Frozen Shoulder: Symptoms, Causes & Treatment Guide

What Is Frozen Shoulder?

Frozen shoulder, medically known as adhesive capsulitis, is a condition characterized by pain and severe stiffness in the shoulder joint. It occurs when the shoulder capsule (the connective tissue surrounding the joint) becomes inflamed, thickened, and develops scar tissue, restricting movement in all directions.

The shoulder is one of the most mobile joints in the human body, allowing movement in multiple directions. This mobility is made possible by the shoulder capsule, a flexible envelope of connective tissue that surrounds the joint. In frozen shoulder, this capsule becomes inflamed and contracts, significantly reducing the joint's range of motion and causing considerable pain.

The condition typically develops gradually and affects people between the ages of 40 and 60, with women being more commonly affected than men. While the exact cause is often unknown (idiopathic), certain conditions like diabetes, thyroid disorders, and prolonged immobilization significantly increase the risk of developing frozen shoulder.

Understanding frozen shoulder requires recognizing that it is fundamentally different from other shoulder conditions like rotator cuff tears or shoulder arthritis. In frozen shoulder, the problem lies primarily in the joint capsule rather than the muscles, tendons, or bones. This distinction is important because it affects both diagnosis and treatment approaches.

The Shoulder Capsule and How It Becomes "Frozen"

The shoulder capsule is made of strong connective tissue that normally allows smooth, pain-free movement of the shoulder joint. In frozen shoulder, the capsule undergoes significant changes: it becomes inflamed, thickens considerably, and develops bands of scar tissue called adhesions. These changes cause the capsule to contract and tighten around the joint, severely limiting movement.

The term "frozen" aptly describes how the shoulder feels—as if it has been locked in place and cannot move freely. Both active movement (moving your own arm) and passive movement (when someone else moves your arm) become restricted, which is a hallmark of this condition that helps distinguish it from other shoulder problems.

What Are the Three Stages of Frozen Shoulder?

Frozen shoulder progresses through three distinct stages: the freezing stage (2-9 months) characterized by increasing pain; the frozen stage (4-12 months) where stiffness is most severe but pain may decrease; and the thawing stage (5-24 months) during which movement gradually returns.

Understanding the three stages of frozen shoulder is crucial for both patients and healthcare providers because it helps set realistic expectations about the condition's progression and recovery timeline. Each stage has distinct characteristics, and recognizing which stage you're in can guide treatment decisions and provide reassurance about the expected course of the condition.

Stage 1: Freezing Stage (2-9 months)

The freezing stage marks the onset of frozen shoulder and is characterized primarily by pain. During this stage, the shoulder capsule begins to inflame and gradually starts to tighten. Pain often develops slowly but progressively worsens over weeks to months. Many patients describe the pain as a deep ache within the shoulder that intensifies with movement.

Night pain is particularly common during this stage and can significantly disrupt sleep, especially when lying on the affected shoulder. The pain may radiate down the arm, sometimes reaching the elbow. As inflammation increases, patients begin to notice their range of motion decreasing, though the loss of movement is often gradual enough that it may not be immediately apparent.

During the freezing stage, many patients unknowingly compensate by avoiding painful movements, which can actually worsen the stiffness. It's during this stage that early intervention with physical therapy and pain management can be most beneficial in potentially limiting the severity of the subsequent stages.

Stage 2: Frozen Stage (4-12 months)

The frozen stage represents the peak of stiffness. Interestingly, while movement becomes most restricted during this stage, the constant pain of the freezing stage often decreases. However, pain typically remains at the end range of motion when attempting to move the shoulder beyond its limited range.

Daily activities become notably challenging during this stage. Tasks that require reaching overhead, behind the back, or to the side become difficult or impossible. Common struggles include reaching for items on high shelves, putting on a coat or shirt, fastening a bra, washing or styling hair, and reaching for a seatbelt.

The frozen stage can be frustrating because while pain may be more manageable, the functional limitations become most apparent. Patients often describe feeling as though their shoulder is "locked" or "stuck." Despite the severity of the restrictions, this stage actually represents the beginning of the healing process as the acute inflammation begins to settle.

