Explanation of Ulnar Deviation: How This Hand Splint for Rheumatoid Arthritis Can Help This hand brace for ulnar deviation supports the knuckles at the base of your fingers, helping to maintain neutral alignment of your metacarpophalangeal (MP or MCP) joints. Though splinting has not been found to prevent deformity, it can help you maintain the function of your hands, reduce pain, prevent morning stiffness, relieve stress, and slow the shifting of your wrist and fingers in an ulnar direction. The ulna is a bone in your forearm, which is present on the same side as your pinky finger.