Distal, bicondylar
Fracture type
Bicondylar fractures of the head of the middle phalanx may be T-shaped, with a long, or a short, T.
Another pattern of fracture is a combination of a long oblique fracture separating one condyle, together with a short oblique, or transverse, fracture separating the other condyle (sometimes called “reversed lambda” fractures, because of their resemblance to the Greek letter “λ“).
Lag screw fixation is indicated both for the short T-shaped and the reversed lambda fractures.
Typically these fractures are the results of axial load combined with lateral angulation of the finger.
Bicondylar fractures tend to be very unstable and should be treated operatively. If conservative treatment is attempted, secondary displacement is likely, leading to angulation of the finger.
Caveat
These fractures are rare, but difficult to treat. There is an increased risk of joint stiffness resulting from these fractures.
It is wise to use magnifying loupes in these procedures. Gentle and precise handling throughout the procedure is mandatory.
Anatomical reduction recommended
Although the DIP joint is somewhat forgiving, articular fractures should be reduced anatomically, otherwise, digital deformity and degenerative joint disease are likely to follow.
Outcomes
Outcome of fractures of the middle phalanx is usually more favorable than those of the proximal phalanx. This is largely due to the fact that limitation of DIP joint motion is not such a disability as similar stiffness of the PIP and MCP joints.
However, since the fragments in middle phalangeal fractures are generally smaller than in the proximal phalanx, fixation and stabilization can be more of a challenge.
Consequences of malunion (pain, deformity, or degenerative joint disease, at the DIP joint) can be dealt with by arthrodesis, which is usually a procedure with an acceptable outcome.