Stage 3: Thawing Stage (5-24 months)

The thawing stage brings gradual improvement in shoulder movement. The capsule begins to release, and range of motion slowly returns. This stage requires patience, as recovery is typically slow and incremental. Many patients notice improvement week by week or month by month rather than day by day.

During the thawing stage, continued physical therapy and regular stretching exercises are important to maximize recovery of movement. While most patients regain significant function, some may be left with a mild permanent reduction in range of motion. Studies suggest that approximately 10-20% of patients have some lasting limitation, though this is often minor and doesn't significantly impact daily activities.

What Are the Symptoms of Frozen Shoulder?

The main symptoms of frozen shoulder include a deep aching pain in the shoulder, severe stiffness limiting movement in all directions, difficulty sleeping on the affected side, and progressive inability to perform daily activities like reaching overhead or behind the back.

Frozen shoulder symptoms develop gradually and typically follow the pattern of the three stages described above. However, understanding the specific symptoms in detail can help with early recognition and differentiation from other shoulder conditions. The combination of pain and restricted movement in all directions is characteristic of frozen shoulder.

Pain Characteristics

The pain of frozen shoulder is typically described as a deep, dull ache located in the outer shoulder area. During the early freezing stage, pain may be constant and often worsens at night, making it difficult to find a comfortable sleeping position. Many patients report that lying on the affected shoulder causes significant discomfort, leading to sleep disturbances and fatigue.

Sharp pain often occurs at the end of the available range of motion—that is, when attempting to move the shoulder beyond its restricted limits. This pain serves as a protective mechanism, preventing movement that would further stress the inflamed and contracted capsule. Pain may also radiate down the arm, typically not extending past the elbow.

Stiffness and Movement Restrictions

The hallmark of frozen shoulder is restriction of both active and passive movement. Active movement is when you move your own arm, while passive movement is when someone else moves your arm for you. In frozen shoulder, both types of movement are equally restricted, which helps distinguish it from conditions like rotator cuff tears where passive movement may be preserved.

Movement is typically restricted in all directions, though external rotation (turning the arm outward) is often most severely affected. Internal rotation (reaching behind the back) and forward flexion (raising the arm in front) are also commonly limited. The pattern of restriction often follows what's called a "capsular pattern," which is characteristic of joint capsule problems.

• External rotation: Difficulty turning arm outward, reaching to the side
• Internal rotation: Cannot reach behind back, difficulty with hygiene tasks
• Forward flexion: Limited ability to raise arm in front or overhead
• Abduction: Difficulty raising arm to the side

Impact on Daily Activities

The functional limitations of frozen shoulder can significantly impact quality of life. Common activities that become difficult or impossible include dressing (particularly putting on shirts, jackets, and fastening back closures), personal hygiene (washing hair, reaching to clean after toileting), reaching for objects on high shelves, driving (particularly reaching for the seatbelt or steering with the affected arm), and sleep.

Many patients develop compensatory movements, using the unaffected arm to assist with tasks or modifying how they perform activities. While these adaptations help maintain function, they can sometimes lead to strain or overuse problems in the opposite shoulder or other body parts.

What Causes Frozen Shoulder?

The exact cause of frozen shoulder is often unknown (idiopathic), but it involves inflammation and thickening of the shoulder capsule with development of scar tissue. Major risk factors include diabetes (10-20% prevalence), thyroid disorders, prolonged immobilization, and certain systemic diseases.

Despite decades of research, the precise mechanisms that trigger frozen shoulder remain incompletely understood. What is known is that the condition involves an inflammatory process that leads to fibrosis (scarring) and contracture of the shoulder capsule. Several theories exist about what initiates this process, and it's likely that multiple factors contribute in different patients.

Frozen shoulder is classified into two main categories: primary (idiopathic) and secondary. Primary frozen shoulder develops without any clear precipitating cause, while secondary frozen shoulder occurs in association with an identifiable condition or event. Understanding these categories helps guide both treatment and prognosis.

Primary (Idiopathic) Frozen Shoulder

In many cases, frozen shoulder develops without any identifiable trigger—this is called primary or idiopathic frozen shoulder. While the cause remains unknown, research suggests that certain individuals may have a genetic predisposition to developing the condition. The inflammatory process appears to be an abnormal response of the immune system that leads to excessive scarring within the joint capsule.

