Left scaphoid waist nonunion with scaphoid foreshortening, carpal collapse, and probable avascular necrosis (AVN) of the proximal pole .

Due to the patient’s young age, absence of degenerative change within the wrist, and carpal collapse, he was recommended a scaphoid waist nonunion debridement, bone grafting, and rigid fixation. In the absence of proximal pole AVN, bone grafting options included cancellous bone (distal radius or iliac crest) [3], bone substitute (beta-tricalcium phosphate and calcium sulfate) [4], and corticocancellous bone (distal radius or iliac crest) [5]. In the presence of proximal pole AVN, bone grafting options included nonvascularized interposition bone graft with arteriovenous (AV) bundle implantation [6], pedicled vascularized corticocancellous bone graft (thumb metacarpal, or dorsal and volar distal radius) [7–9], or free vascularized corticocancellous bone graft (iliac crest or medial femoral condyle) [10, 11].

The patient agreed with the recommended surgical plan and the necessity of a structural bone graft, due to the scaphoid “humpback” deformity and bone resorption. The utilization of a nonvascularized iliac crest corticocancellous bone graft versus a vascularized free medial femoral condyle (MFC) corticocancellous bone graft would be dictated upon the intra-operative findings of proximal pole vascularity, defined by the presence or absence (AVN) of punctate bleeding from the proximal pole of the scaphoid after nonunion debridement and release of the tourniquet [12]. However, if the proximal pole of the scaphoid was noted to be fragmented or devoid of cartilage intra-operatively, a salvage procedure in the form of a scaphoid excision and four corner arthrodesis would be performed .

After the induction of general anesthesia, the patient was positioned supine with the affected arm draped free on a hand table. The entire ipsilateral lower extremity was prepped and draped up toward the flank to allow for iliac crest or MFC bone graft harvest. A well-padded bump was placed distally under the drapes to maintain knee flexion and external rotation of the hip which can greatly improve visualization and exposure during harvest of the free MFC graft [13].

After the exsanguination of the left upper extremity and tourniquet inflation, an extended volar Russe-type approach to the scaphoid was performed. The scaphoid nonunion site was exposed, and the fibrous interposed tissue was debrided. A microsagittal saw was used to create flat bone surfaces with minimal resection of bone. The proximal pole was sclerotic and appeared similar to ivory on inspection, and release of the tourniquet confirmed no bleeding from the proximal pole or the scaphoid waist fragment at the nonunion surface (Fig. 16.3a). However, no cartilage loss was noted at the proximal pole of the scaphoid, the radial styloid, or the scaphoid fossa.

The dense intramedullary bone was excavated from both fragments with curettes to remove the sclerotic bone and to produce a cavitary space into which cancellous bone graft could be packed later on. The DISI deformity was corrected with wrist hyperflexion and confirmed on fluoroscopy by a lunate in neutral position and was temporarily stabilized in this position with a percutaneous 0.0625 in. Kirschner wire driven from the dorsal distal radius into the lunate [13]. A lamina spreader was then placed into the nonunion site, and the proximal and distal scaphoid fragments were over-distracted to correct the scaphoid foreshortening and carpal collapse (Fig. 16.3b). A paper ruler was then used to measure the dimensions of the scaphoid waist bone void (width 10 mm, length 12 mm, and height 12 mm) to serve as a template for free MFC bone graft harvest .

The left lower extremity was gravity-exsanguinated and the sterile thigh tourniquet was inflated. A longitudinal incision (15 cm) was made extending from the medial tibial plateau proximally over the posterior border of the vastus medialis. The vastus medialis fascia was incised, and subfascial dissection was performed posteriorly while retracting the muscle belly anteriorly. The descending genicular artery (DGA) was identified proximally near the adductor hiatus and dissected distally toward the anastomoses of the osteoarticular branch of the DGA and the superior medial genicular artery (SMGA) . The DGA was noted to be larger in diameter than the SMGA; therefore, it and the two accompanying vena comitantes were dissected off of the femur. The area of bone graft harvest was identified in the distal posterior aspect of the MFC, and the dimensions of the approximate bone graft size were marked over the harvest site. The pedicle was ligated, and the bone graft was harvested as described by Jones et al. (Fig. 16.3c) [14]. Additional cancellous bone graft was harvested after the removal of the free MFC bone graft and was packed into the cavitary defects within the two scaphoid fragments .

The free MFC graft was inset into the nonunion site (Fig. 16.3d), which was held open with the lamina spreader. The guide pin for the headless compression screw was inserted from the distal pole of the scaphoid in retrograde fashion. Fluoroscopy was used to confirm proper bone graft and guide pin positioning. After predrilling, the appropriately sized headless compression screw was implanted. There was no compression of the pedicle against the radial styloid; therefore, a radial styloidectomy was not performed . The DGA and one of its vena comitantes was anastomosed to the radial artery (end-to-side) and an accompanying vena comitantes (end-to-end) using microvascular technique. The incisions were closed with monofilament suture, and no attempt was made at repairing the radioscaphocapitate ligament.

The patient was placed into a postoperative long arm, thumb spica plaster splint with the wrist in neutral position. He was observed as an inpatient for pain control without vascular monitoring. Microvascular anastomosis thromboprophylaxis consisted of enteric coated aspirin (325 mg) by mouth daily for 4 weeks. No weight bearing was allowed on the affected upper extremity. However, lower extremity weight bearing and knee range of motion was performed as tolerated immediately postoperative. A knee immobilizer and a single-arm crutch was utilized postoperative as needed and was weaned over a week period .

At 2 weeks postoperative, the sutures were removed and a thumb spica cast was applied for an additional 6 weeks. Plain radiographs at 6 weeks postoperative revealed consolidation of the free MFC graft into the native scaphoid with maintenance of neutral lunate position (Fig. 16.4a–c). A CT scan at 8 weeks postoperative confirmed bridging trabecular bone across the distal and proximal-free MFC bone graft junction sites (Fig. 16.4d, e). The patient was then placed into a removable, short arm, thumb spica brace for an additional 4 weeks until he was nontender to palpation at the anatomic snuffbox. At 4 months postoperative, the patient had no wrist or knee pain and affected wrist range of motion was flexion 50°, extension 60°, radial deviation 10°, and ulnar deviation 20°. He returned to performing push-ups and running 6 miles without discomfort .