EM Ortho 5: Hand

Question 1

most common cause of hand flexor tendor injury

Answer 1

laceration

Question 2

remarks on hand flexor zone 1 injury

Answer 2

• zone I is distal to the insertion of the FDS so that injuries involve the FDP alone

-Jersey finger results from hyperextension of the DIP during active flexion, causing avulsion of the FDP tendon
»most commonly occurs in the dominant 4th digit due to its anatomic weakness and increased protrusion while grasping

• surgical referral is recommended

Question 3

remarks on hand flexor zone II injury

Answer 3

Zone II involves the portion of the digital canal occupied by both FDS and FDP tendons

This zone is known as no man’s land bec injury in this zone has historically resulted in poor outcomes

Question 4

remarkson hand flexor zone III

Answer 4

lumbrical muslces originate from the FDP tendons in this region

outocmes are generally favorable

Question 5

remarks on hand flexor zone IV

Answer 5

Level of the carpal tunnel

the area must be explored carefully because many vital structures traverse this region

Question 6

remarks on hand flexor zone V

Answer 6

proximal to the carpal tunnel

Injuries here tend to be severe and often multiple tendons as well as the median or ulner nerve (i.e., “spaghetti wrist”)

examine and test all major structures

Question 7

remarks on hand extensor tendon injuries

Answer 7

The extensor tendons are the most common site of tendon injuries because of the superficial nature of the tendons on the dorsum of the hand

If repair in the ED is elected, 4-0 or 5-0 nonabsorbable braided suture with tapered needle is recommended.

Question 8

Remarks on hand extensor zone I injury

Answer 8

Zone I involves the area over the distal phalanx and DIP joint

results in Mallet finger.
- tendon-only rupture can be treated with DIP joint immobilized in continuous full extension for 6-8 weeks
- for best outccome, no flexion of the DIP joint is permitted for the duration of splinting

Question 9

remarks on Mallet finger

Answer 9

1. This injury occurs due to forced flexion of the DIP while the joint is in extension
2. most common tendon injury in athletes
3. treatment:
   - tendon-only rupture can be treated with DIP joint immobilized in continuous full extension for 6-8 weeks
   - for best outccome, no flexion of the DIP joint is permitted for the duration of splinting
4. Chronic untreated mallet finger may result in a swan neck deformity.
   » this occurs when the lateral bands are displaced dorsally, resulting in increased extension forces on the PIP joint

Question 10

remarks on hand extensor zone II injuries

Answer 10

Zone II involves the area over the middle phalanx

Question 11

remarks on hand extensor zone III injuries

Answer 11

Zone III involves the area over the PIP joint

The central tendon is the most commonly injured structure.

May result in Boutonniere deformity

Closed injuries are initially treated with the PIP joint immobilized in continuous extension for 5-6 weeks and should be followed closely by a hand specialist

Question 12

remarks on Boutonniere deformity

Answer 12

Zone III central tendon disruption may result in the volar displacement of the lateral bands, causing them to be flexors, along with the unopposed FDP.

Additionally, the extensor hood retracts, causing extension of the DIP joint, resulting in the Boutonniere deformity

Closed injuries are initially treated with the PIP joint immobilized in continuous extension for 5-6 weeks and should be followed closely by a hand specialist

Question 13

remarks on hand extensor zone IV

Answer 13

Zone IV involves the area over the proximal phalanx.

The injuries have clinical findings similar to zone III injuries.

These injuries are often less likely to have long-term morbidity because the joint is not involved and the tendon at this level is broad and flat

Question 14

remarks on hand extensor zone V

Answer 14

Zone V involves the area over the mCP joint

Open injuries to this area should be consisdered human bites until proven otherweise
*wounds from human bites should have delayed repair following hospital admission for a course of broad-spectrum IV antibiotics

Clea, nonbite wounds can be repaired primarily using mattress sutures to reapproximate tendon edges

Question 15

remarks on hand extensor zone VI

Answer 15

Zone VI involves the area over the dorsum of the hand

tendons are so superficial –> minor-appearing lacerations may be assoc’d with one or more tendon injuries

injuries to zone VI, VII, and VIII typically require advanced suture techniques

Question 16

remarks on hand extensor zone VII

Answer 16

Zone VII involves the area over the wrist

Repair can be difficult bec of the presence of extensor retinaculum

due to the anatomic complexity of this region operative repair is needed