Some researchers believe that minor injuries or microtrauma to the shoulder may trigger the inflammatory cascade in susceptible individuals, even when no specific injury is recalled. Psychological factors and stress have also been proposed as potential contributors, though the evidence for this is limited.

Secondary Frozen Shoulder

Secondary frozen shoulder develops in association with other conditions or events. The most significant risk factor is diabetes mellitus, which increases the risk 2-4 times compared to the general population. Studies show that 10-20% of people with diabetes will develop frozen shoulder at some point, compared to 2-5% of the general population.

Other conditions associated with increased risk include thyroid disorders (both hypothyroidism and hyperthyroidism), cardiovascular disease, Parkinson's disease, stroke, and autoimmune conditions. Prolonged immobilization of the shoulder—whether from injury, surgery, or illness—is another well-established cause of secondary frozen shoulder.

• Diabetes mellitus: 10-20% of diabetics develop frozen shoulder; more severe and longer-lasting
• Thyroid disorders: Both overactive and underactive thyroid increase risk
• Shoulder immobilization: After surgery, fracture, rotator cuff injury, or stroke
• Cardiovascular disease: Higher incidence in patients with heart conditions
• Parkinson's disease: Increased risk, possibly related to reduced movement

The Role of Diabetes

The strong association between diabetes and frozen shoulder deserves special attention. People with diabetes not only have a higher risk of developing frozen shoulder but also tend to have more severe and prolonged symptoms. The condition may also be more resistant to treatment in diabetic patients, with longer recovery times and higher rates of residual stiffness.

The mechanism linking diabetes to frozen shoulder is not fully understood but likely involves several factors. High blood sugar levels can lead to glycation of collagen (sugar molecules attaching to collagen fibers), making the connective tissue stiffer and more prone to scarring. Diabetes is also associated with impaired blood circulation and altered immune responses, which may contribute to the abnormal healing process seen in frozen shoulder.

How Is Frozen Shoulder Diagnosed?

Frozen shoulder is primarily diagnosed through physical examination, which reveals characteristic loss of both active and passive shoulder movement. X-rays are often normal but help rule out arthritis, while MRI may show thickening of the joint capsule and can exclude rotator cuff tears.

Diagnosing frozen shoulder relies heavily on clinical assessment—the patient's history and physical examination. There is no single definitive test for frozen shoulder; instead, diagnosis is based on the characteristic pattern of symptoms and findings combined with exclusion of other conditions that can cause similar symptoms.

A thorough medical history is the first step in diagnosis. Your healthcare provider will ask about the onset and progression of symptoms, pain characteristics, functional limitations, and any risk factors such as diabetes, thyroid disease, or recent shoulder injury or surgery. The gradual onset and progression through recognizable stages often points toward frozen shoulder.

Physical Examination

The physical examination is the cornerstone of frozen shoulder diagnosis. The key finding is significant loss of both active and passive range of motion in multiple directions. Your doctor will assess movement in forward flexion (raising the arm in front), abduction (raising the arm to the side), external rotation (turning the arm outward), and internal rotation (reaching behind the back).

The restriction of passive movement is particularly important for diagnosis. In conditions like rotator cuff tears, patients may have difficulty actively moving their arm, but when the examiner moves the arm for them (passive movement), full range of motion is often possible. In frozen shoulder, passive movement is equally restricted as active movement—the shoulder simply won't move beyond certain points regardless of who is moving it.

Your doctor will also check for pain at the end range of motion and may perform specific tests to help rule out other conditions. Strength testing is typically normal in frozen shoulder unless weakness has developed from disuse.

Imaging Studies

While imaging studies are not required to diagnose frozen shoulder, they are often performed to rule out other conditions. X-rays are typically normal in frozen shoulder but can identify osteoarthritis, calcific tendinitis, or other bone abnormalities that might explain the symptoms.

MRI (magnetic resonance imaging) can provide more detailed information about the soft tissues of the shoulder. In frozen shoulder, MRI may show thickening of the joint capsule and the coracohumeral ligament. More importantly, MRI can rule out rotator cuff tears or other soft tissue problems that might require different treatment. MRI is not always necessary if the clinical picture is clear, but it's often helpful when the diagnosis is uncertain.

