapeutic strategy.

The precise identification of the clinical stage may aid in the more specific tailoring of treatment approaches. The goal of treatment during the "freezing" period should be pain control, inflammation decrease, and patient education. Acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) may be used as an initial treatment for adhesive capsulitis.

Although there is limited evidence that NSAIDs can be used to treat frozen shoulder, they can be recommended to provide short-term relief from night pain if it is present. In severe cases, however, opioid analgesics may be required. Physical therapy is essential for pain management and the restoration of normal shoulder movement.

These include soft tissue mobilization and gentle stretching-based manual therapy. In terms of physical modalities, no single agent has proven to be superior. Therapeutic ultrasonography, cryotherapy, or a transcutaneous electrical nerve stimulation (TENS) unit may be prescribed to the patient. Therapeutic exercise should be the focus of physical therapy management.

Although not all patients can tolerate mobilizing exercise due to acute discomfort in the early stages of frozen shoulder, a supervised therapy exercise should be performed to slow down ROM restriction. In addition, patients should be offered a home exercise routine on a daily basis. In patients with moderate to severe pain who have not responded to non-operative therapies, an intra-articular corticosteroid injection should be considered.

To ensure proper needle placement, the injection should be conducted under ultrasonographic or fluoroscopic supervision. Last but not least, after the injection, rehabilitation exercise should be given.

Developed Frozen Shoulder

After the inflammatory-related discomfort subsides, the condition develops to "frozen" and then "thawing" phases. In the advanced stages of treatment, the goal should be to recover ROM limitation. To restore joint mobility, physical therapists should perform more extensive mobilization exercises (as compared, for example, to subacromial disorders).

Patients who do not respond favorably to non-surgical treatments should be considered for more intrusive therapy. Blockage of the suprascapular nerve or the interscalene brachial plexus may result in even more improvement. More aggressive treatments, such as capsular hydrodilatation (stretching the joint capsule with saline injectate pressure), manipulation under anesthesia (tearing of the contracted capsule), and arthroscopic capsular release (particularly in the rotator interval), can be considered in patients with refractory cases of frozen shoulder who do not improve after 6 months of non-operative treatment.

Differential Diagnosis

Adhesive capsulitis, especially in its early (freezing) stage, can be difficult to diagnose since it might mirror subacromial disease and rotator cuff tendinopathy. The above-mentioned manifestations may cause a delay in the diagnosis of AC in its early stages. Patients with shoulder impingement and rotator cuff disease report mostly discomfort with less evident passive range of motion.

Several factors, however, aid in distinguishing frozen shoulder from other shoulder diseases. In terms of reasons other than AC, patients frequently mention lifting a heavy object or doing repetitive overhead movements. Frozen shoulder patients, on the other hand, frequently describe a sudden onset with no apparent reason or a history of excessive activity. In the case of a history of cancer, further care should be taken.

Common conditions that may mimic early adhesive capsulitis:

• Subacromial pathology and rotator cuff tendinopathy
• Post-stroke shoulder subluxation
• Referred pain (cervical spine or malignancy, e.g., Pancoast tumor)

As severe restriction of motion becomes more prominent later in the course of frozen shoulder, the diagnosis becomes clearer. However, glenohumeral joint arthritis should be evaluated as well, which may be ruled out with free shoulder movement after a lidocaine injection to the glenohumeral joint.

The age of onset provides extra information to help diagnose AC. Patients under the age of 40 are unlikely to acquire frozen shoulder, whereas those over the age of 70 are more likely to develop rotator cuff tears or glenohumeral osteoarthritis instead of AC.

Staging

A natural course of AC is characterized by a gradual reduction of passive shoulder mobility. The development is generally described as occurring in three overlapping stages (4 stages classification can also be found in the literature). However, from a practical standpoint, we advocated for a two-stage scheme: early and mature frozen shoulder.

1. Freezing (2 to 9 months): Early
2. Frozen (4 to 12 months): Developed
3. Thawing (12 to 42 months): Developed

Freezing

An initial, painful phase with predominant pain that is worse at night, with gradually increased glenohumeral joint ROM restriction.

Frozen

The second phase with stiffness and persisted glenohumeral joint motion limitation, but with less pain than that at the “Freezing” stage. 

Thawing

The third (recovery) phase with the gradual return of range of motion.

Complications

• Residual shoulder pain and/or stiffness
• Humeral fracture
• Rupture of the biceps and subscapularis tendons

Conclusion 

Given the diagnostic accuracy of frozen shoulder, researchers should continue to look into the pathomechanism of AC. Some recent studies have reported the use of contrast-enhanced ultrasonography in the diagnosis of frozen shoulder. Microbubble-based ultrasound contrast agents (raising liquid material echogenicity) have already been used in musculoskeletal medicine for certain purposes. In the future, the use of contrast agents in the diagnosis of frozen shoulder appears to be promising, especially in ambiguous cases.

A team of healthcare experts, including an orthopedic surgeon, a rehabilitation specialist, a nurse practitioner, a pharmacist, and a pain consultant, usually manages frozen shoulder. Furthermore, the pharmacist must educate the patient about pain management.

Furthermore, individuals receiving corticosteroids will need to be watched for serious drug side effects. Enrolling in a physical therapy program is the key to rehabilitation for the majority of patients. Some patients may benefit from home physical therapy under supervision. Finally, patients must be informed that while healing will occur, it will be gradual and may take several years.

Most people heal from frozen shoulder, but it may take 1-3 years. Physical treatment and arm exercises, in most situations, will gradually reduce symptoms. So far, studies do not indicate that diabetics have worse outcomes than non-diabetics. Around 10% of patients will experience persistent shoulder discomfort and impairment. After arthroscopic surgery, symptoms gradually improve with sluggish recovery. Postoperative physical therapy, on the other hand, is required following surgery to ensure recovery.