Volar Surgical Correction of Madelung's Deformity

HISTORICAL PERSPECTIVE Madelung's deformity comprises a characteristic pattern of anterior-ulnar bowing of the radius and a dorsally prominent ulnar head. It is commonly observed as an isolated deformity, but has been documented in conjunction with Leri Weill dwarfism, multiple enchondromatosis, and posttraumatic/infectious damage to the distal radial physis. 1 Madelung's deformity tends to be bilateral, and it is noted more often in females. 2 Deformity is usually diagnosed in early adolescence, when prominence of the distal ulna and/or nonspecific wrist pain leads the patient and/or their parents to seek orthopaedic opinion. Restriction of pronosupination and extension tend to manifest later. On occasion, presence of a sibling with a similar deformity, or serendipitous discovery of the classic radiograph changes leads to early referral. Infrequently, the patient presents for surgical opinion late, after a tendon rupture or nerve compression syndrome. 3,4 The etiology of true Madelung's deformity is unknown, although some insight is expected from the genetic analysis of patients with Leri Weill dwarfism. 5,6 Current theory suggests that deficient growth in the volar/ulnar portion of the distal radial growth plate results in the characteristic deformity. 7 Early radiographic changes consist of increased dorsal and radial bowing of the distal half of the radius and increased volar and ulnar tilting of the distal radial articular surface. Consistently, the radiographic appearance is worse than the clinical deformity. More advanced deformity manifests as a widening of the distal radioulnar joint (DRUJ) as well as a compensatory pyramidal shape of the proximal carpal row with the apex at the lunate. Dorsal subluxation of the ulnar head is believed to be secondary to the supination deformity of the hand in combination with relative undisturbed linear growth of the distal ulna. Despite the fact that the observation of a mild deformity is clearly indicated, most authorities offer surgical reconstruction for painful or cosmetically unacceptable deformity. 8–11 Since the original description of Madelung's deformity, numerous operative techniques have been proposed. A Darrach-type excision of the prominent distal ulna was the traditional surgical procedure, 2,12,13 but it failed to address the focal point of the deformity, the ulnar half of the distal radius. The development of various combinations of opening- or closing-wedge osteotomies ensued and long-term data is available for some procedures. 10,11,13 Frequently, an ulnar-head excision was performed in addition to the radial osteotomy, although a Sauve–Kapandji type of distal ulnar arthrodesis with proximal pseudarthrosis has also been reported. 14,15 Only recently has preservation of the distal ulna become a priority. 16–18 Traditionally, the radial osteotomy procedures approached the distal radius from its dorsal surface. However, in 1992, Vickers drew attention to the presence of abnormal physeal and ligamentous anatomy on the volar aspect of the radiocarpal joint. 7 He identified a thick fibrous band spanning the radial metaphysis to the proximal carpal row, as well as abnormal growth in the ulnar half of the distal radial growth plate. Vickers subsequently reported success with anterior surgical release of the abnormal ligament and epiphysiolysis for Madelung's deformity identified in early adolescence. This promising procedure does not provide sufficient correction for the typical Madelung's case presenting with more marked deformity and little remaining growth. Recent interest has therefore focused on the surgical correction of the Madelung's deformity with attention directed towards the abnormal volar anatomy and preservation of the native distal radioulnar joint. Carter and Ezaki have recently reported consistently good results using a volar approach to the distal radius with a dome type of distal radial osteotomy combined with the release of Vickers' ligament and preservation of the distal ulna. This article describes the details of the surgical technique used by these authors. INDICATIONS This procedure is indicated in patients with the typical moderate–severe case of Madelung's deformity, who have a painful wrist not responsive to conservative treatment and/or a significant cosmetic deformity. The magnitude of the deformity usually interferes with normal wrist motion or function. Ideally, the procedure should be performed towards the end of growth, or after the growth plate has fused. In the face of rapidly increasing deformity in a skeletally immature patient, the procedure can be used, but a physiolysis procedure may be warranted. 