Ultrasound is another imaging option that can assess the rotator cuff and may show changes in the joint capsule. It has the advantage of being less expensive than MRI and can be performed in the office setting.

Differential Diagnosis

Several other conditions can cause shoulder pain and stiffness and must be differentiated from frozen shoulder. Rotator cuff tears cause pain and weakness but typically allow more passive movement than active movement. Shoulder osteoarthritis causes stiffness but usually shows characteristic changes on X-ray. Calcific tendinitis causes acute pain episodes and shows calcium deposits on imaging.

Referred pain from the neck (cervical radiculopathy) can cause shoulder symptoms but is typically associated with neck pain and follows nerve distribution patterns. Inflammatory conditions like rheumatoid arthritis or polymyalgia rheumatica may affect the shoulder but usually involve other joints or have characteristic blood test abnormalities.

How Is Frozen Shoulder Treated?

Frozen shoulder treatment focuses on pain relief and restoring mobility through a combination of physical therapy, anti-inflammatory medications, and corticosteroid injections. Most cases resolve with conservative treatment, though severe or prolonged cases may require procedures like hydrodilatation or surgical capsular release.

The treatment of frozen shoulder aims to manage pain and restore shoulder function. Since the condition is self-limiting in most cases, the primary goals of treatment are to reduce suffering during the course of the illness and potentially accelerate recovery. Treatment approaches vary depending on the stage of the condition, severity of symptoms, and individual patient factors.

Conservative (non-surgical) treatment is effective for the majority of patients. The main components include physical therapy, pain medications, and corticosteroid injections. For patients who don't respond adequately to conservative measures, several interventional options are available.

Physical Therapy

Physical therapy is a cornerstone of frozen shoulder treatment throughout all stages. The specific approach may vary depending on the stage of the condition. During the painful freezing stage, gentle range-of-motion exercises within pain tolerance are emphasized, along with modalities like heat or ice to manage pain. Aggressive stretching is typically avoided during this stage as it may worsen inflammation.

As the condition progresses to the frozen and thawing stages, more intensive stretching exercises become appropriate to help restore mobility. A physical therapist can design an individualized exercise program and teach proper techniques for home exercises. Consistency with home exercises—typically performed several times daily—is crucial for optimal outcomes.

Common exercises prescribed for frozen shoulder include pendulum exercises (letting the arm swing gently while bent forward), finger walks up a wall, towel stretches behind the back, cross-body reaches, and external rotation stretches using a doorframe or stick. Your therapist may also use manual therapy techniques to help mobilize the shoulder joint.

Medications

Pain medications help manage symptoms and enable participation in physical therapy. Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen are commonly used as first-line treatment. They help reduce both pain and inflammation. Acetaminophen (paracetamol) may be used for pain relief when NSAIDs are contraindicated or not tolerated.

For severe pain, especially during the early freezing stage, short courses of oral corticosteroids may be prescribed. While they can provide significant short-term relief, the benefits typically don't last long term, and they come with potential side effects that limit prolonged use.

Corticosteroid Injections

Corticosteroid injections into the shoulder joint or the surrounding bursa are a common and often effective treatment, particularly during the early stages. Multiple studies have shown that corticosteroid injections can provide significant short-term pain relief and may improve range of motion in the first few weeks to months.

The injections are typically most helpful during the freezing stage when pain is the predominant symptom. They may be less effective during the frozen stage when stiffness has become established. Injections may be repeated if beneficial, though most practitioners limit the number of injections due to potential risks to the tendons and cartilage with repeated use.

Hydrodilatation (Distension Arthrography)

Hydrodilatation, also called distension arthrography, involves injecting a large volume of fluid (usually saline mixed with corticosteroid and sometimes local anesthetic) into the shoulder joint under imaging guidance. The goal is to stretch and sometimes rupture the contracted joint capsule, thereby improving range of motion.

This procedure is typically considered when conservative treatment has not provided adequate improvement. Studies have shown it can accelerate recovery and reduce symptoms, particularly when combined with physical therapy. The procedure is performed as an outpatient and is generally well-tolerated.

