Reconstrucción de la mitad proximal del radio usando peroné vascularizado…(I)

«Reconstrucción de la mitad proximal del radio usando peroné vascularizado: Significado de la reconstrucción del tejido blando.»

Large bony defects in the forearm are occasionally created after tumor resection, trauma, infection, or congenital pseudarthrosis. Such an extensive defect in the forearm, especially in the diaphysis, has been successfully treated by use of vascularized fibula.1, 8, 9 and 10 However, its application for proximal osteochondral defects of the radius has rarely been reported.

This report describes replacement of the proximal half of the radius by use of a vascularized fibula graft, in combination with soft-tissue reconstruction, with a successful intermediate-term result.

Case report

A 68-year-old man had dull pain in his left elbow for 4 months. On initial consultation, there was moderate swelling and tenderness at the radial head. In addition, there was marked bowing in the left upper arm, due to underlying multiple fibrous dysplasia involving the humerus, radius, and first metacarpus. Extension and flexion of the elbow were 0° and 90°, respectively. Pronation and supination were 30° and 45°, respectively.

Plain radiographs showed a radiolucent and ballooning change of the radial head and neck, combined with a ground glass–like appearance of the proximal radius. Computed tomography demonstrated a destructive change of the proximal radius, and approximately one third of the cortex had disappeared. Magnetic resonance imaging confirmed that the lesion included a cystic area. The pathologic diagnosis after open biopsy was secondary aneurysmal bone cyst or low-grade central osteosarcoma. En bloc resection of the lesion and reconstruction by use of vascularized fibula were planned. After osteotomy of the mid shaft, the proximal 13 cm of the radius was resected along with the supinator muscle. The tendinous insertion of the biceps brachii was transected, but its bicipital aponeurosis was maintained. The radial nerve was preserved after being dissected from the fascial tunnel of the supinator. The median nerve and the radial artery were also preserved. The annular ligament and the radial collateral ligament of the elbow were resected, but the lateral ulnar collateral ligament remained intact. The excised specimen showed that the articular cartilage of the radial head was markedly degenerated. A surgical margin of limited area along the radial nerve was minimal, but the other part of the specimen showed a wide resection.

A vascularized fibula measuring 13 cm in length was harvested from the contralateral leg. Fascia lata graft was also harvested to wrap one end of the fibula as a substitution for the articular surface of the radial head. Osteosynthesis of the other end of the graft was accomplished by use of a plate and screws. Then, both the radial collateral and annular ligaments were reconstructed, by use of a palmaris longus tendon graft. The graft was sutured in an interlacing fashion to the remnant of the annular ligament and consecutively sutured to the radial collateral ligament under adequate tension. The severed interosseous membrane was not reattached to the fibula. Finally, microsurgical vascular anastomoses were performed. The peroneal artery was interposed between the radial artery for a flow-through type repair, and each end was anastomosed proximally and distally with the radial artery in an end-to-end fashion. Two peroneal venae comitantes were anastomosed with the cephalic vein and the radial venae comitantes in an end-to-end fashion.

Venous thrombosis was encountered postoperatively. However, it was managed successfully, and uneventful wound healing was obtained. Bony union was achieved by 6 months after surgery. At that time, plain radiographs also showed some absorption at the proximal end of the graft in the elbow. Proximal migration of the radius occurred in relation to the ulna, resulting in a 3-mm ulnar-plus change at the wrist. However, the change was not progressive, and the patient has never complained of any symptoms at the wrist up to the latest follow-up.

The postoperative diagnosis of the lesion was central low-grade osteosarcoma. There has not been any local recurrence over the 4-year postoperative follow-up. Functionally, there has not been any instability at either the elbow or the wrist. Extension and flexion of the elbow were −20° and 90°, respectively. Muscle manual testing of extension and flexion of the elbow joint was nearly normal. Pronation and supination of the forearm were 15° and 50°, respectively. Although there was a slight limitation of motion in the elbow and forearm compared with the preoperative state, the patient has used the reconstructed arm without difficulty during routine daily activity. He expressed satisfaction with the surgical results.

Discussion Reconstruction of the proximal radius is a difficult problem, especially when the interosseous ligament of the forearm is simultaneously disrupted.3 In the case of severe comminuted fracture of the radial head, it is sometimes difficult to preserve the proximal radius, despite every effort. In such a case, either excision of the fragments or implantation of a prosthesis has been performed, but these procedures have occasionally failed, with the remaining radius migrating proximally, resulting in a symptomatic wrist.7

In the case reported here, the proximal half of the radius was excised because of the destructive lesion. Several authors have reported that the thickened central band of the interosseous membrane, namely the interosseous ligament, runs obliquely from the distal ulna to the mid portion of the radius.2 and 6 These anatomic studies suggest that the remaining distal radius is sufficiently unstable to migrate proximally after resection of the proximal half of the radius because radial insertion of the interosseous ligament is lost. The so-called one-bone forearm reconstruction has been one of the established solutions for such extensive defects of the proximal radius.5 The technique, however, sacrifices rotation of the forearm in exchange for achieving a stable forearm.

To our knowledge, only Nonnenmacher et al4 have described reconstruction of a large defect in the proximal radius using a vascularized fibular graft. In that report, the graft could not prevent proximal migration of the radius and marked ulnar-plus change and dorsal subluxation of the distal ulna occurred at the wrist. Those changes were symptomatic, and both forearm rotation and wrist extension were painful. Although the Sauvé-Kapandji procedure temporarily resolved the problem, the long-term results have not been documented. In the current case, we performed soft-tissue reconstruction simultaneously to increase the stability of the fibula at the elbow. The reconstruction consisted of fascia lata interposition arthroplasty as well as ligament repair of the radial side of the elbow by use of the palmaris longus tendon. Although the radius migrated proximally for the first 6 months, there were no progressive changes in the spatial relationship of the radius and ulna thereafter. Both the elbow and the wrist joint have remained sufficiently stable for the patient to continue using the reconstructed arm for daily activities for 4 years since surgery. Thus, combined soft-tissue reconstruction seemed valuable for stability of the elbow and forearm. However, proximal migration of the radius did occur, although it was only 3 mm and asymptomatic. Reattachment of the severed interosseous membrane to the fibula may be of some value as additional stabilization.

In conclusion, a vascularized fibula, combined with soft-tissue reconstruction, can be one of the solutions for extensive defects of the proximal radius. The procedure can maintain the structural integrity of the two-bone forearm, thus preserving forearm rotation. The long-term outcome should be monitored to determine the definitive role of the vascularized fibula for replacement of the proximal radius.

Journal of Shoulder and Elbow Surgery. Volume 15, Issue 1 , January-February 2006, Pages 124-126.

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