What Is Tenosynovitis

Overview 

Tenosynovitis refers to the inflammation of a space called the synovium within the tendon sheath. Tendons are a type of connective tissue that connects the muscle to the bone l. The synovium is a space around the tendon and is filled with fluid for lubrication. 

Tenosynovitis usually presents with localised pain, swelling, and difficulty moving the affected region ). However, the exact manifestation depends on the cause. While this condition can affect any tendon in the body, certain areas like the hand, wrist, and foot are more commonly involved. 

In this article, we will discuss the causes, types, clinical features, and treatment strategies of tenosynovitis, with emphasis on the wrist.

Anatomy of tendons

A tendon connects the skeletal muscles to the bones, passing over joints and controlling their movement. The tendons in the wrist are arranged in an intricate pattern, allowing the hand various specialised movements like gripping, grasping, and precise coordination.

The tendons pass down the forearm and through a canal called the carpal tunnel. This tunnel is formed by a fibrous band over the inner wrist. After exiting the carpal tunnel at the wrist, the tendons stretch past the palm and enter smaller tunnels called fibrous sheaths on the inner surface of each finger. Within each tunnel, the tendons are surrounded by a synovial sheath. The fibrous tunnel and synovial sheath collectively are called the tendon sheath.

The tendon sheath has the following functions:¹

1. The synovial fluid provides nourishment to the tendon and lubrication, allowing the tendon to glide smoothly and preventing damage due to friction.
2. The sheath also prevents the excessive bowing of tendons while moving by fixing the tendons to the bony surfaces.

Causes and risk factors

There are different types of tenosynovitis, which can be categorised based on cause as infective and non-infective. However, regardless of the cause, the mechanism of tenosynovitis is the swelling and thickening of the tendon sheath, which in turn compromises its smooth movement in the joint. This is what causes pain and restriction in the range of motion of that joint.

Autoimmune

Autoimmune tenosynovitis is due to damage to the tendon as a result of excessive immune activity at the site. Rheumatoid arthritis has been linked with tenosynovitis, with up to 87% of rheumatoid arthritis patients having radiological features of tenosynovitis on MRI.² Psoriatic arthritis is also a commonly associated autoimmune condition.³

Overuse

Repetitive movements of the joint can, over time, cause inflammation of the synovial sheath. This is referred to as “repetitive strain injury” or “overuse syndrome”. Common causes may be daily tasks such as working on a computer for a long period of time or lifting a baby, which utilises and strains the fingers, wrist, and forearm. Prolonged repetitive movements of any kind can increase the risk of tendon irritation and, by extension, tenosynovitis.  

Idiopathic

When no existing condition or cause can be attributed to tenosynovitis, it is said to be idiopathic.

Infective

Infective tenosynovitis is caused by infective organisms that colonise and grow within the tendon sheaths. They can enter the sheaths directly during an injury or can originate from a distant or nearby infection site and spread to the tendon sheath through various channels, such as the bloodstream. The common causative organisms implicated in infective tenosynovitis include Staphylococcus aureus (40 to 75%), Methicillin Resistant Staphylococcus Aureus (MRSA) (29%), other common normally present skin bacteria such as Staphylococcus epidermidis, beta-hemolytic Streptococcus, Pseudomonas aeruginosa. Others include Eikinella in human bites and Pasturella multocida in animal bites.

Risk factors

Various conditions can exacerbate or trigger tenosynovitis. A few are:⁴

• Collection of pus in the joint area, 
• Autoimmune conditions such as Rheumatoid arthritis, Scleroderma, Reiter’s syndrome
• Diabetes Mellitus
• Gout
• Crystalline deposits in the joint space 
• Overuse (especially frequent, repetitive movements)
• Injury to the tendon, muscle, soft tissue or joint (sprains and strains)
• Standing for long periods of time

Signs and symptoms of tenosynovitis

Tendons in the areas of the body which are frequently used are more prone to tenosynovitis. These include the wrists, hands, feet, ankles, elbows and knees. The condition usually presents with:

• Pain at the affected tendon 
• Localised swelling with redness
• Reduced range of motion
• Pain during movement
• Joint stiffness
• Catching or locking of the joint
• In later stages, it might progress to contractures

Diagnosis of tenosynovitis 

Clinical examination

A detailed history and physical examination are essential parts of diagnosing tenosynovitis. Your healthcare practitioner will likely ask you many questions to ascertain your symptoms, their onset, their nature, and their progression. They will also perform a general physical examination as well as an examination of the affected joint to assess any tenderness, swelling and range of movement.

