Jersey Finger - Everything You Need To Know - Dr. Nabil Ebraheim

Dr. Ebraheim’s educational animated video describes Jersey Finger - Flexor Digitorum Profundus tendon avulsion injury.
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Jersey Finger
Jersey finger is an avulsion of the flexor digitorum profundus from its insertion at the base of the distal phalanx. The injury zone occurs in Zone I which is located from the insertion of the flexor digitorum superficialis distally. The ring finger is affected in about 75% of the patients. Forced extension of the flexed finger by violent traction on a flexed distal phalanx. Jersey finger typically occurs in sports such as football by grabbing of the opponents jersey who is pulling or running away. The flexor digitorum profundus has a dual innervation. The FDP muscle is supplied by the anterior interosseous nerve and by the ulnar nerve. The FDP muscle is innervated by the anterior interosseous branch of the median nerve on the lateral part and by the ulnar nerve on the medial part. The tendon may be torn from the distal phalanx or it may avulse with a bony fragment. The FDP tendon could retract at different levels. The tendon usually retracts to about the level of the PIP joint, and it stops at the passage through the FDS tendon. The tendon could retract into the palm, and the blood supply can be compromised. In Type I Injuries, the tendon retracts into the palm, treatment is usually surgery done within 10 days, and treatment is urgent due to disruption of the blood supply. In Type II Injuries, the FDP tendon retracts to the level of the PIP joint, and it may be repaired within a few weeks. In Type III Injuries, there is a large avulsion fracture that limits retraction to the DIP. In Type IV Injuries, there is bony avulsion fragment plus avulsion and retraction of the tendon which may go to the palm. The finger lies in slight extension relative to the other fingers in the resting position, and there will be an inability to flex the finger DIP (no active DIP flexion). The patient may have tenderness along the retracted flexor tendon proximally. To check for the integrity of the FDP tendon, you should hold the PIP straight and flex the DIP. If the patient can flex the DIP joint, then the FDP is intact. When there is a FDP tendon avulsion, the patient will be unable to actively flex the DIP. The check for the integrity of the FDS tendon, you should hold the MCP straight and flex the PIP or hold all fingers in extension except the affected one and flex. On x-ray, you may see an avulsion fracture. Direct tendon repair is a form of treatment for Jersey Finger. You may use a dorsal button if the injury is less than 3 weeks. If you advance the tendon more than 1 cm, it may lead to quadriga or DIP flexion contracture. ORIF of the fracture fragment is another treatment of Jersey Finger. It is usually done in Type III and Type IV injuries. In Type IV fix the fracture first then repair the tendon to the bony fragment. If the chronic injury is more than 3 months, and if there is stiffness of the DIP, do arthrodesis of the DIP and fuse the DIP. Another treatment is two stage flexor tendon grafting. This is done in chronic injury of more than 3 months. This is also done in young patients with full passive range of the DIP. You may also excise the palmar mass. Because the pseudosheath that is formed around the implant in the first stage usually reduces the formation of post-operative adhesions to the tendon graft in the second stage. Mallet finger is avulsion of the insertion of the extensor digitorum longus tendon. The patient will be unable to actively extend the distal phalanx and the finger will assume a flexed position. Boutonniere Deformity is chronic rupture of the central slip of the extensor tendon. Flexion in the PIP joint and extension of the DIP and MCP joints (definitely will be flexion of the PIP joint). When the central slip is ruptured acutely, there will be no active PIP extension, but the passive PIP extension will be present. As the condition progresses and becomes chronic, both active and passive PIP extension may not be present. These injuries are extensor tendon injuries. The Jersey Finger injury involves an avulsion of the flexor digitorum profundus tendon.