7 CONTRAINDICATIONS Relative contraindications include patients with mild deformity, or those in whom nonsurgical measures have not yet been attempted. Avoidance of activities that precipitate pain, such as gymnastics, cheerleading, or other upper-extremity weight bearing is generally recommended. Splinting during these activities, as well as a trial of nonsteroidal antiinflammatory drugs can be helpful. Patients with radiographic degeneration of the wrist joint, especially the DRUJ, should also be carefully counseled before surgery. The corrective osteotomy does cause increased incongruity in the DRUJ, and this may cause a patient with significant DRUJ arthritis to experience increasing pain or further loss of motion. This may require distal ulnar recession or resection at a second operation. Patients with Madelung's deformity should also be screened before surgery for a common association of radial head dislocation or incongruity. Limitation of pronation and supination may be a result of the radial head's dislocation, and wrist pain may be referred from a degenerative radiocapitellar articulation. TECHNIQUE The patient is supine, and the arm is placed on a radiolucent operating table. A tourniquet is placed around the upper arm. In adolescents, general anesthesia is normally used, but the procedure can be performed under an axillary block. Prophylactic antibiotic is administered, the arm is exsanguinated, then the tourniquet is inflated, and the forearm is fully supinated. An 8-cm longitudinal volar skin incision is made, starting just proximal to the wrist crease and extending proximally along the radial border of the flexor carpi radialis (Fig. 1). Blunt dissection is carried down to the tendon sheath of the flexor carpi radialis with preservation of large subcutaneous veins. The radial artery and vena commitantes are identified in the radial aspect of the wound, and the interval between the flexor carpi radialis and the vascular bundle is opened to reveal the underlying pronator quadratus (Fig. 2). The radial origin of the pronator is incised leaving a cuff for repair, and the muscle is ulnarly reflected to reveal the volar wrist capsule and the thickened, elongated radiolunate ligament as described by Vickers (Fig. 3). Abnormal insertions of the pronator muscle have been described, but this should not prevent its retraction. 19 The thickened volar ligament is released from the radial metaphysis and reflected distally. An adequate release has been completed when the cartilage of the underlying lunate is clearly visualized (Fig. 4).FIG. 1.: The skin markings for the volar surgical approach to the distal radius. The interval between the flexor carpi radialis and the radial artery is identified.FIG. 2.: Deep dissection between the flexor carpi radialis and the radial artery reveals the underlying pronator quadratus.FIG. 3.: As described by Vickers, ulnar reflection of the pronator quadratus exposes the abnormal radiolunate ligament.FIG. 4.: Release of Vickers' ligament is adequate when the proximal surface of the lunate is just visualized. Care is taken when marking the osteotomy site to avoid the distal radioulnar joint.The remaining soft tissues overlying the distal radius are carefully elevated, and subperiosteal retractors are placed around the ulnar and radial aspects of the radial metaphysis. The crescent-shaped osteotomy, with the mouth opening distally, is then marked on the radial metaphysis. Care must be taken to ensure that the ulnar aspect of the planned osteotomy does not penetrate the distal radioulnar joint (Fig. 4). A 0.045-inch Kirschner wire is used to fenestrate the volar cortex along the marked osteotomy site, and a fine osteotome is then used to connect the marks on the volar surface (Fig. 5). A curved osteotome is then introduced through the volar cut surface and used to complete the “dome-shaped” osteotomy with penetration of the dorsal cortex (Fig. 6).FIG. 5.: Fenestration of the volar cortex of the osteotomy site with a 0.045-inch Kirschner wire.FIG. 6.: The dome osteotomy is curved in coronal and sagittal planes with care to avoid distal radioulnar joint.Initial placement of fixation pins in the distal fragment is best accomplished before reduction. Under fluoroscopic direction, two 2.4-mm smooth Steinman pins are placed in a percutaneous fashion through the radial styloid and advanced just short of the osteotomy. The pins are ideally placed parallel to one another. An additional pin can be placed in the proximal radial