Test 2: Flexor and Extensor Tendons

Question 1

Flexor tendon zone I

Answer 1

Extends from the fingertip to the midportion of the middle phalanx

• FDP is involved thus cannot bend tip of finger
• Injury here= jersey finger (inability to flex the tip of finger, painful and swollen finger)
• ->surgical repair required

Question 2

Flexor tendon zone II

Answer 2

Extends from midportion of middle phalanx to the distal palmar crease

• has the WORST PROGNOSIS (used to be called no man’s land) but most common area for damage
• Deep cut here affects flexor digitorum profundus and superficialis

Question 3

Flexor tendon zone III

Answer 3

Extends from distal palmar crease to the distal portion of the transverse carpal ligament
-not much scarring in this area

Question 4

Flexor tendon zone IV

Answer 4

Overlies the transverse carpal ligament

Question 5

Flexor tendon zone V

Answer 5

Extends from wrist crease to the level of the musculotendinous junction of the flexor tendons
-damage here is called Spaghetti wrist (often seen in failed suicides)

Question 6

Extensor tendon injury: Zone 1 and 2

Answer 6

This injury will lead to mallet finger- cannot extend the DIP
-Mallet finger is the most common injury to the extensor tendon

Question 7

Mallet finger recovery

Answer 7

Splint that keeps PIP at 30 degree flexion and DIP at 10 degrees hyperflexion

• 6-8 weeks, splint can be removed or exercise, but otherwise worn 24/7
• Night splint until 12 weeks, when unrestricted use can begin

Question 8

Extensor tendon injury: Zone 3 and 4

Answer 8

Injury leads to Boutonniere deformity (rupture of the central slip or triangular ligament)
-flexion at PIP, extension at DIP

Question 9

Boutonniere deformity recovery

Answer 9

• 0-6 weeks: Splint the PIP in 0 degrees flexion (MCP and DIP left free)
• 6-8 weeks: gentle AROM for pip flex and extend
• 10-12 weeks: gentle strengthening for full fist
• -> continue to wear splint up to 4 months

Question 10

Extensor tendon injury Zone 5

Answer 10

• Injury can lead to sagittal band rupture
• Splinting at level 5 depends on where injury is: if injury is on ring or middle finger, you have to splint middle, ring and little finger together (because of junctura)

Question 11

Different methods for tendon zone 5 recovery

Answer 11

• Immobilization: wrist and MP’s in extension
• Early controlled mobilization with dynamic splinting: fishing line holding fingers in specific position, but allowing movement
• Relative motion splinting: used in patients with two or more intact long extensor finger tendons (single motor unit)

Question 12

Relative motion splinting

Answer 12

• 1-3 weeks: 2 splints- wrist at 20-25 degrees extension, injured digit at 15 degrees more extension than adjacent MP joint
• 3-6 weeks: wrist splint removed, activity encouraged
• 6 weeks: discontinued

Question 13

Rupture of tendon repair

Answer 13

Most common between 7th an 10th postoperative days

-due to poor repair, poor nutrition, non-compliance, etc

Question 14

Sagittal band function (in Zone 5)

Answer 14

Encircles the MCP joints to stabilize and centralize the extensor tendons during motion

Question 15

Flexor tendon blood supply

Answer 15

• Flexor tendons in fingers are supplied by neurovascular bundles (contain artery, vein and N)- one radial and one ulnar
• Hand supplied by superficial and palmar arches (branches of ulnar and radial arteries)

Question 16

Lateral bands

Answer 16

Connect the middle and distal phalanx- extensor muscle contracts to shorten and pull these bands to straighten the finger
-Lateral band injury can contribute to mallet finger