A15 GENETIC OR DIET-ASSOCIATED DEFECTS IN MUCUS FACILITATE ULCERATIVE COLITIS PATHOBIONT-DRIVEN COLITIS

Background

The Inflammatory Bowel Diseases (IBD), Crohn’s Disease (CD) and ulcerative colitis (UC) affect > 270,000 Canadians and are increasing in incidence. Ileal CD has been linked to the overgrowth of mucosal adherent E. coli. Recent studies have also implicated the adherence of Escherichia coli pathobionts to the colonic mucosa of UC patients. Using the representative UC E. coli pathobiont p19A, we recently demonstrated it aggravated chemical-induced colitis in susceptible mice, through the actions of the toxin alpha-hemolysin, and by adhering to the inflamed colonic mucosa via the adhesin FimH. It is less clear what host factors control susceptibility to the UC pathobionts. One of the potential candidates is the glycosylated mucin (Muc2) which forms the mucus layer that covers the colonic epithelium and is often impaired in UC patients.

Purpose

To define the role of mucus structure and function in determining susceptibility to the p19A pathobiont, and its ability to cause colitis in mice.

Method

In vitro growth was assessed to test p19A’s ability to utilize mucin-derived sugars as nutrients. Susceptibility to p19A was tested in two mouse models of colonic mucus impairment. The first is a mouse strain deficient in core 1 derived O-glycans in their intestinal epithelial cells (IEC C1galt1^-/-), resulting in reduced Muc2 glycosylation, and thus a thin and impaired mucus barrier. The second model involves feeding wildtype (WT) C57BL/6CR mice a fiber-free (FF) diet, resulting in a significantly thinner colonic mucus layer. The mice were subsequently orally gavaged with p19A and their susceptibility determined by p19A burdens, intestinal histopathology, inflammatory cytokine and short chain fatty acid (SCFA) production.

Result(s)

When tested in vitro, the p19A pathobiont was found to use an array of mucin-derived sugars as sole carbon source to proliferate. Following oral gavage of WT mice fed a normal diet, immunostaining identified p19A within the colonic mucus but it did not reach the colonic mucosa or cause disease. In contrast, p19A was found at the colonic mucosal surface of mucus-defective IEC C1galt1^-/- mice (as compared to IEC C1galt1^flox/flox mice) and in WT mice fed a fiber-free diet. This mucosal adherence was associated with increased body weight loss during the course of infection, as well as increased p19A burdens, colonic pathology and pro-inflammatory cytokine expression. Especially fiber-free diet-fed mice showed reduced SCFA levels in their feces at baseline. When the mice were given exogenous SCFA (tributyrin) orally, p19A infection was reduced.

Conclusion(s)

Our results indicate that UC E. coli pathobionts are able to dwell within colonic mucus and utilize mucin sugars as nutrients. Moreover, they can reach the mucosal surface and induce colitis in hosts suffering genetic or diet-based mucus dysfunction. In part, this susceptibility reflects the important role played by mucus in the production of SCFA, suggesting potential therapeutic approaches for patients suffering UC.

Please acknowledge all funding agencies by checking the applicable boxes below

CCC, CIHR

Disclosure of Interest

None Declared

A142 APPROPRIATENESS OF POST-ENDOSCOPY CARE IN PATIENTS PRESENTING WITH FOOD BOLUS IMPACTIONS OVERNIGHT: A POPULATION-BASED MULTICENTER COHORT STUDY

Background

Appropriate management of esophageal food bolus impactions includes endoscopic evaluation and follow-up for potential underlying esophageal pathology. Patients who present with impactions at night may not receive optimal long-term post-endoscopy care due to patient-, physician-, or system-related factors.

Purpose

We aimed to evaluate the appropriateness of care for patients who present with food bolus impactions after regular daytime hours.

