Chemosynoviorthesis: Treatment, Effects & Risks

Chemosynoviorthesis is the name given to a procedure used in the therapy of arthritic changes in the synovium (synovial membrane, joint mucosa) in inflammatory joint diseases. Analogous to radiosynoviorthesis (injection of radioactive substances), a chemical pharmaceutical is injected into the affected joint to obliterate the synovial membrane.

What is chemosynoviorthesis?

Chemosynoviorthesis represents a therapeutic procedure for rheumatic or arthritic joint diseases such as chronic polyarthritis (also known as rheumatoid arthritis). For this purpose, a chemical pharmaceutical is injected into the affected joint.

Chemosynoviorthesis is a therapeutic procedure for rheumatic or arthritic joint diseases such as chronic polyarthritis (also rheumatism). For this purpose, a chemical pharmaceutical (including osmic acid, sodium morrhuate) is injected into the affected joint in order to destroy the pathologically altered synovium. Sclerotherapy of the synovium is intended to stimulate renewal and reconstruction of the affected synovial membrane. The treatment procedure often leads to a longer-term improvement in swelling, pain as well as the function of the treated joint. Particularly in larger joints (including the knee joint), chemosynoviorthesis is often performed following surgical removal of the synovial membrane (synovectomy) to obliterate any remaining synovial membrane in the joint.

Function, effect, and goals

Chemosynoviorthesis is used primarily for recurrent or chronic inflammation of the synovium (including chronic polyarthritis, rheumatoid arthritis) that is associated with painful joint swelling. Particularly in monarthritic courses, in which a single joint is affected, chemosynoviorthesis is used in an attempt to locally eliminate the soil or the pathologically altered tissue structures on which the arthritis can develop by means of a chemical pharmaceutical, so that a healthy synovium can subsequently develop in the affected joint. Chemosynoviorthesis may further be indicated when there is no indication for joint surgery or synovectomy, or when other surgical procedures are contraindicated. Similarly, chemosynoviorthesis is used in the presence of active mono- or oligoarthritis (a few joints are affected) as well as chronic polyarthritis with synovitis (inflammation of the synovial membrane) of individual, especially smaller joints. Chemically induced obliteration may also be indicated for recurrent synovialitis secondary to surgical synovectomy. Prior to chemosynoviorthesis, an x-ray of the joint to be treated should be obtained to rule out marked signs of destruction, exposed joint bodies, and aseptic bone necrosis. In addition, a sonogram (ultrasound image) should be used to localize joint effusions and differentiate them from proliferating tissue structures. Following the disinfecting measures, any joint effusions present are first punctured. This should be followed by a diagnostic injection with a local anesthetic (including scandicaine) to rule out periarticular injection before the sclerosing drug is injected intraarticularly. The most common substances used in chemosynoviorthesis are, osmic acid and sodium morrhuate. Osmium acid is absorbed by synovial cells and causes coagulation necrosis in the treated tissue structures. After intra-articular injection, sodium morrhuate causes cytolysis (cell dissolution) via cell membrane damage, which is locally accompanied by a massive inflammatory reaction and synovial membrane necrosis. In addition, immunocompetent tissue structures such as pathologically altered T cells, which among other things are held responsible for rheumatic inflammation, are destroyed by the inflammatory reaction. For the 48 hours following chemosynoviorthesis, the affected joint should be immobilized and sufficiently cooled (e.g. with ice packs). In some cases, chemosynoviorthesis is repeated once or several times.

Risks, side effects and dangers

Common side effects following chemosynoviorthesis include swelling, redness, and pain in the area of the affected joint (worsening of findings), which are induced by the breakdown of the sclerosed mucosa and corresponding inflammatory processes and are treated as part of symptomatic therapy (including cooling, anti-inflammatory, and analgesic medications). Serious side effects or complications are rarely observed with chemosynoviorthesis. However, spread of pathogens located on the skin to the interior of the joint can have dangerous consequences. In extremely rare cases, swelling of soft tissues near the treated joint, which may lead to thrombosis, can be observed. Systemically, i.e. related to the entire human organism, fever and elevated liver and blood cell counts may occur temporarily. In addition, unintentional injection of the sclerosing drugs into soft tissue structures may cause pain and local inflammation, which, however, usually remain inconsequential. Chemosynoviorthesis is also contraindicated in the presence of pregnancy and liver and/or kidney insufficiencies. On the patient’s side, attention must be paid to the consistent pursuit of physiotherapy and the complaint-dependent build-up of stress in order to avoid drug-induced capsular shrinkage after chemosynoviorthesis. Damage to articular cartilage can usually be ruled out with chemosynoviorthesis.