Between 5% and 10% of people with lupus develop finger joint deformities ... and the ulnar drift (in which the fingers are angled toward the pinkie). Ankylosing spondylitis (AS) is a rare form ...

Box joints are sometimes called "finger joints ... octagonal trays. Angled box joints are more challenging to cut, requiring a custom jig. These allow the front side of the joint to stay hidden ...