Frozen Shoulder: Causes, Symptoms and Treatment

Frozen shoulder, also known as adhesive capsulitis, is a common and painful condition affecting the shoulder joint. It involves inflammation, motion restriction, and shoulder and arm pain. Frozen shoulder occurs in 2-5% of the general population, mostly affecting people between 40-60 years old.

What is a Frozen Shoulder?

A frozen shoulder involves progressive stiffness and loss of range of motion in the shoulder joint. It often follows a pattern of three stages:

• Freezing Stage – Gradual onset of pain felt predominantly at night. Activities become increasingly difficult as motion is restricted. This stage can last from 6 weeks to 9 months.
• Frozen Stage – Pain may improve, but significant stiffness and restricted mobility in all directions of shoulder movement persists. It usually lasts 4-6 months.
• Thawing Stage – Shoulder motion slowly improves over several months to years. Pain is minimal, and function restores.

While the exact cause is unclear, risk factors like diabetes, hypothyroidism, Parkinson’s disease, and cardiac disease are associated with frozen shoulder. Trauma, surgery, and immobilization can also contribute. With appropriate treatment, most people fully regain their shoulder function.

What Causes Frozen Shoulder?

Researchers have not fully understood the etiology of frozen shoulder. However, they have identified some plausible causes of frozen shoulder.

• Inflammation – Chronic inflammation affecting the shoulder joint capsule and surrounding tissues results in thickening and contraction. This mechanically limits the range of motion.
• Immobility – Prolonged periods of shoulder inactivity lead to tightened connective tissue and loss of elasticity. This makes movement difficult when resumed.
• Scar Tissue – Dense internal and external scar tissue can form and restrict normal shoulder motion after injury or surgery.
• Metabolic Disorders – Medical conditions like diabetes mellitus, stroke, thyroid disorder, Dupuytren disease, cancer, hypothyroidism, Parkinson’s, etc.
• Age – Loss of elasticity in tendons and joints due to aging combined with minor repetitive overuse makes the frozen shoulder more common in those over 40.
• Genetic Predisposition – Variations in molecular markers and proteins may genetically predispose some individuals to frozen shoulder.

While the exact mechanisms are still debated, a frozen shoulder involves substantial disruption of the normal smooth gliding between layers that allow full, pain-free shoulder joint mobility.

Symptoms of Frozen Shoulder

Carefully evaluating the symptoms or pathophysiology of a potential frozen shoulder can inform appropriate diagnosis and management.

Early Freezing Stage (4-8 weeks duration)

• Dull ache localized to anterior shoulder and upper arm
• Intermittent sharp pain with certain motions like external rotation
• Mild nighttime shoulder stiffness but no pain
• Tightening the coracohumeral ligament limits external rotation
• Synovial inflammation and cytokine release initiate contracture

Freezing Stage (4-6 month duration)

• Worsening rest pain and night stiffness disturb sleep
• External rotation lost; reaching behind the back difficult
• Posterior capsule tightness limits internal rotation
• Inflammation spreads widening rotator cuff interval
• Fibroplasia and collagen deposition thicken tissues

Frozen Stage (4-6 month duration)

• Severe constant shoulder pain and stiffness
• Glenohumeral inflammation stiffens the capsule limiting all planes
• Significant pain reaching overhead or across the body
• Dressing and combing hair are extremely painful
• Global guarding and disuse of contract shoulder
• Depression and anxiety over loss of function

Thawing Stage (6-9 months+)

• Very gradual improvements in pain
• Extreme stiffness persists for many months
• Function slowly recovers but deficits may remain
• The complete recovery timeframe is widely variable

Carefully noting the initial mild symptoms resulting from ligamentous tightness can enable early intervention before inflammation and contracture advance leading to disability. Tracking symptom stages provides insight into expected disease progression and recovery from a frozen shoulder.

Frozen Shoulder Diagnosis

Frozen shoulder, medically termed adhesive capsulitis, is notoriously challenging to evaluate and definitively diagnose. Unlike most musculoskeletal conditions, there are no specific laboratory tests or imaging findings that can conclusively distinguish pathologies contributing to a stiff, painful shoulder. Therefore, arriving at a diagnosis relies substantially on the health practitioner’s skill in obtaining an appropriate history, conducting a focused physical examination, and synthesizing subtle imaging clues while ruling out competing etiologies.

