Clinical Outcomes and Ulnar Carpal Translocation after Volar Plating with Vascularized Bone Graft for Scaphoid Fracture Non-unions
Yonghoon Lee, BA1; Anthony R Martin, MD2; Aouod Agenor, MD3; Seth D Dodds, MD2
1University of Miami, Miller School of Medicine, Miami, FL; 2University of Miami, Miami, FL; 3Plastic and Reconstructive Surgery, University of Miami / Jackson Heatlh Systems, Miami, FL
Introduction: Scaphoid fracture non-union remains a challenging clinical problem due to tenuous vascularity and possible avascular necrosis of the proximal pole. High union rates have been reported in previous studies of scaphoid volar plating with pedicled vascularized bone graft. This study aims to assess union rates, deformity, and ulnar carpal translocation after scaphoid volar plate fixation.
Materials and Methods: This was a retrospective cohort study of individuals aged 18+ with recalcitrant scaphoid fracture non-union treated with volar scaphoid plating and vascularized bone graft. Radiographs were followed for a target of 3 months post-operatively. Ulnar subluxation of the carpus was assessed by change in lunate uncovering (Shuind method), and carpal translocation was assessed by the relative change in carpal-radial distance (DiBenedetto method). Studentís paired t-tests were used for analyses.
Results: Twelve patients were included, with an average age of 27.4 years (standard deviation (SD) 8.9), average follow-up interval of 12.0 months (SD 7.7), and average interval from injury to surgery of 9.2 months (SD 0.55). Ten patients were males (83%), three patients (25%) were smokers, and six patients (50%) had radiographic avascular necrosis of the scaphoid pre-operatively.
Post-operatively, eleven patients (91.7%) had fracture union. Average pre-operative lunate uncovering was 36% (SD 11%), with normal values between 41-47%. Average post-operative uncovering was 44% (SD 10%). There was a significant increase in initial post-operative lunate uncovering (mean difference: 11.6% of lunate, 95% confidence interval (CI) 6.1%-17.1%, p<0.001) and carpal translocation (mean difference: 0.042mm, 95% CI 0.020mm-0.064mm, p=0.002). Subsequently, when comparing initial post-operative to final follow-up imaging, there was no significant change in lunate uncovering or carpal translocation. There was a significant increase in post-operative wrist extension (mean difference: 6.67o, 95% CI 1.25o-12.09o, p=0.025). There were six patients who had hardware removal due to pain and stiffness at an average interval of 12.3 months (SD 5.50) from surgery.
Conclusion: This study found pre-operative lunate uncovering to be lower than normal values and post-operative measurements were near normal values. Initial changes were likely due to the restoration of normal scaphoid length and anatomy with bone grafting and plate stabilization. Slight ulnar carpal translocation was noted on initial postoperative imaging, but remained stable over time, suggesting stable extrinsic ligaments post-operatively. Clinically, improved symptoms of pain and stiffness were noted. High rates of union and symptom relief make volar scaphoid plating with vascularized bone grafts a promising alternative to headless screw fixation for recalcitrant scaphoid fracture non-unions.
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