Volar Shear Fractures

Fig. 7.1 The term volar shearing fracture comprises a varied group of fractures. In the simplest form, the volar fragment is just broken at the metaphysis and subchondral bone. In more severe forms there is comminution of the metaphysis or multifragmentation. However, what makes this fracture “complex” is the existence of compression in the dorsal fragment (much like in the fracture-dislocation of the PIP joint). This has been underrecognized in the literature, probably because arthroscopy is not commonly used. This chapter discusses only the complex group; the other might only exist in the prearthroscopic era.

Fig. 7.2 All volar shearing fractures are managed similarly. With a Henry approach the metaphyseal cortex is restored to length (by applying traction), and a plate is applied with the intention of creating a buttress effect. Notice the amount of anterior projection of the distal end of the radius fragment (e) in relation to the metaphysis (m).

Fig. 7.3 A plate is apposed on the volar aspect of the radius. No attempt is made to reduce the articular component, because the plate will do so by its buttress effect. Notice that there is plenty of space underneath the plate for a forceps to pass.

Fig. 7.4 There are two important considerations when buttress plating a distal radius fracture. The first is that the plate needs to be stabilized with one K-wire to prevent uncontrollable proximal migration. The second is that the surgeon should estimate the degree of proximal migration of the plate on the anterior metaphysis, because gliding always occurs as the screw in the elliptical hole of the stem of the plate is tightened. If the plate is placed in the theoretically correct position (for a dorsal bending fracture), the distal edge of the plate will end up too proximal and separated from the bone (red arrow), risking irritation of the flexor tendons and/or loss of reduction (top). The plate should be placed close to the rim of the radius, so as it migrates proximally it will end up in the intended position (bottom).

Fig. 7.5 The screw (arrow) has been tightened (the plate is in contact with the metaphysis), and the fracture is now compressed by the “buttress plate.” An arthroscopic evaluation will follow. In very few cases will the joint be perfectly reduced (simple fracture configurations); if it is, you should proceed the surgery as recommended in Fig. 3.27. In most cases (complex forms), however, there is a step-off and the following steps should be followed.

Fig. 7.6 Scenario one: Sunken dorsal fragment, in which there has only been compression of the dorsal fragment with minimal or no comminution in the metaphysis. (a,b) Notice that after applying the buttress plate the length of the volar metaphysis is restored but the joint is not reduced, because of the compressed dorsal fragment. (c) The paradigmatic arthroscopic findings of (b). Let’s now go over the case presented in Figs. 7.2–7.6.

Fig. 7.7 The patient is a 34-year-old police officer. Notice that although this is a typical volar shearing fracture, a concomitant component of compression can be inferred by the increased volar tilt of the dorsal fragment more evident in S3 and S4. The normal contour of the radius has been outlined in S3. The scaphoid facet is a single large fragment that should not present any problems.

Fig. 7.8 Notice in the “articular view” that the fracture is not as simple: The increased volar tilt is now evident. Also the subchondral compression can be appreciated.

Fig. 7.9 The fracture has been reduced following the steps explained in Figs. 7.2–7.5, to the point of the arthroscopic exploration. (As expected, the “buttressing” screw is now proud dorsally and will need to be replaced at the end of the operation.) The arthroscopic findings are shown in Fig. 7.6c, and this “perfect” fluoroscopic reduction needs to be modified.