Cell-adhesive double network self-healing hydrogel capable of cell and drug encapsulation: New platform to construct biomimetic environment with bottom-up approach.

This study presents the development and characterization of a novel double-network self-healing hydrogel based on N-carboxyethyl chitosan (CEC) and oxidized dextran (OD) with the incorporation of crosslinked collagen (CEC-OD/COL-GP) to enhance its biological and physicochemical properties. The hydrogel formed via dynamic imine bond formation exhibited efficient self-healing within 30 min, and a compressive modulus recovery of 92 % within 2 h. In addition to its self-healing ability, CEC-OD/COL-GP possesses unique physicochemical characteristics including transparency, injectability, and adhesiveness to various substrates and tissues. Cell encapsulation studies confirmed the biocompatibility and suitability of the hydrogel as a cell-culture scaffold, with the presence of a collagen network that enhances cell adhesion, spreading, long-term cell viability, and proliferation. Leveraging their unique properties, we engineered assemblies of self-healing hydrogel modules for controlled spatiotemporal drug delivery and constructed co-culture models that simulate angiogenesis in tumor microenvironments. Overall, the CEC-OD/COL-GP hydrogel is a versatile and promising material for biomedical applications, offering a bottom-up approach for constructing complex structures with self-healing capabilities, controlled drug release, and support for diverse cell types in 3D environments. This hydrogel platform has considerable potential for advancements in tissue engineering and therapeutic interventions.

The Efficacy of Suture Fixation of the Greater Trochanter in Unstable Intertrochanteric Fractures.

BACKGROUD: Intertrochanteric fractures are one of the most common fractures in the elderly, especially those having osteoporosis. Stable intertrochanteric fractures may be fixed with implants including the dynamic hip screw and proximal femoral nail antirotation; however, this method is difficult to apply to unstable fractures. Bipolar hemiarthroplasty can be applied to unstable fractures and it prevents complications by facilitating early ambulation in the elderly. Many studies reported on how to fix the greater trochanter in unstable fractures during arthroplasty. We suggest that suture fixation alone can be a useful, effective, and affordable method. METHODS: We retrospectively enrolled 294 patients who underwent hemiarthroplasty for an unstable intertrochanteric fracture, and 225 patients were included in this study after excluding 69 patients who had not been available for follow-up until 1 year after surgery or died. The patients were divided into suture fixation and wiring fixation groups. Relationships of operation time, estimated blood loss, tip-to-stem distance, union rate, and physical performance in the groups of suture fixation and wiring were analyzed respectively. RESULTS: Changes in the tip-to-stem distance between the initial assessment at 1 year after surgery were statistically significantly different between the suture fixation group and wiring group (p < 0.001). There was no significant difference in change of the Koval score between the suture fixation and wiring groups (p = 0.362). The operation time and estimated intraoperative blood loss were statistically significantly lower in the suture group than in the wiring group (p < 0.001). There was no significant difference in the union rate between the groups (p = 0.470). CONCLUSIONS: Compared to tension-band wiring, the suture fixation technique demonstrated an effective fixing force. In addition to the clinical results, it had an advantage of preventing complications due to shortening of the operation time and estimated intraoperative blood loss. Suture fixation of the greater trochanter is recommended for elderly patients with unstable intertrochanteric fractures.

Assessing Low Skeletal Mass in Patients Undergoing Hip Surgery: The Role of Sonoelastography.

PURPOSE: To analyze the utility of sonoelastography-a radiation-free procedure to characterize muscle properties-as an instrument to qualitatively and quantitatively assess the rectus femoris muscle. MATERIALS AND METHODS: Fifty-one consecutive patients who underwent a pelvic computed tomography (CT) exam were enrolled prospectively. The final analysis was conducted using data from 39 patients after 12 were removed due to exclusion criteria (muscle strength could not be measured due to poor cognition [n=11]; too young [n=1]). The potential correlation between average Hounsfield unit (HFU) at the rectus femoris muscle (measured by CT) and muscle quality grade (determined by sonoelastography) was assessed along with a retrospective analysis of the relationship between hand grip strength, knee extensor power, history of intensive care unit stay, length of hospital day and sonoelastographic grade. RESULTS: There was a significant correlation between sonoelastographic grade and the average HFU (P<0.001). Furthermore, hand grip strength (P<0.001) and knee extensor power (P<0.001) decreased significantly as the sonoelastographic grade increased. The likelihood of an intensive care unit stay and prevalence of low skeletal mass increased significantly with an increase in sonoelastography grade (P=0.037, P<0.001, respectively). The sensitivity, specificity, and accuracy of sonoelastographic images for predicting low skeletal mass were 77.3%, 100%, and 87.5%, respectively. CONCLUSION: Sonoelastography advantages, including the lack of radiation and greater accessibility, may make it a valuable alternative to qualitatively and quantitatively identify sarcopenia and low skeletal mass.

Prognostic Factors Affecting Clinical Outcomes of Arthroscopic Assisted Reduction and Volar Plating through Preservation of Pronator Quadratus for Intra-Articular Distal Radius Fracture.

Background: This study aimed to evaluate the clinical and radiological outcomes following an arthroscopic-assisted reduction and volar plating (AR-VP) surgery through pronator quadratus (PQ) preservation for treating intra-articular distal radius fractures (IA-DRFs) and to assess prognostic factors that affect functional outcomes. Methods: Between March 2014 and February 2017, 54 patients who had intra-articular DRF and underwent AR-VP through the PQ preservation technique and completed 1-year follow-up were enrolled. Patients were divided into the satisfactory group (excellent and good results) and an unsatisfactory group (fair and poor results) based on the modified Mayo Wrist Scoring System (MMWS) scored at 1-year follow-up to determinate prognostic factors that affected clinical outcomes. Patients' demographics, clinical outcome measures (VAS, DASH, PRWE, etc.), and pre-and post-operative radiographic parameters were analyzed. Results: The outcomes according to MMWS were 10 excellent, 22 good, 14 fair, and 8 poor. A univariate analysis showed a significant difference between the groups (p < .05) for all radiographic parameters, sex, and the presence of an intra-articular comminution. In the multivariate analysis, female gender, presence of an intra-articular comminution, and difference of palmar articular tilt compared to uninjured wrist (> 20.1°) at trauma were considered as significant poor prognostic factors of functional outcome. Conclusions: AR-VP surgery through PQ preservation for intra-articular DRFs has reliable clinical and radiological outcomes. However, female gender, presence of an intra-articular comminution, and difference of palmar articular tilt compared to the uninjured wrist (> 20.1°) at initial injury were considered poor prognostic factors for AR-VP through PQ preservation for intra-articular DRF.