Method

We conducted a retrospective, population-based, multi-center cohort study of adult patients undergoing endoscopy for food impaction between 19:00-06:59 from 2016-2018 in the Calgary Health Zone, Canada. Appropriate post-endoscopy care was defined by a composite of a follow-up clinic visit, repeat endoscopy, other appropriate investigations (e.g., manometry), or appropriate medical treatment (e.g., proton pump inhibitor). Predictors of inappropriate care were assessed using multivariable logistic regression, expressed as adjusted odds ratios (aOR) with 95% confidence intervals (CI).

Result(s)

A total of 323 patients underwent an after-hours or overnight endoscopy for food bolus impaction. 25.4% (82/323) of patients did not receive appropriate post-endoscopy care. Predictors of inappropriate care included rural residence (aOR 2.66 [95% CI: 1.18-6.01], p=0.02), first food bolus presentation (aOR 2.38 [95% CI: 1.04-5.44], p=0.04), and absence of a specific pathology during the index procedure (aOR 3.01 [95% CI: 0.97-9.29], p=0.05), suggesting a potential association with clinician cognitive bias. Among patients who were followed, 18.9% (35/185) had a change in the original diagnosis.

Image

Conclusion(s)

One quarter of patients presenting with a food bolus impaction at night do not receive appropriate post-endoscopy care. System-based interventions should target this high-risk population as the diagnosis and management may change with follow-up.

Please acknowledge all funding agencies by checking the applicable boxes below

None

Disclosure of Interest

None Declared

A195 DURABILITY OF SEROLOGICAL RESPONSES AFTER SECOND, THIRD AND FOURTH DOSE OF SARS-COV-2 VACCINATION IN INFLAMMATORY BOWEL DISEASE: A PROSPECTIVE COHORT STUDY

Background

Adequate serological responses following two-dose regimens and additional doses of SARS-CoV-2 vaccination have been demonstrated for the vast majority of those with IBD. However, antibody levels following 2^nd, 3^rd, and 4^th dose SARS-CoV-2 vaccination may decrease over time in the IBD population.

Purpose

We assessed the durability of serological responses to 2^nd, 3^rd, and 4^th dose SARS-CoV-2 vaccination over time in a cohort of IBD patients.

Method

Adults with IBD who received at least one dose of a SARS-CoV-2 vaccine (n=559) were evaluated for serological response to the spike protein of SARS-CoV-2 using the Abbott IgG II Quant assay with a seroconversion threshold of ≥ 50 AU/mL. The geometric mean titer (GMT) with 95% confidence intervals (CI) were calculated and stratified by weeks (1–8, 8–16, 16–24, 24+ weeks) after each vaccine dose. We compared stratified GMTs with Mann–Whitney U tests using a significance level of 0.05.

Result(s)

Our cohort (n=559) comprised the following patient characteristics: 82.8% were 18–65 years-old (n = 463), 53.1% were female (n =297), and 71.6% had Crohn’s disease (n =400). IBD medications were classified in the following mutually exclusive groups: No immunosuppressives 10.5% (n = 59), anti-TNF monotherapy 35.8% (n = 200), immunomodulatory monotherapy 2.1% (n =12 ), vedolizumab 11.8% (n =66 ), ustekinumab 20.4% (n =114 ), tofacitinib 1.2% (n =7 ), combination therapy 15.9% (n = 89), and prednisone 2.1% (n =12). For vaccine type, 85.6% and 82.3% had Pfizer for 3^rd and 4^th dose, respectively, while the remainder had Moderna. Seroconversion rates 1–8 weeks after 3^rd and 4^th dose were both 99.9%.

