Orthopaedic Hand Trauma CH35

CHAPTER 35 Jersey Finger

Nisha J. Crouser, Steven R. Niedermeier, and Hisham M. Awan

INTRODUCTION

■ ■ Jersey finger is an injury to the terminal flexor mechanism at the level of the distal interphalangeal (DIP) joint. This can be due to either rupture of the flexor digitorum profundus (FDP) tendon in Zone 1 or an avulsion fracture of the distal phalanx with a fragment of bone that remains attached to the tendon ( Figure 35.1 ). The degree of retraction of the tendon ranges fromminimal displacement to retraction into the palm. ■ ■ Mechanismof injury —Injury occurs when a flexed DIP joint is forcefully hyperextended and the FDP tendon ruptures at its weakest point, which is the insertion site ( Figure 35.2 ). The term “jersey finger” is derived from the classic scenario in which an athlete grabs an opponent’s jersey and the DIP joint is hyperextended. Rupture most often occurs at the bony insertion and less often at the musculotendinous junction. ■ ■ Epidemiology —The injury commonly occurs in athletes who are involved in contact sports, most notably rugby and football, but can occur in nonathletes as well. Musculotendinous rupture is rare and occurs most often in a traumatic distal phalanx amputation injury or in patients with underlying inflammatory conditions. The ring finger is

Zone II

Zone I

Flexor digitorum profundus (FDP)

Flexor digitorum superficialis (FDS)

Figure 35.1  Anatomic location of injury in jersey finger. FDS, flexor digitorum superficialis; FDP, flexor digitorum profundus.

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CHAPTER 35  | Jersey Finger

Figure 35.2  Mechanism of injury for jersey finger.

involved in 75% of FDP avulsions. The higher susceptibility of the ring finger to this injury is related to several anatomic differences. It has been demonstrated that the ring finger has the least independent motion of all the digits. Also the insertion of the ring finger FDP is weaker than the FDP insertion of the long finger. Finally, the ring finger extends farther than the other digits during full grip and absorbs the most force during pull-away testing, making it prone to avulsion.

EVALUATION

■ ■ Presentation —Patients often present with acute pain and swelling over the volar surface of the distal finger. The point of maximal tenderness may indicate the location of the avulsed tendon. ■ ■ Physical Examination —On examination, the affected finger lies in ex- tension relative to other fingers in resting position ( Figure 35.3 ). Patients are unable to actively flex the DIP joint when asked to make a fist. Often

Figure 35.3  Clinic photograph of jersey finger injury with ring finger held in extension.

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SECTION 3  | Tendon Injuries

patients will resist flexion of the entire finger as a result of pain, which can obscure the diagnosis. In the acute setting, an FDP avulsion can be misdiagnosed as a “sprained finger.” It is essential that the clinician isolates DIP and proximal interphalangeal (PIP) joint motion to pre- vent a delay in diagnosis. In some cases, the physician may be able to palpate the flexor tendon retracted proximally along the flexor sheath. ■ ■ Imaging —Anteroposterior, lateral, and oblique radiographs should be obtained to assess for avulsion fractures or articular injuries. A bony avulsion fragment of the volar lip of the distal phalanx articular surface may be present ( Figure 35.4 ). Approximately 50% of FDP avulsions are associated with an osseous fragment. If the injury is purely tendinous, the only radiographic finding will be slight extension of the DIP in resting position. MRI can be used if the diagnosis is unclear or the location of the retracted tendon is unknown. ■ ■ Differential diagnosis ● ● Anterior interosseous nerve paralysis ● ● Trigger finger ● ● Swan neck deformity ■ ■ Classification —The Leddy and Packer classification system is used most commonly ( Table 35.1 ). Type I, II, and III injuries are most common. ● ● In type I injuries, there is complete tendon rupture with retraction into the palm. The tendon is tethered in the palm by the lumbrical origin and both the vinculum longus profundus (VLP) and brevis profundus (VBP) are ruptured. As a result, there is significant vas- cular compromise, and expedited surgical intervention is required within 7 to 10 days of the injury.

Figure 35.4  Lateral radiograph showing Leddy and Packer type III FDP avulsion. FDP, flexor digitorum profundus.

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CHAPTER 35  | Jersey Finger

Table 35.1  The Leddy and Packer Classification System

Vincular System Disrupted

Type Level of Retraction

Treatment

I

Palm

VLP and VBP

Primary tendon repair within 7–10 d Primary tendon repair within 10 d (may be delayed) Repair of fracture fragment within 8–12 wk Fix fracture first then reattach tendon within 12 wk

II

PIP and/or small volar cortical avulsion A4 pulley (entrapped large osseous fragment) Bony avulsion + tendon avulsion with variable retraction Bony avulsion + comminuted P3 fracture

VBP

III

None

IV

Variable

V

Variable

Repair within 12 wk

Abbreviations: PIP, proximal interphalangeal; VBP, vinculum brevis profundus; VLP, vinculum longus profundus.

● ● Type II injuries involve retraction of the FDP tendon to the level of the PIP joint, and there may be a small volar cortical avulsion. The VLP is preserved in this case because it arises at the level of the PIP volar plate, but the VBP is disrupted. ● ● Type III injuries are defined as FDP retraction to the level of the A4 pulley of the middle phalanx. Retraction to this level is the result of a large bony fragment avulsion. Both vincula are intact with type III injuries permitting a delay in surgical correction, if necessary. ● ● Type IV injuries are complex and defined as simultaneous osseous distal phalanx avulsion and distal phalanx fracture. ● ● Type V injuries are similar to type IV with comminution of the distal phalanx.

