Treatment of the loss of the distal part of the radius, including the physis and epiphysis, in a skeletally immature patient requires both replacement of the osseous defect and restoration of longitudinal growth. Autologous vascularized epiphyseal transfer is the only possible procedure that can meet both requirements.
Between 1993 and 2002, six patients with a mean age of 8.4 years (range, six to eleven years) who had a malignant bone tumor in the distal part of the radius underwent microsurgical reconstruction of the distal part of the radius with a vascularized proximal fibular transfer, including the physis and a variable length of the diaphysis. All of the grafts were supplied by the anterior tibial vascular network. The rate of survival and bone union of the graft, the growth rate per year, the ratio between the lengths of the ulna and the reconstructed radius, and the range of motion of the wrist were evaluated for five of the six patients who had been followed for three years or more.
The mean duration of follow-up of the six patients was 4.4 years (range, eight months to nine years). All six transfers survived and united with the host bone within two months postoperatively. The five patients who were followed for three years or more had consistent and predictable longitudinal growth. Serial radiographs revealed remodeling of the articular surface. The functional result was rated as excellent for all but one patient, in whom the distal part of the ulna had also been resected because of neoplastic involvement. No major complication occurred at the recipient site, whereas a peroneal nerve palsy occurred at the donor site in three patients. The palsy was transient in two patients, but it persisted in one. No instability of the knee joint was observed.
After radical resection of the distal part of the radius because of a neoplasm in children, vascularized proximal fibular transfer, based on the anterior tibial artery, permits a one-stage skeletal and joint reconstruction, provides excellent function, and minimizes the discrepancy between the distal radial and ulnar lengths.
Epiphyseal reconstruction of long bones in children is a challenging issue in orthopaedics. The double goal of restoring joint function and growth potential cannot be achieved by means of conventional procedures such as insertion of a prosthesis or a nonvascularized allograft. A vascularized autograft consisting of the proximal fibular epiphysis and a variable amount of the proximal diaphysis is an effective biological alternative in the reconstruction of the distal aspect of the radius and the proximal part of the humerus in children1,2. The purpose of this report is to describe the technical details of this procedure.
Harvesting of the Proximal Part of the Fibula
The aim of this procedure is the harvest of the proximal epiphysis and a variable amount of the diaphysis of the fibula with use of the anterior tibial artery and veins as a vascular pedicle3,4. This artery (Fig. 1) supplies the epiphysis by means of a recurrent epiphyseal branch as well as the proximal two-thirds of the diaphysis by means of tiny musculoperiosteal branches, which must be carefully preserved during the dissection. During the surgical exposure of the fibula, great care also should be taken to prevent damage to the motor branches of the peroneal nerve and to the epiphyseal vascular pedicle.
Because of its anatomical similarities with the distal part of the radius, the proximal part of the contralateral fibula is preferred for reconstruction following distal radial loss. The patient is placed on the operating table in the supine position. The hip and the knee of the selected donor extremity are flexed, and a sterilized tourniquet is applied. Since the dissection can be difficult and time-consuming, the tourniquet should be inflated at the last minute in order to take full advantage of the ischemia time, which should not exceed two hours.
A vascularized transfer of the proximal fibular epiphysis is indicated in the reconstruction of the proximal part of the humerus and the distal aspect of the radius in children. The procedure is appropriate for the treatment of a tumor, congenital deformity, or traumatic injury. The longer the expected period of time between surgery and the end of growth, the stronger is the indication for this technique, which can provide substantial longitudinal growth. The anatomical similarities between the proximal aspect of the fibula and the distal aspect of the radius make this procedure particularly useful in the reconstruction of this segment, especially when taking into account the severe functional impairment that can result from the length discrepancy with the adjacent ulna with other reconstructive options.
Anatomical variations of the vascular network of the leg represent the major contraindication for this technique. Preoperative angiography (Fig. 9) provides crucial information regarding the epiphyseal vascular supply and is able to demonstrate the recurrent branch of the anterior tibial artery and its contribution to the blood supply of the proximal fibular epiphysis. With the absence and/or hypoplasia of this branch, the procedure cannot be performed. In addition, the anterior tibial artery cannot be harvested as the vascular pedicle of such a graft in patients in whom this artery is the dominant vascular supply to the foot.
Injury to the recurrent epiphyseal branch of the anterior tibial artery during the dissection is the major technical mistake. To prevent this complication, which substantially reduces the value of this procedure, a direct dissection of the fragile epiphyseal vessels should be avoided and they should be protected with a full-thickness muscular cuff consisting of the proximal portion of the extensor digitorum longus and peroneus longus muscles.
In addition, the diaphyseal musculoperiosteal branches to the fibula are very thin (Fig. 10), and they cannot be dissected safely. Once again, a certain amount of soft tissue around the pedicle, including the interosseous membrane (Figs. 11-A and 11-B) and a longitudinal strip of muscle (Fig. 12) that contains the tiny perforator arteries to the fibular periosteum, should be preserved.
Finally, great care should be taken in dissecting the peroneal nerve from the vascular pedicle. The motor branches to the anterior and lateral muscles are quite thin and fragile and require a very tedious and gentle dissection. If a motor branch is severed, it should be repaired with use of a microsurgical technique.
