Metacarpal/Phalanx Fractures & Dislocations

Question 1

What is a general rule for acceptable tolerances of metacarpal neck or shaft fractures?

Answer 1

Neck (2-5): 10-20-30-40
Shaft (2-5): 10-10-20-20
Some sources up to neck: 10-20-40-60, shaft: 10-20-30-40
Can tolerate 2-4mm shortening; no rotational tolerance

Question 2

What technique can be used to reduce metacarpal neck fractures?

Answer 2

Jahss; flex MCP to 90° then push dorsally through proximal phalanx while stabilizing at metacarpal shaft

Question 3

What deformity do proximal phalanx fractures exhibit and why?

Answer 3

Apex volar

Interossei flex proximal fragment, central slip pulls distal segment into extension

Question 4

How are proximal phalanx fractures treated?

Answer 4

Buddy taping if: extraarticular with less than 10° angulation or less than 2mm shortening and no rotational deformity
3 weeks of immobilization followed by aggressive motion
CRPP vs ORIF if otherwise or transverse fx: can use 2 lag screws (1.3mm) if long oblique fx

Question 5

How are dorsal PIP dislocations managed?

Answer 5

1) If simple perform reduction with direct volar force and no traction; if complex (volar plate blocks reduction) may need to hyperextend PIP first
2) Buddy tape for 3-6 weeks then aggressive mobilization
3) If irreducible, dorsal approach btw central slip and lateral band

Question 6

What amount of joint involvement require operative treatment of dorsal PIP fracture-dislocations?

Answer 6

> 40%; if less than 40% and stable can reduce and place in dorsal extension block splint

Question 7

What deformities result from dorsal/volar PIP dislocations?

Answer 7

Volar- Boutonneire (central slip injury)

Dorsal- Swan neck (volar plate injury)

Question 8

How are volar PIP dislocations managed?

Answer 8

Reduction with extension splinting for 6-8 weeks; similar for fracture-dislocations unless >40% joint surface involved, then CRPP vs ORIF

Question 9

How are rotatory PIP dislocations reduced?

Answer 9

Applying traction to finger with MP and PIP joints in 90 degrees of flexion; one of the condyles of the phalanx are button-holed btw the lateral band and central slip

Question 10

How are DIP fracture dislocations managed?

Answer 10

Reduction and placed in dorsal splint with slight flexion for 2-3 weeks