Tendon Pain Explained: A Physical Therapist's Guide to Tendonitis and Tendinosis

As a physical therapist, you’re undoubtedly familiar with tendon-related injuries and conditions. Two of the most common tendon issues are tendonitis and tendinosis. Although these terms are often used interchangeably, they represent very different conditions, each with its own causes, symptoms, and treatment approaches. Distinguishing between the two is essential for effective treatment and long-term recovery.

This comprehensive guide will help you understand the differences between tendonitis and tendinosis, including how to diagnose each condition, what causes them, and the best approaches to treatment and prevention. By the end of this article, you’ll be well-equipped to assess these conditions in your patients and develop a care plan that promotes healing and functional recovery.

What Are Tendons?

Tendons are strong, fibrous bands of connective tissue that attach muscles to bones. When a muscle contracts, the tendon transmits the force to the bone, enabling movement. Tendons are composed primarily of collagen, arranged in parallel bundles to provide strength and flexibility. Despite their toughness, tendons are susceptible to injury from overuse, trauma, or age-related degeneration.

When tendons are damaged, the result is typically one of two conditions: tendonitis or tendinosis. Though they may seem similar at first glance, these two issues require distinct diagnostic approaches and treatment protocols.

What is Tendonitis?

Definition:

Tendonitis is the inflammation of a tendon. It is usually an acute condition that arises from repetitive use, excessive strain, or sudden increases in activity. The inflammation occurs as the body’s natural response to stress or injury, leading to localized pain, swelling, and limited movement.

Causes of Tendonitis:

Tendonitis typically occurs in response to repetitive motions or activities that place excessive strain on a tendon. This condition is particularly common in athletes, manual laborers, and individuals who engage in physically demanding hobbies. Common triggers include:

• Sudden increase in activity, such as an abrupt transition from a sedentary lifestyle to vigorous exercise
• Repetitive motions, including typing, painting, or gardening
• Poor biomechanics during physical activity or exercise
• Inadequate warm-up before engaging in physical activities
• Muscle imbalances or tightness, which can place additional stress on tendons

These factors contribute to an overload of the tendon, causing microscopic tears and inflammation.

Symptoms of Tendonitis:

The primary symptoms of tendonitis are directly related to the inflammation of the tendon. Patients typically present with:

• Pain localized to the affected tendon, especially during movement or physical activity
• Swelling and tenderness around the joint or tendon
• A feeling of warmth or redness in the area of inflammation
• Difficulty performing specific movements due to pain or stiffness
• Crepitus, a "crunchy" sensation, may occur with movement of the affected tendon

The pain from tendonitis usually increases with activity and improves with rest. However, if left untreated, the condition can worsen and become chronic.

Common Types of Tendonitis:

Tendonitis can occur in various tendons throughout the body, with some of the most common types including:

• Rotator Cuff Tendonitis: Inflammation of the tendons in the shoulder, often affecting athletes or individuals performing repetitive overhead motions.
• Achilles Tendonitis: Affects the Achilles tendon, causing pain and stiffness in the back of the ankle, frequently seen in runners.
• Patellar Tendonitis (Jumper's Knee): Involves the tendon connecting the kneecap to the shinbone, common in athletes who engage in jumping sports.
• Tennis Elbow (Lateral Epicondylitis): Inflammation of the tendons attached to the lateral epicondyle of the elbow, common in racquet sports players or individuals who frequently grip objects.

Diagnosis of Tendonitis:

To diagnose tendonitis, a medical professional typically starts by reviewing the patient’s medical history and conducting a physical examination. The examination may include palpation of the affected area to assess tenderness, swelling, and range of motion. If needed, imaging tests such as ultrasound or MRI may be used to confirm inflammation and rule out other conditions, such as tears or calcifications.

What is Tendinosis?

Definition:

Tendinosis is a chronic, degenerative condition of the tendon, characterized by the breakdown of collagen fibers within the tendon itself. Unlike tendonitis, tendinosis is not an inflammatory condition. Instead, it results from long-term overuse or insufficient recovery time between activities, leading to a failure of the tendon to heal properly after repeated microtraumas.

Causes of Tendinosis:

Tendinosis typically develops over time due to chronic overuse of a tendon, with minimal opportunity for recovery. Some contributing factors to tendinosis include:

• Repeated strain on the tendon from overuse or improper mechanics
• Insufficient rest between bouts of activity, leading to accumulated microtrauma
• Poor biomechanics or technique during physical activities or repetitive tasks
• Age-related degeneration, as tendons lose elasticity and strength over time
• Inadequate blood supply to the tendon, which limits the body’s ability to heal microtears

Tendinosis is most commonly seen in middle-aged individuals or athletes who have engaged in repetitive activities over a long period.

Symptoms of Tendinosis:

Because tendinosis is a degenerative condition rather than an inflammatory one, its symptoms differ from those of tendonitis. Patients with tendinosis typically experience:

• Chronic, dull pain that may persist at rest and worsen with activity
• Stiffness in the affected tendon, particularly in the morning or after periods of inactivity
• Thickening or a “ropy” feel in the tendon, often with nodular changes upon palpation
• Weakened function or decreased range of motion in the affected joint
• A prolonged recovery time, with symptoms persisting for months rather than weeks

Tendinosis is generally more difficult to treat than tendonitis because the condition involves degeneration of the tendon tissue itself.

