7: Acute Repair of Zone 1 Flexor Digitorum Profundus Avulsion

Procedure 7 Acute Repair of Zone 1 Flexor Digitorum Profundus Avulsion



Brent M. Egeland, Sandeep J. Sebastin, Kevin C. Chung


image See Video 4: Acute Repair of Zone 1 Flexor Digitorum Profundus Avulsion



Indications




image Loss of flexion of the distal interphalangeal (DIP) joint may occur owing to avulsion of the flexor digitorum profundus (FDP) from its insertion into the distal phalanx.


image Typical etiology is forced extension of the flexed finger, typically when tackling an opponent in football, which is often called “jersey finger.”


image Reattachment is possible if presented 10 to 14 days after injury, or longer if FDP is not retracted proximally because of the restraint provided by the intact vincula.


image If there is a late presentation, the potential need for tendon grafting or other procedures such as DIP fusion or tenodesis must be discussed.


image If tendon grafting is contemplated for late presentation, the patient must have a supple DIP joint. In addition, patient expectations must be appropriate.


• Patient has a need for DIP joint function.

• Patient is willing to comply with postoperative precautions and therapy to optimize success.


Examination/Imaging



Clinical Examination




image With the metacarpophalangeal (MCP) and PIP joints in extension, the patient is unable to actively flex the DIP joint (Fig. 7-1).


image A soft tissue mass may be felt, and there may be localized bruising over the volar finger at the location of the retracted stump.


image

FIGURE 7-1



Imaging




image Standard anteroposterior and lateral radiographs are necessary.


image Lateral radiographs may demonstrate an avulsed bony fragment at the DIP or proximally in the finger or palm corresponding to the proximal retraction of the FDP tendon to which the bone fragment is attached (Fig. 7-2).


image Ultrasound may be beneficial in confirming the injury, identifying the location of the retracted tendon preoperatively, and aiding in surgical planning, particularly in late presentations.


image

FIGURE 7-2



Surgical Anatomy




image Flexor zone 1 is distal to flexor digitorum superficialis (FDS) insertion over the middle third of the middle phalanx and contains only the FDP, C3, and A5 pulleys (Fig. 7-3).


image Blood supply to the distal FDP is from the vinculum longus profundus (VLP), vinculum brevis profundus (VBP), and distal phalanx at its bony insertion (Fig. 7-4).


image Avulsed tendon can retract proximally in three patterns as defined by Leddy and Packer (1977). Additional types 4 and 5 have been described (Fig. 7-5).


• Type 1: FDP has pulled though zone 2 to lie in the palm or A1 pulley—vincular blood supply is disrupted. The tendon and bone fragment can be passed through the pulley system and repaired with a pullout button.

• Type 2: Most frequent; the FDP retracts to the PIP joint at the FDS chiasma between the A2 and A4 pulleys. Proximal retraction is prevented by intact vincula brevis. Because blood supply is not completely disrupted, delayed repair is possible.

• Type 3: A large bone fragment remains attached to the FDP, and tendon does not retract proximal to the A4 pulley.

• Type 4: Similar to type 3 except with simultaneous avulsion of the tendon from the bone fragment.

• Type 5: Like type 3, but with concomitant fracture of the distal phalanx.

image In most cases, the tendon can be retrieved from the above locations, passed through the pulley system, and reattached to the distal phalanx via pullout button or bone anchor.


image With late presentation of greater than 4 weeks, the myostatic contracture of the avulsed tendon may preclude distal reconstruction, obligating a tendon graft.


image

FIGURE 7-3


image

FIGURE 7-4

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Mar 5, 2016 | Posted by in Hand surgery | Comments Off on 7: Acute Repair of Zone 1 Flexor Digitorum Profundus Avulsion

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