Frozen shoulder, medically termed adhesive capsulitis, is an orthopedic condition characterized by stiffness and pain in the shoulder joint.

Its hallmark feature is a progressive restriction in the range of motion, significantly affecting daily activities involving arm movement.

Pathophysiology and Stages

Adhesive capsulitis is believed to result from an inflammatory process within the synovial lining of the shoulder capsule. This inflammation triggers fibrosis and contracture of the capsule, reducing joint volume and flexibility. The disease evolves through three recognized stages: the painful “freezing” phase, the stiff “frozen” phase, and finally, the recovery or “thawing” phase.

During the freezing stage, inflammation predominates, causing pain and progressive loss of motion. The frozen stage is marked by decreased inflammation but persistent stiffness due to capsular thickening and adhesions. Gradual remodeling and resolution of fibrosis characterize the thawing phase, with gradual return of motion over months to years.

Risk Factors and Epidemiology

Frozen shoulder primarily affects individuals aged 40 to 60, with a higher incidence in women than men. It is also more common in individuals with systemic conditions such as diabetes mellitus and thyroid disorders. The association with diabetes is particularly notable, as diabetic patients are at increased risk and often experience more prolonged and severe symptoms.

Other risk factors include prolonged immobilization following trauma or surgery and certain autoimmune conditions, which may predispose to abnormal inflammatory responses in the joint capsule.

Clinical Presentation and Diagnosis

Patients typically present with gradually worsening shoulder pain followed by restricted range of motion in all directions. The limitation is both active and passive, distinguishing adhesive capsulitis from other shoulder pathologies.

Diagnosis is primarily clinical but is supported by imaging studies such as magnetic resonance imaging (MRI) or ultrasound to exclude other causes like rotator cuff tears or arthritis. MRI may reveal capsular thickening and decreased joint volume, while ultrasound can detect synovial inflammation. A thorough history and physical examination remain critical for accurate diagnosis.

Management Strategies

Treating frozen shoulder involves a multimodal approach aimed at pain relief and restoration of mobility. Nonsteroidal anti-inflammatory drugs (NSAIDs) are used initially to control inflammation and alleviate pain.

Physical therapy focusing on stretching and range of motion exercises is fundamental in preventing further stiffness. Corticosteroid injections into the joint capsule may be employed to reduce inflammation, particularly during the freezing phase.

In cases refractory to conservative management, more invasive procedures may be considered. Manipulation under anesthesia (MUA) involves forcibly moving the shoulder to break adhesions, while arthroscopic capsular release surgically removes fibrotic tissue. Both methods aim to restore motion but require careful patient selection and post-procedural rehabilitation to optimize outcomes.

Emerging Research

Recent studies have investigated the molecular mechanisms underpinning frozen shoulder, highlighting the role of cytokines and growth factors in driving inflammation and fibrosis. Targeting these pathways with biologic agents represents a promising area for future therapies. Moreover, advances in regenerative medicine, including platelet-rich plasma (PRP) and stem cell therapies, are under investigation for their potential to accelerate healing and reduce fibrosis.

According to multiple orthopedic experts, frozen shoulder often begins without a clear trigger. Dr. Jacob Calcei (University Hospitals) points out that many patients “just wake up with it,” and every small motion can become painfully inflamed. Dr. Brian Lee (Cedars‑Sinai) similarly describes its onset as idiopathic, frequently with no obvious injury. Dr. Scott Smith (Texas Orthopedics) outlines the classic three‑stage progression, including an early, intensely painful inflammatory phase. Dr. J. Michael Bennett adds that in many cases, “severe shoulder pain … comes about without really a significant history of trauma.”

Frozen shoulder (adhesive capsulitis) is a debilitating condition marked by shoulder pain and restricted mobility due to inflammation and fibrosis of the joint capsule. Recognizing its clinical stages, risk factors, and appropriate diagnostic modalities is critical for effective management.

Treatment typically involves anti-inflammatory medications, physical therapy, and sometimes surgical interventions. Ongoing research into the molecular basis of the disease offers hope for innovative therapies in the future, aiming to enhance recovery and reduce the impact of this challenging disorder.