Figure 1 compares GMTs with 95% CI by weeks after each vaccine dose. GMTs are highest 1–8 weeks after 2^nd dose (4053 AU/mL; 95% CI: 3468, 4737 AU/mL; n=337), 3^rd dose (12116 AU/mL; 10413, 14098 AU/mL; n=256), and 4^th dose (14337 AU/mL; 10429, 19710 AU/mL; n=67). Subsequently, antibody levels decay from 1–8 weeks to 8–16 weeks (p<0.001) for 2^nd dose (mean difference: –2224 AU/mL), 3^rd dose (mean difference: –7526 AU/mL), and 4^th dose (mean difference: –9715 AU/mL). Compared to 16–24 weeks after 2^nd dose, antibody levels 24+ weeks after were similar (GMTs: 795 AU/mL vs. 1043 AU/mL, p=0.52). For third dose, antibody levels 8–16 weeks and 16–24 weeks after vaccination were similar (4590 AU/mL vs. 4073 AU/mL, p=0.73) along with 16–24 weeks compared to 24+ weeks after vaccination (4073 AU/mL vs. 5876 AU/mL, p=0.18).

Image

Conclusion(s)

Within 1–8 weeks after each dose of vaccine, serological responses spikes with each subsequent dose yielding a higher GMT. While antibody levels decay 8–16 weeks after each dose, similar GMT levels beyond 16 weeks may indicate durability of antibody levels over a longer duration of time.

Disclosure of Interest

None Declared

Clinical comparison of superior thyroid artery perforator flap and sternocleidomastoid myocutaneous flap for intraoral reconstruction

The aim was to evaluate the techniques and outcomes of superior thyroid artery perforator flaps (STAPF) for intraoral reconstruction and to compare them with those of the sternocleidomastoid myocutaneous flap (SCMMF). The cases of 43 patients who underwent reconstruction with either a SCMMF or STAPF for the repair of a medium-sized intraoral defect, between January 2013 and December 2020, were reviewed retrospectively. Although both flaps are based on the superior thyroid artery, their specific harvesting techniques largely differ. All SCMMF (n = 23) were superiorly-based rotational flaps with myocutaneous designs. The STAPF cases (n = 20) included 18 septocutaneous flaps and two chimeric flaps. The flap size was larger in the STAPF group (P = 0.008), while incomplete level IIB dissection (oncological safety) was more frequent in the SCMMF group (P = 0.002). The flap necrosis rate was lower in the STAPF group (STAPF 15% vs SCMMF 34.8%, though this was not statistically significant). Cox multivariate analysis showed that the postoperative flap outcome (total flap necrosis vs flap survival; hazard ratio 27, 95% confidence interval 2.149-336.05; P = 0.001) and complications (excluding fistula) (hazard ratio 14, 95% confidence interval 1.314-142.767; P = 0.029) were associated with overall patient survival. Both speech (P < 0.001) and neck mobility (P < 0.001) functions were superior with STAPF reconstruction. Compared with the traditional SCMMF, the STAPF was found to have a lower necrosis rate with uncompromised oncological safety during harvesting. The STAPF is a good alternative for the repair of medium-sized head and neck defects.

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Pharmacological targeting of MTHFD2 suppresses NSCLC via the regulation of ILK signaling pathway

Lung cancer is the most common cause of cancer related deaths worldwide with the highest mortality rate. Non-small cell lung cancer (NSCLC) accounts for about 85 % of lung cancers. Mitochondrial methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) is a bifunctional enzyme and is the most differentially expressed metabolic enzyme in various tumors including lung cancer. However, little is known about how MTHFD2 functions in NSCLC. Integrin-linked kinase (ILK) signaling plays key a role in tumor progression including metastasis, proliferation and migration. Here, we show that MTHFD2 inhibition results in suppression of cell growth, migration, invasion and epithelial-mesenchymal transition (EMT) in NSCLC. Microarray analysis suggests that MTHFD2 is positively associated with ILK signaling based on western blotting results. In addition, the phosphorylation of AMPKα plays an essential role in MTHFD2 regulation of ILK signaling. Further, the small-molecule compound C18 inhibits MTHFD2 with great efficiency. C18 blocks MTHFD2/ILK signaling pathway and restrains cell growth, migration, invasion, and EMT of NSCLC and induces apoptosis. In brief, our study found that the positive impact of MTHFD2 is mediated via ILK signaling pathway in NSCLC. Thus, blocking MTHFD2 represents a promising therapeutic strategy against NSCLC clinically.