shaft and directed at the free distal fragment if more secure fixation is required. The reduction maneuver is now performed. The patient's forearm is held with one hand, placing a thumb on the distal fragment through the volar wound (Fig. 7). Longitudinal traction is applied to the patient's hand, and then the hand is radially deviated and pronated. When the hand is in correct longitudinal alignment the surgeon's thumb displaces the distal fragment dorsally to provide the remaining sagittal plane correction. The assistant then drives the Steinman pins across the osteotomy site, and fluoroscopic images are obtained to ensure accurate pin placement (Fig. 8). A rongeur is used to smooth the raised volar edge at the osteotomy site.FIG. 7.: The reduction maneuver is completed with longitudinal traction, radial deviation, pronation applied to the patient's hand, and dorsal displacement applied to the distal fragment by the surgeon's thumb.FIG. 8.: The completed osteotomy is secured with parallel 2.4-mm Steinman pins. A rongeur is used to smooth the volar ridge of the proximal fragment.The radiographic images taken before surgery and during surgery are then carefully analyzed. In a minority of patients with severe deformity present before surgery, additional bony procedures may be indicated. In the rare patient with marked radial bowing, a proximal radial wedge osteotomy can be performed and rigidly plated through a proximal extension of the volar incision. Likewise, if the ulnar variance remains notably positive after the dome osteotomy, a shortening osteotomy of the distal ulna with rigid plating through a separate longitudinal incision over the subcutaneous ulna can be carried out. Closure of the volar incision is carried out after the wound is irrigated with sterile saline. The pronator is laid back on the volar radial metaphysis and can be sutured to its insertion. The skin is approximated with one or two subcutaneous sutures, and a running subcuticular suture is used to complete the closure. The wound is loosely dressed and an above elbow slab applied. The tourniquet can be released before or after wound closure depending upon the surgeon's preference. The patient is seen at 1 week for a wound check and application of an above elbow cast. The pins and long-arm cast are usually removed at 6 weeks. Four weeks of additional below-elbow casting or thermoplastic splinting is usually provided. More prolonged casting is indicated if the osteotomy site remains tender or is healing slowly. COMPLICATIONS The most-common complication observed with the technique described is pin-site irritation after surgery. In our experience, this resolves after pin removal. In this mostly adolescent female population, unsightly scars over the radial styloid may be excised after bone healing. The dome osteotomy does not lend itself well to plate fixation, and Steinman-pin fixation has been found to be adequate fixation in all patients to date. The advantage of the pins is the ease of insertion and fixation compared with plates, and a second operation for plate removal is not required. Nonunion has not been observed in the authors' series to date, but would be a possible and obviously undesirable outcome. Rigid volar plating and bone grafting would be indicated for a nonunion if active infection has been ruled out. In our experience, symptomatic distal radioulnar joint incongruity and/or residual ulnocarpal abutment represent the most-likely reason for an unsatisfactory outcome after a corrective osteotomy is performed. The ligamentous laxity in the DRUJ seems to work to these patients' advantage; however, most patients experience painless pronation and supination in a functional range after surgery. The authors' have identified one patient in their series with severe symptoms at the distal ulna, and this patient was treated with a late Darrach resection and ligament reconstruction (Fig. 9).FIG. 9.: A–C: Salvage of the painful distal ulna is by Darrach-type excision with stabilization of the ulnar stump. Half of the flexor carpi ulnaris is woven through the medullary canal and out the dorsal surface, then sutured back to itself, a modification of the procedure described by Tsai and Stillwell. 20The cosmetic correction is reliable with the procedure, and patients are usually quite pleased with the result. As mentioned previously, patients with a significant growth remaining after surgery do constitute a relative contraindication, and the authors' have had to repeat the radial osteotomy for one patient who had recurrence of deformity with continued growth of the distal radius.