Machine learning-based models for prediction of the risk of stroke in coronary artery disease patients receiving coronary revascularization.

BACKGROUND: To construct several prediction models for the risk of stroke in coronary artery disease (CAD) patients receiving coronary revascularization based on machine learning methods. METHODS: In total, 5757 CAD patients receiving coronary revascularization admitted to ICU in Medical Information Mart for Intensive Care IV (MIMIC-IV) were included in this cohort study. All the data were randomly split into the training set (n = 4029) and testing set (n = 1728) at 7:3. Pearson correlation analysis and least absolute shrinkage and selection operator (LASSO) regression model were applied for feature screening. Variables with Pearson correlation coefficient<9 were included, and the regression coefficients were set to 0. Features more closely related to the outcome were selected from the 10-fold cross-validation, and features with non-0 Coefficent were retained and included in the final model. The predictive values of the models were evaluated by sensitivity, specificity, area under the curve (AUC), accuracy, and 95% confidence interval (CI). RESULTS: The Catboost model presented the best predictive performance with the AUC of 0.831 (95%CI: 0.811-0.851) in the training set, and 0.760 (95%CI: 0.722-0.798) in the testing set. The AUC of the logistic regression model was 0.789 (95%CI: 0.764-0.814) in the training set and 0.731 (95%CI: 0.686-0.776) in the testing set. The results of Delong test revealed that the predictive value of the Catboost model was significantly higher than the logistic regression model (P<0.05). Charlson Comorbidity Index (CCI) was the most important variable associated with the risk of stroke in CAD patients receiving coronary revascularization. CONCLUSION: The Catboost model was the optimal model for predicting the risk of stroke in CAD patients receiving coronary revascularization, which might provide a tool to quickly identify CAD patients who were at high risk of postoperative stroke.

Morphological analysis and classification of posterior malleolar fractures based on CT scans.

OBJECTIVES: The aim of the study was to propose a classification system of posterior malleolar fractures by fracture lines with the use of CT scans, including 3D CT reconstruction, which can better understand morphological characteristics, analyze the mechanism and guide the surgeon to choose the optimal approach and fixation. METHODS: Patients with OTA/AO type 44 fractures involving the posterior malleolus and preoperative CT scans were included. We retrospectively analyzed 128 consecutive patients with posterior malleolar fractures from January 2013 to December 2019 at our institution. CT data were loaded into Mimics software (V20.0, Materialize), in which 3D CT reconstruction, morphological analysis and data measurements were made. RESULTS: Based on the number of fracture lines in 128 consecutive patients, posterior malleolar fractures were classified into three types: type 1 with a single fracture line, type 2 with double fracture lines and type 3 with multiple fracture lines. According to the distribution of the fracture line, type 1 was divided into types 1A, 1B and 1C, and type 2 was divided into types 2A, 2B and 2C. The fracture line from the fibular notch to the posterior rim of the distal tibia was defined as type 1A, and the fracture line to the medial malleolus was defined as type 1B. Type 1C was a small fragment in the posterior rim of the distal tibia. Type 2A was regarded as type 1A with type 1C. It was considered type 2B because another fracture line started from the fracture line of type 1A and extended to the medial malleolus. In type 2C, we could see that the double fracture lines were all from the fibular notch to the posterior rim of the distal tibia and did not cross. Type 3 fractures were comminuted fractures with multiple fracture lines. CONCLUSION: The morphology of posterior malleolar fractures, involvement of the fibular notch, or the medial malleolus can be obviously assessed by our classification system. We found the relation of the injury mechanism between type 1 and type 2 by comparing the area of the fragment. We have indicated that each type of fracture corresponds to its associated injury mechanism and which surgical approach and fixation can be chosen.

Mid-term follow-up evaluation of a new arthroscopic Broström procedure for chronic lateral ankle instability.

BACKGROUND: Chronic lateral ankle instability (CLAI) usually progresses from a previous lateral ankle sprain that was not treated properly. Several procedures have been introduced to address these patients, including open or arthroscopic techniques, the most common of which is the Broström procedure. Here, we describe a new outside-in arthroscopic Broström procedure and its results for treating patients with CLAI. METHODS: Thirty-nine patients (16 male and 23 female; mean age, 35 years [range, 16-60 years]) with CLAI were treated arthroscopically after failing non-operative management. All patients were symptomatic with a combination of recurrent ankle sprains, "giving way," and avoidance of sports and presented with a positive anterior drawer test upon the physical examination. All patients underwent arthroscopic lateral ligament reconstruction using the new technique. Patient characteristics and pre- and postoperative visual analog scale (VAS), American Orthopedic Foot and Ankle Society Ankle-Hindfoot Scale system (AOFAS), and Karlsson scores were recorded. RESULTS: The mean AOFAS score increased from 48 (mean 48, range 33-72) preoperatively to 91 (mean 91, range 75-98) at the final follow-up, Karlsson-Peterson and FAAM scores were also significantly improved. Two patients (5.13%) reported superficial peroneal nerve irritation symptoms postoperatively. Three patients (7.69%) complained of mild pain anteroinferior to the lateral ankle. CONCLUSIONS: The arthroscopic outside-in Broström procedure with a single suture anchor was a safe, effective, and reproducible technique for CLAI. Ankle stability resumed with a high clinical success rate. The main complication was injury to the superficial peroneal nerve, which crossed the area of repair.