[Directed differentiation of human induced pluripotent stem cells into midbrain]

OBJECTIVE

To establish an efficient protocol for directed differentiation of human induced pluripotent stem cells (hiPSCs) into functional midbrain dopaminergic progenitor cells (DAPs) in vitro.

METHODS

hiPSCs were induced to differentiate into DAPs in two developmental stages. In the first stage (the first 13 days), hiPSCs were induced into intermediate cells morphologically similar to primitive neuroepithelial cells (NECs) in neural induction medium containing a combination of small molecule compounds. In the second stage, the intermediate cells were further induced in neural differentiation medium until day 28 to obtain DAPs. After CM-DiI staining, the induced DAPs were stereotactically transplanted into the right medial forebrain bundle (MFB) of rat models of Parkinson's disease (PD). Eight weeks after transplantation, the motor behaviors of PD rats was evaluated. Immunofluorescence assay of brain sections of the rats was performed at 2 weeks after transplantation to observe the survival, migration and differentiation of the transplanted cells in the host brain microenvironment.

RESULTS

hiPSCs passaged stably on Matrigel showed a normal diploid karyotype, expressed the pluripotency markers OCT4, SOX2, and Nanog, and were positive for alkaline phosphatase. The primitive neuroepithelial cells obtained on day 13 formed dense cell colonies in the form of neural rosettes and expressed the neuroepithelial markers (SOX2, Nestin, and PAX6, 91.3%-92.8%). The DAPs on day 28 highly expressed the specific markers (TH, FOXA2, LMX1A and NURR1, 93.3-96.7%). In rat models of PD, the hiPSCs-DAPs survived and differentiated into TH⁺, FOXA2⁺ and Tuj1⁺ neurons at 2 weeks after transplantation. Eight weeks after transplantation, the motor function of PD rats was significantly improved as shown by water maze test (P < 0.0001) and apomorphine-induced rotation test (P < 0.0001) compared with rats receiving vehicle injection.

CONCLUSION

HiPSCs can be effectively induced to differentiate into DAPs capable of differentiating into functional neurons both in vivo and in vitro. In rat models of PD, the transplanted hiPSCs-DAPs can survive for more than 8 weeks in the MFB and differentiate into multiple functional neurocytes to ameliorate neurological deficits of the rats, suggesting the potential value of hiPSCs-DAPs transplantation for treatment of neurological diseases.

Water-Air Interface Imaging: Recovering the Images Distorted by Surface Waves via an Efficient Registration Algorithm

Imaging through the wavy water-air interface is challenging since the random fluctuations of water will cause complex geometric distortion and motion blur in the images, seriously affecting the effective identification of the monitored object. Considering the problems of image recovery accuracy and computational efficiency, an efficient reconstruction scheme that combines lucky-patch search and image registration technologies was proposed in this paper. Firstly, a high-quality reference frame is rebuilt using a lucky-patch search strategy. Then an iterative registration algorithm is employed to remove severe geometric distortions by registering warped frames to the reference frame. During the registration process, we integrate JADE and LBFGS algorithms as an optimization strategy to expedite the control parameter optimization process. Finally, the registered frames are refined using PCA and the lucky-patch search algorithm to remove residual distortions and random noise. Experimental results demonstrate that the proposed method significantly outperforms the state-of-the-art methods in terms of sharpness and contrast.

