When a finger won’t straighten the way it used to
Dr Nicola Tik
It can happen in a split second, catching a ball, tucking in a sheet or knocking your hand on a door, and suddenly the tip of your finger droops or the middle joint stays bent. Even one small finger can get in the way of typing, buttoning a shirt or holding a mug of tea. Here is what is going on inside the finger, and some practical ways to look after it while it settles.
Running along the back of each finger is a thin, cord-like tendon that pulls the finger straight. It splits into slips that attach to different joints, so it works a bit like a set of reins. One part straightens the joint nearest your nail, and another part straightens the middle joint.
When one of those slips is stretched or torn, the balance between straightening and bending shifts. The finger then settles into a particular shape, depending on which part of the tendon has been affected.
Mallet finger is when the very tip of the finger droops and you cannot lift it on your own, even though you can push it straight with your other hand. It often happens when something knocks the fingertip and bends it suddenly.
Boutonnière (French for buttonhole) is when the middle joint stays bent and the tip tilts backwards. The name comes from the way the joint can push through the injured tendon, a little like a button through a buttonhole. It usually follows a knock or jam to the middle of the finger.
Swan neck is the reverse shape, with the middle joint bending backwards and the tip curling down. It can develop after a mallet finger that has not had a chance to heal, or more gradually alongside conditions that affect the joints, such as rheumatoid arthritis.
If your finger straightens fully and it feels like a sprain, gentle care in the first few days tends to help it settle. Taping it loosely to the finger next to it, sometimes called buddy strapping, gives support while still letting it move.
Swelling around a jammed joint can take a few weeks to fully go down, and that is common. Many people find it feels noticeably better within the first week or two.
When a tendon is involved, a small splint usually does most of the work, because the torn ends need to stay close together while they heal. For mallet finger, the splint holds the tip straight day and night, typically for six to eight weeks. Research comparing splint types suggests wearing it consistently matters more than which design you use. Many hand therapists suggest keeping the finger flat on a table whenever the splint comes off for cleaning, so the tip does not bend.
For boutonnière, the splint keeps the middle joint straight, usually for around six weeks. For swan neck, small ring-shaped splints stop the middle joint bending too far back.
At work, many people find it easier to let the other fingers take over at the keyboard, or to try voice typing. While one finger is held still, gentle movement keeps the rest of your hand comfortable. You could make a loose fist with your other fingers, circle your wrist, and roll your shoulders a few times through the day.
Once your finger feels comfortable, or your splint is off, building up gradually tends to work best. You could start with light tasks like typing or carrying a cup, then move towards firmer gripping and ball sports over the following weeks. Research on mallet finger suggests most people regain good everyday use, even if a slight droop remains.
Your VIDA pain check-in is a good way to keep track of how things are shifting as you get back to the things you enjoy.
If a joint in your finger stays bent and you cannot straighten it yourself, it is worth speaking to your GP soon, as splinting tends to work best when it starts early.