Mallet Finger

Mallet finger is an injury to the extensor mechanism of the finger at the level of the distal interphalangeal joint, it occurs due to forced flexion of the DIP (stubbing your finger). Sometimes it can be bony (an avulsion at the insertion of the common extensor tendon) others it can be purely a mid tendon injury.

Clinically they both present with the finger in fixed flexion ( inability to extend the finger at the DIP joint).

Above is a simplified illustration of the mechanism leading to either a bony avulsion of mid-tendon injury,


Rupture of extender tendon

Avulsion fracture at base of distal phalanx

Mallet splint for 6 weeks daily, and then 6 weeks nightly

A 31-year-old female presents with finger pain and deformity after a ball hit her finger while she was playing netball 4

days ago. The clinical picture of her finger is shown below.

A. #14. What is the diagnosis? (1 mark)

 Mallet finger

B. #15. What investigation would you order for this patient? (2 marks)

 X-ray of finger (1 mark) – PA (0.5 mark) and lateral (0.5 mark)

C. #16. List THREE (3) possible findings on the radiograph of this patient. (3 marks)

 Normal x-ray (1 mark)

 Bony mallet (1 mark)

 DIPJ subluxation (1 mark)

D. #17. List 2 treatment options for this patient. (2 marks)



 Closed reduction percutaneous pinning (CRPP)

(any 2, 1 mark each)

E. #18. List 2 complications that may arise from this condition. (2 marks)

 Extensor lag

 Loss of flexion

 Swan neck deformity

(1 mark each, any 2)

Jammed finger injury