Nonunion of the Scaphoid with Flexion (“Humpback”) Deformity Comparison of Arthroscopic Bone Graft (ABG) and Vascularised Medial Femoral Bone Graft (VMFBG)

Abstract

Introduction Comparison of arthroscopic bone graft of the scaphoid (ABG) and vascularized medial femoral bone graft (VMFBG) techniques in the treatment of scaphoid nonunion. Materials and Methods Retrospective study on surgery performed by a single surgeon. Bone-graft incorporation and scaphoid union determined on CT scan. The surgical technique for both ABG and VMFBG comprised excision of the nonunion to trabecular bone and correction of the DISI deformity. The VMFBG was performed through an anterior FCR approach, internal fixation with a headless compression screw (HCS) and an antirotation Kw buried within the scaphoid, and vascularized by an end-to-side anastomosis to the radial artery and end-to-end anastomosis to the venae comitantes. The ABG was performed with a 1.9 mm scope and an Arc Traction tower using two midcarpal portals. Once the nonunion was excised, the DISI was corrected with a temporary Kw inserted into the lunate through the dorsal radius. The scaphoid was internally fixed with two to three 1.2 mm Kwires. The scaphoid defect was then packed with cancellous bone graft harvested with a tube saw from the iliac crest. Additional Kwires (maximum four Kwires) were then inserted from distal to proximal in the scaphoid and the bone graft sealed on its midcarpal surface with fibrin glue. In the initial cases, an HCS was used to internally fix the scaphoid. The Kwires were cut beneath the skin. When the bone graft had incorporated and the scaphoid united, the Kwires were removed and a HCS compression screw was inserted into the scaphoid using a percutaneous technique inserted from distal to proximal. Results VMFBG Eight cases were performed. The mean follow up was four years. The time to bone graft incorporation and scaphoid union averaged four months (range 2 to 7 months). Mean palmar flexion was 42° (range 35 to 47°) and mean dorsiflexion was 56° (range 40 to 70°). All VMFBG cases united. ABG Fourteen cases were included in this study. Three cases were not included because they are currently in process. Four cases that had united were not included in the study because they did not have wrist motion measurements accurately recorded. The mean time to union was four months (range 2 to 6 months). The average range of palmar flexion was 57° (range 35 to 81°) and the average range of dorsiflexion was 60.7° (range 35 to 76°). All ABG cases united. Conclusion Both ABG and VMFBG healed in the same time. The postoperative recovery was much less painful for the arthroscopic technique. There was a slightly increased range of motion using the arthroscopic technique in both palmar flexion and dorsi flexion. There were no nonunions after bone graft and internal fixation using either the VMFBG or the ABG techniques.