Common Types of Tendinosis:

Tendinosis can affect various tendons in the body, with the following being common areas of occurrence:

• Achilles Tendinosis: Degeneration of the Achilles tendon, often seen in middle-aged runners or those who have experienced repetitive strain.
• Rotator Cuff Tendinosis: Degeneration of the rotator cuff tendons in the shoulder, leading to chronic pain and weakness, especially during overhead activities.
• Tennis Elbow (Lateral Epicondylosis): Tendinosis affecting the tendons of the lateral epicondyle, causing persistent elbow pain and dysfunction.
• Patellar Tendinosis: Degeneration of the patellar tendon, frequently affecting athletes in jumping sports, such as basketball or volleyball.

Diagnosis of Tendinosis:

Diagnosing tendinosis often requires more advanced imaging than tendonitis. While a physical examination is still crucial, imaging studies like MRI or ultrasound may be used to assess the extent of collagen degeneration, scar tissue formation, and potential calcification within the tendon.

Tendonitis vs. Tendinosis: Key Differences

While both conditions affect tendons, they differ significantly in their pathology, symptoms, and treatment. Tendonitis is an acute inflammatory condition, whereas tendinosis is a chronic degenerative one. Tendonitis results from sudden strain or injury, while tendinosis develops over time from chronic overuse. Additionally, tendonitis is characterized by pain and swelling due to inflammation, whereas tendinosis presents with chronic pain, stiffness, and thickening of the tendon without inflammation.

Treatment Approaches for Tendonitis and Tendinosis

Because tendonitis and tendinosis have different underlying mechanisms, their treatment approaches also differ significantly.

Treatment for Tendonitis:

Since tendonitis is an inflammatory condition, the primary goal is to reduce inflammation and promote healing. Common treatments for tendonitis include:

• Rest and Activity Modification: The affected tendon needs rest to allow inflammation to subside. This may involve avoiding activities that exacerbate the pain and modifying movements to reduce strain on the tendon.
• Cold Therapy: Applying ice to the affected area can help reduce swelling and inflammation, especially in the early stages of tendonitis.
• Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): Medications like ibuprofen can reduce inflammation and alleviate pain.
• Physical Therapy: Stretching and strengthening exercises are critical to addressing muscle imbalances and improving flexibility, which can help prevent recurrence.
• Corticosteroid Injections: In cases of severe pain, corticosteroid injections may be used to reduce inflammation. However, these are typically a short-term solution and should be used cautiously due to potential tendon weakening.

Treatment for Tendinosis:

Tendinosis treatment focuses on stimulating tendon healing and collagen repair, as inflammation is not a factor. Key treatments include:

• Eccentric Strengthening Exercises: These exercises, which focus on lengthening the muscle as it contracts, are particularly effective in promoting tendon healing and improving collagen synthesis.
• Soft Tissue Therapy: Techniques such as deep friction massage or instrument-assisted soft tissue mobilization (IASTM) can help break down scar tissue and stimulate blood flow to the affected area.
• Platelet-Rich Plasma (PRP) Therapy: PRP involves injecting the patient’s own platelet-rich plasma into the affected tendon to stimulate healing and tissue regeneration.
• Extracorporeal Shockwave Therapy (ESWT): This non-invasive treatment uses acoustic waves to increase blood flow to the damaged tissue, promoting healing.
• Nutritional Support: Collagen supplements, vitamin C, and other nutrients that support tissue repair can aid in the healing process for tendinosis.
• Activity Modification: It’s important to reduce the load on the tendon, but complete immobilization should be avoided, as this can weaken the tendon further.

Prevention of Tendon Injuries

Both tendonitis and tendinosis can often be prevented by taking certain precautions, especially for individuals at higher risk, such as athletes or those with physically demanding jobs. Key prevention strategies include:

• Proper Warm-Up: Ensuring that patients warm up properly before engaging in physical activity can reduce the risk of tendon injuries. Dynamic stretches and light aerobic activity help prepare the tendons for more intense exercise.
• Gradual Progression: Encourage patients to gradually increase the intensity and duration of their physical activities. Sudden increases in exercise or workload can lead to tendon overload.
• Correct Biomechanics: Proper technique is crucial to reducing strain on tendons. Physical therapists should emphasize the importance of maintaining correct form during exercises or repetitive tasks.
• Strengthening and Flexibility Training: Regular strengthening and stretching exercises can help support tendon health by reducing muscle imbalances and improving range of motion.
• Rest and Recovery: Allowing adequate rest between training sessions or bouts of physical activity is essential for tendon recovery and injury prevention.
• Use of Proper Equipment: Proper footwear, ergonomic tools, and other equipment can reduce the strain placed on tendons during work or sports activities.

Conclusion

Tendonitis and tendinosis are two distinct tendon conditions that require different treatment approaches. Tendonitis is characterized by inflammation and is typically an acute condition, while tendinosis involves chronic degeneration without inflammation. Proper diagnosis and treatment are crucial for achieving a full recovery and preventing future injury.

By understanding the underlying causes, symptoms, and treatment options for each condition, physical therapists can develop individualized care plans that promote healing, restore function, and reduce the risk of recurrence.