The patient is placed in the supine position with the hand on an arm table. A tourniquet is placed on the upper arm. Either regional or general anesthesia is used. Initially, manual examination of the involved wrist is performed, followed by an arthroscopic examination of the proximal wrist joint and midcarpal wrist joint, if appropriate. The arthroscopic examination is performed with the hand in the upright position and with the assistance of traction. Once the diagnosis of scapholunate dissociation and the absence of degenerative changes is confirmed, the extremity is taken out of the traction and placed in pronation on the hand table. The surgical approach utilizes a dorsal longitudinal incision made over the dorsum of the wrist just ulnar to Lister's tubercle. The skin incision is carried down to the extensor retinaculum. The dorsal venous complex of the wrist should be saved whenever possible, and the dissection plane is extended radially and ulnarly over the extensor retinaculum. A step-cut incision is made in the extensor retinaculum, leaving a radial and an ulnar-based flap. The terminal branch of the posterior interosseous nerve is identified at the floor of the fourth dorsal compartment lying immediately to the ulnar side of the septum separating the third and fourth compartments. A segment of the terminal branch of the posterior interosseous nerve is harvested, making sure to resect the nerve proximal to the distal end ofthe radius. The extensor tendons are retracted and a transverse incision is made through the wrist capsule just proximal and parallel to the DIC ligament. The DIC is often not easily identified from the dorsal approach, and running a probe or closed forceps from distal to proximal over the dorsal capsule helps isolate the thickened edge of the tissue, which is the DIC ligament. The capsular incision is then extended proximal and obliquely parallel to the radial aspect of the dorsal radiocarpal ligament. The DIC ligament can be reflected distally ifit is an acute injury. If it is a chronic injury, the DIC ligament has typically contracted and already lies distal to its normal level of attachment to the lunate and the dorsal groove of the scaphoid. Most typically, the central, more membranous portion of the scapholunate interosseous ligament and the more substantial dorsal distal portion of the scapholunate interosseous ligament complex are usually avulsed off the scaphoid. The DIC ligament is often avulsed off the dorsal groove of the scaphoid and it is also often detached from the dorsal aspect of the lunate. The proximal wrist and mid-carpal joints are examined through the capsular incisions for any osteochondral or chondral lesions. Any free fragments are excised. A trial reduction of the scapholu-nate joint is performed manually, and, if there is any difficulty in obtaining the reduction, 0.062-inch-diameter Kirschner wires (K wires) can be placed dorsally in the scaphoid and in the lunate and used as "joysticks" to assist in the reduction. While maintaining the scapholunate reduction, 0.045-inch-diameter K wires are used to percutaneously pin the scapholunate joint both from the radial and from the ulnar sides to maintain the reduction.
Once the scapholunate joint has been pinned, radiographs are obtained to confirm the reduction in both AP and lateral projections. Once the reduction has been confirmed radiographically, a 2.0- or 2.5-mm suture anchor is placed in the dorsal rim of the proximal half of the scaphoid in the area where the dorsal segment of the scapholunate interosseous ligament and the DIC ligament have been avulsed. Another suture anchor is placed at the dorsal aspect of the lunate, if the DIC ligament has been avulsed off the lunate (Fig. 63—2A). The suture attached to the scaphoid suture anchor is utilized to reattach the dSLIL and the DIC to their origin on the scaphoid. The suture attached to the lunate suture anchor is utilized to reattach the DIC to its origin on the lunate. If the injury is chronic, and the DIC has contracted and lies distal to its normal location, then the DIC is released distally while maintaining its triquetral attachment and is relocated and attached to the lunate and scaphoid. Once these sutures are tied, the same sutures are used to repair the capsular incision with a slight vest-over-pants imbrication (Fig. 63-2B).
Reattachment of the proximal membranous portion of the scapholunate in-terosseous ligament has also been described. This portion of the ligament, however, is often seen to be disrupted or attenuated in several cadaver dissections. Mechanically, it is not as substantial as the dorsal portion of the scapholunate interosseous ligament complex or the DIC ligament and is an intraarticular structure bathed in synovial fluid with questionable potential for healing. In addition, the degree of fur-
Dorsal capsule _ DIC _ dSLIL
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