Tendinitis is the inflammation of the tendons, which connect muscles to bones. This condition occurs as a result of repetitive movements. It is commonly seen in athletes or people who do manual work. This inflammation in the tendons manifests as pain during movement, often described as a dull ache. Other signs of tendinitis include tenderness and slight swelling in the affected area. The pain intensifies with activity and, if left untreated, can lead to stiffness and loss of strength in joint movements. This condition can significantly impact the daily activities of the affected person.
| Medical Name | Tendinitis |
| Affected Areas | Tendons (commonly in the shoulder, elbow, wrist, knee, and heel regions) |
| Causes | Repetitive movements, overuse, injuries, aging, inflammatory diseases (e.g., arthritis) |
| Symptoms | Pain, swelling, tenderness, limited range of motion, stiffness in the affected area |
| Diagnostic Methods | Physical examination, ultrasound, MRI (Magnetic Resonance Imaging), X‑ray (rarely) |
| Treatment Methods | Rest, ice application, anti‑inflammatory medications, physical therapy, steroid injections, radiofrequency, embolization |
| Possible Complications | Chronic pain, tendon rupture, tendon degeneration |
| Prevention Methods | Regular exercise, proper warm‑up and cool‑down techniques, good posture, avoiding overexertion |
| Recovery Time | A few weeks for mild cases, several months for more severe cases |
Prof. Dr. Özgür KILIÇKESMEZ
Interventional Radiology / Interventional Neuroradiology
What Is Tendinitis?
Tendinitis is an inflammatory condition that arises when tendons are damaged. This health issue typically develops due to repetitive physical activities. It is especially common in areas such as the shoulder, elbow, knee, ankle, and heel. Tendons are structures that connect muscles to bones and play a critical role in your ability to move. Overuse can lead to micro‑tears in the tendons, resulting in inflammation and pain. Prominent symptoms of tendinitis include pain that increases during movement, stiffness in the joints, and cracking sounds during motion. These symptoms can make daily activities difficult and reduce quality of life.
What Are the Causes of Tendinitis?
Tendinitis is a multifactorial condition that can arise from various factors. The primary causes include mechanical overload of the tendons due to repetitive strain and overuse. These stresses often occur during specific jobs or sports activities. Tendons gradually wear down and suffer micro‑traumas from continuous repeated movements, leading to degenerative changes in the tendon tissue.
- Jobs requiring continuous repetitive movements, such as construction work or assembly line tasks, place additional stress on tendons.
- Sports involving repetitive motions like running and jumping can particularly affect the Achilles tendon.
Over time, the tendons’ capacity to repair is exceeded by repeated injuries, resulting in pain, stiffness, and functional loss. Genetic factors can also increase the risk of tendon injuries. Mutations in collagen genes can compromise the structural integrity of tendons, making them more prone to damage.
- Genetic variations affecting collagen structure increase the risk of tendinopathy.
Additionally, age and certain health conditions can elevate tendinopathy risk. Reduced tendon elasticity and vascularity with age lead to a higher risk of degeneration.
- Older individuals experience decreased tendon elasticity, increasing degeneration risk.
- Diabetes, obesity, and rheumatic diseases can impair tendon health.
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How Common Is Tendinitis?
Tendinitis affects approximately 5% of the general population. It is more prevalent among athletes and individuals engaged in repetitive-motion activities. Incidence increases with age, particularly in middle-aged and older adults.
Age Group Distribution:
- Rotator cuff tendinopathy is especially common in older adults, affecting up to 50% of individuals over age 70.
- Among athletes, Achilles and patellar tendinopathies are prominent. Sports involving jumping, such as volleyball and basketball, predispose to these conditions.
Gender Distribution:
- Men are more prone to certain tendon inflammations, such as Achilles tendinopathy, with a male‑to‑female ratio of approximately 3:1.
- Rotator cuff tendinitis becomes more common in women with advancing age.
Activity Level Analysis:
- High‑activity sports trigger the development of Achilles and patellar tendinopathies. Among runners, Achilles tendinitis prevalence can reach 40%.
- Patellar tendon injuries occur in jumping sports at a rate of about 24.8%.
What Happens During Tendinitis?
The tendinitis process is characterized by significant structural changes in the tendon. Mechanical overuse disrupts the tendon’s structural integrity and initiates various cellular processes. Initially, tendon fibers lose their normally organized and strong structure. Collagen fibers become disorganized, especially with an increase in Type III collagen, reducing the tendon’s elasticity and strength.
