Bennetts Fracture

Question 1

What is the most frequent thumb fracture

Answer 1

Bennetts fracture

Question 2

What is the MOI?

Answer 2

1. Generally occurs as a result of a fall on the thumb or a direct blow to the thumb
   *punch/fist fight
   *axial blow against the partially flexed MC

Question 3

Where is the fracture located?

Answer 3

1. Intra-articular fracture at base of CMC joint of thumb
   *involves an oblique Intraarticular MC fracture (palmar beak)

Question 4

Where does the fracture first start?

Answer 4

1. At the ulnar base of the thumb MC
   *disruption of the ulnar fragment destabilizes the thumb
2. Volar fracture fragment remains attached to CMC by volar anterior oblique ligament

Question 5

How will the fragment be displaced>

Answer 5

1. Proximally
2. Radially
3. And dorsally
   *due to the pull of the APL

Question 6

What is the clinical presentation?

Answer 6

1. Pain and swelling at base of the thumb (proximal side)
2. Decreased strength and motion

Question 7

What will be found on the PE?

Answer 7

1. Tender at base of first MC
2. Edema
3. Decreased muscled strength
4. Decreased ROM
5. May appear to be shortened compared to unaffected thumb
   *since the bone and ligament isn’t there to hold the thumb in place

Question 8

What will be found on the radiograph?

Answer 8

1. Oblique fracture line with triangular fragment at ulnar base of MC
2. Triangular fragment remains attached to trapezium

Question 9

What is a rolando fracture?

Answer 9

1. There will be three distinct pieces shaped like a Y

Question 10

What is the treatment for Bennetts fracture?

Answer 10

1. Percutaneous pinning
   *CRRP good option when there is less than a 3mm of displacement and when the beak of the fragment involves less than 50%
2. Complete ORIF with screw if CRPP not possible
3. Spica cast 4-6 weeks
4. ORIF if greater than 3mm of displacement