Jersey Finger

                                     Dr. KS Dhillon

Introduction

A Jersey finger is also known as a rugby finger. It is an avulsion of the flexor digitorium profundus tendon (FDP) from its distal insertion on the distal phalanx [1-3]. This injury occurs due to a forced extension of a flexed digit. It is often seen when a person tries to grab the jersey of an opponent during a high-speed sporting event. Examination shows that the affected finger remains in slight extension compared to the other fingers. Active flexion of the distal interphalangeal joint (DIP) is not possible. Treatment is by surgery.

Etiology

There are substantial forces on the distal phalanx during pull-away activities. Distal avulsion of the flexor digitorium profundus commonly occurs in young athletes during contact sports [4]. The mechanism of injury is forceful extension of a flexed digit. This is commonly seen when a player grabs the jersey of an opposing player to make a tackle during rugby or American football. This results in a forced extension of the flexor digitorium profundus tendon during maximum contraction.

Epidemiology

Thirty-eight percent of all acute upper limb injuries are finger injuries [5]. Tendon injuries in the hand occur at a rate of 33.2 per 100,000 person years. About 4% of these injuries occur in the flexor tendon zone one i.e distal to the insertion of flexor digitorum superficialis on the middle phalanx [6].

Jersey finger injury can occur in any digit. It represents the most common closed flexor tendon injury [7]. In 75% of the cases, the ring finger is involved. The ring finger is bound on both sides by lumbrical muscles, making it more prone to hyperextension injuries. The load for the failure of the FDP tendon is lower for the ring finger as compared to other fingers [8].

Pathophysiology

Hyperextension of the DIP joint during maximal FDP muscle contraction leads to FDP injury. The injury occurs at the FDP tendon insertion at the base of the distal phalanx as this is the weakest point [9].

History and Physical examination

The patient presents with pain in the finger. This is especially seen in athletes who have sports-related trauma. Pain and tenderness on the volar aspect of the injured finger is common in such patients. In a resting position, the injured finger will usually remain in extension as compared to the other digits. The retracted tendon can sometimes be palpated proximal to the avulsion. Active flexion of the DIP joint is absent. Grip and flexion against resistance will cause pain.

Evaluation

Usually, a physical examination is enough to reach the diagnosis of jersey finger.  X-rays play an important role in the diagnosis. Plain radiographs are necessary to rule out fractures. Antero-posterior and lateral views of the finger can reveal a bony fragment. Ultrasound may be useful to assess the tendon anatomy in cases where there is no fracture. In chronic injuries, ultrasound becomes crucial to evaluate tendon retraction.

MRI is usually not necessary. It is sometimes performed to determine the tendon-bone distance more accurately [10].

Staging

Jersey finger injury can be classified as follows [9]:

• Type 1: Severe avulsion. Here the tendon retracts into the palm and the blood supply is severely compromised.

• Type 2: The tendon retracts but remains at the A3 pulley at the proximal interphalangeal joint.

• Type 3: The avulsion includes a bony fragment. Here both the tendon and fracture fragment remain at the A4 pulley.

• Type 4: Rare injury. Here there is the presence of both a fracture and a tendon avulsion from the bony fragment. The tendon may retract into the palm.

• Type 5: Ruptured tendon with bone avulsion with bony comminution of the remaining distal phalanx.

Treatment

Jersey finger injuries are treated by surgery. Early treatment is important to restore blood supply and function. The blood supply to the flexor tendons comes from the blood vessels located inside the mesotendon (long and short vincula). Conservative treatment is rarely carried out. It is done in patients who are not fit for surgical intervention [11][12].

Surgical Management

1. Acute injuries: within 3 weeks after injury.

Acute injuries without a fracture are treated by direct tendon repair or tendon reinsertion to the bone. When there is a fracture open reduction and internal fixation with miniscrews or wires is carried out.

Suture anchors are being used in cases of bony avulsions. There are multiple treatment techniques for acute injuries. None of them seem to be significantly superior to the others [13].

2. Chronic injuries: more than 3 months after injury.

If the range of movements of the DIP joint is full a two-stage tendon grafting is carried out. If there is chronic stiffness of the DIP joint then arthrodesis of the joint is carried out following discussions with the patient. For some patients in whom the distal interphalangeal joint motion is essential for occupation and hobbies then tendon reconstruction may become a valid alternative. Tendon reconstruction requires a significant time commitment from the patient to achieve a successful long-term outcome.