Extracellular Matrix (ECM) Disruptions:
- Disorganization of the ECM
- Mucoid degeneration leading to separation of collagen fibers
These structural changes decrease the tendon’s resistance to mechanical loads, resulting in pain and functional limitations. New blood vessels and nerves develop around the tendon—structures not typically present in healthy tendons—which contribute to increased pain.
The interaction of cellular changes and mechanical stress is a primary cause of tendinopathy. Overloading activates tenocytes excessively and increases inflammatory responses. Tenocytes produce matrix metalloproteinases that degrade the ECM and accelerate tendon degeneration. Thermal and hypoxic conditions from mechanical stress can also induce tenocyte death.
Microscopic Examination of Tendinitis
Under the microscope, acute inflammatory changes in tendinitis are evident. Initially, collagen fibers appear disorganized, whereas they are normally parallel and well‑aligned:
- Collagen Disarray: Fibers lose their organized structure, becoming wavy and irregular.
- Hypercellularity: Increased cell count, particularly inflammatory cells such as tenocytes, macrophages, and neutrophils.
- Neovascularization: New blood vessel formation in the inflamed area to aid tissue repair.
In chronic degeneration (tendinosis), the picture is more complex. Unlike acute tendinitis, chronic tendinosis shows severely fragmented and degraded collagen fibers, directly impairing tendon elasticity and function. Key microscopic features in the chronic phase include:
- Collagen Disarray: A chaotic and irregular collagen matrix.
- Fibrosis with Hypercellularity: Abnormally increased tenocyte-like fibroblast cells.
- Neovascularization and Hypoxia: Functionally poor new vessels causing localized hypoxia.
- Absence of Classic Inflammation: Lack of inflammatory cell infiltration, highlighting the degenerative nature.
What Are the Symptoms of Tendinitis?
Tendinitis manifests as inflammation in the tendons, presenting with gradually onset pain that worsens over time, particularly during certain physical activities. The most prominent symptom is localized pain at the affected tendon site. This pain often intensifies with movement and may subside with rest.
Patients report tenderness and pain upon palpation of the affected area. Mild to moderate swelling may also be present as an inflammation indicator.
- Severe or dull pain
- Tenderness at the affected site
- Pain that increases with movement
- Pain that eases with rest
- Mild to moderate swelling
Inflammation of the tendon and surrounding tissues can reduce joint mobility. Patients may struggle to move the affected joint normally, limiting daily activities and reducing quality of life. Another common finding is increased pain when pressure is applied to the inflamed tendon. If left untreated, tendinitis can progress to chronic pain and permanent functional loss, making early and appropriate treatment essential.
How Is Tendinitis Diagnosed?
Diagnosis of tendinitis relies on characteristic symptoms and detailed medical evaluations. Physicians use various methods to assess tendon health and range of motion. The initial step is a physical examination, during which the doctor evaluates tenderness, swelling, and pain in the tendon. Special tests may be performed to detect tears or inflammation.
Imaging techniques play a critical role in diagnosing tendinitis. The two most commonly used methods are:
- Ultrasound: Provides dynamic visualization of tendon structure and movement. Tendon thickening and echogenic changes are identified. Doppler ultrasound highlights increased blood flow, indicating disease presence and severity.
- Magnetic Resonance Imaging (MRI): Used for complex or deep tendon injuries. Offers high-resolution images of soft tissues, clearly showing tears and degeneration.
How Is Tendinitis Treated?
Various effective treatment methods are available for tendinitis. Each method offers potential benefits depending on the specific case:
- Platelet-Rich Plasma (PRP) Injections: Uses concentrated platelets from the patient’s own blood to accelerate tendon healing. Particularly beneficial for chronic tendinitis, PRP supports tendon cell regeneration, improves tendon structure, and reduces pain. Long‑term outcomes may surpass those of other treatments.
- Corticosteroid Injections: Used for acute pain management. Corticosteroids are potent anti‑inflammatory agents that quickly reduce pain and swelling. However, long‑term use can weaken tendons and increase rupture risk, so they are typically reserved for short‑term relief.
- Extracorporeal Shock Wave Therapy (ESWT): A non‑invasive treatment that uses sound waves to promote tissue repair. Effective for conditions like calcific tendinitis. ESWT has shown success in reducing pain and improving tendon function.
Embolization: For refractory tendinitis unresponsive to other treatments, embolization is performed via angiography as a day‑case procedure. It reduces blood supply to the problematic tissue, preventing inflammation and promoting healing.
Prognosis of Tendinitis
The recovery process and expectations for tendinitis vary based on severity and treatment adherence. In acute cases, early intervention with rest and ice application often leads to significant improvement within three to six months. Physical therapy is crucial for accelerating healing and preventing recurrence. Chronic cases may take six months to a year to recover fully. Severe cases requiring surgery have a longer recovery, typically six to twelve months.
