Tenosynovitis is defined as an inflamed tendon sheath. The sheath is the membrane covering a muscle tendon unit. Soft tissue swelling and pain with movement are usually associated with this disorder.

The cause of the condition is often unknown. Repeated or extreme trauma, arthritis, strain or excessive exercise or both are frequently implicated as causes of the condition.

Signs and symptoms of the condition may include: pain, which may be severe and associated with disabling pain on movement; swelling; tenderness; inflammation; and friction rubs, which may be felt on movement of the tendon in its sheath, or heard with a stethoscope. When the thumb is involved, there is local tenderness and occasional swelling along the course of the tendon. Sharp pain may be felt when the thumb rests across the palm and the thumb is closed over by the fingers.

Tests include x-rays that may show calcium deposits. Also, other useful diagnostic tests are:

• A complete blood count (CBC), white blood count (WBC) with differential

• An acute phase reactant such as erythyrocyte sedimentation rate (ESR) or C-reactive protein (CRP)

• Ultrasonography can be helpful in diagnosing soft tissue abnormalities and magnetic resonance imaging (MRI) scans are occasionally useful for diagnosis.

Treatment for the condition includes: temporary rest or splinting; application of heat for chronic inflammation and cold for acute inflammation; high doses of nonsteroidal anti-inflammatory drugs (NSAIDs); corticosteroids; narcotic pain relievers; and anesthetics. Removal of fluid and restrictions to activities that aggravate the condition are also treatment options. There may be injections into the tendon sheath of long-acting corticosteroids mixed with a local anesthetic. The treatment for chronic tenosynovitis may include the removal of the tenosynovial membrane (tenosynovectomy) if the condition is a chronic inflammatory process associated with rheumatoid arthritis.

There may be little or no residuals in acute tenosynovitis. In chronic tenosynovitis, the joint may remain weak with restricted movement on extension. There also may be repeated injections of corticosteroids. Factors affecting the incidence of residuals depend on the severity of the disease or injury, the timeliness of treatments, the effectiveness of treatments, and the individual's response to the disease and treatments. Residuals can vary from zero disability to total disability (complete immobility in affected joints).

• The rating schedule for musculoskeletal was updated on February 7, 2021. Protection still does apply and should be considered with existing evaluations (38 CFR 3.951(a)).

• When rating severity the shoulder, elbow, wrist, hip, knee, and ankle are considered major joints.

• When rating severity multiple involvement of the interphalangeal, metacarpal, and carpal joints; interphalangeal, metatarsal, and tarsal joints; and cervical vertebrae, thoracic/dorsal vertebrae, and lumbar vertebrae are considered minor joints, ratable as major joints.

• The minimum compensable evaluation may be assigned under 38 CFR 4.59 based on subjective painful motion, and does not require objective evidence of painful motion.

• To properly rate disability, accurate measurement of joint movement limitations is required and must be reported in degrees. The use of a goniometer in the measurement of range of motion in a joint is indispensable. 38 CFR 4.46 [Accurate measurement])

• The provisions for 10 and 20 percent evaluations for arthritis with multiple joint involvement without limitation of motion do not apply to these conditions as is reflected in Note (2) under DC 5003.

• Since tenosynovitis is not always chronic, chronic residuals are required to establish service connection.

• May be entitled to special monthly compensation where the veteran has a single service-connected disability rated as 100% with additional service-connected disability or disabilities independently ratable at 60% or more, which are separate and distinct from the 100% service-connected disability and involves different anatomical segments or bodily systems. See  38 CFR 3.350(i)(1) – Special Monthly Compensation (SMC).

• Evaluate the diseases under diagnostic codes 5013 through 5024 as degenerative arthritis, based on limitation of motion of affected parts.