Supraspinatus tendinosis is a common condition affecting the shoulder, specifically involving the supraspinatus tendon. It is characterized by changes within the tendon structure, leading to discomfort and reduced shoulder function. It often develops gradually, impacting daily activities and overall quality of life for those affected. Understanding this condition involves recognizing its specific nature, distinct from other shoulder issues. This article explores the anatomy of the affected tendon, the characteristics of tendinosis, its presenting signs, and common factors contributing to its development.
Understanding the Supraspinatus Tendon and Tendinosis
The supraspinatus tendon forms a part of the rotator cuff, a group of four muscles and their tendons surrounding the shoulder joint. This particular tendon originates from the upper part of the shoulder blade, known as the supraspinous fossa, and attaches to the upper arm bone, the humerus. The supraspinatus muscle plays a role in stabilizing the shoulder joint and is primarily responsible for initiating arm abduction (lifting the arm away from the body), especially during the first 0-15 degrees of motion. It also assists the deltoid muscle in lifting the arm further, up to 90 degrees.
When discussing tendon issues, it is important to differentiate between “tendinitis” and “tendinosis.” Tendinitis refers to acute inflammation of a tendon, typically resulting from micro-tears due to sudden overload. In contrast, tendinosis describes a chronic degenerative process within the tendon, where the collagen fibers, which provide the tendon’s strength and structure, break down and become disorganized. This degeneration occurs often without significant inflammation, distinguishing it from tendinitis.
Tendinosis is a long-term condition resulting from overuse and repetitive strain, where tissue breakdown exceeds healing. The microscopic view of tendinosis reveals an increase in immature collagen fibers and a loss of collagen continuity, which weakens the tendon’s ability to bear load. Consequently, treatment strategies for tendinosis focus on promoting tendon regeneration and remodeling rather than primarily reducing inflammation.
Identifying Symptoms and Causes
Individuals experiencing supraspinatus tendinosis often report a range of symptoms, with pain being a primary concern. This pain typically manifests as a dull ache in the shoulder, which can sharpen with specific movements. Pain is frequently worsened by activities involving lifting the arm, especially overhead motions, or reaching behind the back. Many people also notice increased pain at night, particularly when lying on the affected shoulder, which can disrupt sleep.
Beyond pain, individuals may experience weakness in the affected arm, making it difficult to lift objects or perform tasks that require shoulder strength. A limited range of motion in the shoulder is another common symptom, particularly when attempting to raise the arm overhead. Tenderness to the touch around the front or top of the shoulder can also indicate the presence of this condition. These symptoms generally progress, becoming more noticeable over time rather than appearing suddenly.
The development of supraspinatus tendinosis is often attributed to a combination of factors, frequently cumulative rather than a single event. Repetitive overhead activities, common in certain sports like tennis, baseball, or swimming, or occupations requiring frequent arm elevation, place significant stress on the supraspinatus tendon. Age-related wear and tear also contributes, as tendons naturally become less flexible and more prone to degeneration after middle age, commonly affecting individuals over 50.
Other contributing factors include poor posture, which can narrow the space available for the tendon and lead to friction or reduced blood supply. Direct injury, such as a fall, can also initiate or worsen tendon degeneration. Insufficient blood supply to the tendon, often seen in conditions like diabetes or as a result of smoking, can further impair the tendon’s ability to repair itself, increasing the risk for tendinosis.
Diagnosis and Management Strategies
Diagnosing supraspinatus tendinosis typically involves a thorough evaluation by a healthcare professional. This process begins with a detailed medical history, focusing on the nature of the pain, aggravating factors, and any previous injuries. A physical examination assesses the shoulder’s range of motion, strength, and identifies specific points of tenderness. During this examination, tests like the Jobe (empty can) test or Hawkins test may be performed, which can help indicate supraspinatus involvement by reproducing pain or demonstrating weakness.
While clinical examination provides strong indications, imaging studies are often used to confirm the diagnosis and rule out other conditions. Ultrasound can visualize the tendon, showing thickening or microtears, and detect changes in the subacromial bursa. Magnetic Resonance Imaging (MRI) offers a more detailed view of the tendon’s internal structure, helping to assess the degree of degeneration, identify any tears, and differentiate tendinosis from other shoulder pathologies.
Management of supraspinatus tendinosis primarily focuses on non-surgical approaches. Initial steps often involve relative rest and modifying activities that exacerbate symptoms, particularly avoiding repetitive overhead movements. Pain management may include over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) for short-term relief, though their long-term use is generally not recommended for tendinosis.
Physical therapy is a core component of recovery, aiming to restore shoulder strength, flexibility, and proper movement patterns. A physical therapist guides individuals through exercises that strengthen the rotator cuff muscles, improve posture, and enhance overall shoulder mechanics.
In some cases, injections may be considered; corticosteroid injections can offer temporary pain relief by reducing inflammation, while treatments like Platelet-Rich Plasma (PRP) injections or prolotherapy aim to promote tendon healing.
Surgical intervention is typically reserved as a last resort for severe cases that have not responded to a comprehensive course of conservative treatment over several months, often between three to six months.