Jersey finger refers to the avulsion of the flexor digitorum profundus tendon off of its insertion at the volar aspect of the distal phalanx due to forced hyperextension of the distal interphalangeal joint.
It is a type of zone I tendon injury.
It is also called a sweater finger or rugby finger and typically occurs while grasping the jersey of an opponent who quickly pulls away.
Relevant Anatomy
Flexor digitorum along with the flexor digitorum superficialis has tendons that run down the arm and through the carpal tunnel and attach to the palmar side of the phalanges of the fingers.
In the finger, the Flexor digitorum profundus lies deep to the superficialis, but it attaches more distally and thus go through the tendons of superficialis after perforating them, That us why the profundus is, also called perforator muscle.
The lumbricals of the hand arise from the radial side of its tendons.
It is both supplied by the anterior interosseous nerve and ulnar nerve. Index and middle finger slips by anterior interosseous nerve and ring finger and little finger slips by the ulnar nerve.
Pathophysiology of Jersey Finger Injury
Jersey finger occurs mainly during football and rugby.
The flexor digitorum profundus is most commonly involved. This could be due to the fact that during grip ring fingertip is 5 mm more prominent than other digits in about 90 percent of people. Therefore, ring finger exposed to greater average force than other fingers during pull-away
Another reason given is that this digit is tethered on both the radial and ulnar sides by lumbrical muscles and as a consequence is more vulnerable to hyperextension injury.
During the injury, flexor digitorum is avulsed because of the profundus belly in maximal contraction during forceful digital interphalangeal joint extension
Classification of Jersey Finger Injury
Leddy and Packer’s classification is based on the level of tendon retraction and the presence of fracture
Type I
After the injury, the flexor digitorum tendon retracted to palm. The long and short vincula [These are the bands that connect flexor digitorum superficialis and profundus to each other and to the phalanges. They also arry the blood supply to the tendons ] are both ruptured, leading to compromised tendon nutrition.
The injury requires treatment within 7-10 days as the tendon contracts and become less viable.
Type II
It is the most common type of Jersey finger injury the tendon retracts to the level of the proximal interphalangeal joint. There is the preservation of the long vinculum and retaining more of its blood supply.
As the blood supply is not affected, the tendon can be successfully repaired up to a few months following injury.
Type III
A large bony fragment is avulsed off the distal phalanx. The distal pulley prevents retraction beyond the middle phalanx and can be repaired within several weeks with an optimal outcome.
Type IV
There is a bony fragment and there is a simultaneous avulsion of the tendon from the fracture fragment. Also called double avulsion and the tendon subsequently retracts into palm.
Treatment involves open reduction and internal fixation of the fracture fragment and then tendon surgery.
Type V
There is a ruptured tendon with avulsion of the bone with bony comminution of the remaining distal phalanx. The injury could be extraarticular or intra-articular.
Clinical presentation
Image Credit: Orthobullet
Typically there is an extension injury to the finger and the finger is painful. On examination, the finger lies in a slight extension to other fingers in resting position.
Tenderness would be present on volar distal part.
Finger lies in a slight extension relative to other fingers in resting position.
There is no active flexion of distal interphalangeal joint thought there is passive movement present.
Retracted flexor tendon may be palpated.
Imaging
X-rays
X-rays are mostly normal unless there is bony avulsion which typically shows a triangular avulsion fragment at the flexor aspect of the distal phalanx at the distal interphalangeal joint.
MRI
MRI can provide an accurate preoperative determination of the level of tendon retraction. It could also differentiate if the injury is not a typical Jersey finger and instead of a zone II or III injury.
[Read more on zones of the flexor tendon of hand]
MRI is often not required but lately due to its accurate evaluation, is being increasingly used.
Treatment of Jersey Finger
Jersey finger is treated surgically. The following procedures are used in treatment depending on the indication.
Direct tendon repair or tendon reinsertion with dorsal button
It is performed in an acute injury of the duration of fewer than 3 weeks. The tendon is reattached to the avulsion site while a pull out suture is used to maintain the position till the tendon is incorporated fully.
It should be noted that the advancement of more than 1 cm carries the risk of a distal interphalangeal joint flexion contracture or quadrigia.
After sufficient strength is attained, the rehabilitation is begun.
This procedure can be used in type I and II injuries.
ORIF fracture fragment
This method is used in type III and IV injuries. It involves fixation of the fracture fragment followed by tendon repair. The fracture fragment is fixed by The tendon repair can be aided by a screw or pull out suture or wire.
This surgery is done in acute cases.
Two-stage flexor tendon grafting
It is performed in a chronic injury of a duration of more than 3 months. The passive range of motion at the distal interphalangeal joint should be full.
Distal interphalangeal joint arthrodesis
It is done in cases of chronic injury with chronic painful stiffness. The surgery blocks the distal joint movement and should be considered only if the patient has trouble in using the hand in daily routine.
Complications
- Adhesion formation
- Joint contracture
- Quadriga- Advancement of a contracted FDP tendon leads to the inability of the adjacent digits to fully flex at the distal interphalangeal joint.
- Development of secondary osteoarthritic changes
- Joint instability
References
- Goodson A, Morgan M, Rajeswaran G, Lee J, Katsarma E. Current management of Jersey finger in rugby players: case series and literature review. Hand Surg. 2010;15(2):103–7. doi: 10.1142/S0218810410004710.
- Al-Qattan MM. Use of the volar plate of the distal interphalangeal joint as a distally based flap in flexor tendon surgery. J Hand Surg [Am] 2016;41:287–90. doi: 10.1016/j.jhsa.2015.11.004.
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