Surgical technique

Scapulo-humeral defect

Scapulo-humeral defects most typically result from extra-articular resections of malignant bone lesions of the proximal humerus. This situation presents significant technical challenges in securing adequate fixation between the end of the transferred fibula and the remaining scapula. The authors have used successfully a compression plate and screws bridging from the remaining scapular spine to the proximal segment of the fibula. However, because of the cancellous nature of the scapula and small diameter of the fibula, such fixation requires the additional use of external fixation using a shoulder spica cast. Because of the problems associated with immobilization of this type of construct in this location, the authors prefer to combine fibula transfer with a proximal humerus allograft (Fig. 4A-C). Such a construct better ensures scapula-to-allograft and allograft to the remaining humerus fixation by the use of

Fig. 3. (A) Radiograph of extensive radionecrosis of humerus with nonunion following external beam radiation for Ew-ing's sarcoma. (B) Immediate postoperative radiograph of humerus following debridement of necrotic diaphysis and reconstruction by vascularized fibula transfer. (C) Radiograph of healed humerus (depicted in Fig. 3A, B) 58 months after surgery with incorporation and hypertrophy of vascularized fibula segment.

Fig. 3. (A) Radiograph of extensive radionecrosis of humerus with nonunion following external beam radiation for Ew-ing's sarcoma. (B) Immediate postoperative radiograph of humerus following debridement of necrotic diaphysis and reconstruction by vascularized fibula transfer. (C) Radiograph of healed humerus (depicted in Fig. 3A, B) 58 months after surgery with incorporation and hypertrophy of vascularized fibula segment.

larger screws and plates. The fibula is placed parallel to the allograft with contact proximally into the neck of the scapula and distally to the remaining humerus, using a transosseous screw at each end. The authors prefer to revascularize the fibula in most patients by end-to-side anastomosis of the donor bone peroneal artery to the recipient site brachial artery. Venous anastomosis is usually end-to-end between the peroneal venae commitans and either the brachial venae commitans or the cephalic vein. It is much easier to perform the vascular anastomosis and to isolate the recipient vessels more

Fig. 4. (A) Radiograph of proximal humerus with parosteal osteogenic sarcoma. (B) Immediate postoperative radiograph of proximal humerus following extra-articular resection of proximal humerus and glenoid and reconstruction with whole bone allograft and side-by-side vascularized fibula. (C) Radiograph of humerus (depicted in Fig. 4A, B) 75 months after surgery showing shoulder-proximal humerus construct. Note marked atrophy of allograft with hypertrophy of side-by-side vascularized fibula.

Fig. 4. (A) Radiograph of proximal humerus with parosteal osteogenic sarcoma. (B) Immediate postoperative radiograph of proximal humerus following extra-articular resection of proximal humerus and glenoid and reconstruction with whole bone allograft and side-by-side vascularized fibula. (C) Radiograph of humerus (depicted in Fig. 4A, B) 75 months after surgery showing shoulder-proximal humerus construct. Note marked atrophy of allograft with hypertrophy of side-by-side vascularized fibula.

distally in the upper limb. Thus, the fibular segment should be positioned in a retrograde manner to position its vascular pedicle closer to the elbow.

Humeral diaphyseal defect

A large defect of the diaphysis of the humerus is probably the ideal application of vascularized fibula transfer, because, when successful, it results in a functioning shoulder and elbow joint. Typically, defects of the humerus shaft result from penetrating trauma, infected nonunions, tumor resection, or radiation necrosis. Fixation of these constructs is usually easier than with scapulo-humeral defects. Preferentially, and when there is an adequate remaining length of the proximal and distal humerus, a compression plate or trans-osseous screws at each end are used (see Fig. 2A-C; Fig. 5A, B). If a compression plate is used at each end, screw fixation to at least six cortices (three screws, each with two cortex purchase) should be obtained on either side of the osteosyn-thesis site. A single plate spanning the entire construct may be used but preferentially should be avoided as it may act as a stress-shield and inhibit appropriate fibular hypertrophy after healing. Even with compression plate fixation, the additional protection of a shoulder spica case should be considered for the first 2 postoperative months. As was mentioned for the scapulo-humeral reconstructions, retrograde positioning of the fibula should be done to facilitate access to the vascular pedicle for anastomosis. Preferentially, end-to-side arterial and end-to-end venous anastomoses as discussed previously are used.