Manipulation Under Anesthesia

Manipulation under anesthesia (MUA) involves moving the shoulder through its full range of motion while the patient is under general anesthesia. This forcefully breaks up the scar tissue and adhesions in the joint capsule, immediately improving range of motion. The procedure carries some risks, including potential fracture (rare) and possible damage to the surrounding structures.

MUA is generally reserved for cases that haven't responded to other treatments. Following the procedure, intensive physical therapy is essential to maintain the gains in motion achieved and prevent recurrence of stiffness.

Arthroscopic Capsular Release

Arthroscopic capsular release is a surgical procedure performed using small incisions and a camera to directly cut and release the thickened, contracted joint capsule. This approach provides more controlled release compared to manipulation and allows the surgeon to visualize and address specific areas of the capsule.

Surgery is typically reserved for severe cases that have failed to improve with prolonged conservative treatment. Outcomes are generally good, with most patients achieving significant improvement in both pain and motion. As with MUA, post-operative physical therapy is crucial for optimal results.

What Exercises Help Frozen Shoulder?

Effective exercises for frozen shoulder include pendulum swings, towel stretches, finger walks up a wall, cross-body reaches, and external rotation stretches. These should be performed several times daily within pain tolerance, ideally after warming the shoulder with heat.

Exercise is essential for frozen shoulder recovery and should be performed consistently throughout all stages of the condition. The key is to exercise regularly—ideally several times per day—while staying within pain tolerance. Forcing through severe pain can worsen inflammation and may slow recovery. A "no pain, no gain" approach is not appropriate for frozen shoulder.

Before exercising, warming the shoulder can help prepare the tissues for stretching and make exercises more comfortable. Apply a warm towel, heating pad, or take a warm shower for 10-15 minutes before beginning your exercise routine. After exercises, applying ice for 15-20 minutes can help reduce any inflammation caused by stretching.

Pendulum Exercise

The pendulum exercise is gentle and often the first exercise prescribed. Stand and lean forward, supporting yourself with your unaffected arm on a table or chair. Let your affected arm hang down relaxed. Gently swing your arm in small circles, gradually increasing the size of the circles as comfortable. Also swing forward and back, and side to side. The movement should come from your body swaying, not from actively contracting shoulder muscles. Perform for 5 minutes several times daily.

Towel Stretch

Hold one end of a towel behind your back with your affected arm, and grasp the other end with your good arm over your shoulder. Use your good arm to gently pull the towel upward, stretching your affected shoulder into internal rotation. You should feel a stretch at the front of the affected shoulder. Hold for 15-30 seconds, then slowly lower. Repeat 10-20 times. This exercise can be made easier or harder by adjusting how much pull you apply.

Finger Walk

Face a wall at arm's length and touch the wall at waist level with the fingertips of your affected arm. Slowly walk your fingers up the wall, spider-like, raising your arm as high as you comfortably can. Your fingers should be doing the work, not your shoulder muscles. Go as high as you can without pain, hold for a few seconds, then slowly walk your fingers back down. Repeat 10-20 times. This can also be done facing sideways to the wall to stretch in a different direction.

Cross-Body Reach

Stand or sit and use your good arm to lift your affected arm at the elbow. Bring the affected arm across your body toward the opposite shoulder, stretching the back of the shoulder. Keep the affected arm relaxed—let the good arm do the work. Hold the stretch for 15-30 seconds. You should feel a gentle stretch at the back of the affected shoulder. Repeat 10-20 times.

External Rotation Stretch

Stand in a doorway with your affected arm bent at 90 degrees at the elbow and your forearm resting against the door frame. Slowly turn your body away from the door frame, keeping your elbow at your side. You should feel a stretch at the front of your shoulder. Hold for 15-30 seconds. This can also be done lying down with a stick or cane, using the good arm to push the affected arm into external rotation.

How Long Does Frozen Shoulder Take to Heal?

Frozen shoulder typically takes 1 to 3 years to fully resolve, though treatment may shorten this timeline. The freezing stage lasts 2-9 months, the frozen stage 4-12 months, and the thawing stage 5-24 months. About 10-20% of patients may have some permanent limitation.

