Comparative Analysis of Supplemental Medial Buttress Plate Fixation for High-Energy Displaced Femoral Neck Fractures in Young Adults.

OBJECTIVES: To evaluate whether augmenting traditional fixation with a femoral neck buttress plate (FNBP) improves clinical outcomes in young adults with high-energy displaced femoral neck fractures. DESIGN: Multicenter retrospective matched cohort comparative clinical study. SETTING: Twenty-seven North American Level 1 trauma centers. PATIENTS: Adult patients younger than 55 years who sustained a high-energy (nonpathologic) displaced femoral neck fracture. INTERVENTION: Operative reduction and stabilization of a displaced femoral neck fracture with (group 1) and without (group 2) an FNBP. MAIN OUTCOME MEASUREMENTS: Complications including failed fixation, nonunion, osteonecrosis, malunion, and need for subsequent major reconstructive surgery (early revision of reduction and/or fixation), proximal femoral osteotomy, or arthroplasty. RESULTS: Of 478 patients younger than 55 years treated operatively for a displaced femoral neck fracture, 11% (n = 51) had the definitive fixation augmented with an FNBP. One or more forms of treatment failure occurred in 29% (n = 15/51) for group 1 and 49% (209/427) for group 2 ( P < 0.01). When FNBP fixation was used, mini-fragment (2.4/2.7 mm) fixation failed significantly more often than small-fragment (3.5 mm) fixation (42% vs. 5%, P < 0.01). Irrespective of plate size, anterior and anteromedial plates failed significantly more often than direct medial plates (75% and 33% vs. 9%, P < 0.001). CONCLUSIONS: The use of a femoral neck buttress plate to augment traditional fixation in displaced femoral neck fractures is associated with improved clinical outcomes, including lower rates of failed fixation, nonunion, osteonecrosis, and need for secondary reconstructive surgery. The benefits of this technique are optimized when a small-fragment (3.5 mm) plate is applied directly to the medial aspect of the femoral neck, avoiding more anterior positioning . LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effects of Technical Errors on the Outcomes of Operatively Managed Femoral Neck Fractures in Adults Less than 50 Years of Age.

OBJECTIVE: To evaluate the effect of technical errors (TEs) on the outcomes after repair of femoral neck fractures in young adults. DESIGN: Multicenter retrospective clinical study. SETTING: 26 North American Level 1 Trauma Centers. PATIENTS: Skeletally mature patients younger than 50 years of age with 492 femoral neck fractures treated between 2005 and 2017. INTERVENTION: Operative repair of femoral neck fracture. MAIN OUTCOME MEASUREMENTS: The association between TE (malreduction and deviation from optimal technique) and treatment failure (fixation failure, nonunion, malunion, osteonecrosis, malunion, and revision surgery) were examined using logistic regression analysis. RESULTS: Overall, a TE was observed in 50% (n = 245/492) of operatively managed femoral neck fractures in young patients. Two or more TEs were observed in 10% of displaced fractures. Treatment failure in displaced fractures occurred in 27% of cases without a TE, 56% of cases with 1 TE, and 86% of cases with 2 or more TEs. TEs were encountered less frequently in treatment of nondisplaced fractures compared with displaced fractures (39% vs. 53%, P < 0.001). Although TE(s) in nondisplaced fractures increased the risk of treatment failure and/or major reconstructive surgery (22% vs. 9%, P < 0.001), they were less frequently associated with treatment failure when compared with displaced fractures with a TE (22% vs. 69% P < 0.001). CONCLUSIONS: TEs were found in half of all femoral neck fractures in young adults undergoing operative repair. Both the occurrence and number of TEs were associated with an increased risk for failure of treatment. Preoperative planning for thoughtful and well-executed reduction and fixation techniques should lead to improved outcomes for young patients with femoral neck fractures. This study should also highlight the need for educational forums to address this subject. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The endothelin receptor antagonist macitentan ameliorates endothelin-mediated vasoconstriction and promotes the survival of retinal ganglion cells in rats.

Glaucoma is a chronic and progressive eye disease, commonly associated with elevated intraocular pressure (IOP) and characterized by optic nerve degeneration, cupping of the optic disc, and loss of retinal ganglion cells (RGCs). The pathological changes in glaucoma are triggered by multiple mechanisms and both mechanical effects and vascular factors are thought to contribute to the etiology of glaucoma. Various studies have shown that endothelin-1 (ET-1), a vasoactive peptide, acting through its G protein coupled receptors, ETA and ETB, plays a pathophysiologic role in glaucoma. However, the mechanisms by which ET-1 contribute to neurodegeneration remain to be completely understood. Our laboratory and others demonstrated that macitentan (MAC), a pan endothelin receptor antagonist, has neuroprotective effects in rodent models of IOP elevation. The current study aimed to determine if oral administration of a dual endothelin antagonist, macitentan, could promote neuroprotection in an acute model of intravitreal administration of ET-1. We demonstrate that vasoconstriction following the intravitreal administration of ET-1 was attenuated by dietary administration of the ETA/ETB dual receptor antagonist, macitentan (5 mg/kg body weight) in retired breeder Brown Norway rats. ET-1 intravitreal injection produced a 40% loss of RGCs, which was significantly lower in macitentan-treated rats. We also evaluated the expression levels of glial fibrillary acidic protein (GFAP) at 24 h and 7 days post intravitreal administration of ET-1 in Brown Norway rats as well as following ET-1 treatment in cultured human optic nerve head astrocytes. We observed that at the 24 h time point the expression levels of GFAP was upregulated (indicative of glial activation) following intravitreal ET-1 administration in both retina and optic nerve head regions. However, following macitentan administration for 7 days after intravitreal ET-1 administration, we observed an upregulation of GFAP expression, compared to untreated rats injected intravitreally with ET-1 alone. Macitentan treatment in ET-1 administered rats showed protection of RGC somas but was not able to preserve axonal integrity and functionality. The endothelin receptor antagonist, macitentan, has neuroprotective effects in the retinas of Brown Norway rats acting through different mechanisms, including enhancement of RGC survival and reduction of ET-1 mediated vasoconstriction.