A physician will typically start by asking pointed questions about the onset, nature, duration, aggravating motions, relieving factors, and associated symptoms of shoulder pain to recognize patterns consistent with adhesive capsulitis stages. Details like lack of trauma, other joint involvement, worsening nighttime discomfort, and progressive loss of external rotation and overhead reaches are revealing.

Next, methodical evaluation of passive and active shoulder range of motion in multiple movement planes helps quantify restrictions. An adhesive capsulitis shoulder will demonstrate proportionally severe loss of external rotation compared to other limited directions. Assessment for concurrent cervical spine, elbow, and hand pathology is also important.

Plain shoulder x-rays are routinely done, not to confirm frozen shoulder, but to exclude alternate anatomical explanations like fracture, tumor, or advanced osteoarthritis. An MRI may show some thickening of the joint capsule and ligaments which can support the diagnosis but lacks definitive precision. Ultrasound by an experienced user can complement the clinical picture through subtle changes around the rotator cuff interval but remains user-dependent.

In ambiguous presentations where the diagnosis remains unclear, injecting anesthetic into the subacromial space followed by reassessment can help distinguish intrinsic causes like adhesive capsulitis from extrinsic subacromial impingement etiologies.

Staging of Frozen Shoulder

Frozen shoulder involves a gradual, progressive loss of shoulder mobility passing through overlapping phases termed freezing, frozen, and thawing. For simplicity, this is often condensed into a 2-stage classification system categorizing patients as either early or developed in the disease course.

Early Freezing Stage

The early freezing stage represents the initial 2 to 9 months after symptom onset. It is marked by moderate to severe shoulder pain, predominantly at night, and mild restrictions in range of motion that chiefly impacts external rotation. Patients experience pain with movements and difficulty reaching behind their backs or combing their hair. Sleep is disrupted by pain.

Developed Frozen Stage

The developed frozen stage encompasses the period from around 4 months extending to 12 months or longer after the appearance of the first symptoms. This phase demonstrates a slight improvement in resting pain levels but persistent stiffness and loss of shoulder mobility. Restricted range of motion continues to worsen and hampers activities. The joint appears locked in place and frozen. Night discomfort may continue.

Some utilize a 3-phase thawing scheme, though recovery is highly variable. Ultimately over 12-42 months, early treatment can help restore range of motion and function to near-normal levels. Careful staging guides prognosis and therapeutic interventions.

The clinical course of a frozen shoulder reliably passes through early painful and later stiff phases. Tracking the stage and applying appropriately timed treatment provides the greatest chance of regaining shoulder mobility before extensive, stubborn contracture sets in.

Stage	Duration	Symptoms	Treatment Focus	Recovery
Early Freezing	2-9 months	Pain at night, limited external rotation	Modalities, maintain mobility	Gradual over months
Frozen	4-12 months	Stiffness, pain with motion	Stretching, joint mobilization	Partial over months
Thawing	12+ months	Improving stiffness	Restore strength and function	Complete by 18+ months

Fast Relief Options for Frozen Shoulder

Before undergoing more conservative treatments for frozen shoulders lasting months, some fast-acting modalities can provide interim pain relief and regain limited mobility when symptoms first manifest. These include:

Manipulation Under Anesthesia

Manipulation under anesthesia (MUA) involves manually moving the arm to stretch the joint capsule and break up scar tissue in the frozen shoulder while the patient is under general anesthesia. This allows for a gentle controlled stretch that would otherwise be too painful. After MUA, aggressive physical therapy maintains improved mobility.

Electrotherapy Modalities

Electrotherapies like ultrasound, TENS, laser, and interferential use electrical currents or soundwaves to deliver deep heating effects, stimulate nerve fibers, enhance blood flow, reduce inflammation, and encourage shoulder soft tissue healing. Consistent electrotherapy combined with mobilization exercises shows promising outcomes for a stiff, painful frozen shoulder.