Radius/ulna diaphyseal defect

Large defects of either radius or ulna most commonly result from penetrating trauma, infected nonunion, or tumor resection. Based on size and shape considerations, the fibula is a near perfect match for the diaphyseal segment of radius or ulna. Because of their similarity, post-union hypertrophy of the fibular segment is usually not a significant issue. Fixation may employ a compression plate and screws at each end or a single long-spanning plate may be used (see Fig. 3A-C). However, if the latter technique is selected, it is important to avoid screw placement in the central portion of the fibula or near the nutrient foramen. Moreover, six-cortex fixation is required in both the distal and proximal forearm bone segments whether one or two plates are used. For reconstruction requiring fixation to the distal metaphyseal flare of the radius, it is preferable to dowel the fibula well into the metaphysis of the radius (Fig. 6A-D). Internal fixation by any method should be additionally protected by the use of

Fig. 5. (A) Immediate postoperative radiograph of resected humerus diaphysis for chondrosarcoma with reconstruction by vascularized fibula transfer. (B) Radiograph of reconstructed humerus (depicted in Fig. 5A) 13 months after surgery. Note hypertrophy of fibula segment to normal dimensions of humerus.

Fig. 5. (A) Immediate postoperative radiograph of resected humerus diaphysis for chondrosarcoma with reconstruction by vascularized fibula transfer. (B) Radiograph of reconstructed humerus (depicted in Fig. 5A) 13 months after surgery. Note hypertrophy of fibula segment to normal dimensions of humerus.

Fig. 6. (A) Radiograph of forearm showing recurrent adamantinoma of radius with history of prior curettage 14 months earlier. (B) Immediate postoperative radiograph of forearm following en-bloc radius diaphyseal resection and reconstruction by vascularized fibula transfer. (C) Radiograph of forearm 3 months following reconstruction by vascularized fibula transfer. Note mature union both proximally and distally. (D) Radiograph of forearm (depicted in Fig. 6A-C) 38 months after surgery with intervening removal of internal fixation hardware. Note hypertrophy of fibula segment to near-normal dimensions of radius.

Fig. 6. (A) Radiograph of forearm showing recurrent adamantinoma of radius with history of prior curettage 14 months earlier. (B) Immediate postoperative radiograph of forearm following en-bloc radius diaphyseal resection and reconstruction by vascularized fibula transfer. (C) Radiograph of forearm 3 months following reconstruction by vascularized fibula transfer. Note mature union both proximally and distally. (D) Radiograph of forearm (depicted in Fig. 6A-C) 38 months after surgery with intervening removal of internal fixation hardware. Note hypertrophy of fibula segment to near-normal dimensions of radius.

a long arm cast or splint for 6 to 8 weeks postoperatively. The fibular segment may be placed orthograde or retrograde depending on the most convenient vascular access site. Anastomoses usually use end-to-end coaptation to either the radial or ulnar arteries, provided the second vessel is patent and the superficial palmar arterial arch permits adequate flow to all digits with the selected recipient artery occluded. As a final comment, whenever one is considering the use of a free vascu-larized fibula for reconstructing a defect of either the radius or ulna, the possibility of developing a rather refractory radio-ulnar synostosis should be weighed—especially if the simpler approach of a one-bone forearm construct is considered a viable option for the patient's functional needs and expectations.

Forearm-carpal defect

Forearm-carpal defects most often result from either penetrating trauma or aggressive tumors, especially recurrent giant cell tumors of the distal radius. In this situation, the usual goal is to obtain a stable wrist arthrodesis (Fig. 7A-C). The technique of vascularized bone transfer in this area is essentially identical to that of reconstructing forearm defects, with the exception of distal osteo-synthesis fixation. It can be technically challenging to obtain secure fixation to either the carpal bones or the metacarpals and the selection of the best form of internal fixation will thus differ with the unique circumstances of each patient. The authors have used mini-plate fixation, screws alone, Kirschner wires, and cerclage wiring. In all

Fig. 7. (A) Radiograph of wrist with malignant, recurrent giant cell tumor of distal radius with invasion of proximal carpal row. (B) Immediate postoperative radiograph of wrist following en-bloc resection of distal radius and ulna and entire carpal bone complex with reconstruction using vascularized fibula transfer. (C) Radiograph of wrist (depicted in Fig. 7A, B) 15 months after surgery showing union of fibula to radius and ulna proximally and to metacarpals 2, 3, and 4 distally. Note fibula hypertrophy and spontaneous radio-ulnar synostosis.

Fig. 7. (A) Radiograph of wrist with malignant, recurrent giant cell tumor of distal radius with invasion of proximal carpal row. (B) Immediate postoperative radiograph of wrist following en-bloc resection of distal radius and ulna and entire carpal bone complex with reconstruction using vascularized fibula transfer. (C) Radiograph of wrist (depicted in Fig. 7A, B) 15 months after surgery showing union of fibula to radius and ulna proximally and to metacarpals 2, 3, and 4 distally. Note fibula hypertrophy and spontaneous radio-ulnar synostosis.

patients firm cast support until union is confirmed is recommended.

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