Frozen Shoulder. Maybe you’ve heard of it. Maybe you’ve treated a patient or client that has had it. It can be a tricky diagnosis for rehabilitation clinicians to treat and manage due to it’s unknown etiology (cause) and symptoms. Frozen Shoulder, or Adhesive Capsulitis, is characterized by painful and limited active and passive range of motion (ROM) > 25% at the glenohumeral joint in at least two directions; most often abduction and external rotation . It requires management and treatment that is much different than other shoulder conditions like rotator cuff pathology or osteoarthritis. Therefore, clinicians must understand the unique signs of adhesive capsulitis or frozen shoulder and how to effectively manage and treat it.
In this article, we will cover the following:
- An overview of adhesive capsulitis or frozen shoulder
- Types of frozen shoulder
- Relevant clinical anatomy
- Signs & symptoms
- Physical assessment and evaluation
In Part 2, we will discuss rehabilitation management and treatment for conservative treatment as well as following surgical interventions (ie. manipulation under anesthesia & arthroscopic scapular release).
What is Adhesive Capsulitis or Frozen Shoulder?
Also known as Frozen Shoulder, Adhesive Capsulitis refers to a condition of the glenohumeral joint involving synovitis and capsular contracture of the shoulder joint . There are 2 types of frozen shoulder: primary and secondary. True primary adhesive capsulitis is classified by and idiopathic onset, while secondary adhesive capsulitis results from some known event or surgical intervention . Breaking it down even further, secondary frozen shoulder can be classified into 3 sub-categories:
- Examples: Diabetes mellitus or other metabolic conditions
- Examples: Parkinson’s disease, CVA/stroke, humerus fractures, CPD, or cervical disc dysfunction
- Examples: Rotator cuff pathology, AC joint arthritis, biceps tendinopathy, calcific tendinopathy
Individuals at higher risk of being diagnoses with frozen shoulder include women, individuals 40-65 years old, and those diagnosed with diabetes . In fact, roughly 2-5% of the general population is diagnosed with frozen shoulder, in comparison to 10-20% of the diabetic population . Additionally, those diagnosed with frozen shoulder on one side have up to a 34% chance of experiencing it on the contralateral (other) side . Aside from these risk factors, trauma, prolonged immobilization, thyroid disease, autoimmune disease, myocardial infarction, and stroke/CVA also increase the risk of contracting frozen shoulder .
Frozen shoulder typically affects the axillary recess, the coracohumeral ligament, and the anteriosuperior joint capsule. Read a brief overview of the anatomy of the shoulder here. Through arthroscopy, these patients tend to have a loss of the axillary fold, tight anterior capsules, and mild to moderate synovitis —though no actual adhesions . Patients diagnosed with adhesive capsulitis have also been observed to have contracture of the rotator interval .
The rotator interval (RI), located in the anterior superior aspect of the shoulder, is a triangular space defined by the tendons of the subscapularis medially and the supraspinatus anteriorly, and the base of the coracoid process . It’s anatomy can be a bit complicated due to the amount of structures located in the area such as: a portion of the coracohumeral ligament (CHL), the superior and and middle GH ligaments, the long head of the biceps tendon, and a portion of the joint capsule. The rotator interval plays a roll in stabilizing the glenohumeral (GH) joint by preventing any excessive inferior or posterior translation of the humeral head. The theory is that the RI maintains negative intra-articular pressure of the GH joint, which resists movements of the humeral head in an inferior direction. It is also believed to prevent extreme shoulder flexion, adduction, external rotation, and extension .
There continues to be disagreement on what the underlying pathology of frozen shoulder actually is. Some posit that it is an inflammatory condition, while others believe it may be a fibrosing condition or an algoneurodystrophic process (such as complex regional pain syndrome/CRPS). Research does suggest that frozen shoulder involves synovial inflammation that is followed by fibrosis of the joint capsule which may also lead to tissue contracture . This results in pain, lack of motion, and ultimately functional decline in patients diagnosed with frozen shoulder.
Signs & Symptoms
Patients diagnosed with frozen shoulder typically report a subtle or insidious onset of symptoms along with a progressive increase in pain and a gradual decrease in range of motion (ROM), both active and passive  . Typical limitations reported by patients include difficulty grooming, dressing, performing overhead tasks, and especially limitations involving shoulder extension and internal rotation (ie. tucking in a shirt tail or reaching a back pocket) . Though symptoms can begin to dissipate after only 6 months, some patients may continue to experience pain and limitations for up to 11 years, with some never experiencing full recovery .