ACUTE MANAGEMENT

■ ■ Splinting is used as initial management prior to surgical intervention. The forearm can be included in the splint to try and limit retraction.

DEFINITIVE TREATMENT

■ ■ All cases of jersey finger in which the tendon has completely avulsed from its insertion require surgical intervention. The accepted length of time until surgery and type of procedure are dependent upon the

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classification of the injury. It is important to determine the extent of injury at the time of diagnosis because certain cases require surgical correction within 7 to 10 days of the injury. Timely management is recommended in all cases, because it can be difficult to determine the degree of retraction of the tendon on physical examination. ■ ■ Type I/II ● ● Surgical options include dorsal button, direct tie around bone, suture anchor, or a combination of techniques. ● ● An attempt to localize the level of retraction preoperatively should be made using physical examination and imaging modalities. Intraop- eratively, the tendon is identified using a Bruner approach, in which a volar zigzag incision is made from the level of tendon retraction proximally to the distal DIP joint. The flexor sheath is then exposed. An incision is made just distal to the A2 pulley to locate the tendon. A suture is passed through the tendon and the tendon is advanced through the flexor tendon pulley system to the distal phalanx. This often requires dilation of the pulley system. A pediatric feeding tube may be helpful in passing the tendon under the pulleys. Attempts should be made to preserve the A2 and A4 pulleys. Overadvance- ment of the tendon should be avoided to prevent quadriga. In type I injuries, the distal end of the tendon will be avascular as a result of the disrupted vincula and should be trimmed prior to reapprox- imation. In type II rupture, the vincula remain intact, but fibrosis may develop at the FDS chiasm, which may limit tendon gliding. The fibrotic end should be debrided in these cases. ● ● Dorsal button technique ( Figure 35.5 ) ◆ ◆ The bone bed on the distal phalanx should be prepared by removing any soft tissue, while still preserving the palmar plate to promote direct tendon-bone healing. Next, Keith needles are drilled into the distal phalangeal bone bed exiting through the mid portion of the nail plate and paired sutures are passed through the tendon and tied over a button on top of the nail plate via the Keith needles. ◆ ◆ Disadvantages—The pull-through button technique may lead to tendon-bone gapping due to the distance between the fixation point of the tendon-bone and the suture knot. This can also damage the nail plate, including deformity and nail fold necrosis, but these complications are rare. ● ● Suture anchor technique ◆ ◆ This technique has potential advantages of complete internaliza- tion of the suture anchor without disruption of the nail plate or

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CHAPTER 35  | Jersey Finger

Flexor digitorum profundus (FDP)

Figure 35.5  Dorsal button repair. FDP, flexor digitorum profundus.

dorsal incision. For this technique, holes are drilled at a 45° angle from distal-volar to proximal-dorsal to increase the resistance to pullout of the implant. Intraoperative fluoroscopy is used to ensure that there has been no disruption of the dorsal cortex or the DIP joint. To allow for direct tendon-bone healing, the FDP must be flush with the bone. ◆ ◆ Disadvantages—This technique is less successful in patients with osteoporotic bone or avulsion fractures. It also has been associated with higher risk of contracture after the procedure. ● ● Currently, there is not enough literature to the support the use of one technique over another. Future studies are needed to make evidence-based recommendations; the surgical technique used is left to surgeon preference. ■ ■ Type III/IV/V ● ● The presence of an intact vincula systemmakes type III to V injuries more amenable to later repair. These injuries are repaired with open reduction internal fixation (ORIF) of the fracture. Various techniques have been proposed with successful results, including fixation with

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SECTION 3  | Tendon Injuries

Kirschner wires, mini-fragment screws, or interosseous wires. A two-stage approach with independent repair of the tendon after fixation of the fracture is recommended in type IV and V injuries. ■ ■ Late management ● ● DIP arthrodesis is indicated as a salvage procedure in chronic injuries ( > 3 months) in patients with chronic stiffness. Reconstructing the FDP tendon with a tendon graft in a two-stage procedure can be considered in a select group of patients who require fine dexterity of the DIP joint for everyday life (ie, perhaps certain musicians and athletes). ■ ■ Postoperative protocol ● ● A forearm-based dorsal block splint is used with the wrist and meta- carpophalangeal joints held at 30° of flexion and the interphalangeal joints fully extended. A separate finger splint should be used for the injured fingers, holding the DIP in 45° of flexion for the first 3 weeks. Some passive movement is permitted at this stage but no active DIP flexion, wrist flexion, or finger extension. At the 4-week postoperative visit, the DIP finger splint can be removed and the forearm splint can be converted to a hand splint. Active motion can be initiated at this time. Return to resistive exercises is most commonly allowed at 8 weeks. ■ ■ The main complications after FDP avulsion injury repair are DIP joint stiffness and contracture. Studies estimate an average loss of 10 to 15° of extension after injury. There is also a risk of rerupture or loss of fix- ation postsurgical intervention. Another complication that can occur is quadriga caused by a functional shortening of the FDP tendon due to overadvancement of the FDP during repair, adhesions, or retraction of the tendon. The result is an inability to fully flex the fingers adjacent to the injured finger, which manifests as decreased grip strength. Ad- ditional complications can be seen with associated fractures, including decreased joint stability and arthrodesis. SUGGESTED READING Ruchelsman DE, Christoforou D, Wasserman B, Lee SK, Rettig ME. Avulsion injuries of the flexor digitorum profundus. J Am Acad Orthop Surg. 2011;19(3):152-162. COMPLICATIONS