Prognosis

Early diagnosis and treatment leads to excellent functional outcomes. Surgery within 10 days after the injury produces excellent patient-reported outcomes [14].

In about 8 to 10 weeks patients can return to sports with full active range of motion and absence of pain. Impaired DIP joint motion produces loss of dexterity and loss of pinch strength [3].

Postoperative functional and aesthetic results depend on a good reduction of the fracture, quality of tendon repair, and a good rehabilitation protocol. Scar contracture must be prevented to maintain good finger function [15,16].

Complications

Surgical complications include skin necrosis, infection, tendon repair rupture, nail matrix injury, and adhesions [17,18]. When the tendon advancement is more than 1 cm there is a risk of quadriga. Quadriga refers to an inability to flex the digits adjacent to the involved digit due to increased tension over the repaired tendon [19]. 

References

1. Lunn PG, Lamb DW. "Rugby finger"--avulsion of profundus of ring finger. J Hand Surg Br. 1984 Feb;9(1):69-71. 

2. Folmar RC, Nelson CL, Phalen GS. Ruptures of the flexor tendons in hands of non-rheumatoid patients. J Bone Joint Surg Am. 1972 Apr;54(3):579-84. 

3. Bachoura A, Ferikes AJ, Lubahn JD. A review of mallet finger and jersey finger injuries in the athlete. Curr Rev Musculoskelet Med. 2017 Mar;10(1):1-9.

4. Yeh PC, Shin SS. Tendon ruptures: mallet, flexor digitorum profundus. Hand Clin. 2012 Aug;28(3):425-30, xi.

5. Ootes D, Lambers KT, Ring DC. The epidemiology of upper extremity injuries presenting to the emergency department in the United States. Hand (N Y). 2012 Mar;7(1):18-22.

6. e Jong JP, Nguyen JT, Sonnema AJ, Nguyen EC, Amadio PC, Moran SL. The incidence of acute traumatic tendon injuries in the hand and wrist: a 10-year population-based study. Clin Orthop Surg. 2014 Jun;6(2):196-202.

7. Boyes JH, Wilson JN, Smith JW. Flexor-tendon ruptures in the forearm and hand. J Bone Joint Surg Am. 1960 Jun;42-A:637-46.

8. Manske PR, Lesker PA. Avulsion of the ring finger flexor digitorum profundus tendon: an experimental study. Hand. 1978 Feb;10(1):52-5.

9. Leddy JP, Packer JW. Avulsion of the profundus tendon insertion in athletes. J Hand Surg Am. 1977 Jan;2(1):66-9.

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. Zemirline A, Asmar G, Liverneaux PA. Conservative treatment in Jersey finger: a case report. J Plast Reconstr Aesthet Surg. 2013 Nov;66(11):1616-8. 

12. Pappas N, Gay AN, Major N, Bozentka D. Case report: pseudotendon formation after a type III flexor digitorum profundus avulsion. Clin Orthop Relat Res. 2011 Aug;469(8):2385-8.

13. Polfer EM, Sabino JM, Katz RD. Zone I Flexor Digitorum Profundus Repair: A Surgical Technique. J Hand Surg Am. 2019 Feb;44(2):164.e1-164.e5.

14. Tuttle HG, Olvey SP, Stern PJ. Tendon avulsion injuries of the distal phalanx. Clin Orthop Relat Res. 2006 Apr;445:157-68.

15. Becker H. Primary repair of flexor tendons in the hand without immobilisation-preliminary report. Hand. 1978 Feb;10(1):37-47. 

16. Becker H, Orak F, Duponselle E. Early active motion following a beveled technique of flexor tendon repair: report on fifty cases. J Hand Surg Am. 1979 Sep;4(5):454-60.

17. McCallister WV, Ambrose HC, Katolik LI, Trumble TE. Comparison of pullout button versus suture anchor for zone I flexor tendon repair. J Hand Surg Am. 2006 Feb;31(2):246-51. 

18. Zook EG. Complications of the perionychium. Hand Clin. 1986 May;2(2):407-27.

19. Gillig JD, Smith MD, Hutton WC, Jarrett CD. The effect of flexor digitorum profundus tendon shortening on jersey finger surgical repair: a cadaveric biomechanical study. J Hand Surg Eur Vol. 2015 Sep;40(7):729-34.