Synovitis and tenosynovitis are both inflammatory conditions affecting the synovial membrane, a type of specialized connective tissue that lines the inner surfaces of joints and tendon sheaths. This membrane serves many purposes, including:
Inflammation of this structure can lead to the development of swelling and pain in joints, especially during movement.
Certain joints, such as the knees, hips, wrists, shoulders, and ankles, contain a synovial fluid lined by a synovial membrane. When the membrane becomes inflamed, it leads to a condition called synovitis, often resulting in swelling, joint pain, and bleeding within the joint. If not treated early or correctly, the synovial membrane can become thickened, growing additional blood vessels and leading to repeated causes of bleeding in the affected joint.
Tenosynovitis affects tendon sheaths, which are tube-like connective tissue filled with lubricating fluid surrounding tendons. Tendons are flexible but inelastic strong fibrous collagen tissue that attaches muscle to bone, allowing us to passively modulate forces during movement. If the outside covering of these tendons becomes inflamed, it is called tenosynovitis, leading to the development of pain with movement.
Synovitis is a defining characteristic of rheumatoid arthritis, an autoimmune disease that causes chronic inflammation of the joints. In this condition, cells in the inflamed membrane attract other inflammatory cells from all around the body to induce an inflammatory process causing joint pain.
Synovitis joint pain can be seen in other illnesses such as juvenile arthritis, lupus, psoriatic arthritis, rheumatic fever, tuberculosis, injury, or gout. However, there are some cases where the cause of synovitis is not known, with the affected individual possibly sustaining a minor injury or not recalling having an injury at all, yet the signs of synovitis inflammatory condition are appreciated.
It is believed that inflammation of the tendon sheath is caused by overuse, however, the exact mechanisms behind this condition are not clear in some cases. Overuse can result in injury to the tendon or surrounding muscle and bone, making tenosynovitis development very likely. The condition can occur in those who perform a variety of repetitive motions, such as assembly line work, weeding, and even excessive keyboard typing, with the wrists, hands, and feet being common locations.
Inflammation of the synovial membrane within joints produces excess synovial fluid, which aids in the perpetuation of joint inflammation. Excess fluid in the affected joint often leads to swelling and is commonly called “water on the knee.” Pain is the most common presenting symptom that occurs at nearly any level of activity. It can even occur at night time, disrupting sleep.
If left untreated, synovitis may cause joint damage and be the main cause of joint pain and dysfunction. Because the autoimmune condition can result in synovitis, an affected joint may be warm to the touch, owing to increased blood flow and inflammatory constituents that have collected there. The joints often feel puffy or boggy to the touch, leading to joint stiffness and the inability to move the joint freely.
Tenosynovitis is characterized by pain and tenderness of the affected tendon, with common sites being the hands, wrist, and foot areas. This may result in movement difficulty and the joint appearing red due to inflammation.
In cases caused by infection, symptoms may also include tenderness, swelling, and fever. These are common features of the gonococcal type of tenosynovitis, which begins as a sexually transmitted infection that can spread to the joints if not promptly treated.
Tenosynovitis that affects smaller joints of the fingers may lead to sustained flexion of the fingers, giving the appearance that they are locked in place. In serious cases, manual finger manipulation may be deeded to help alleviate this condition.
The first thing your doctor will do is examine the affected joint. Documentation of the presence of pain, warmth, any discoloration, the range of motion, and the size will be done. Detailed information about how the joint becomes swollen will be asked to get a better idea about its onset.
Preliminary tests using ultrasound or MRI can help give an image of how much fluid accumulation has occurred within the joint. Ultrasounds, in particular, can be a speedy and convenient choice for a quick diagnosis. An x-ray may also be obtained to rule out a potential fracture. Blood tests may also be taken to help diagnose any causes of bacterial infection affecting the body. However, simply knowing that there is fluid surrounding the joint is not enough information to guide treatment. This would require the use for more specific testing.
Synovial fluid analysis involves using a syringe to collect synovial fluid directly from the affected joint – also known as joint aspiration. Once this fluid is collected it can be analyzed looking at color, clarity, viscosity, white blood cells, and polymorphonuclear leukocytes (PMN) – a category of white blood cells.
The initial evaluation will occur in a very similar fashion to that of synovitis, with patient history and physical examination, including palpation or specific maneuvers to assess pain. The use of imaging tests such as ultrasound or MRI may also be done to confirm or rule out other disorders.
If the infection is suspected as being a cause, a culture of the suppurative synovial fluid will be taken to choose the best treatment against it. The joint fluid analysis may also be done and will help diagnose infections. Obtaining blood samples may also help to support a diagnosis of infection or other causes of tenosynovitis such as an autoimmune disease.
There are a number of different causes for synovitis and tenosynovitis. Some may be due to an infection or disease, causing symptoms over time, while others may occur more acutely, such as a traumatic injury. The underlying cause of your particular cause of synovitis or tenosynovitis will ultimately guide treatment.
For the most part, regardless of the underlying cause, non-steroidal anti-inflammatory drugs (NSAIDs) will be prescribed to reduce swelling and pain associated with synovitis and tenosynovitis. Corticosteroids are another class of drugs that may be utilized to help reduce these symptoms if NSAIDs are found to be insufficient, however, they are seldom used due to increased side effects
Constant stress on the affected joint will make it difficult for the healing process to occur, which is why rest is an important part of recovery. Stress can occur even by simply standing for long periods of time, taking a toll on weight-bearing joints. Applying ice on the affected knee to help reduce pain and swelling.
Those affected by gout, leading to joint swelling, are often recommended to take colchicine, which helps to prevent gout flare-ups. The use of NSAIDs and corticosteroid injections may also help with pain in these patients. Drugs such as allopurinol or probenecid help to lower the production of uric acid in the body.
In cases where there’s an infection causing fluid buildup, antibiotics can be used.
In severe cases where damage is serious, surgical repair or even joint replacement may be the only option.
Recover for synovitis may take a few days to weeks once treatment has been implemented. In contrast, tenosynovitis may take a couple of weeks depending on the cause. Both conditions outcomes will ultimately depend on the severity of the condition and how prompt treatment was given. Avoiding trigger factors and appropriate activity restriction can prevent recurrence and further damage to joints and tendons.