Imaging techniques

Radiographic tests may be helpful but are not always necessary when diagnosing tenosynovitis. Plain X-rays often show areas of calcification in the synovial membrane or signs of inflammation. However, in some cases, they may be normal, with no signs, even when clinical signs are present. Computed tomography (CT) scan produces more specific images that may display bony abnormalities such as bone erosions or any abnormalities in the bone and joint structure. Even so, its sensitivity in detecting soft tissue signs for synovitis and tenosynovitis is low.

Ultrasound scans can be beneficial in diagnosis at times, especially in the hands, where they can show texture changes in the tendons and blurring of the tendon margins. When ultrasound images are not adequate or if further details are necessary, Magnetic Resonance Imaging (MRI) is a possible option. A contrast MRI may be suggested, which involves injecting a dye through the blood vessels to make certain structures appear more clearly during the scan. 

Laboratory tests for underlying conditions

Lab tests do not identify the presence of tenosynovitis. The importance of laboratory investigations is to determine the cause of tenosynovitis, especially if it is suspected to be due to an infection. Thus, it may not always be prescribed. Autoimmune aetiologies reflect raised inflammatory markers, such as RA factor in Rheumatoid Arthritis.

Treatment of tenosynovitis

Treatment for tenosynovitis depends on the underlying cause. However, certain modifications are beneficial in most cases. Most cases are treated conservatively with medications, physical therapy, rest, and activity changes. Common management strategies include:

Medications for pain and inflammation

• Non-steroidal anti-inflammatory drugs (NSAIDs) are the first line of management.⁵
• Another group of drugs are Disease-modifying antirheumatic drugs (DMARDs) such as glucocorticoids. These are prescribed in patients who do not respond to a trial of NSAIDs.⁶
• Antibiotics are required if the underlying cause is due to an infection
• Glucocorticoid injections into the tendon sheath can help reduce inflammation and pain.
• Surgical intervention may become necessary after 3 to 6 months of progression despite conservative therapy.⁵

Physical therapies and activity modification

Physiotherapy and simple exercises are often helpful in managing the stiffness associated with tenosynovitis. It is also important to rest the affected joint and tendon. Sometimes, your healthcare provider may suggest a splint to support and restrict movement in the region. This splinting is done in a joint position that is the most comfortable and least painful. It is also helpful to be worn at night. Resting also includes avoiding any movements or actions that cause pain and reducing frequent repetitive movements of the affected area

Surgical intervention

Surgeries are indicated in situations where the inflammation is severe or where it has been three to six months of disease progression, even after initiating medical treatments and activity modifications. The intervention aims to decompress the affected tendons and clear away any inflammatory tissues.

The overall prognosis of tenosynovitis due to overuse or tunnel narrowing remains promising, with most patients reporting an improvement within six to ten weeks of wearing a splint. Most individuals will have complete resolution. However, the recovery in other forms depends on the underlying cause and how well it is managed.

FAQs

How can I prevent tenosynovitis?

The prevention of tenosynovitis depends on the cause. Avoiding situations that can increase the risk of infection is vital in preventing infectious tenosynovitis. This may include proper cleaning of any wounds and following instructions with regard to dressing an injury. Early detection of any signs of infection, such as tenderness, pain, and swelling by the patient, is important in ensuring good healing.
Patients who have a history of tenosynovitis due to overuse or autoimmune causes should identify and avoid activities that worsen symptoms. Medical care to address any underlying systemic disease, such as autoimmune conditions or diabetes, also influences tenosynovitis.

When should I see a doctor for tenosynovitis?

If you have noticed any of the symptoms mentioned above, it would be best to consult your physician. These include, but are not limited to:

• Pain
• Swelling
• Localised redness
• Stiffness
• Reduced range of movement of the joint

It is important to contact a healthcare professional and seek their guidance if you feel you may have tenosynovitis. Self-medicating can be unhelpful at best and dangerous at worst, so it is important to take medicines when prescribed and as instructed.

Summary

Tenosynovitis is inflammation of the tendon sheath, causing pain and swelling. The condition may have many causes but is more common in those with pre-existing health conditions, such as diabetes and autoimmune illnesses. It may also be caused by an infection of the tendon sheath. Patients usually notice pain, stiffness, inflammation, and, in some cases, contractures.

Treatment focuses primarily on reducing pain, resting the joint and modifying activities to facilitate healing. Disease-modifying antirheumatic drugs (DMARDs), steroids, and antibiotics are used when specifically indicated. If you believe you or your loved one may have tenosynovitis, it is best to consult your healthcare professional for advice.