Concrete Multi-Type Defect Classification Algorithm Based on MSSMA-SVM

In order to realize the automatic classification of internal defects for non-contact nondestructive testing of concrete, a concrete multi-type defect classification algorithm based on the mixed strategy slime mold algorithm support vector machine (MSSMA-SVM) was proposed. The concrete surface's vibration signal was obtained using a laser Doppler vibrometer (LDV) for four classification targets for no defect, segregation, cavity, and foreign matter concrete classification targets. The wavelet packet transform (WPT) decomposes the detected signals to get information on different frequency bands. The energy ratio change rate, energy ratio, and wavelet packet singular entropy of each node after the WPT were used as the feature input of MSSMA-SVM. The experimental results show that the designed MSSMA-SVM classifier can accurately detect the type, which provides a practical algorithm for classifying concrete defects by laser vibration measurement.

[Consolidate the foundation, steadily promote and comprehensively improve the quality control in prevention and management of venous thromboembolism in China]

Hospital-associated venous thromboembolism (HA-VTE) has become a public health problem that seriously affects the quality of medical care and patient safety. Many countries regarded VTE prevention as a key element of medical quality management, carried out quality improvement work in VTE prevention and achieved remarkable results. In China, there is also unremitting efforts and explorations in the field of VTE prevention and management. The national program for prevention and management of pulmonary embolism and deep vein thrombosis was officially launched. Through a series of measures such as excellent center construction, regional alliance, and strengthening of quality control and informatization, the national program has greatly promoted the construction of VTE prevention and management system in hospitals across the country. Strengthening the prevention and treatment of VTE has become the common will of the government, hospital administrators, clinical medical staff and the public. In the future, we need to continue to steadily promote the prevention and management of VTE, and comprehensively improve the quality control management level of VTE prevention and management in hospitals.

[Quality of life and risk factors in patients with herpes zoster]

Objective: To evaluate the quality of life and influencing factors of patients with herpes zoster (HZ) seen in hospitals. Methods: Based on Zoster Brief Pain Inventory (ZBPI) and Five-level EuroQol Five-dimensional Questionnaire (EQ-5D-5L), a cross-sectional survey was conducted to evaluate the pain severity and quality of life of 332 HZ cases seen in 22 hospitals of Lu'an City (Anhui Province), Zibo City (Shandong Province) and Tongchuan City (Shaanxi Province) from October to December 2021. The censored least absolute deviations (CLAD) model was used to analyze the related factors affecting the changes of patients' health utility values. Results: The 45.5% of 332 HZ cases were male. The median (Q₁,Q₃) age was 59 (50, 68) years. 59.64% of them assessed by ZBPI had moderate to severe pain in the past 24 hours (worst pain score≥5), and that of PHN cases was 84.8%(39/46). 77.7% (258/332), 77.4% (257/332) and 74.1% (246/332) of all patients reported that pain interfered with sleep, mood and general activities, respectively. Aging [β_40-49y (95%CI)=-0.11 (-0.15, -0.08); β_50-59y (95%CI)=-0.03 (-0.05, 0.00); β_60-69y (95%CI)=-0.09 (-0.12, -0.06); β_70-90y(95%CI)=-0.16 (-0.19, -0.12)], working status (unemployed) [β_farmer (95%CI)=0.15 (0.13, 0.18); β_retirees(95%CI)=0.21 (0.18, 0.24); β_employee (95%CI)=0.13 (0.10, 0.16) ], complications[β_PHN (95%CI)=-0.08 (-0.13, -0.04); β_{other complications} (95%CI)=-0.12 (-0.15, -0.08)], within 30 days after onset [β(95%CI)=-0.01 (-0.03, 0.01)] and treatment [β_{other complications} (95%CI)=-0.09 (-0.11, -0.06)] were related factors for the decline of health utility value (all P values <0.05). Conclusions: More than half of the patients with HZ had moderate to severe pain in the past 24 hours, which had a serious negative impact on the physical and mental health of the patients. Elderly patients, acute patients and patients with complications had lower health utility values and worse health status. We suggest that eligible people be vaccinated with HZ vaccine as soon as possible.

