Jersey finger injury refers to the damage done to the tip of the ring finger when an athlete grabs the shirt (jersey) of another player while that player is pulling away. The hand grasping the jersey is closed in a fist. But the force of the player wearing the shirt pulls the tip of the ring finger into extension.
The result is a rupture of the tendon away from the bone. A piece of the bone may come with the tendon (still attached). This is called an avulsion injury. There can be a bone fracture along with the tendon rupture.
And although it sounds like this is an injury only an athlete can have, in fact, “jersey” finger injuries occur in nonathletes of all ages. Older adults with rheumatoid arthritis or other inflammatory joint conditions experience this injury as well. The same mechanism takes place: forceful extension of the tip of the finger when it is bent that causes the problem.
Any finger can be affected. The ring finger seems to be the most commonly injured digit because of its unique anatomy. It is the weakest of the fingers and least able to move by itself. The flexor digitorum profundus (or FDP) tendon pulls away from the bone more easily than any other finger tendon.
When the fingers are in a fisted position, the ring finger is actually just a tiny bit more forward than the other fingers. So it absorbs more of the force during a pull-away maneuver compared with the other fingers.
Treatment is based on a classification scheme. The injury can be described as a type I, II, III, IV, or V level of retraction. Retraction refers to how far back toward the palm the tendon has recoiled. Type I describes a flexor digitorum profundus tendon (FDP) that has pulled away from the bone and snapped all the way back to the palm.
Type II injury means the tendon has pulled away from the tip of the finger taking a tiny bit of bone with it but without retracting past the next bone. With a type III injury, the tendon has avulsed with a large bone fragment that has gotten caught or entrapped without moving.
Type IV level of retraction has a ruptured tendon with bone avulsion and retraction back toward the palm. And Type V is a ruptured tendon with bone avulsion. The bone where the tendon has pulled away is broken into tiny pieces (called a comminuted fracture). Type V injuries are further divided into Va and Vb. Type Va means the damage is outside the joint (extra-articular). Type Vb tells us there is intraarticular (inside the joint) damage.
When planning the type of surgery to perform, the surgeon evaluates how far back the tendon has retracted, how much bone damage is present, and if the joint is involved. For example, full retraction of the tendon often means the pulley system that holds the tendon in place has also been disrupted. When the force of the injury is enough to strip the tendon from the bone carrying the pulley mechanism along with it, then the blood supply is also affected.
Besides considering the classification type of jersey injury, the surgeon must also consider how long ago the finger was damaged. The longer the time between the trauma and the treatment, the more likely it is that fibrosis and scar tissue has set in. Pre-operative X-rays and MRIs are helpful in showing the surgeon the extent of the damage and where the retracted tendon is located.
There is limited evidence from high quality studies to guide surgeons as to the very best surgical procedure to use for jersey finger injuries. Sometimes it is possible to reattach the tendon to the bone. In other cases, the tendon must be threaded back where it belongs.
If the tendon has to be pulled from the palm all the way forward to the tip of the finger, then it must be secured to hold it in place. The surgeon can choose between a button repair, anchor repair, locking sutures, or multiple strand sutures. The goals of surgical treatment are 1) to avoid a gap between where the tendon should be attached and where it can be attached and 2) provide a strong enough repair to withstand normal load on the finger.
Even with the best results, patients should expect some loss of motion. The tip of the affected finger may be permanently bent or flexed. Stiffness of the joint at the tip of the finger is common. Restoring full range-of-motion requires an aggressive hand therapy program and a motivated patient. Complications such as infection, too much stretching on the repaired tendon, or rupture of the repair can limit results as well.