The Sauvé-Kapandji Procedure

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INTRODUCTION

Arthrodesis is the most reliable and durable surgical procedure for the treatment of a joint disorder, with the main disadvantage of loss of motion of the fused joint. The distal radioulnar joint (DRUJ) can be arthrodesed, whereas forearm pronation and supination are maintained or even improved by creating a pseudarthrosis of the ulna just proximal to the arthrodesis. This is known as the Sauvé-Kapandji (S-K) procedure.

The S-K procedure differs from the Darrach procedure in that it preserves ulnar support of the wrist, since the distal radioulnar ligaments and ulnocarpal ligaments are maintained. Aesthetic appearance is also superior after an S-K procedure, since the normal prominence of the ulnar head, most noticeable when the forearm is in pronation, is not lost. However, the S-K is not void of possible complications, such as nonunion or delayed union of the arthrodesis, fibrous or osseous union at the pseudarthrosis, and painful instability at the proximal ulnar stump. All of the latter can be prevented when a careful surgical technique is performed.

HISTORICAL BACKGROUND

Many procedures have been described for the management of the altered DRUJ, not only because there is no single procedure superior to another, but mainly because of the broad spectrum of pathology requiring different surgical techniques for each lesion. The most common alterations of the DRUJ are joint incongruencies secondary to deformities of the distal radius from malunited fractures, distal radial epiphysiodesis, or Madelung’s deformities. Isolated joint instabilities after ruptures of the distal radioulnar ligaments are also common. Primary degenerative arthritis is unusual but may be observed after fractures of the distal radius or ulna. In other cases, the problems may be related to the ulnocarpal joint rather than the DRUJ, as in triangular fibrocartilage complex (TFCC) tears or the so-called ulnocarpal impaction syndrome when the ulna is longer than the radius.

Resection of the ulnar head was first described by Malgaine in 1855 and later popularized by Darrach in 1912 and 1913. It is an easy procedure to perform with early good functional results, though not free of complications. These consist mainly of instability of the proximal ulna, loss of grip strength, and possible ulnar translation of the carpus from loss of ulnar support in patients with rheumatoid arthritis. To avoid these possible complications, Bowers, Watson and colleagues, and Feldon and colleagues described techniques of partial resection of the ulnar head while preserving the ulnar styloid and the ligaments inserting at its base.

Chronic instability of the DRUJ can be treated by various ligament reconstructive procedures, but all require a long period of postoperative immobilization and not infrequently fail to restore normal joint stability.

In 1921, Baldwin reported a loss of pronation and supination of the forearm after malunited distal radial fractures that he had successfully treated by excising a 2-cm segment of the ulna proximal to the DRUJ, thus creating a pseudarthrosis. In 1936, Sauvé and Kapandji described a similar technique, with the variant that a DRUJ arthrodesis was added to the ulnar pseudarthrosis. This technique was attributed to Lauenstein by Arthur Steindler in his book, The Traumatic Deformities and Disabilities of the Upper Extremity . For many years Lauenstein was referred to as the author of the technique in the English medical literature. What Lauenstein had actually described was a resection of the head of the ulna.

However, the so-called S-K technique had already been published by Allan J. Berry from New Zealand in 1931; therefore this technique should be known by the eponym the Berry-Sauvé-Kapandji procedure. Berry had performed this procedure the year before its publication, the only difference being that rather than a screw or a Kirschner (K) wire, he used a bone peg to stabilize the DRUJ arthrodesis. Arthrodesis of the DRUJ with ulnar resection-osteotomy proximal to the arthrodesis for restoration of pronation and supination of the forearm has the advantage over ulnar head resection of preserving ulnar support of the wrist, since the distal radioulnar ligaments and ulnocarpal ligaments are preserved. It also allows for shortening of the ulnar head, which cannot always be done with resection arthroplasties that preserve distal radioulnar ligaments, such as the Bowers, Feldon, or Watson technique. Another advantage of the S-K technique is that the postoperative immobilization is shorter, which is an added benefit for the patient.

INDICATIONS

The S-K technique can be successfully used for the treatment of any pathology involving the distal radioulnar and the ulnocarpal joints. The most common indication is distal radioulnar instability or incongruency after a distal metaphyseal radius fracture. The technique allows for shortening of the ulna for treating ulnocarpal impaction, as well as recovery of forearm rotation at the pseudarthrosis created in the ulna. Simultaneous correction of a severe distal radial angulation can be performed at the same time, but this adds a technical difficulty to the procedure. In some distal radial osteotomies, rigid screw fixation of the ulnar head is not possible, and nonrigid K-wire fixation is necessary.

The S-K technique is also indicated for the treatment of isolated DRUJ instabilities secondary to ligament ruptures. Ligament repair techniques do not always offer adequate joint stability and require long periods of immobilization of the wrist and elbow, which may be very uncomfortable and disabling for the patient, as well as leading to a loss of forearm rotation in some cases.

Chronic or difficult to repair TFCC tears can also be treated with the S-K procedure. The patient can resume normal daily activities after the skin sutures are removed, since the screw provides for stabilization of the DRUJ, thus preventing the long periods of immobilization that are needed after TFCC repairs. When the DRUJ is arthrodesed, there are no strains into the TFCC, and lesions “spontaneously” repair if their vascularity allows for it. We started treating chronic TFCC tears with the S-K technique after observing spontaneous healing of delayed unions of styloid fractures of the ulna after DRUJ arthrodesis ( Figs. 29-1 and 29-2 ).

