Displaced femoral neck fractures in young adults are most likely to result from high energy trauma that causes a vertically-oriented shearing injury through the femoral neck. The optimal strategy for treatment of displaced femoral neck fractures remains an unsolved challenge in orthopedic surgery. our group has previously designed a medial anatomical buttress plate (MABP) based on the analysis of the computed tomography (CT) data of anatomical structures derived from a large sample population. In this study, finite element analyses (FEA) were carried out to compare the outcomes of the combination of our MABP with cannulated screws to those of the combination of tubular plate with cannulated screws, and to those of using cannulated screws alone. MABP resulted in a more stable fixation as compared to the other two approaches, with respect to the femur and the stress distributions, stress peaks, and Z axis displacements. The FEA encouraged us that addition of a medial buttress plate not only achieved superior medial buttress stability but also achieves superior performance because it perfectly fits with the existing anatomic structure of medial femoral neck. The results from our study may provide references for clinical decision making in dealing with such patients.

Atrophic non-union is a serious complication of fractures. The underlying biological mechanisms involved in its pathogenesis are not yet completely understood. MicroRNAs (miRNAs or miRs) are a type of endogenous small non-coding RNA, which participate in various physiological and pathophysiological processes. In this study, differentially expressed miRNAs were screened in patients with atrophic non-union. In total, 4 miRNAs (miR‑149*, miR‑221, miR‑628-3p and miR‑654-5p) were upregulated and 7 miRNAs (let-7b*, miR‑220b, miR‑513a-3p, miR‑551a, miR‑576-5p, miR‑1236 and kshv-miR‑K12-6-5p) were downregulated at the fracture sites in patients with atrophic non-union. Among the upregulated miRNAs, miR‑628-3p and miR‑654-5p expression was found to be persistently decreased during osteoblast differentiation, indicating their possible inhibitory effect on osteogenesis. Gain-of-function experiment demonstrated that miR‑628-3p, but not miR‑654-5p, attenuated osteoblast differentiation. Further, in silico analysis revealed that runt-related transcription factor 2 (RUNX2), the master transcript factor for osteoblast differentiation, was the target of miR-628-3p, which had two binding site-condense regions in the 3' untranslated region. The exact binding site of miR-628-3p was further identified with luciferase reporter assay. In addition, the overexpression of miR‑628-3p appeared to be associated with the suppression of RUNX2 expression at both the mRNA and protein level, suggesting that miR‑628-3p inhibits osteoblast differentiation via RUNX2. On the whole, the findings of this study provide evidence of the upregulation of miR‑628-3p in patients with atrophic non-union and that miR‑628-3p may exert an inhibitory effect on osteogenesis via the suppression of its target gene, RUNX2. The study provides valuable insight into the pathogenesis of atrophic non-union and suggests new potential therapeutic targets for the treatment of this disorder.

Currently, the common treatment for femoral nonunion with large segmental bone defect is difficult and complex. The effective surgical methods are rare, include vascularized bone grafting, Masquelet technique and Ilizarov distraction osteogenesis. The objective of this study is to investigate the outcomes of segmental femoral defects treated with monolateral external fixation using the distraction osteogenesis. We retrospectively analyzed patients with femoral nonunion with segmental bone defects (> 6 cm) between January 2010 and January 2014 in our single trauma center. All patients were treated by distraction osteogenesis with monolateral external fixation. All surgeries were performed by the same surgeon. Bone union, duration of distraction osteogenesis in days, time to consolidation in months, external fixation index (EFI), complications, and additional surgical interventions were recorded postoperatively. The modified Application of Methods of Illizarov (ASAMI) criteria were used to evaluate the operative effectiveness. Forty-one patients were enrolled in this study for analysis. The length of the bone defect ranged from 6 to 17 cm. All patients eventually achieved healing, and no patient experienced recurrence of infection or newly developed infection. The average time needed for healing was 13 months. In terms of the incidence of complications, 3 cases axial deviations, 5 cases docking site nonunion, 23 cases pin-tract infection, 14 cases knee joint stiffness or their joint mobility declined, 2 cases osteogenesis insufficient in the distraction area,1 case refracture, and 2 cases loose external fixation pins. In terms of the evaluations of fracture healing and function, 30 patients excellent, 6 patients good, 5 patients fair, and 0 patient poor. In terms of postoperative function evaluations, 21 patients excellent, 9 patients good, 7 patients fair, and 4 patients poor. For patients with femoral nonunion with large segmental bone defects, the monolateral external fixation can provide effective stability, improve compliance, and reduce complications.

The aim of this study is to explore the clinical outcomes of anatomical allograft or fibula shaft augmentation with locking compression plates (LCPs) in elderly patients with four-part proximal humeral fracture (PHF). A total of 22 elderly patients with four-part PHF underwent allograft augmentation with LCPs for treatment. Among them, 7 cases received anatomical allograft and 15 patients received fibula shaft. Constant-Murley score (CMS), the disability of the arm, shoulder and hand (DASH) score, and subjective ratings, radiographic imaging, range of motion (ROM), and complications were recorded as postoperative evaluations. Although the ROM and strength were considerably limited compared with the normal side, there were no significant differences in pain and daily activity between the unaffected and affected sides at the last follow-up according to the CMS. Additionally, no significant differences were found in the subjective ratings and CMS and DASH scores between the patients augmented with fibular shaft and anatomical allograft. Among the 15 patients who received fibular shaft, one case developed avascular necrosis (AVN) and screw cutout, but satisfactory outcomes were obtained after removal of implant. Besides, varus displacement occurred in one case, the patient acquired good function without revision. There were no infection, bone nonunion, and hardware-related complications occurred in any case. Both anatomical allograft and fibula shaft with LCPs showed relatively good clinical outcomes for elderly patients with four-part PHF.