[Research progress of mesenchymal stem cell in the treatment of diabetic bladder dysfunction]

Diabetic bladder dysfunction (DBD) is a common complication in the lower urinary tract of diabetes. In recent years, mesenchymal stem cell (MSC) have broad application prospects in the treatment of DBD. MSC can migrate to damaged bladder tissue and differentiate into various cell types, such as urothelial cells, myofibroblasts, smooth muscle cells and nerve cells, promote bladder tissue repair and regeneration through paracrine effects. In addition, MSC also intervene in the pathological process of DBD, reverse disease progression, and restore partial bladder function through immune regulation, improvement of oxidative stress, and regulation of blood glucose. At present, the treatment of DBD with MSC is limited to preclinical animal experiments, clinical research and application should be pursued further.

Quantitative Intracerebral Iodine Extravasation in Risk Stratification for Intracranial Hemorrhage in Patients with Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Intracerebral hemorrhage poses a severe threat to the outcomes in patients with postthrombectomy acute stroke. We aimed to compare the absolute intracerebral iodine concentration and normalized iodine concentration ratio in predicting intracerebral hemorrhage in patients postthrombectomy.

MATERIALS AND METHODS

Patients with acute anterior circulation large-vessel occlusion who underwent mechanical thrombectomy and had successful recanalization were retrospectively included in the study. Dual-energy CT was performed within 1 hour after mechanical thrombectomy. Postprocessing was performed to measure the absolute intracerebral iodine concentration and the normalized iodine concentration ratio. The correlation between the absolute intracerebral iodine concentration and the normalized iodine concentration ratio was analyzed using the Spearman rank correlation coefficient. We compared the area under the receiver operating characteristic curve of the absolute intracerebral iodine concentration and the normalized iodine concentration ratio using the DeLong test.

RESULTS

We included 138 patients with successful recanalization. Of 43 patients who did not have parenchymal contrast staining on postthrombectomy dual-energy CT, 5 (11.6%) developed intracerebral hemorrhage. Among patients (95/138, 68.8%) with parenchymal contrast staining, 37 (38.9%, 37/95) developed intracerebral hemorrhage. The absolute intracerebral iodine concentration was significantly correlated with the normalized iodine concentration ratio (ρ = 0.807; 95% CI, 0.718-0.867; P < .001). The cutoffs of the normalized iodine concentration ratio and absolute intracerebral iodine concentration for identifying patients with intracerebral hemorrhage development were 222.8%, with a sensitivity of 67.6% and specificity of 76.4%, and 2.7 mg I/mL, with a sensitivity of 75.7% and specificity of 65.5%, respectively. No significant difference was found between the areas under the receiver operating characteristic curve for the absolute intracerebral iodine concentration and the normalized iodine concentration ratio (0.753 versus 0.738) (P = .694).

CONCLUSIONS

The hemorrhagic transformation predictive power of the normalized iodine concentration ratio is similar to that of the absolute intracerebral iodine concentration in patients with successful recanalization.

AB1474 LIPIDOMIC PROFILING IDENTIFIES SERUM LIPIDS ASSOCIATED WITH PERSISTENT MULTISITE MUSCULOSKELETAL PAIN

Background

Lipid mediators have been suggested to have a role in pain sensitivity and response; however, longitudinal data on lipid metabolites and persistent multisite musculoskeletal pain (MSMP) are lacking.

Objectives

This study was to identify lipid metabolic markers for persistent MSMP.

Methods

Lipidomic profiling of 807 lipid species was performed on serum samples of 536 participants from a cohort study. MSMP was measured by a questionnaire and defined as painful sites ≥4. Persistent MSMP was defined as having MSMP at every visit. Logistic regression was used with adjustment for potential confounders. The Benjamini Hochberg method was used to control for multiple testing.

