Jersey Finger

Jersey finger, also called rugby finger, is an avulsion injury where the flexor digitorum profundus (FDP) tendon detaches from its insertion on the distal phalanx (zone I).¹ This means the tendon is torn away from the bone where it normally inserts, leading to loss of the ability to flex the distal interphalangeal joint (DIP). The ring finger is most at risk because it protrudes furthest in the grip position and is therefore more often caught in an opponent’s jersey during sport. The FDP tendon is the only muscle–tendon unit that flexes the distal joint, and without it active flexion is not possible.

Clinically Relevant Anatomy

Flexor Digitorum Profundus (FDP)

• FDP is a deep forearm muscle that provides strong grip force, especially when the wrist is extended.

• It is innervated by two nerves: the ulnar nerve to the medial portion and the anterior interosseous nerve to the lateral portion.

• FDP is the only muscle that flexes the distal interphalangeal joints (DIP) of digits 2–5.

• Loss of this tendon therefore results in complete loss of active flexion at the terminal joint.

Mechanism of Injury

• Most injuries occur in the ring finger at the tendon’s insertion on the distal phalanx, which is the weakest point in the tendon complex.

• The typical scenario is an opponent’s jersey catching the finger as the player pulls away.

• This produces a strong extending force against an actively contracting FDP, causing avulsion of the tendon from the bone.

• Acute sports injuries (e.g., rugby, handball, football/soccer) are common triggers.

Clinical Presentation

• Inability to actively flex the DIP joint.

• Swelling, pain and bruising around the finger and palm.

• Some patients describe a “pop” or tearing sensation at the time of injury.

• Numbness may occur at the fingertip with associated nerve injury.

• Palpation proximally may sometimes reveal a retracted tendon.

• With complete avulsion, flexion is impossible and resisted flexion testing is very painful.

• Type I ruptures often cause marked pain in the palm near the finger base.

Injury Classification

Leddy and Packer classification

• Type I: FDP tendon has retracted into the palm to the origin of the lumbrical muscle.

• Type II: Tendon has retracted to the A3 pulley at the PIP joint.

• Type III: Avulsion with a large bony fragment; tendon and fragment stop at the A4 pulley.

• Type IV: Avulsion of a bony fragment with the tendon torn off the fragment and retracted into the palm.

• Type V: Avulsion with a large bony fragment plus concomitant fracture of the distal phalanx.

Diagnostic Procedures

• Physical examination shows the finger resting straight and unable to actively flex at the DIP.

• Palpation may sometimes detect the retracted tendon.

• Plain radiographs (AP and lateral) to identify bony fragments.

• Ultrasound to localise the tendon and guide management.

• MRI is rarely required but can detail the degree of retraction.

Differential Diagnoses

• Muscle strain

• Phalangeal fracture

Non-Surgical Management

• Partial tears are rare but may be treated non-operatively.

• Finger immobilisation in a splint to stabilise the tendon during healing.

• NSAIDs for pain.• After 1–3 weeks of immobilisation, begin physiotherapy with gradual range-of-motion and strengthening.

Surgical Management

• Jersey finger is primarily managed surgically; conservative care is reserved for very small tears or when surgery is contraindicated.

• Operate within three weeks where possible.

• Tendon and bony fragments may be fixed with:

• Bunnell pull-out suture• Suture anchors

• Suture combined with a volar plate (newer technique with limited evidence)

• The Bunnell method is most commonly used.

• With late presentation (>3 weeks), arthrodesis or staged tendon reconstruction may be considered.• With appropriate rehabilitation, athletes may often return to training after 8–12 weeks.

Physiotherapy and Rehabilitation

Principles of physiotherapy

• Athletes should expect 8–12 weeks away from sport after surgery.

• A sport-specific rehabilitation plan should be tailored to the sport and playing position.

• Key elements include:

• Dorsal Blocking Splint (DBS): used early to protect the repair.

• Passive range-of-motion exercises: initiated early post-op to prevent adhesions.

• Active or active-assisted motion: introduced gradually as tendon loading becomes safe.

• Place-and-hold drills: to stimulate controlled tendon activation.

• Strength and power-grip training: progressively increased towards normal function.

• Scar massage: to limit adhesions and improve mobility.

• Tendon-gliding exercises: critical to reduce adhesion risk and ensure normal tendon excursion.

• Programmes progress through hook fist, straight fist and full fist patterns to promote free FDP gliding and prevent tethering.

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Conclusion

Jersey finger is a serious injury requiring prompt diagnosis and surgical management. Early physiotherapy with appropriately staged exercises is essential for good functional outcome. Passive stretching is avoided initially, while progressive active use and sport-specific rehabilitation are emphasised for an optimal return to activity.

References:

1. Manske PR, Lesker PA. Avulsion of the ring finger flexor digitorum profundus tendon: an experimental study. Hand. 1978 Feb(1):52-5.

2. Gjennomgått - Trukket

3. BAILEY STEVEN. Jersey Finger Treatment - Atlanta, GA - flexor tendon injury procedures. Hand, Wrist, Elbow Surgery - Atlanta, GA - Marietta - Dr. Steven Bailey. 2018.

4. Jersey Finger. Hand Care: The upper extremity expert. American Society for Surgery of the Hand. https://www.assh.org/handcare/condition/jersey-finger#:~:text=A%20%E2%80%9Cjersey%20finger%E2%80%9D%20refers%20to,is%20trying%20to%20get%20away.

5. Leddy JP, Packer JW. Avulsion of the profundus tendon insertion in athletes. The Journal of hand surgery. 1977 Jan 1;2(1):66-9.

6. Al-Qattan MM. Type 5 avulsion of the insertion of the flexor digitorum profundus tendon. The Journal of Hand Surgery: British & European Volume. 2001 Oct 1;26(5):427-31.

7. Abrego MO, Shamrock AG. Jersey Finger. 2021 Aug 9. : https://www.ncbi.nlm.nih.gov/books/NBK545291/

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9. Gjennomgått - Trukket

10. Klauser A, Frauscher F, Bodner G, Halpern EJ, Schocke MF, Springer P, Gabl M, Judmaier W, zur Nedden D. Finger pulley injuries in extreme rock climbers: depiction with dynamic US. Radiology. 2002 Mar;222(3):755-61

11. Ilyas A, Drummey R. Jersey Finger Repair. Journal of Medical Insight. 2021: https://jomi.com/article/297/Jersey-Finger-Repair

12. Bachoura A, Ferikes AJ, Lubahn JD. A review of mallet finger and jersey finger injuries in the athlete. Current reviews in musculoskeletal medicine. 2017 Mar 1;10(1):1-9.

13. Wilk KE. Clinical orthopaedic rehabilitation. Brotzman SB, Daugherty K, editors. Philadelphia: Mosby; 2003 Jan.