CAUSE
A bending force to the tip of the finger leads to the tendon that straightens the tip becoming incompetent. This can be due to the tendon itself being pulled off the bone or a fracture of the bone with the tendon attached to it.
MALLET FRACTURE
This leads to the tip of the finger “sagging” which can worsen with time and importantly can lead to a problem with the joint adjacent to it which can be even more disabling “swan neck deformity”.
DIAGNOSIS
Initially clinical with a loss of extension of the tip of the finger. An x-ray should be obtained to determine if there is a bone fracture and to make sure that the joint is reduced.
TREATMENT
The majority of these injuries can be treated non-operatively with splinting alone. The length of time the splint is worn depends on whether the injury involves the bone or not.
Tendon takes longer to heal than bone, therefore:
Tendon only: Splint for 8 weeks full time then night splint for a further 4 weeks.
Bone: Splint for 6 weeks full time and then night splint for 4 weeks.
There are a number of splints available but a comfortable fit is important without undue pressure on the skin and this can be best achieved with a custom-made splint. These can then be adjusted as swelling improves.
If the splint needs to be taken off the joint must be maintained in a straight position. If the tip of the finger droops at all with the splint off, the clock is reset and splinting has to start all over again.
During the period of splinting the other joints in the finger need to be moved to maintain motion.
As the splint is weaned, a motion should be gradually regained to protect the tendon, especially in tendon avulsions.
SURGERY
Not usually needed. The main need for surgery is if the joint is unstable and starts to dislocate, usually due to a relatively large fracture fragment. The results of surgery in simple cases are inferior to non-operative treatment.