Injuries of the distal phalanx can be a fingertip injury,
which will be a different topic by itself. Fracture of the distal phalanx is
the most common phalangeal fracture, and it can occur from a crushing injury
that produces major soft tissue injury. It can involve the tuft, the shaft, or
the base of the phalanx. If it involves the tuft, then it is usually a crush
injury and may be associated with a nail bed injury. Usually it is associated
with subungual hematoma. If the hematoma involves more than 25% of the nail,
especially if there is a fracture, then you need to remove the nail, as well as
explore and suture the nail bed. Most of the time the fracture is comminuted
and probably will need a splint. In some cases, the fracture may need k-wire
fixation. The fracture may fail to unite. Fracture of the distal phalanx shaft
is usually stable and can be treated conservatively by a splint or buddy
taping, and surgery is rarely needed. Distal phalanx nonunion, if symptomatic
and painful, do reduction and internal fixation with bone graft. With fracture
of the distal phalanx base, there are two types jersey finger and mallet
finger. The patient that is unable to flex the DIP joint is the patient that
has a Jersey finger, or volar base fracture. The patient with a mallet finger,
or dorsal base fracture, is unable to extend the DIP joint. If the fracture is
large, there may be a volar subluxation of the distal phalanx. Be aware of
avulsion fracture at the base of the distal phalanx, because it must be
evaluated thoroughly. It could be an avulsion of the insertion of the flexor or
the extensor tendon, and the fracture appearing small and benign. If the
fragment is large or if there is volar subluxation of the joint, then this can
be treated by different techniques. K-wire utilization is a very common
technique. The goal is to keep the DIP extended until the bone or the tendon
heals. Some orthopaedic surgeons will continue to treat this injury by closed
means (splint), even if there is a volar subluxation of the joint. The rationale
is that a stiff finger that is treated by closed means is better than a stiff
finger that is treated by surgery. When the tendon is avulsed with a bony
fragment, the tendon with a piece of bone could be retracted at different
levels, and it can be seen in the x-ray. In general, if the tendon is retracted
to the palm, then the blood supply could be affected and surgery should be done
within 10 days. If the fragment is large, then usually the retraction is
limited to the DIP. The finger lies in extension relative to the other fingers,
and the patient will not be able to do active DIP flexion. Seymour fracture is
an epiphyseal fracture of the distal phalanx. It is a flexion injury that leads
to physeal separation between the extensor tendon dorsally and the flexor
digitorum profundus volarly. This flexion injury causes an avulsion of the nail
from the nail fold with disruption of the nail matrix. The patient’s finger
will appear flexed, which looks like a mallet finger, and the nail appears to
be larger compared to the nail on the other side. This injury is really an open
fracture and needs to be treated by antibiotics, removal of the nail,
irrigation and debridement of the fracture, reduction and pinning of the
fracture and nail bed repair.
