FRACTURE OF SHAFT OF RADIUS
Isolated fractures of the radial shaft are often accompanied by a disruption of the distal radioulnar joint, usually at the junction of the middle and distal thirds. The eponyms Galeazzi fracture and Piedmont fracture are frequently used to describe this type of injury. The injury is called the fracture of (surgical) necessity because of the difficulties and historically poor results associated with closed treatment methods.
Initially, Galeazzi postulated that a direct blow to the dorsolateral wrist caused this fracture dislocation. More recent studies suggest that the usual mechanism of injury is a fall on the outstretched hand with the forearm in extreme pronation. The force across the radiocarpal joint causes fracture and shortening of the radial shaft. As further displacement occurs, the distal radioulnar joint dislocates, tearing the triangular fibrocartilage within it.
Hughston, in his classic report of 35 of 38 unsatisfactory results after closed treatment, delineated four deforming forces that lead to treatment failure: (1) the weight of the hand and the force of gravity cause sub-luxation of the DRUJ and dorsal angulation of the fracture; (2) the pronator quadratus muscle rotates the distal radius fragment in a volar, ulnar, and proximal direction; (3) the brachioradialis muscle rotates the distal fragment and produces shortening at the site of the radius fracture; and (4) the thumb abductors and extensors cause further shortening and displacement of the radius.
A volar surgical approach is used for ORIF of the radial shaft fracture. Retracting the flexor carpi radialis muscle ulnarly and the radial artery and brachioradialis muscle radially exposes the fracture site, which can be fixated with a compression plate. Reduction and secure fixation of the radius fracture usually reduce the distal radioulnar dislocation as well.
After fixation of a radius fracture, the surgeon must look for any residual dislocation or subluxation of the DRUJ. Full passive supination of the forearm usually restores joint congruity. If the DRUJ cannot be satisfactorily aligned with closed means (e.g., supination), the joint must be surgically reduced and either pinned with Kirschner wires or with operative reattachment of the TFCC. A long-arm cast is applied, with the elbow flexed 90 degrees and the forearm in full supination. The limb is immobilized for 6 weeks to maintain the reduction. If a transfixation pin has been used to stabilize the DRUJ, it is left in place for 6 to 8 weeks.
If this fracture-dislocation is not diagnosed and appropriately treated soon after injury, later reconstructive surgery is often needed to correct the deformity of the radius and restore the function of the DRUJ. If the distal ulna cannot be adequately reduced, reconstruction or salvage excision must be undertaken.