High-heeled shoes have the capability to alter the strain and tension of ligamentous structures between the foot and ankle, which may result in ankle instability. However, high-heeled shoes can also reduce the strain on plantar fascia, which may be beneficial for the treatment of plantar fasciitis. In this study, the influence of heel height on strain and tension force applied to the anterior talofibular ligament (ATL) and plantar fascia were investigated. A three-dimensional finite element model of coupled foot-ankle-shoe complex was constructed. Four heel heights were studied in balanced standing: 0 in. (0cm), 1 in. (2.54cm), 2 in. (5.08cm), and 3 in. (7.62cm). A walking analysis was performed using 2-in. (5.08cm) high-heeled shoes. During balanced standing, the tension force on the ATL increased from 14.8N to 97.0N, with a six-fold increase in strain from 0 in. to 3 in. (0-7.62cm). The tension force and the average strain on the plantar fascia decreased from 151.0N (strain: 0.74%) to 59.6N (strain: 0.28%) when the heel height increased from 0 in. to 2 in. (0-5.08cm). When heel height reached 3 in. (7.62cm), the force and average strain increased to 278.3N (strain: 1.33%). The walking simulation showed that the fascia stretched out while the ATL loading decreased during push off. The simulation outcome demonstrated the influence of heel height on ATL alteration and plantar fascia strain, which implies risks for ankle injury and suggests guidance for the treatment of plantar fasciitis.

Osteoarthritis is a chronic degenerative joint disease involving both articular cartilage and subchondral bone. Kartogenin (KGN) was recently identified to improve in vivo cartilage repair; however, its effect on bone formation is unknown. The aim of this study was to investigate the effect of KGN on antioxidant properties and osteogenic differentiation of bone marrow‐derived mesenchymal stem cells (BM‐MSCs). Human BM‐MSCs were treated with KGN at concentrations ranging from 10⁻⁸ M to 10⁻⁶ M. Our results indicated that KGN improved cell proliferation and attenuated intracellular reactive oxygen species. The levels of antioxidant enzymes and osteogenic differentiation of BM‐MSCs were enhanced by KGN in a dose‐dependent manner. Furthermore, KGN‐treated BM‐MSCs showed upregulation of silent information regulator type 1 (SIRT1) and increased phosphorylation of adenosine 5 ^′‐monophosphate‐activated protein kinase (AMPK), indicating that KGN activated the AMPK‐SIRT1 signaling pathway in BM‐MSCs. Inhibition of SIRT1 by nicotinamide reversed the antioxidant effect of KGN on BM‐MSCs and suppressed osteogenic differentiation. In conclusion, our results demonstrated that KGN improved intracellular antioxidant properties and promoted osteogenic differentiation of BM‐MSCs by activating the AMPK‐SIRT1 signaling pathway. Thus, KGN may have the potential for not only articular cartilage repair but also the clinical application of MSCs in bone tissue engineering.

Mueller-Weiss disease is a rarely diagnosed deformity where the navicular bone undergoes spontaneous osteonecrosis in adults. Until now, there is no widely accepted operative treatment for this unusual disease. We aimed to compare clinical and radiological outcomes between the open triple fusion and talonavicular-cuneiform arthrodesis for Mueller-Weiss disease of stage 4. During the period from February 2012 to June 2016, 10 patients (11 feet) suffering from Mueller-Weiss disease of stage 4 were treated by the same senior surgeon. Among them, 5 patients (5 feet) were treated with open triple fusion and 5 patients (6 feet) were treated with talonavicular-cuneiform arthrodesis. Clinical outcomes were evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score. Radiological results were assessed based on the X-ray and CT. Postoperative complications were also recorded. There were no significant differences in AOFAS score between the two groups (p = 0.1 > 0.05). For the open triple fusion, the average AOFAS ankle-hindfoot score improved from 30.2 ± 3.27 preoperatively to 79 ± 3.81 at the last follow-up (p = 0.008). And for the talonavicular-cuneiform (TNC) arthrodesis, the average AOFAS ankle-hindfoot score improved from 33.2 ± 5.63 preoperatively to 86.2 ± 3.49 at the last follow-up (p = 0.007). Both triple fusion and TNC arthrodesis are reasonable methods for the treatment of Mueller-Weiss disease if properly used. It is crucial to use radiological assessment to evaluate the involved joints preoperatively and then chose the appropriate method to treat different patients.

Esophageal stent implantation can relieve esophageal stenosis and obstructions in benign esophageal strictures, and magnesium alloy stents are a good candidate because of biodegradation and biological safety. However, biodegradable esophageal stents show a poor corrosion resistance and a quick loss of mechanical support in vivo. In this study, we chose the elastic and biodegradable mixed polymer of Poly(ε-caprolactone) (PCL) and poly(trimethylene carbonate) (PTMC) as the coated membrane on magnesium alloy stents for fabricating a fully biodegradable esophageal stent, which showed an ability to delay the degradation time and maintain mechanical performance in the long term. After 48 repeated compressions, the mechanical testing demonstrated that the PCL-PTMC-coated magnesium stents possess good flexibility and elasticity, and could provide enough support against lesion compression when used in vivo. According to the in vitro degradation evaluation, the PCL-PTMC membrane coated on magnesium was a good material combination for biodegradable stents. During the in vivo evaluation, the proliferation of the smooth muscle cells showed no signs of cell toxicity. Histological examination revealed the inflammation scores at four weeks in the magnesium-(PCL-PTMC) stent group were similar to those in the control group (p > 0.05). The α-smooth muscle actin layer in the media was thinner in the magnesium-(PCL-PTMC) stent group than in the control group (p < 0.05). Both the epithelial and smooth muscle cell layers were significantly thinner in the magnesium-(PCL-PTMC) stent group than in the control group. The stent insertion was feasible and provided reliable support for at least four weeks, without causing severe injury or collagen deposition. Thus, this stent provides a new stent for the treatment of benign esophageal stricture and a novel research path in the development of temporary stents in other cases of benign stricture.

Background: This study aims to explore the relationship between surgically-induced ankle instability and posttraumatic osteoarthritis (PTOA) in a mouse model, and to provide reference for clinical practice. Results: Ligamentectomy was performed on 24 eight-week-old male C57BL/6 J mice, which were divided into three groups. Both the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) were severed in the CFL + ATFL group, while only the CFL was removed in the CFL group. The SHAM group was set as the blank control group. A wheel-running device was used to accelerate the development of ankle osteoarthritis (OA). Balance measurement, footprint analysis, and histological analysis were used to assess the degree of ankle instability and OA. According to the balance test results, the CFL + ATFL group demonstrated the highest number of slips and the longest crossing beam time at 8 weeks postoperatively. The results of gait analysis exhibited that the CFL + ATFL group had the most significant asymmetry in stride length, stance length, and foot base width compared to the CFL and SHAM groups. The OARSI score of the CFL + ATFL group (16.7 ± 2.18) was also much higher than those of the CFL group (5.1 ± 0.96) and the SHAM group (1.6 ± 1.14). Conclusion: Based on the mouse model, the findings indicate that severe ankle instability has nearly three times the chance to develop into ankle OA compared to moderate ankle instability.