Shoulder pain and stiffness are common complaints. While many suspect “frozen shoulder” (adhesive capsulitis), numerous other conditions present with similar symptoms. Understanding these distinctions is important for accurate diagnosis and effective treatment. This article explores frozen shoulder and other conditions that mimic its symptoms, highlighting their unique characteristics.
Understanding Frozen Shoulder
Frozen shoulder is a condition marked by pain and a gradual, severe loss of motion in the shoulder joint. It occurs when the connective tissue capsule surrounding the shoulder joint thickens, stiffens, and contracts, restricting movement. This condition typically progresses through three distinct stages.
The “freezing” stage involves increasing pain and decreasing range of motion, often worsening at night. This stage can last anywhere from six weeks to nine months. The “frozen” stage follows, during which pain may lessen, but the shoulder becomes significantly stiffer, making daily tasks difficult. This phase typically lasts for two to twelve months. Finally, the “thawing” stage involves a gradual improvement in shoulder movement, with symptoms typically getting better over one to three years.
Common Shoulder Conditions Mimicking Frozen Shoulder
Several conditions can cause shoulder pain and limited movement, leading to confusion with frozen shoulder. Rotator cuff tears damage shoulder-stabilizing muscles and tendons, often from trauma, repetitive motions, or degeneration. Rotator cuff tendinitis (subacromial impingement syndrome) is tendon inflammation, often due to overuse or pressure under the shoulder blade.
Shoulder osteoarthritis (glenohumeral arthritis) is a degenerative condition where joint cartilage wears away, causing bone-on-bone friction. Calcific tendinitis involves calcium deposits within rotator cuff tendons, typically the supraspinatus. Bursitis (e.g., subacromial bursitis) is inflammation of bursae, small fluid-filled sacs cushioning shoulder bones and soft tissues. Cervical radiculopathy, a “pinched nerve” in the neck, can cause pain, numbness, and weakness radiating into the shoulder and arm, mimicking a shoulder issue.
Key Distinguishing Features
Many shoulder conditions share overlapping symptoms, but distinguishing features lie in pain nature, motion restriction, and associated symptoms. Rotator cuff tears and tendinitis, for instance, cause pain during specific movements like overhead lifting or reaching behind the back. Unlike frozen shoulder, passive range of motion is often preserved or mildly limited by pain, not global joint capsule stiffness. Weakness in the affected arm is common with rotator cuff issues, especially tears.
Shoulder osteoarthritis causes deep, aching pain worsening with activity and improving with rest. Arthritis stiffness is worse in the morning or after inactivity, with grinding or popping (crepitus) on movement. Unlike frozen shoulder’s pervasive stiffness, osteoarthritis’s range of motion loss is usually gradual and may not affect all directions equally. Calcific tendinitis causes sudden, intense, localized shoulder pain, severe enough to disrupt sleep. This acute onset and sharp, localized pain differ from frozen shoulder’s gradual, diffuse pain.
Bursitis causes outer shoulder pain, especially when lying on the affected side or lifting the arm. While it can cause stiffness from pain and swelling, passive range of motion is generally better than active, meaning the joint isn’t inherently stiffened like in frozen shoulder. Cervical radiculopathy, in contrast, presents with neck pain radiating into the shoulder, arm, and hand. This referred pain may include numbness, tingling, or weakness, and neck movements often reproduce or worsen shoulder pain, unlike primary shoulder joint conditions.
Seeking a Professional Diagnosis
Given symptom similarities across shoulder conditions, professional medical diagnosis is essential. Self-diagnosis can mislead and delay treatment, potentially prolonging discomfort or worsening the condition. Healthcare providers use a comprehensive approach to identify the root cause of shoulder pain.
This process involves a detailed medical history (pain nature, onset, accompanying symptoms) and a thorough physical examination assessing shoulder range of motion, strength, and tenderness. Depending on findings, imaging studies (X-rays, MRI, ultrasound) may visualize internal shoulder structures and rule out conditions like fractures, tears, or arthritis. Since different conditions require distinct treatment, accurate diagnosis ensures effective, targeted therapies for better patient outcomes.