The Role of Vascularized Bone Graft in Adolescent Scaphoid Nonunion
Jacqueline S. Israel, MD1, Nicholas A. Pulos, MD1, Joseph S. Khouri, MD, BSc1, Allen T. Bishop, MD2 and Alexander Y. Shin, MD3, (1)Mayo Clinic, Rochester, MN, (2)Microvascular Research Laboratory, Mayo Clinic, Rochester, MN, (3)Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN
Introduction: Scaphoid nonunions with proximal pole avascular necrosis and/or large humpback deformity with carpal collapse can occur in a pediatric patient population. This study reports our results in treating such complex nonunions with free or pedicled vascularized bone grafts (VBGs) from either the medial femoral condyle (MFC) or dorsal distal radius in patients 18 years or younger.
Materials and Methods: A retrospective review was performed of patients aged 18 years and under who underwent a VBG for scaphoid nonunion. Indications for this procedure were patients with proximal pole avascular necrosis, a failed conventional bone graft, or significant foreshortening and carpal collapse. Demographics, previous treatments, time to union, functional outcomes, and complications were recorded.
Results: Fifty-two scaphoid nonunions were treated in 52 adolescent patients (82% male, mean age 16.8 years) from 2002 to 2020. Prior surgery had failed in 24 (46%) of these cases. Forty-three had proximal pole avascular necrosis (AVN), defined by absent proximal pole punctate bleeding with the tourniquet released at surgery. The remaining 9 had diminished blood flow and/or significant scaphoid foreshortening. Those with dorsal intercalated segment instability due to scaphoid foreshortening and flexion deformity required an interposition wedge graft using a free medial femoral condyle graft. Proximal pole nonunions with AVN or severely compromised vascularity and no carpal instability were treated with pedicled dorsal radius grafts based on the 1,2-intercompartmental supraretinacular artery (1,2-ICSRA). There were 38 MFC and 14 1,2-ICSRA grafts performed. Of patients with available follow-up imaging (n=48), we observed signs of persistent nonunion in 5 patients (90% union rate). Three patients underwent a salvage procedure for symptomatic radiocarpal arthritis. No differences in outcomes or graft failure rate was noted between patients treated with either MFC or 1,2-ICSRA. There was one perioperative complication of self-limited radial sensory nerve neuropraxia. No donor site complications were noted in the MFC group.
Conclusions: We believe that careful patient and fracture selection is mandatory when offering VBG to adolescent patients with scaphoid nonunion. Pedicled or free VBG in this patient population is safe and effective, with a union rate of at least 90%.
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