Frozen Shoulder Treatment

For most patients diagnosed with frozen shoulder, these conservative treatment methods are effective at restoring mobility and function:

• Medications – Oral NSAIDs, topical creams, lidocaine patches, or corticosteroid shoulder injections can relieve inflammation and pain.
• Physical therapy – Stretching, joint mobilization, therapeutic exercises like pilates, and modalities like heat, ice, ultrasound, and electrical stimulation help regain motion and strength.
• Home exercise – Following a structured home program for stretching and shoulder exercises is key between physical therapy visits.
• Posture correction – Addressing rounded shoulders, neck dysfunction, and poor posture reduces strain on the shoulder joints. Proper body mechanics are also vital.
• Activity modification – Avoiding repetitive overhead motions and heavy lifting prevents exacerbating symptoms while allowing healing.
• Stress management – Controlling pain levels during flares using relaxation techniques helps prevent compensation injuries like neck strain. Managing associated stress supports recovery.
• Shoulder manipulation – Under anesthesia, manually moving the shoulder through its full range of motion can help stretch the capsule.

With a commitment to these conservative treatments for 6-12 months, most patients see significant improvement and can resume normal function. Surgery may be warranted in refractory cases.

Thyroid Dysfunction and Frozen Shoulder

Thyroid problems like hypothyroidism are closely associated with the development of adhesive capsulitis. The reasons theorized behind this relationship include:

• Thyroid hormones directly impact joint capsule tissues
• Chronic inflammation and fluid balance changes
• Autoimmune factors co-occurring
• Fibrosis and scar tissue processes interaction

For this reason, ensuring thyroid levels are optimized forms an important part of integrative treatment for frozen shoulders linked to hypothyroid and other thyroid conditions.

Surgical Interventions

If a frozen shoulder persists despite focused conservative treatment for 6-9 months, one of these surgical procedures may be beneficial:

Arthroscopic Capsular Release

This outpatient procedure involves inserting a tiny camera (arthroscope) through small incisions around the shoulder joint. The surgeon then uses arthroscopic tools to cut through scar tissue and contracture in the joint capsule to release stiffness. Early aggressive physical therapy after surgery facilitates faster recovery.

Benefits:

• Less invasive procedure with smaller incisions
• Quicker recovery and return to activities
• Lower risk of complications

Limitations:

• Does not address extra-articular causes
• Requires extensive participation in post-op rehab

Open Capsular Release

A more extensive open surgical approach cuts through the joint capsule and releases tight scar tissue around the shoulder. This allows for complete visualization and release of contractures. Physical therapy starts approximately 6 weeks after open surgery due to recovery time.

Benefits:

• Allows full access to treat all causative tissue
• One surgery often resolves the problem

Limitations:

• Invasive with a larger incision
• Higher risk of complications
• Slower return to function after surgery

The orthopedic surgeon will determine the optimal surgical technique based on the individual’s specific anatomy and condition. Factors like diabetes control, thyroid function, age, activity level, and anatomical changes are also considered. Surgery can provide significant pain relief and restore range of motion when conservative care does not adequately resolve a frozen shoulder.

Physical Therapy for Frozen Shoulder

Physical therapy is a critical component of frozen shoulder recovery following surgery. A rehabilitation program or physical therapy for a frozen shoulder focuses on:

• Gentle range of motion exercises – Gradually progress pendulum, passive, active assisted, and ultimately active exercises to improve mobility.
• Stretching tight structures – Use stretches that target the posterior capsule, anterior capsule, and internal rotators.
• Rotator cuff and scapular strengthening – Once ranging of motion permits, incorporate theraband exercises.
• Postural education – Teach proper posture, shoulder mechanics, ergonomics, and activity modifications.
• Pain modalities – Use ice, heat, electrotherapy, etc., to control pain and inflammation as needed.
• Functional retraining – Integrate exercises and activities using the arm into daily life.

Physical therapists ensure patients progress through each rehabilitation phase appropriately after surgery without overstressing healing tissues. This lays the foundation for the best possible recovery of shoulder function.

Frozen Shoulder Recovery Timelines

Frozen shoulder follows a gradual onset, intensely painful and stiff middle stage, and final phase of slowly improving motion and function. The condition can be frustrating to manage. Understanding general recovery timelines provides a helpful perspective.

Conservative Treatment Course

• Initial physical therapy evaluation starts once the range of motion loss and pain is recognized.
• 6-9 months of active participation in exercise, stretching, joint mobilization, ice/heat, etc., is typically needed.
• Pain is usually controlled in 2-4 months, but stiffness persists for 6 or more months.
• Complete recovery of range of motion and strength is achieved by 12-18 months in most cases.

