JERSEY FINGER

Question 1

Blood supply to FDP insertion

Answer 1

1. Periosteal vessels at insertion
2. Long vincula
   - FDP tendon has a hypovascular area over DIPJ, 1cm proximal to its insertion = most common site for FDP rupture

Question 2

4 reasons why the RF is the most common location for jersey finger

Answer 2

1. RF extends 5mm further distally with finger flexion = absorbs more force
2. RF FDP has a weaker insertion
3. RF FDP has the least amount of independent motion
4. RF FDP has a bipennate lumbrical = tethers tendon in palm and limits excursion

Question 3

Classification of jersey finger

Answer 3

Modified Leddy and Packer classification = 5 types based on

• degree of tendon retraction
• presence/ absence of avulsion fracture
  1. Type I = retraction into palm
• long and short vinculae disrupted
• requires surgical treatment within 1 week
  2. Type II = retraction to PIPJ
• short vincula disrupted, long vincula intact
  3. Type III = large bony avulsion with retraction to DIPJ
• long and short vinculae intact
  4. Type IV = double avulsion
• avulsion fracture and disruption of tendon from avulsed fragment
  5. Type V = large bony avulsion with comminuted distal phalanx fracture

Question 4

3 prognostic factors for jersey finger injuries

Answer 4

1. Acuity of injury
2. Degree of tendon retraction = affects vascularity
3. Size of avulsed fragment

Question 5

2 main surgical techniques for direct repair

Answer 5

Suture anchors vs. dorsal button
Studies show no difference in outcomes
Suture anchors:
1. Advantages
- all inside technique
- no risk of nail plate deformity 
- no risk of dorsal skin deformity
2. Technique
- deadman angle theory = 45deg retrograde insertion
- increased resistance to pullout
- decreased gap formation
Dorsal button:
1. Advantages 
- better option with osteoporotic bone or comminuted fracture
2. Disadvantages
- risk of nail plate deformity and dorsal skin necrosis

Question 6

3 main surgical options with chronic jersey finger or with irrepairable/ irretrievable tendon intraoperatively

Answer 6

1. Do nothing as FDS still intact
   - consider in elderly low-demand patients
2. Reconstruction = 1-stage vs. 2-stage
   - consider in high-demand patients (manual dexterity = musicians, athletes, labourers)
3. DIP arthrodesis
   - consider with arthritic joint

Question 7

Quadrigia effect with flexor tendon repair

Answer 7

• Loss of active flexion of adjacent digits due to overtensioning or overadvancement (> 1cm) of FDP repair
• FDP tendons to MF, RF and LF share a common muscle belly so their excursion is limited to excursion of the shortest tendon