The most common type of middle phalanx base fracture is a small volar plate avulsion fracture, which commonly accompanies a sprain or dislocation of the proximal interphalangeal joint. This usually heals with a painless fibrous union. This injury requires no specific treatment other than what is indicated for the associated joint injury. Less common but much more troublesome are fracture-dislocations of the proximal interphalangeal joint. If the fracture line extends through the proper collateral ligament, the joint will become unstable, and the middle phalanx will displace with subluxation. Dorsal fracture-dislocations with a large palmar fragment are more common than volar fracture-dislocations. Either can be complicated by central articular impaction (Fig. 3). Treatment is controversial with advocates for internal or external fixation using a variety of techniques, including dynamic external traction, external fixation with distraction, internal fixation, and joint reconstruction with an osteochondral graft. Common principles include correction of subluxation, bone graft to correct impaction, and early motion.
Proximal interphalangeal joint fractures