Jersey finger

Jersey finger (also called rugby finger or sweater finger) describes a type of injury where there is avulsion of the flexor digitorum profundus (FDP) atfrom the volar base of the distal phalanx base (volar) ¹.

Most commonly affects the 4^th digit as the FDP insertion into the ring finger is anatomically weaker than the middle finger ².

It classically occurs during certain sports resulting from sudden hyperextension of actively flexed finger (e.g. grabbing opponent's jersey during rugby or American football.)

It most commonly affects the 4^th digit as the FDP insertion into the ring finger is anatomically weaker than the middle finger ².

Clinical presentation

It is characterised by inability to flex the finger at the distal interphalangeal (DIP) joint. There is a slight extension at this joint.  There is pain and tenderness over the volar distal finger.¹

Radiographic features

Plain radiograph

Radiographs can often be normal ³. If there is a bony avulsion, plain film would classically show a triangular avulsion fragment at the flexor aspect of the distal phalanx at the distal interphalangeal (DIP) joint and overlying soft tissue swelling.

MRI

Disruption of flexor digitorum profundus (FDP) at volar base of distal phalanx ± avulsion fragment.  MRI also allows visualisation of the location of the end of tendons which will affect the surgical classification and management of the patient ^4,5.

Complications

• unstable DIP joint
• development of secondary osteoarthritic changes
• DIP flexion contracture or quadrigia

Treatment and prognosis

• conservative for partial tear (i.e. splinting, NSAIDs, physical therapy)
• surgical intervention: all complete flexor tendon injuries should be surgically repaired or at least referred to an orthopaedic hand surgeon; tendon retraction and time from injury are key ¹