An ulnar gutter splint is a medical device designed to provide external support and immobilization for specific injuries of the hand and wrist. Its primary function is to stabilize the affected area, limiting movement to facilitate the natural healing process of bones and soft tissues.
Understanding the Ulnar Gutter Splint
The ulnar gutter splint is named for its characteristic “U” shape, fitting along the ulnar side of the forearm and hand. It extends from the mid-forearm to the fingertips of the fourth (ring) and fifth (little) digits, effectively enclosing and supporting the area. It specifically immobilizes these two fingers, their metacarpophalangeal (MCP) joints, and the wrist, while leaving the thumb, index, and middle fingers free for function.
The splint holds the wrist in slight extension (typically 10-20 degrees). It also maintains the MCP joints of the ring and little fingers in 70-90 degrees of flexion, with proximal and distal interphalangeal (PIP and DIP) joints in slight flexion. This “safe position” prevents complications like shortening of collateral ligaments and rotational deformities, which can impact hand function and grip strength. Splints are commonly constructed from plaster or fiberglass, applied over stockinette and soft padding for comfort and skin protection.
Conditions Requiring the Splint
The ulnar gutter splint is prescribed for injuries primarily affecting the ulnar side of the hand. It is commonly used for fractures of the fourth (ring) and fifth (little) metacarpal bones, which are the long bones in the palm connecting to these fingers. A notable example is “Boxer’s fracture,” a fracture of the neck of the fifth metacarpal, often resulting from striking an object with a closed fist.
Beyond metacarpal injuries, the splint is indicated for angulated or unstable fractures of the proximal and middle phalanges of the fourth and fifth digits. It also provides support for certain soft-tissue injuries or dislocations affecting these same fingers. In some cases, it may be used for post-surgical immobilization or to maintain proper positioning for conditions like rheumatoid arthritis to prevent joint deviation.
The splint’s effectiveness stems from its ability to provide stable immobilization, which is important for promoting healing. By restricting movement, it helps keep bone fragments aligned, protects healing tissues, and reduces pain. This controlled environment helps prevent deformities, such as bone shortening or rotational issues, which could affect the long-term function of the hand.
Care and Daily Living with the Splint
Proper care of an ulnar gutter splint is important for effective healing and complication prevention. Keeping the splint clean and dry is a primary instruction, as moisture can weaken materials and irritate the skin underneath. If the splint gets wet, drying it thoroughly by patting is important.
Maintaining hygiene around the splinted area is important. Avoid inserting any objects into the splint to scratch an itch, as this can lead to skin irritation, pressure sores, or infection. Blowing cool air into the splint with a hairdryer may alleviate discomfort. Do not make any adjustments to the splint without consulting a healthcare professional.
During healing, monitor closely for potential complications. These include increased pain, worsening swelling, and changes in sensation like numbness or tingling. Discoloration of the fingers (pale, blue, or purple) also warrants immediate attention.
Signs of skin irritation (burning or stinging beneath the splint) or pressure sores should be reported promptly. If any of these symptoms arise, or if the splint feels too tight, too loose, or becomes damaged, seek immediate medical attention. Elevating the injured hand above heart level helps reduce swelling, and wiggling the un-splinted fingers and thumb promotes circulation and prevents stiffness.