An anterolateral approach is used to isolate the proximal part of the fibula on the basis of the anterior tibial arterial network (Figs. 2-A, 2-B, and 2-C). The dissection is carried out in the intermuscular plane between the tibialis anterior and the extensor digitorum longus muscles (Fig. 2-C). The neurovascular bundle is better exposed from distal to proximal, since the dissection of the peroneal nerve from the anterior tibial artery and veins is easier in the distal portion of the operating field (Fig. 3-A). In the proximal one-half of the leg, the nerve surrounds the vascular bundle in an intricate three-dimensional pattern and sends many branches to the muscles of the anterior compartment (Fig. 3-B). Some of these motor branches may perforate the space between the vascular bundle and the bone and therefore cannot be dissected (Fig. 3-C). In this case, the motor branch is divided and then repaired with use of microsurgical techniques.
In order to expose the fibula, the extensor digitorum longus muscle, together with the peroneus longus muscle, is sharply detached from its proximal insertion at the level of the emergence of the peroneal nerve into the anterior compartment of the leg (Figs. 4-A, 4-B, and 4-C). The proximal muscular cuff must be left attached to the fibular head since it contains the recurrent epiphyseal branch of the anterior tibial artery on which this transfer is based. During the diaphyseal dissection, as many periosteal branches as possible are preserved. For this reason, it is recommended that the interosseous membrane and a longitudinal strip of muscle be harvested as well in order to protect the small branches from the main artery to the diaphyseal periosteum of the proximal part of the fibula.
The fibula is resected and is separated from the surrounding muscles and the peroneal artery, which is located in close proximity to the posteromedial aspect of the middle and distal parts of the fibula. An extra portion of periosteum (Fig. 5) should be harvested so that it can overlap the osteotomy site of the recipient bone, to enhance the bone-healing. The segment of diaphysis should not extend beyond the proximal two-thirds in order to preserve an adequate vascular supply to the periosteum.
The proximal tibiofibular joint is then opened, with care taken to preserve as much of the lateral collateral ligament of the knee as possible. The biceps femoris tendon is divided longitudinally (Fig. 6), and the posterior strip is incorporated in the graft in order to reinforce the soft-tissue repair at the recipient site. The anterior half is sutured to the lateral collateral ligament, which is going to be fixed to the lateral aspect of the tibial metaphysis. Finally, the proximal dissection of the pedicle is carried out until the origin of the anterior tibial artery is exposed and ligated. In order to obtain a longer and more conveniently located pedicle, this graft has been hemodynamically modified according to a reverse flow model. The long distal portion of the pedicle is therefore preferred for anastomosis to the recipient vessels. As has been reported in the literature5 and confirmed by our clinical experience, the venous flow can be reversed, provided that the small shunts that interconnect the two venae comitantes are preserved during the dissection of the vascular bundle. Usually, only one of the two venae comitantes has adequate flow, and the surgeon should be aware of which vein is the better choice for the anastomosis in the recipient site.
Care is taken when repairing the lateral structures that stabilize the knee joint. The lateral collateral ligament, enhanced by the residual portion of the biceps femoris tendon, is fixed to the lateral aspect of the tibia with nonabsorbable sutures into the periosteum, and stability is evaluated. The donor extremity is protected by an above-the-knee cast, which should be worn for one month.
Reconstruction of the Distal Part of the Radius
Fixation of the proximal part of the fibula to the distal part of the radius can be achieved either with a plate and screws (Fig. 7-A) or with lag screws if a step-cut osteotomy is performed. Either procedure is facilitated by the similarity between the diameters of the donor and recipient bones. In the case of a total resection of the radius, the fibula should be fixed, end to side, to the ulna (Fig. 7-B) with lag screws in order to achieve adequate stability. When the distal part of the ulna has been resected as well, the fibula should be fixed to the residual proximal part of the ulna to create a one-bone forearm (Fig. 7-C).
The wrist is temporarily stabilized with a 1.2-mm Kirschner wire, which is removed one month postoperatively. The strip of biceps femoris tendon remaining attached to the fibular head is used for soft-tissue repair and is anchored to the remaining distal radiocarpal capsule and ligaments (Fig. 8). In contrast, the distal radioulnar joint is usually left slightly lax in order to prevent any possible impingement during pronation and supination.
A reverse-flow arterial end-to-end anastomosis is then performed with either the radial artery or the common interosseous artery. The recipient vein is usually the cephalic vein. At the end of the vascular repair, bleeding should be observed from the muscular cuff surrounding the transferred proximal part of the fibula. An above-the-elbow cast is worn during the first two months postoperatively and is then replaced with a wrist splint.
The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
The line drawings in this article are the work of Joanne Haderer Müller of Haderer & Müller ().
Investigation performed at Azienda Ospedaliera Careggi, Florence, and Istituto Ortopedico Rizzoli, Bologna, Italy
The original scientific article in which the surgical technique was presented was published in JBJS Vol. 86-A, pp. 1504-1511, July 2004
- Copyright © 2005 by The Journal of Bone and Joint Surgery, Incorporated