Factors affecting recovery include:
- Age: Older patients may experience slower healing.
- Early Intervention: Prompt and effective treatment shortens recovery time.
- Activity Modification: Reducing stress on the affected tendon supports healing.
- Underlying Health Conditions: Conditions like diabetes can delay recovery.
Tendinitis recurrence risk and long‑term outcomes are also influenced by addressing underlying biomechanical issues. Conservative treatments may achieve initial healing, but failure to correct biomechanical factors increases the likelihood of recurrence.
What Are the Complications of Tendinitis?
If tendinitis is not treated appropriately and in a timely manner, it can lead to serious complications. The most common and severe complications include tendon rupture and chronic pain due to tendinosis.
Tendon Rupture:
- Tendons can tear due to excessive strain or repetitive movements.
- Weakened tendon structure increases rupture frequency.
- Some tendons, such as the Achilles tendon, are at higher risk of rupture.
- Inappropriate treatments, like excessive corticosteroid injections, can elevate risk.
Chronic Pain and Tendinosis:
- Progression of untreated tendinitis can lead to tendinosis.
- Tendinosis is characterized by structural degeneration and collagen breakdown in the tendon.
- Long‑term inflammation leads to scarring and loss of tendon function.
- Untreated tendinosis causes permanent pain and discomfort.
Frequently Asked Questions
Tendinitis is most commonly seen in the following areas:
- Shoulder: Rotator cuff tendons are frequently affected, causing shoulder pain.
- Elbow: Tennis elbow (lateral epicondylitis) and golfer’s elbow (medial epicondylitis) are common types.
- Wrist: Tendons responsible for hand and finger movements are affected by repetitive motions.
- Knee: Patellar tendonitis (“jumper’s knee”) is common in athletes.
- Ankle: Achilles tendinitis is prevalent among runners and those engaging in ankle‑motion activities.
- Thumb: De Quervain’s tendinitis causes pain in thumb and wrist movements.
These areas are more susceptible to tendinitis due to repetitive stress and overuse.
Tendinitis is characterized by localized pain and tenderness along a tendon, which increases with movement or pressure and may be accompanied by swelling. In contrast, bursitis involves inflammation of the bursae, causing joint pain and swelling, while arthritis affects the joints themselves, resulting in pain, stiffness, and swelling. The distinguishing feature of tendinitis is that it exclusively affects tendons and the pain typically occurs during active movement or direct pressure on the tendon; other conditions present more generalized symptoms.
Physical therapy is highly effective in tendinitis treatment. Exercise therapy, including isometric and isotonic exercises, has demonstrated meaningful effects in pain reduction and functional improvement, with standardized mean differences of small (0.34), medium (0.73), and large (1.21) effect sizes. Isometric exercises, while not superior to isotonic exercises, are key components of rehabilitation programs. In calcific tendinitis of the shoulder, radial shock wave therapy (RSWT) resolved calcification completely in 86.6% of patients, outperforming other control treatments. Low‑level laser therapy (LLLT) provides short‑term pain relief for subacromial impingement syndrome (shoulder tendinitis). Overall, therapeutic exercises and specialized modalities like RSWT and LLLT offer significant improvements in pain and function in tendinitis management.
Untreated chronic tendinitis leads to tendon degeneration, increasing the risk of partial or complete tendon tears, which may necessitate surgical intervention. In the shoulder, it can cause adhesive capsulitis (“frozen shoulder”), rotator cuff tears, greater tuberosity osteolysis, and ossifying tendinitis. Additionally, it results in chronic pain and disability, significantly impairing daily activities and quality of life.
To prevent tendinitis in daily activities:
- Perform regular warm‑ups to prepare muscles and tendons before physical activity.
- Use proper posture and techniques during exercise and work to avoid excessive tendon stress.
- Avoid repetitive movements; vary activities and take frequent breaks to prevent overuse.
- Gradually increase activity levels to allow your body to adapt and reduce tendon strain.
- Listen to your body’s signals; stop activities that cause pain and allow time for rest.
These measures can significantly lower the risk of developing tendinitis.
Prof. Dr. Özgür Kılıçkesmez graduated from Cerrahpaşa Medical Faculty in 1997. He completed his specialization at Istanbul Education and Research Hospital. He received training in interventional radiology and oncology in London. He founded the interventional radiology department at Istanbul Çam and Sakura City Hospital and became a professor in 2020. He holds many international awards and certificates, has over 150 scientific publications, and has been cited more than 1500 times. He is currently working at Medicana Ataköy Hospital.
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