The S-K technique is also indicated for the treatment of early synovitis of the DRUJ in patients with rheumatoid arthritis. After the arthrodesis, the synovitis permanently disappears, preventing rupture of the distal radioulnar and ulnocarpal ligaments. When the ulnar head is completely dislocated, the procedure does not provide ligamentous stability, since the ligaments will already have been destroyed, but will give bone support for the carpus. This may be of benefit if a simultaneous radiolunate arthrodesis has to be performed, since it provides a greater surface area for bone contact between the lunate and the distal radius and ulna.

One of the best indications for the S-K technique is ulnocarpal impaction from a long ulna secondary to a fracture of the distal radius. If the DRUJ ligaments are not destroyed, one can consider a shortening of the ulna as an alternative.

SURGICAL TECHNIQUE

An axillary block anesthesia is recommended for the S-K procedure because it is better tolerated by the patient and because surgery may be carried out on an ambulatory basis.

The DRUJ is approached dorsally through a V incision centered over the ulnar head ( Fig. 29-3 ). The dorsal sensory branch of the ulnar nerve runs obliquely from proximal-anterior to distal-dorsal at the level of the triquetrum, which can be identified and protected at the distal part of the incision and just anterior to the head of the ulna. The fifth extensor compartment is divided longitudinally, and the extensor digiti minimi tendon is retracted toward the radial side. This maneuver provides better visualization of the dorsal edge of the sigmoid notch of the radius, in addition to preventing inadvertent injury to this small-caliber tendon. The dorsal DRUJ capsule is divided longitudinally close to its insertion into the radius and is then removed to allow for adequate exposure of the ulnar head and neck. The extensor carpi ulnaris (ECU) tendon glides inside an osteofibrous tunnel radial to the styloid process of the ulna, and it is independent of the extensor retinaculum. The ECU and its osteofibrous tunnel should not be disturbed, since they are important DRUJ stabilizers.

With the forearm in pronation, the joint cartilage and subchondral bone of the ulnar head facing the surgeon are removed, leaving a slightly convex surface of cancellous bone ( Fig. 29-4 ). This corresponds to that part of the ulnar head dorsal to the ECU tendon sheath. The ulnar head is perforated with a 3.2-mm drill, with the entrance at the center of the denuded ulnar head and the exit anterior to the ECU sheath. The direction of the drill should be perpendicular to the long axis of the radius and ulna ( Fig. 29-5 ). The triangular skin flap should be retracted to visualize and confirm that the exit of the drill bit is just anterior to the sixth compartment of the extensor retinaculum containing the ECU tendon. With a small knife blade, the puncture wound into the extensor retinaculum produced by the drill bit should be slightly enlarged longitudinally to later facilitate easy identification of the screw entrance point.

The head of the ulna is next osteotomized just proximal to where the joint cartilage ends. The osteotomy can be done with an oscillating saw or with small cutting forceps. If a power saw is used, the blade should be thin with fine serration to prevent excessive seeding of bone particles into the soft tissues. The osteotomized head of the ulna can then be displaced and rotated into supination, allowing visualization of the sigmoid notch of the radius and the proximal ulnar stump ( Fig. 29-6 ).

Next, a segment of the proximal ulnar stump should be removed. In cases in which there is no length discrepancy between radius and ulna, only 5 mm of ulna should be removed. If the ulna is longer than the radius, an additional segment of the ulna, equivalent to the length discrepancy, should be removed. A power saw or preferably a small bone rongeur can be used. The dorsal cortex of the proximal ulna should be rounded off to prevent impingement against the radius from a sharp bony edge. Bone excision of the proximal ulna should be done without damaging the insertions of the pronator quadratus (PQ) muscle and the interosseous membrane (IOM) into the proximal ulna. Retractors should be placed very carefully around the proximal ulna, and all resection should be done looking directly from the space created after the ulnar head has been displaced while rotating the radius into pronation and supination. After this is accomplished, all bone debris should be removed as well as the periosteum in the depth of the wound corresponding to the segment of ulna that has already been removed.

The joint cartilage and subchondral bone of the sigmoid notch of the radius are then excised. Since the joint surface is slightly concave, it is difficult to bite into it with a bone rongeur. The procedure is facilitated if one starts at the angle formed by the union of the dorsal cortex and the dorsal rim of the sigmoid notch. Removal of the cartilage and subchondral bone can later be continued with a bone rongeur. A small osteotome and a curette can be used to make some indentations into the sigmoid joint of the radius, facilitating posterior removal of the cartilage and subchondral bone with a curette (see Fig. 29-6 ).

After rotating the head of the ulna into pronation, a malleolar lag screw is inserted perpendicularly into the head of the ulna through the previously made drill hole. The entrance of the screw should be just anterior to the compartment for the ECU tendon and introduced until its tip protrudes about 3 mm from the center of the denuded surface of the head of the ulna ( Fig. 29-7 ). Using the screwdriver, the head of the ulna is reduced opposite the radius until the protruding tip of the screw is placed at the center of the sigmoid notch of the radius. Before inserting the screw into the radius, one should carefully check the correct position of the head of the ulna in relation to the radius. The most distal part of the ulnar head should be about 2 mm shorter than the distal ulnar edge of the radius. A slightly shorter ulnar head prevents ulnocarpal impingement and damage to the triangular fibrocartilage and also places the ulnocarpal ligaments under slight tension. The DRUJ surface may be difficult to visualize, because its ulnar edge is covered by the radial insertion of the dorsal radioulnar ligament and the triangular fibrocartilage. Because it is very important not to arthrodese the ulnar head in a position longer than the radius, one may need to partially detach the dorsal radioulnar ligament for more precise identification of the DRW as well as the proximal joint surface of the lunate.