R. Capanna, M. Innocenti, M. Ceruso, P. Caldora,
D.A. Campanacci, G. Beltrami, B. Gluckert
Department of Orthopaedics and Traumatology / Department of Oncology - Florence - Italy
The greatest problem with limb reconstruction after resection of bone tumours in children is the loss of potential growth from the resected articular part, with the consequent risk of residual limb-length discrepancy.
A vascularised fibular autograft complete with its growth plate may be used to replace the resected metaphysis with a viable bone segment which is able to grow over time, as well as restoring the anatomy and function of the joint.
For mechanical and anatomical reasons, vascularised fibular grafts in growing children are only indicated in cases of defects (loss of substance) of the upper limb.
The low mechanical strength of the graft makes it more suitable for an anatomical region which is not subject to load-bearing, and the fibular epiphysis is able to replace the proximal humerus or the distal radius of the immature skeleton, while providing good congruency.
There has been some debate about the best choice of blood supply; some authors prefer to use the peroneal artery, on its own or in combination with the lateral inferior genicular artery, while others have shown that the anterior tibial artery is able to supply the fibular epiphysis together with the proximal two-thirds of the diaphysis (Figs. 1 and 2). We harvest the fibula complete with its anterior tibial artery pedicle, in order to provide a good blood supply for the fibular graft.
The tendon of biceps femoris is divided longitudinally into two, and partially removed with the fibula.
The remaining part of the tendon and the lateral collateral ligament are sutured to the tibia to stabilise the joint. If the proximal vascular pedicle is found to be too short, a reversed-flow anastomosis can be made on the distal end of the pedicle. For the proximal humerus, the anastomosis is normally made into the deep brachial artery and the cephalic vein, and for the distal radius, the anastomosis is made into the anterior interosseous artery. It is preferabler to make the venous anastomosis first, followed by the arterial anastomosis, in order to minimize intraoperative bleeding and microcirculatory stasis. Internal fixation is applied in the form of a compression plate, and the wrist is temporarily stabilised with K-wires.
Fig. 1 : The anterior tibial artery (ATA) supplies the epiphysis and the proximal two-thirds of the fibular diaphysis. Some authors feel that a good blood supply can be provided by using the peroneal artery (PA on diagram) and the inferior genicular artery. Fig. 2 : The preoperative angiogram clearly shows the principal blood supply of the fibular epiphysis to come from the anterior tibial artery.
Fig. 3 : Detail of intraroperative isolation of the anterior tibial artery (ATA) pedicle. Fig. 4 : The common fibular (peroneal) nerve must be carefully identified and held out of the way while the fibula is being removed.
Fig. 5 A : Osteosarcoma of the proximal humerus after preoperative chemotherapy in a 7-year-old girl.0
Fig. 5 B : The proximal humerus.has been resected intra-articularly.
Fig. 5 C : The tendon of biceps femoris is sutured to the rotators, while the joint capsule is sutured to the fibular periosteum.
Fig. 5 D : Comparative radiographs provide evidence of fibular graft growth at 16 months from surgery.
Fig. 5 E . Excellent clinical result with full abduction of the shoulder.
The joint is immobilised for four weeks. Any K-wires used for temporary internal fixation are removed, and a programme of passive and active mobilisation is begun, with a protective brace kept on until the osteotomy has healed; this generally takes about twelve weeks. The patient's condition should be assessed clinically and radiographically every two months, to ensure that complete control of the tumour has been obtained, and to monitor graft growth and joint congruency.
Fig. 6 A : Osteosarcoma of the distal radius after preoperative chemotherapy in a 4-year-old girl.
Fig. 6 B : Postoperative radiograph, with radiocarpal and distal radio-ulnar temporary stabilising wires in situ (left). The 3-year radiograph shows obvious growth of the graft (right).
Fig. 6 C and 6 D : Clinical follow-up shows excellent flexion/extension.
We have used this reconstruction in 12 patients (10 osteosarcomas and 2 Ewing's sarcomas) for tumours of the humerus (10) or the distal radius (2).
The following complications were recorded:
Two cases of fractures, which were treated conservatively (1) or with internal fixation (1); and 2 cases of upward subluxation of the shoulder (with a single case where the complication was visible on the radiograph but had no functional consequences); in 11 patients, the transplanted fibula was viable (with mean growth of 1 cm per year); in 1 patient only, the transplanted growth plate closed prematurely (this patient was the only case where the graft was vascularized by a peroneal pedicle).