Jersey Finger (Flexor Tendon Avulsion) Info

What you're feeling

Jersey finger usually happens in a moment you remember clearly, most often while gripping during sport. A classic example is grabbing a fistful of an opponent's jersey in rugby or football as they pull away, which is where the name comes from. There is a sudden sharp pain at the fingertip, and afterwards the finger swells and may bruise.

The tell-tale sign is that you can't bend the very tip of the finger. The fingertip joint (the small joint nearest the nail, called the DIP joint) won't curl into your palm when you try to make a fist, even though the rest of the finger moves. The ring finger is by far the most commonly affected. Some people also notice a tender lump further down the finger or even in the palm: that lump is the end of the tendon, which has snapped off the bone and sprung back like a released elastic band.

What's actually happening

A strong tendon called the flexor digitorum profundus (FDP) runs along the palm side of each finger and attaches to the small bone at the fingertip. Its job is to bend that last joint. In a jersey finger, the finger is being forced straight at the exact moment the muscle is pulling hard to bend it, and the tendon tears away from where it anchors to the fingertip bone, sometimes pulling off a small chip of bone with it.

How far the loose tendon end springs back matters a great deal, and surgeons group these injuries by exactly that (the Leddy–Packer classification). When the tendon retracts only a short way and stays in the finger, it usually keeps some of its blood supply and can wait a little. When it springs all the way back into the palm, it loses its blood supply and the channel it normally glides through (the pulley system) starts to scar and close. That is why a fully retracted jersey finger is time-critical: the longer it is left, the harder it becomes to bring the tendon back and reattach it. An injury where a fragment of bone is still attached often stays put and can sometimes be dealt with a little later.

What we can do about it

Jersey finger is almost always treated with surgery to reattach the tendon to the bone. There are a couple of ways to do this depending on what the tendon did:

• If the tendon has pulled clean off the bone, it is reattached using a small anchor placed in the bone, or with stitches passed through the fingertip and tied over a button (a "pull-out" repair).
• If it took a fragment of bone with it, that fragment is put back and held in place, usually with a tiny screw, wire or small plate.

The single most important factor is timing. A tendon that has retracted into the palm generally needs to be repaired within about 7 to 10 days, before it loses too much length and blood supply. An injury held by a bony fragment can often be fixed a little later. This is why getting assessed quickly genuinely changes what is possible.

If the injury is missed or only picked up weeks or months later, a simple reattachment may no longer be possible. In that situation the options are bigger operations: rebuilding the tendon with a graft, or, if the fingertip joint is the problem, fusing that small joint to give a stable, pain-free finger. After any of these repairs, a carefully staged hand-therapy programme is essential to get the tendon moving safely without it pulling apart while it heals.

What to expect

When a jersey finger is caught early and repaired well, the outlook is good and most people regain strong, useful movement of the fingertip. Recovery is not quick, though. A repaired flexor tendon is fragile for the first several weeks, so you will wear a protective splint and follow a hand therapist's programme that gradually and safely reintroduces movement, and rushing this is the main way a repair fails. It typically takes a few months to get back to full grip and heavier activities, and your therapist and surgeon will guide the timing of your return to sport or manual work.

It is worth knowing that even a good repair may leave the fingertip joint a little stiffer than the other side. Injuries that were treated late, or that needed a graft or a joint fusion, tend to have more limited fingertip movement, which is exactly why early treatment is so worthwhile.

When to see someone

• You can't bend the tip of a finger after a gripping injury. This is the key sign of a jersey finger and it should be checked promptly: do not wait to see if it settles. What looks like a "jammed" or sprained finger can be a tendon that has torn off the bone, and the best results come from early repair.
• A tender lump in the finger or palm after such an injury, especially with loss of fingertip bending.
• Significant pain, swelling or bruising of a finger after a sporting or gripping injury that isn't settling.
• Any finger injury where movement, sensation or the look of the finger seems wrong: when in doubt, have it assessed, because the window for the best outcome can be short.