Post-Operative Rehabilitation

• Gentle rehab exercises generally start 6 weeks after open surgery or within days after arthroscopic release.
• 3-4 months focused on regaining mobility and light strengthening.
• 6-9 months of dedicated therapy helps most achieve 85-90% function.
• Full shoulder motion and strength were restored by 12-15 months.

So, while the prolonged frozen phase of around 6 months can feel discouraging, most patients see marked improvements by 9-12 months with diligent conservative or post-operative treatment. Regaining pain-free shoulder function requires patience. Support resources help manage frustration and anxiety during the recovery process.

Frozen shoulder is a common cause of shoulder pain and disability, especially in middle age. It involves progressive loss of normal shoulder range of motion and significant pain and stiffness. Though the exact mechanisms causing frozen shoulder are still debated, associated factors like diabetes, inactivity, and trauma likely contribute.

Conservative treatments focused on stretching, therapeutic exercises, spinal posture correction, anti-inflammatory modalities, and activity adjustments help most patients recover function within 12-18 months. Manipulation under anesthesia or surgery may be considered for a stubborn frozen shoulder. Post-operative physical therapy is crucial. While prevention is challenging, maintaining shoulder flexibility and promptly treating injuries appropriately may decrease risks. Patience and diligently working with health professionals lead to an improved quality of life for most dealing with frozen shoulder.

Epidemiology of Frozen Shoulder: Adhesive capsulitis affects up to 5% of the population, with a higher prevalence in females, who are four times more likely to be affected than men. Additionally, the non-dominant shoulder is more susceptible to this condition.

FAQs

Glossary

Term	Definition
Adhesive Capsulitis	Also known as frozen shoulder, it’s a condition involving inflammation, motion restriction, and pain in the shoulder joint.
Etiology	The study of the cause or causes of a disease or condition.
Cytokine	A small protein is involved in cell signaling, especially in the immune response.
Collagen Deposition	The accumulation of collagen fibers, a structural protein, in a particular area.
Genetic Predisposition	A genetic tendency or susceptibility to a particular condition or disease.
Arthroscopic Capsular Release	A surgical procedure involving the use of an arthroscope to cut through scar tissue and contracture in the joint capsule.
Open Capsular Release	A surgical procedure involving a larger incision to cut through the joint capsule and release tight scar tissue.
Contra-lateral	Pertaining to the opposite side of the body.
Prognosis	The likely course and outcome of a medical condition.
Contralateral Shoulder	The shoulder is on the opposite side of the body.
Cervical Spine	The portion of the spine comprising the neck.
Dupuytren Disease	A condition causing thickening and contracture of the connective tissue in the hand.
Glenohumeral Inflammation	Inflammation affects the ball-and-socket joint of the shoulder.
Pendulum Stretches	A gentle swinging motion to mobilize the shoulder joint.
Supine External Rotation	A stretching exercise is performed while lying on the back, turning the arm outward.
Isometric Internal and External Rotation	Muscle contractions without significant joint movement.
Scapular Retraction	Pulling the shoulder blades together.
Prophylactic Measures	Preventive or protective measures to avoid the development of a condition.

References

Hubbard MJ, Hildebrand BA, Battafarano MM, Battafarano DF. Common Soft Tissue Musculoskeletal Pain Disorders. Prim Care. 2018 Jun;45(2):289-303.

Xiao RC, DeAngelis JP, Smith CC, Ramappa AJ. Evaluating Nonoperative Treatments for Adhesive Capsulitis. 2017 WINTERJ Surg Orthop Adv. 26(4):193-199.

Murakami AM, Kompel AJ, Engebretsen L, Li X, Forster BB, Crema MD, Hayashi D, Jarraya M, Roemer FW, Guermazi A. The epidemiology of MRI detected shoulder injuries in athletes participating in the Rio de Janeiro 2016 Summer Olympics. BMC Musculoskelet Disord. 2018 Aug 17;19(1):296.

Kingston K, Curry EJ, Galvin JW, Li X. Shoulder adhesive capsulitis: epidemiology and predictors of surgery. J Shoulder Elbow Surg. 2018 Aug;27(8):1437-1443.