Rheumatoid arthritis is an autoimmune condition in which the body mistakenly attacks healthy joint tissue. Although any joint can be affected, hand joints are often affected. These hand and finger joints become painful and swollen, limiting movement. As the disease progresses, deformities often develop in the joints of the hand. Several different splints are used to reduce pain and correct positioning of these joints to improve daily function.
Rheumatoid arthritis makes the body to attack healthy joint tissue, causing inflammation and breakdown of the synovium -- the soft tissue that lines joints. Arthritis can damage the synovium between the eight bones in the base of the hand and the forearm bones that form the wrist joint. Wrist splints are worn to support painful joints and improve function with daily tasks such as laundry, cooking and leisure activities. Wrist splints may extend to support the base of the thumb, reducing pinching and helping to facilitate writing and other activities. Hand splints used for people with rheumatoid arthritis typically cover approximately half of the length of the forearm and end in the palm. The wrist is prevented from bending forward or backward, helping the muscles relax. Wrist splints can be premade or custom-molded from low-temperature thermoplastic materials. Prefabricated splints may be suitable early in the disease process, but custom splints are often necessary to accommodate joint deformities that have developed.
Ulnar Deviation Splint
Rheumatoid arthritis often damages the joints and ligaments around the large knuckles of the hand, the metacarpophalangeal or MCP joints. As damage progresses, a joint deformity called ulnar deviation occurs. The fingers become angled toward the pinky side of the wrist, limiting gripping, pinching and fine motor skills such as writing. A hand-based splint with soft supports between the base of each finger can be worn to support the MCP joints in proper alignment. This splint is worn during the day to improve finger function. The splint holds the fingers straight so that the hand can be used to grip objects. Ulnar deviation splints are used early in the disease process to decrease inflammation of the synovium. With time, hand deformities often worsen and cannot be corrected with this splint.
Post-Operative Dynamic Splint
Severe ulnar deviation of the MCP joints may require surgical correction. Diseased joints are removed and replaced with silicone implants. After the procedure, a custom thermoplastic splint is made to allow movement of the fingers while supporting the healing joints. A forearm piece covering half the length of the back of the forearm is made first. A metal attachment with four slings is permanently attached to this base and positioned over the back of the hand. Each finger is placed into a sling. Rubber bands attached to the slings are used to provide assistance with straightening the fingers. They can actively bend and then return to a straight position by the pull of the rubber bands. This splint is worn during the day for up to three months to protect the tendons that have been realigned over the back of the knuckles.
Hand pain from rheumatoid arthritis can make it difficult to sleep. A resting splint is helpful for reducing nighttime pain, allowing the joints to rest and decreasing inflammation. A custom splint is molded, covering half of the length of the forearm through the fingertips. The thumb can be included if it is painful. This splint is molded with the hand in a comfortable position. Typically, the wrist is bent backward slightly, the large knuckles are bent to approximately 60 degrees, and the fingers are straight. This splint can also be worn as needed during the day to rest the hand, although function will be restricted.
Rheumatoid arthritis often attacks the middle finger joints, known as the proximal interphalangeal or PIP joints. This leads to soft tissue damage and two common deformities. A swan neck deformity causes the PIP joint to bend excessively backward. A boutonniere deformity bends the knuckle forward. Plastic or metal oval-shaped splints are worn at this joint to correct its position and improve function. These splints are low profile and don't restrict motion at any other finger joints. Finger splints are most effective early in the course of rheumatoid arthritis, before deformities develop that cannot be corrected.