Hand CASE 39

CASE                               39                               

The patient is a 68-year-old, right-handed male who presents to the emergency department following a tablesaw injury to his nondominant left index finger (Fig. 4–21A and B). The patient states that he was working at home after having “a few” beers, when his hand slipped and his nondominant index finger was drawn into the blade of the saw. On examination, he has sustained an amputation to the index finger at the mid-shaft of the proximal phalanx, with a stellate, multilevel soft tissue injury to the index finger base. Radiographs demonstrate a comminuted fracture of the proximal phalanx with intra-articular involvement and a fracture of the metacarpal head. The amputated index finger was irretrievable and not brought to the hospital.

 

 

 

Figure 4–21 A–B

 

What flexor tendon zone is the injury located in, according to Verdan?

1. Zone 1

2. Zone 2

3. Zone 3

4. Zone 4

5. Zone 5

 

Discussion

The correct answer is (B). There are five flexor tendon zones. Zone 1 is distal to the FDS insertion. Zone 2 is from the A1 pulley to the FDS insertion. Zone 3 is from the carpal tunnel to the A1 pulley. Zone 4 is in the carpal tunnel. Zone 5 is proximal to the carpal tunnel. Injuries in zone 2 are known as “no-man’s land,” and portend a worse functional prognosis than injuries in other zones.

Which of the following is the most appropriate treatment of this patient?

1. Immediate closure of the laceration in the emergency room

2. Reconnaissance of the amputated part and delayed attempt at replantation

3. Operative exploration with revision amputation of the index finger, without digital neurectomy, leaving the wound open

4. Operative exploration with ray amputation of the index finger and digital neurectomy

5. Application of a dressing and have the patient follow-up in clinic in 3 weeks

 

Discussion

The correct answer is (D). The functional results of successful single digit replantation in zone 2 have historically been poor. It is often better to perform a revision or a ray amputation with digital neurectomy than to proceed with a single digit replantation at this level, particularly in the index finger. A ray amputation for index finger amputations can provide an aesthetic appearance of the hand, while deepening the first web space to allow for pinch grip.

If replantation were to have been attempted, and the finger remained viable postoperatively, what would be the most likely functional result?

1. Significant stiffness of the index finger with bypass of pinch grasp to the middle finger

2. Index finger total active motion of 240 degrees with minimal residual stiffness

3. Index finger total active motion of 140 degrees with two-point discrimination 4 mm at the fingertip

4. Stiffness of the index finger with 170 degrees total active motion, normal sensibility, and normal motion in all other digits

5. Normal range of motion in the index finger but stiffness in all other digits

 

Discussion

The correct answer is (A). Index finger replantations in zone 2 are notorious for poor functional results, and often lead to significant stiffness with PIP range of motion <40 degrees. If the middle finger is uninjured and the index finger lacks mobility, individuals often bypass the index to the middle finger for pinch grasp. This is the most likely outcome for the patient mentioned in this question. Total active motion in the digits range from 0 to 270 degrees, with 0 to 90 degrees at the MP joint, 0 to 110 degrees at the PIP joint, and 0 to 70 degrees at the DIP joint.

 

Objectives: Did you learn...?

 

 

Describe the zones of injury according to Verdan? Treat Zone 2 amputations?

 

Identify the functional outcomes of replantation?