Stages or Phases
According to the literature, progression of frozen shoulder or adhesive capsulitis is marked by 3 overlapping “phases” or stages of the disease :
- Acute or “Freezing” Stage: This stage last approximately 3-9 months. It is marked by a gradual onset of symptoms: pain at rest, sharp pain at end ranges of motion, nocturnal pain which may interrupt sleep.
- “Frozen” or Stiffening Stage: Occurring at around 4 months and lasting until roughly 12 months, this stage includes subsiding of pain and a progressive loss of GH motion due to capsular restrictions. The patient typically experiences pain only at the maximum end range of movements.
- “Thawing” or Resolution Stage: “Thawing” typically begins to occur after approximately 1 year and can last anywhere from 1-3.5 years. The patient will experience a spontaneous and progressive improvement in range of motion and overall functional movement of the shoulder.
As mentioned above, this is a general description of the three phases of adhesive capsulitis. Not every patient will follow this timeline. Some may experience a shorter overall duration of the disease, while others may experience a prolonged period in the “frozen” stage. And it is also important to remember that, while the majority of patients diagnosed with frozen shoulder will recover most or all of their functional movement, some patients may never experience a full recovery .
Diagnosis & Assessment of Frozen Shoulder
Because management of frozen shoulder greatly differs from management of other common shoulder disorders, clinicians must ensure that the patient they are treating actually has adhesive capsulitis and not some other shoulder condition. Some of the conditions to rule out include: osteoarthritis, acute bursitis or tendinitis, pathology of the rotator cuff, Parsonage-Turner Syndrome, a locked posterior GH dislocation, or a humeral fracture . Below are some guidelines and clinical tips to help rule out other pathologies that may be affecting the shoulder rather than adhesive capsulitis.
Patients that present with osteoarthritis (OA) which may be misdiagnosed as frozen shoulder may present with ROM limitations, leading some clinicians to apply the diagnosis of adhesive capsulitis. There are some marked differences between OA and frozen shoulder when it comes to ROM. The first thing to test is PROM vs AROM. Both frozen shoulder and OA can lead to limitations with active movement, however patients with OA will normally have full passive ROM. Also, patients with OA generally experience the greatest ROM limitation in shoulder flexion, while this is the least affected shoulder motion with true adhesive capsulitis .
Acute bursitis presents similarly to frozen shoulder, especially in the early phases. Non-traumatic onset of symptoms with pain in most shoulder motions lead many clinicians to believe they are treating a patient suffering from adhesive capsulitis. Like OA, the main difference between frozen shoulder and bursitis is the amount of PROM available. Patients with bursitis will demonstrate larger PROM than those with adhesive capsulitis .
Many patients suspected of having frozen shoulder demonstrate a significant increase in ROM while under anesthesia. This confirms that many cases of adhesive capsulitis are misdiagnosed and that the loss of ROM may be due to other factors such as muscle guarding, fear of movement, or fear of pain . Read out article on explaining pain to patients and how that may help decrease some of this pain avoidance and fear of movement here.
Coracoid Pain Test
The Coracoid Pain Test is helpful for determining whether a patient’s ROM limitations are due to capsular contracture vs muscle guarding. Research shows it to have a sensitivity of 96% and a specificity of 87-89%, making it a reliable test to rule in/out true adhesive capsulitis .
Here are the steps to complete the test :
- The therapist manually palpates the patient’s AC joint, the anterolateral subacromial area, and the coracoid process.
- Record the patient’s reported level of pain at every palpation, using the Visual Analogue Scale.
- A positive test —indicating true frozen shoulder— is indicated by the pain rating during palpation of the coracoid process is at least 30 mm greater than the ratings of the anterolateral subacromial area and AC joint.
Reasoning for this test is that MRI findings of true frozen shoulder typically show a thickening of the coracohumeral ligament, RI, and the coracoid triangle which become sensitive to pressure or palpation .
In the end, ruling out other conditions which may present similarly to true frozen shoulder typically involves observing the differences between AROM & PROM. With true adhesive capsulitis, patients will experience global ROM limitations, whereas other conditions may only limit AROM.
