What is Flexor Tenosynovitis?
Flexor tenosynovitis is a condition where there is inflammation around the flexor tendons of the finger.1 Tenosynovitis means inflammation of a tendon and the surrounding sheath. Flexor tenosynovitis is the condition where there is irritation and inflammation of the sheath surrounding the flexor tendons. When this happens, the flexor tendon catches and the patient is unable to extend or flex the finger. Majority of the cases of flexor tenosynovitis are infectious in nature; however, flexor tenosynovitis can also occur due to inflammation from noninfectious causes, such as overuse, diabetes and arthritis.
The exact cause of flexor tenosynovitis is not clear. Individuals with diabetes are at an increased risk for developing this condition. According to research, increased glucose levels increase the risk of development of flexor tenosynovitis. The longer the patient has diabetes, the higher the risk for having flexor tenosynovitis.
Causes of Flexor Tenosynovitis
Flexor tenosynovitis occurs when there is proliferation of fibrous tissue in the tendon sheath, the exact cause of why this happens is not known. There are certain factors which are thought to lead to development of flexor tenosynovitis such as:
- Repetitive movements or overuse of the fingers.
- Systemic disorders, such as arthritis, diabetes, systemic sclerosis or gout.
- Infection can also lead to development of flexor tenosynovitis.2
- The risk for having flexor tenosynovitis increases as the person’s age increases, due to the decreased vascularity of the tendons.
Symptoms of Flexor Tenosynovitis
- Patient suffering from flexor tenosynovitis can experience symptoms of stiffness in the fingers after waking up.
- A clicking sound can be felt when the finger is moved and patient feels increased pain with the finger movement. This is commonly in the thumb or in a single finger.
- Patient with flexor tenosynovitis can have symptoms of redness and swelling in the entire finger.
- Symptoms of flexor tenosynovitis can also include tenderness or a bump present at the base of the affected finger and where the tendon is catching.
- Eventually, patient cannot completely extend the finger and it becomes locked. In such cases, manipulation is needed to extend the finger.
Difference between Infectious Flexor Tenosynovitis & Inflammatory Flexor Tenosynovitis
Infectious Flexor Tenosynovitis occurs as a result of trauma or injury occurs due to direct inoculation through a laceration, bite or puncture. Common pathogens seen in trauma are streptococci and staphylococcus aureus. In case of Infectious Flexor Tenosynovitis, patient has the Kanavel’s signs which are:
- There is fusiform swelling of the finger (sausage finger).
- The finger is held or bent in a slightly flexed position.
- Patient feels pain with passive extension of the affected digit.
- There is tenderness present along the flexor tendon sheath.
Inflammatory Flexor Tenosynovitis occurs as a result of an underlying disease process. The disease progression is slow; however, the condition worsens if treatment is not started. Symptoms are similar to infectious flexor tenosynovitis with swelling being the commonest initial sign. There is a difference in passive versus active flexion. As there is expansion of the tissue along with impingement, patient will experience pain and decreased movements.
Diagnosis of Flexor Tenosynovitis
Physical examination of the patient is done, which includes tendon-specific maneuvers that include stretching of the tendon to see if the patient has pain.3 Ultrasound or MRI scan can be done to exclude other disorders such as rotator cuff tendonitis and to confirm the diagnosis of flexor tenosynovitis. Diagnosis can also be confirmed through histopathological and microbiological evaluation. If the patient has joint effusion then diagnostic arthrocentesis can be done.
Treatment of Flexor Tenosynovitis
Infectious flexor tenosynovitis requires immediate medical attention, as the tendon sheath is a closed space and increased or excessive swelling can result in compartment syndrome and necrosis. Treatment of Flexor Tenosynovitis consists of:
- Patient suffering from flexor tenosynovitis is started on antibiotics.
- Corticosteroid injections can be given to help relieve the inflammation of the flexor tendon.
- Rest is important to relieve pain and inflammation of the flexor tendon. Heat or cold application can also be done to relieve the symptoms.
- Surgical intervention is started and in case of early or mild infection, tendon sheath irrigation and drainage with or without debridement is usually sufficient. For advanced infection, debridement of the tendon sheaths and the necrotic tissue around it is done.
- If treatment is started within 24 hours of development of infection, then flexor tenosynovitis can be managed medically; otherwise, surgical intervention is necessary.
- After relief from flexor tenosynovitis, patient should follow strengthening exercises of the muscles around the flexor tendon. This helps in prevention and recurrence of symptoms and injury.