The natural history of frozen shoulder is one of gradual resolution over time. Without any treatment, most cases will eventually improve and resolve, though this process typically takes 1-3 years from onset to full recovery. The condition is considered "self-limiting," meaning it runs its course and resolves without necessarily requiring intervention.

However, waiting 1-3 years for natural resolution involves significant pain and functional limitation during that time. Treatment aims to reduce suffering during this period and potentially accelerate recovery. Studies on treatment effectiveness show mixed results, with some treatments providing clear short-term benefits even if long-term outcomes are similar to natural history.

Factors Affecting Recovery Time

Several factors influence how long frozen shoulder takes to resolve. Diabetes is perhaps the most significant—patients with diabetes tend to have more severe and prolonged symptoms, with longer recovery times and higher rates of residual stiffness. Good blood sugar control may help improve outcomes in diabetic patients.

The stage at which treatment begins may also affect recovery. Early intervention during the freezing stage may help limit progression and potentially shorten the overall course. Compliance with physical therapy and home exercises appears to influence outcomes, with consistent exercise typically associated with better recovery.

Individual variation is significant—some patients recover quickly within months, while others may take years. Age, overall health, and possibly genetic factors may play roles that are not yet fully understood.

What to Expect During Recovery

Recovery from frozen shoulder is typically gradual and non-linear. Patients may notice slow improvement over weeks to months rather than dramatic changes from day to day. There may be periods of apparent plateau followed by noticeable improvement. This can be frustrating, and patients benefit from understanding that this pattern is normal.

Pain typically improves before motion returns. During the thawing stage, patients often note that their shoulder no longer hurts constantly, but significant stiffness remains. Range of motion then gradually improves over the following months. Most patients regain enough movement to perform daily activities, though some may notice subtle limitations in extreme ranges of motion.

Long-Term Outcomes

The majority of patients with frozen shoulder achieve good long-term outcomes. Studies suggest that 80-90% of patients recover satisfactory function, defined as ability to perform normal daily activities without significant limitation. However, detailed assessment often reveals that some degree of motion restriction persists in many patients, even years after apparent recovery.

About 10-20% of patients have some permanent reduction in range of motion, though this is often mild and may not cause functional problems. Recurrence in the same shoulder is uncommon but possible, particularly in patients with diabetes. More significantly, 20-30% of patients develop frozen shoulder in the opposite shoulder within 5 years, making awareness of early symptoms important.

When Should You See a Doctor for Shoulder Pain?

See a doctor if you have shoulder pain and stiffness lasting more than 2-3 weeks, difficulty with daily activities, inability to sleep due to pain, or if you have diabetes or thyroid disease. Seek immediate care if shoulder pain is accompanied by chest pain, shortness of breath, or follows a significant injury.

While not every case of shoulder discomfort requires medical attention, certain symptoms and circumstances warrant evaluation by a healthcare provider. Early diagnosis and treatment of frozen shoulder may help reduce the overall duration and severity of the condition. Additionally, shoulder pain can sometimes indicate other conditions that require different approaches.

If you have risk factors for frozen shoulder—particularly diabetes or thyroid disease—you should have a lower threshold for seeking evaluation if shoulder symptoms develop. Early intervention in high-risk individuals may be particularly beneficial.

Signs That Warrant Medical Evaluation

• Progressive stiffness: Gradual loss of shoulder movement over days to weeks
• Persistent pain: Shoulder pain lasting more than 2-3 weeks
• Night pain: Pain that regularly disturbs sleep
• Functional limitation: Difficulty with dressing, hygiene, or daily activities
• No improvement: Symptoms not responding to rest and over-the-counter pain relievers
• Risk factors present: Diabetes, thyroid disease, or recent shoulder surgery/injury

Preparing for Your Appointment

To make the most of your appointment, consider documenting your symptoms before you go. Note when the symptoms started, how they've progressed, what makes them better or worse, and how they affect your daily activities. List any relevant medical conditions (especially diabetes and thyroid disease) and any recent injuries or surgeries to the shoulder.

Your doctor will likely ask about your medical history, examine your shoulder, and may order imaging studies. Based on the findings, they can confirm or rule out frozen shoulder and discuss treatment options appropriate for your stage of the condition.