Jersey finger (football finger) is an avulsion of the deep flexor tendon (FDP) from its distal insertion on the distal phalanx (Zone I). The ring finger is most commonly affected. FDP avulsions are more likely to occur due to the ring finger protruding furthest in the grasping position Resulting in inability to bend at DIPJ.
Clinically Relevant Anatomy
Flexor Digitorum Profundus
The FDP is one of the deep veins in the frontal lobe. It is a compound muscle supplied by two types of muscles: the medial part is supplied by the ulnar muscle and the posterior part is supplied by the facial muscles. It is the main muscle that grasps when the wrist is extended. Alright Distal Interphalangeal (DIP) Joint of 2nd to 5th digits only flexors.
Mechanism of Injury
Most injuries occur in the ring finger at the point of insertion which is the most vulnerable area of the tendon. Injury occurs to the finger if it is caught in a player’s shirt as the little finger continues to flex and FDP extension occurs as the tackled player escapes. A strong man expansion when FDP contraction causes rupture of the vein.
- Inability to flex DIP joint actively
- Unbending of one or more joints in a wrist
- Painful bruising and edema may occur around the fingers and palms
- Numbness in your fingertip
- The palmar part of the hand
- Fingertip may be swollen and painful
- A popping or ripping sensation felt upon injury
- Severe pain in the elbow before the base of the elbow can be a sign of a Type 1 fracture
Stages and classification of injury
The classification system for jersey sleeve injuries is based on the degree of muscle contraction and the presence or absence of a fracture. Types I-III were first described by Leddy and Packer in 1977 and two additional types IV and V have since been added.
- Type I: The FDP muscle returns to the wrist at lumbrical origin.
- Type II: The FDP tendon retracts to the A3 pulley at the proximal interphalangeal (PIP) joint.
- Type III: A large bone fragment is avulsed. Both the FDP tendon and fracture fragments retract into the A4 pulley as bone fragments limit further retraction.
- Type IV: Avulsion of a large bone fragment with rupture of the FDP tendon from the bone fragment. Since the avulsed FDP is not attached to the bone fragment, the FDP retracts into the palm.
- Type V: Avulsion of a large bone fragment with another apparent fracture of the distal phalanx.
- A physical examination along with x-rays and ultrasounds to rule out fractures is important, highly suspicious of athlete’s finger pain with jersey fingers, and linking these injuries to sports-related trauma.  MRI can aid in the detailed assessment of damage and may Recognizes the extent of tendon contraction, but is rarely used. The following tests are used to check for FDP avulsion :-
- Physical examination will also show that the injured wrist stays in extension relative to the other lines. Also the retracted veins can be palpated proximally to the avulsion; There is no flexion of the DIP joint along with grip and flexion against resistance which is very painful.
- Anterior-posterior and lateral views of the x-ray can produce bone fragments. Ultrasound is often necessary to assess contraction and guide further treatment.
- MRI is rarely performed but can be used to more accurately determine increased tendon-bone distance.  
- Muscle sprain
- Phalanx fracture
Non Surgical Management
- If the flexor tendon is only partially torn (which is rare), surgery may not be needed.
- The patient may be advised to wear a splint to help stabilize the finger and allow the damaged tendon to repair itself.
- Any pain or discomfort from a tendon injury can be relieved with nonsteroidal anti-inflammatory drugs (NSAIDs).
- The use of a splint will be combined with exercises to help restore strength and motion to the affected wrist after 1-3 weeks of immobility and rest.  .
- The treatment referred to by Jersey is mainly based on surgery, and conservative treatment is considered only when surgery cannot be performed due to complications. Surgery is necessary to re-establish a painless active range of motion in the affected finger. 
- Surgery is definitive treatment and should usually be done as early as possible within 3 weeks of injury. Surgical salvage procedures for late manifestations include DIP arthrodesis and staged tendon reconstruction.
- A number of surgical techniques are used to treat avulsions of FDP, including:
- The Bunnell pull-out suture technique
- Suture anchor repair
- Combined with the volar plate to repair the tendon.
The latter is the latest descriptive technique, and clinical outcome studies are still under development.
- The pull-out suture procedure has historically been the most commonly used technique .
- With effective post-operative rehabilitation, patients should be able to return to sports and normal activities within 8-12 weeks.
Athletes may lose 8-12 weeks of playing time following surgery.  A sport-specific hand rehabilitation protocol was considered for the postoperative athlete’s position and level of play in competition, which included −
- Dorsal Blocking Splint (DBS)
- Early Postoperative Passive Range of Motion (ROM) Exercises
- Active or assisted ROM exercises
- Place and hold exercises
- Strengthening/power grasping exercises
- Scar massage
- Tendon gliding exercises
Clinical Orthopedic Rehabilitation (Second Edition) – S. Brent Brotzman Kevin E. Wilk
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