Results

A total of 530 samples with 807 lipid metabolites passed quality control. Mean age at baseline was 61.54±6.57 years and 50% were females. One hundred and twelve (21%) of the participants had persistent MSMP. Persistent MSMP was significantly associated with lower levels of monohexosylceramide (HexCer)(d18:1/22:0 and d18:1/24:0), acylcarnitine (AC)(26:0) and lysophosphatidylcholine (LPC)(18:1 [sn1], 18:2 [sn1], 18:2 [sn2], and 15-MHDA[sn1] [104_sn1]) after controlling for multiple testing. After adjustment for age, sex, body mass index, diabetes status, and physical activity, HexCer(d18:1/22:0 and d18:1/24:0) and LPC(18:1 [sn1] and 15-MHDA [sn1] [104_sn1]) were significantly associated with persistent MSMP [Odds Ratio (OR) ranging from 0.24 - 0.32]. Two lipid classes -- HexCer and LPC were negatively associated with persistent MSMP after adjustment for covariates (OR=0.19 and 0.21, respectively).

Conclusion

This study identified four novel lipid signatures of persistent MSMP, suggesting that lipid metabolism is involved in the pathogenesis of persistent pain.

Disclosure of Interests

None declared

[All-inside subtalar arthroscopy through three portals combined with rafting screws technique for the treatment of the calcaneal fractures of Sanders Ⅱ and Ⅲ]

Objective: To investigate the surgical technology and clinical efficacy of using the all-inside subtalar arthroscopy through three portals combined with rafting screws technique for the treatment of the calcaneal fractures of Sanders Ⅱ and Ⅲ. Methods: The clinical data of 33 patients (33 feet) with intra-articular displaced calcaneal fractures treated by modified all-inside arthroscopic from March 2017 to March 2019 at Department of Orthopedics,Xuzhou Central Hospital were retrospectively analyzed.There were 19 male patients,and 14 female patients,aged (32.6±11.3) years(range:20 to 55 years). According to the Sanders classification,there were 12 cases of type Ⅱ and 21 cases of type Ⅲ. The duration from injury to surgery was (101.2±32.1) hours(range:6 to 140 hours).The preoperative visual analogue scale (VAS) was 6.4±2.9 (range: 4 to 8); The preoperative American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scale and the SF-36 score was 63.3±11.8 (range:50 to 75) and 94.8±9.1 (range:70 to 105) respectively.All the patients were managed with the all-side subtalar arthroscopy through three portals combined with rafting screws technique.The incision healing,reduction of fracture,and fracture healing were recorded.The VAS,AOFAS ankle-hindfoot scale,and SF-36 score were used to assess the pain and functional outcomes.Repeated-measurement was used to compare the scores before and after surgery. Results: The time of operation was (69.7±10.4) minutes (range:40 to 110 minutes). All patients did not undergo bone grafting.The incision healed in one stage without complications of skin sensory and peroneal tendon injury.All patients were followed up for 24 months.At the last follow-up,all the patients were satisfied with the hindfoot alignment,function,and hindfoot appearance.Postoperative calcaneal imaging indicators (calcaneal length,calcaneal width,calcaneal height,Bohler angle and Gissane angle) were significantly improved compared with those before surgery (P<0.01).There was no statistically significant difference in the imaging indexes of calcaneus at 1 day,1 year and 2 years after surgery,indicating no loss of fracture reduction (all P>0.05).The VAS,AOFAS ankle-hindfoot scale,and SF-36 score were 1.5±0.4 (range: 0 to 2),94.0±6.5 (range:90 to 100),and 119.1±7.2 (range:105 to 130),respectively,which were better than those before surgery (all P>0.05).According to the AOFAS scoring system,27 cases were excellent,4 cases were good, 2 cases were fair,and the excellent and good rate was 94.0%. Conclusion: All-inside subtalar arthroscopy through three portals combined with rafting screws technique for the treatment of the calcaneal fractures of Sanders Ⅱ and Ⅲ provides precise reduction,reliable fixation,satisfactory function and limited complications,which is an alternative method.