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To evaluate the risk factors for the development of postoperative delirium and design a predictive nomogram for the prevention of delirium in elderly patients with a hip fracture, we retrospectively studied 825 patients who sustained a femoral neck fracture from January 2005 to December 2015. Independent risk factors for developing delirium within 6 months of surgery were identified using multivariable logistic regression analyses. A predictive nomogram model was built based on the results, and the discrimination and calibration were determined by C-index and calibration plot. Of the 825 patients who met inclusion criteria, 118 (14.3%) developed postoperative delirium. According to the results, preoperative cognitive impairment (OR, 4.132, 95% CI, 1.831 to 9.324, P<0.001), multiple medical comorbidities (OR, 1.452, 95% CI, 0.958-2.202, P = 0.079), ASA classification (OR, 1.655, 95% CI, 1.073-2.553, P = 0.023), transfusion exceeding 2 units of red blood cell (OR, 1.599, 95% CI, 1.043-2.451, P = 0.035), and intensive care (OR, 1.817, 95% CI, 1.127-2.930, P = 0.014) were identified to be the independent predictors of the development of postoperative delirium. The risk of postoperative delirium increased with the increasing risk score of predictive nomogram, and the C-index was 0.67 (0.62-0.72). The calibration showed that the predicted probabilities of delirium in the predictive nomogram were close to the observed frequency of delirium, and the decision curve analysis confirmed the clinical utility of the nomogram when the threshold probabilities were between 8% and 35% due to the net benefit.

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Since transplantation of meniscal allograft or artificial menisci is limited by graft sources and a series of adverse events, substitution for meniscus reconstruction still needs to be explored. Natural biomaterials, which can provide a unique 3-D microenvironment, remain a promising alternative for tissue engineering. Among them, autograft is a preferred option for its safety and excellent biocompatibility. In this study, we utilized semitendinosus tendon autograft in meniscus reconstruction to investigate its fibrochondrogenic metaplasticity potential and chondroprotective effect. Tendon-derived stem cells (TDSCs) and synovial-derived mesenchymal stem cells (SMSCs), two most important stem cell sources in our strategy, exhibited excellent viability, distribution, proliferation and fibrochondrogenic differentiation ability in decellularized semitendinosus tendon (DST) scaffolds in vitro. Histologic evaluation of the tendon grafts in vivo suggested endogenous stem cells differentiated into fibrochondrocytes, synthesized proteoglycan, type II collagen and radial type I collagen at 12 weeks and 24 weeks post-surgery. As for elastic modulus and hardness of the grafts, there were no significant differences between native meniscus and regenerated meniscus at 24 weeks. The protection of condylar cartilage from degeneration was significantly better in the reconstruction group comparing to control group. Overall, semitendinosus tendon autograft seems to be a promising substitution in meniscus reconstruction.

In this study, we have successfully fabricated magnesium (Mg) substituted hydroxyapatite nanocomposites (Mg-HA) by utilizing type I collagen (COL I) and citric acid (CA) through a bitemplate-induced biomimetic mineralization approach. The obtained composite nanoparticles were subsequently mixed with chitosan (CHI) and gelatin (Gel) to prepare porous scaffolds with interconnected structures by three-dimensional (3D) printing technique. The Mg-HA powders and composite scaffolds were characterized. The results showed that the substitution of Mg for Ca ions reduced the crystallinity of HA crystals, but did not significantly affect the size and structure of the nanocomposites. The morphology of Mg-HA scaffolds turned smoother compared with the HA scaffolds with Mg substitution. Furthermore, the biocompatibility of Mg-HA composite scaffolds was evaluated by metal ion release, cell attachment, proliferation, and differentiation of MC3T3-E1 cells.According to the results, as the more Ca 2+ was substituted by Mg 2+ , the more Mg 2+ was released from the samples and the pH in cultured medium was more acidic. It was suggested that Mg-HA scaffolds presented higher cell attachment, proliferation rate, increased expression of alkaline phosphatase (ALP) activity and osteogenic related gene, including osteocalcin (OCN), runt-related transcription factor 2 (RUNX2), and COL I. Therefore, it was indicated that the 3D printed Mg-HA composite scaffolds with excellent biocompatibility and bioactivity were a potential candidate in bone tissue engineering.