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Background: Vascularized composite allotransplantation (VCA) has become a viable option for restoration of devastating injuries that are not amenable to conventional reconstructive techniques. However, the relative scarcity of procedures performed worldwide, as well as the potential for iatrogenic injury with biopsies, makes studying the immunopathogenesis of acute rejection challenging. Translational VCA research focuses on developing strategies to overcome these barriers with the use of animal models can be technically challenging and difficult to replicate without highly trained microsurgeons. Methods: We describe a modified model of a femur-based composite tissue allograft using an adapted vascular cuff anastomotic technique with a tunneled skin flap in a rodent model. Results: The use of a heterotopic osteomyocutaneous flap with a subcutaneously tunneled-skin paddle to the posterolateral aspect of the recipient rodent allows for ease of flap monitoring and reduces the risk of self-mutilation. A total of six transplantations were conducted with no signs of self-mutilation. Operative time decreased as our surgical technique improved, and long-term graft tolerance was possible under our immunosuppressive regimen. Additionally, we demonstrate cases of successful transplantation in both an allogeneic and syngeneic rodent model. Conclusion: Animal models, although technically challenging, are a reliable and reproducible modality that has been used to investigate various aspects of VCA immunology. We describe the success of an osteomyocutaneous flap with a modified vascular cuff anastomosis that can be used by investigators with less experience in microsurgical techniques to further our understanding of VCA physiology. Furthermore, tunneling of the skin paddle reduces the risk of self-mutilation and other external factors affecting the graft.
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PURPOSE: Offering the benefits of rigid fixation while minimizing soft tissue dissection, intramedullary implants have become a popular choice among hand surgeons. Their placement often requires traversing or passing in proximity to joint surfaces. This study aimed to assess the damage to the articular cartilage of the base of the proximal phalanx resulting from antegrade placement of threaded headless intramedullary nails. METHODS: A cadaveric study comparing two techniques for antegrade placement of threaded headless intramedullary nails was conducted in 56 digits. The first entailed a single 2.1 mm intramedullary nail placed via the dorsal base of the proximal phalanx, whereas the second used two 1.8 mm intramedullary nails inserted via the collateral recesses of the phalangeal base. All specimens were analyzed for articular surface damage with the cartilage defect measured as a percentage of total joint surface area. Damage to the extensor tendons was also assessed in a subset of specimens. RESULTS: No significant difference in the percentage of articular surface damage was observed, with an average 3.21% ± 2.34% defect in the single 2.1 mm nail group and a 2.71% ± 3.42% mean defect in the two 1.8 mm nails group. There was no articular surface injury in 18% of digits in each group. Damage to extensor tendons was seen in three (9.4%) specimens and in all cases involved either the extensor indicis proprius or extensor digiti minimi. CONCLUSIONS: Hardware insertion using either the dorsal base of the proximal phalanx or the collateral recesses of the phalangeal base both demonstrated minimal articular cartilage damage and infrequent injury to the extensor tendons. CLINICAL RELEVANCE: With proper technique for antegrade insertion into the proximal phalanx, the cartilage defect observed often encompasses only a small percentage of the overall joint surface area.
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BACKGROUND: An update on the epidemiology of distal radius fractures in the United States is necessary, particularly as the elderly population grows. Additionally, age and frailty have been associated with complications following surgical fixation of DRFs. Herein, we utilize the National Trauma Data Bank, a robust nationwide resource, to investigate the relationship between demographics, comorbidities, injury and fracture characteristics, and admission details. METHODS: Patients with isolated distal radius fractures were identified from the National Trauma Data Bank (2016-2019) according to ICD-10 codes. Univariate and multivariate regressions were conducted to determine independent risk factors for bilateral fractures, displaced fractures, open fractures, as well as length of hospital stay and adverse discharge disposition for patients undergoing inpatient surgical fixation. RESULTS: The incidence of DRFs was 3.6/1,000 trauma-related emergency department visits and 10.8/1,000 upper extremity traumas. Trauma mechanism was significantly associated with displaced and open fractures. Age (OR 1.01, 95% CI 1.01-1.01), BMI (OR 1.02, 95% CI 1.01-1.02), smoking (OR 1.34, 95% CI 1.15-1.57), and alcohol level (trace: OR 2.18, 95% CI 1.41-3.29; intoxicated: OR 2.20, 95% CI 1.63-2.95) were significantly associated with open fractures. Machinery (ß=2.04, 95% CI 1.00-3.08) and MVT (ß=0.39, 95% CI 0.08-0.69) mechanisms were independent risk factors for longer length of stay. mFI-5 was an independent risk factor, in a stepwise fashion, for both length of stay and adverse discharge disposition. CONCLUSIONS: High-energy mechanisms and risk factors for poor skin quality were significantly associated with open fractures. mFI-5 was an independent risk factor for longer length of stay and non-routine discharges in patients of all ages, despite controlling for other comorbidities, unrelated complications, and mechanism of injury. Trauma mechanism was an independent risk factor for prolonged length of stay only, particularly in patients younger than 65 years of age.