Examination of Frozen Shoulder
Currently diagnoses of frozen shoulder is based on the patient’s reported history and findings of physical examination of the patient’s shoulder . Range of motion should be assessed in all available planes and motions, taking note of any limitations. Patients with adhesive capsulitis will demonstrate a greater limitation in external rotation (ER) when compared to internal rotation (IR) and abduction. For example, ER may be limited by 20 degrees, while IR and abduction are limited by 10.  Also, any scapular compensation or substitution should be documented as this typically accompanies frozen shoulder .
Manual muscle testing (MMT) should include shoulder external rotation (ER), internal rotation (IR), and abduction. Patients with adhesive capsulitis or frozen shoulder demonstrate weakness in each of these movements relative to their opposite or unaffected side .
Frozen shoulder typically involves the following components :
- Strong component of nocturnal pain
- Pain during unguarded or rapid movement
- Pain or discomfort when lying on affected shoulder
- Pain aggravated by movement
- Movement Limitations
- Patients experience a global loss of both Active and Passive ROM
- Pain present at all end ranges of movement
- Age of Onset
- Typically > 35 years of age
It is also important to assess functional limitations caused by limitations in combined shoulder movements such as flexion and ER.
3 Function-Related Tests for First Stage of Primary Adhesive Capsulitis
This is an adapted version of a simple, 3-test assessment for frozen shoulder described by Yang et al in 2002 for assessing functional limitations in patients with frozen shoulder . Grab a free copy of a handout for these three tests here.
Head-to-Neck (Shoulder Flexion + External Rotation)*
0- The fingers reach the posterior median line of the neck with the shoulder in full abduction and external rotation without wrist extension.
1- The fingers reach the median line of the neck but do not have full abduction and/or external rotation.
2- The fingers reach the median line of the neck but with compensation by adduction in the horizontal plane or by shoulder elevation
3- The fingers touch the neck
4- The fingers do not reach the neck
Hand-to-Scapula (Shoulder Extension + Internal Rotation) **
0- The hand reaches behind the trunk to the opposite scapula or 5cm beneath it in full internal rotation
1- The hand almost reaches the opposite scapula, 6-15 cm beneath it
2- The hand reaches the opposite illiac crest
3- The hand reaches the buttock
4- Subject cannot move the hand behind the trunk
Hand-to-Opposite Scapula (Shoulder Horizontal Adduction)***
0- The hand reaches to the spine of the opposite scapula in full adduction without wrist flexion
1- The hand reaches to the spine of the opposite scapula in full adduction
2- The hand passes the midline of the trunk
3- The hand cannot pass the midline of the trunk
* This test measures an action essential for daily activities, such as using the arm to reach, pull, or hang an object overhead or using the arm to pick up and drink a cup of water.
** This test measures an action essential for daily activities, such as using the arm to pull an object out of a back pocket or tasks related to personal care.
*** This test measures an action important for daily activities, such as using the arm to reach across the body to get a car’s seat belt or using the arm to turn a steering wheel.
Summary (Clinical Bottom Line)
Frozen shoulder or adhesive capsulitis is a debilitating condition that includes a global loss of AROM & PROM. Patients experience pain at end ranges of motion as well as functional limitations due to ROM restrictions. It’s cause is related to capsular restrictions/contracture and synovitis of the GH joint. The axillary recess, the coracohumeral ligament, and the anteriosuperior joint capsule are the structures typically affected. The rotator interval (RI) is also typically affected. The disease is marked by 3 clinically overlapping phases which can last anywhere from 12 months to 3+ years, with most patients experiencing a full functional recovery. Assessment of adhesive capsulitis should include AROM & PROM limitations to rule out other potential diagnoses as well as functional limitations. The coracoid pain test is a useful tool in determining the presence of true adhesive capsulitis. The simple 3 functional-related tests described by Yan et al is helpful for assessing and documenting functional limitations caused by adhesive capsulitis.
In Part 2, we will review management and treatment of frozen shoulder. Stay tuned!
You can grab a free copy of a handout for the three functional tests for frozen shoulder here.
Have you treated patients with frozen shoulder or adhesive capsulitis? Share any additional resources that you found helpful in the comments below!
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