ORIF Proximal Phalangeal Fractures
Fractures of the proximal phalanx are potentially the most disabling fractures in the hand. Direct blows tend to cause transverse or comminuted fracture, where as twisting injury may cause oblique or spiral fractures. Proximal phalanx fractures typically present with volar apical angulation because of the the extrinsic and intrinsic muscle tension. Typically the proximal fragments are flexed by the bony insertion of the interossei into the base of the proximal phalanx while distal fragments tends to be pulled into hyperextension by the central slip acting on the base of the middle phalanx.
Most frequent complication of this type of fracture is extensor mechanism adhesions with subsequent loss of motion. The periosteum of the proximal and middle phalanges form the dorsal wall of fibro-osseous tunnel in which flexor tendon glide, when violated by a fracture flexor tendon adhesions may develop and reduce motion in this manor as well.
Case #1 Transverse Fracture Proximal Phalanx Little Finger
Case #2 Spiral Oblique Fracture Little Finger
Spiral oblique fractures lend themselves to repair with a lag screw technique which involves typically placing two screws across the fracture site. One perpendicular to the fracture site and the second perpendicular to the long axis of the bone. The technique also involved over-drilling one cortex of the bone so the screw threads only capture the distal cortex on the other side of the fracture thereby compressing the fragments when tightened. This type of reduction generally leads towards primary bone healing instead of secondary.
Case #3 Proximal Phalanx Fracture Ring Finger
Hyper-extension of the distal fragment is evident secondary to the pull of the extensor mechanism on the distal fragment and the intrinsics on the proximal fragment causing volar apical angulation as well.