A Transosseous Suture as an Alternative to Suture Anchor on Anterior-Avulsion Greater Tuberosity Fragment Fixation in Neer Three-Part Proximal Humeral Fracture: A Biomechanical Study.

OBJECTIVE: Greater tuberosity (GT) fragments were communicated, and additional techniques to increase the GT fragment stability after the locking plate fixation was necessary. This study aimed to analyze the reinforcement effects on the anterior-avulsion GT fragment in Neer three-part proximal humeral fractures (PHFs) using transosseous suture and suture anchor techniques. METHODS: Eighteen fresh-frozen human cadaveric shoulder specimens were used in the study. Standardized fracture of the GT and surgical neck was created in 18 human cadaveric proximal humerus. The GT fragments were reinforced with transosseous suture (TS), suture anchor (SA), and suture in addition to the PHILOS plate fixation. The fixed humerus was tested by applying static loading to the supraspinatus tendon. Load forces and fragment displacement were evaluated by a biomechanical testing machine, and the load to 3- and 5-mm displacements, load to failure, and mode of failure were recorded for all specimens. Nonparametric variables were examined by the Kruskal-Wallis test, and the Bonferroni post hoc test was used to analyze the mean loads to create 3- and 5-mm displacements as well as the failure load. RESULTS: The age, female proportion, and bone mineral density showed no statistically significant differences between the three groups. The mean loading force to create 3-mm and 5-mm displacement in the TS group (254.9 ± 77.4, 309.6 ± 152.7) were significantly higher than those in the suture group (136.1 ± 16.7, 193.4 ± 14.5) (P = 0.024, P = 0.005). For the SA group, the force to create 3- and 5-mm displacement (204.3 ± 60.9, 307.8 ± 73.5) were comparable to those in the TS group (P = 0.236, P = 0.983). Moreover, the loading force to failure in the TS group (508.6 ± 217.7) and SA group (406.6 ± 114.9) was significantly higher than that in the suture group (265.9 ± 52.1) (P = 0.021, P = 0.024). In the TS group, three failed due to tendon-bone junction rupture; bone tunnel broken occurred in two specimens; suture rupture could also be seen in one specimen. All specimens in the suture group failed because of suture rupture. In the SA group, three specimens failed due to suture rupture; two failed secondary to tendon-bone junction rupture; and one failed because of shaft fracture. CONCLUSIONS: Transosseous suture is a new type of reinforcement for GT fragment in Neer-three part PHFs. The transosseous suture was superior to the suture only in the reinforcement of the anterior-avulsion GT fragment of Neer three-part PHFs, and it had comparable biomechanical strength to the suture anchor.

Outcomes of posterior malleolar fractures with intra-articular impacted fragment.

INTRODUCTION: An intra-articular impacted fragment (IAIF) could lead to articular incongruity and malreduction in ankle fractures with posterior malleolar fractures (PMFs). No studies have been conducted to determine whether the presence of IAIF affects the outcome of ankle fractures with PMF. The aim of our retrospective study was to evaluate the effect of IAIF on postoperative outcomes in PMF and analyze the relationship between area of IAIF and outcomes. MATERIALS AND METHODS: We conducted a retrospective study of patients with a posterior malleolar fractures between June 2012 and January 2019 with a minimum follow-up of 2 years. Results of the Olerud-Molander ankle score (OMAS), EuroQol-5D (EQ-5D) index, EQ-5D visual analog scale (VAS), AOFAS (American orthopedic foot and ankle society ankle-hindfoot scale), visual analog scale (VAS) pain score and overall patient satisfaction scale were recorded. Outcomes of the PMF with IAIF group and PMF without IAIF group were compared. Sub-group analysis was given emphasis on the AIAIF > 40 mm2 group and AIAIF < 40 mm2 group in PMF with IAIF. RESULTS: A total of 128 patients were included in the study, consisting of 86 patients with IAIF and 42 patients without IAIF. Regarding the osteoarthritis grade (> 1, ≤ 1), the differences werestatistically significant between the two groups (P = 0.044). The risk of articular malreduction was higher in the PMF with IAIF group than in the PMF without IAIF group (P = 0.035). Osteoarthritis grade (> 1, ≤ 1) was closely related to articular malreduction (P < 0.001). There were 51 patients in the AIAIF > 40 mm2 group and 35 patients in the AIAIF < 40 mm2 group of 86 patients in PMF with IAIF. There were statistically significant differences in trimalleolar fracture (P = 0.004), malreduction (P = 0.022), osteoarthritis grade (> 1, ≤ 1; P = 0.027), EQ-5D VAS score (P = 0.031), and AOFAS score (P = 0.047) between the subgroups. CONCLUSION: The incidence of IAIF is associated with the area of the posterior malleolar fragment. Articular malreduction can lead to post-traumatic osteoarthritis, while IAIF is an important element for the quality of reduction, which is more likely to lead to articular malreduction. IAIF should be reduced if AIAIF is over 40 mm2. Otherwise, the patient will suffer a poor prognosis and post-traumatic osteoarthritis. Therefore, ankle fractures with PMF should undergo a CT scan preoperatively in order for providers to optimal treatment protocols. LEVEL OF EVIDENCE: Level III.

Fracture Line Morphology of Greater Tuberosity Fragments of Neer Three- and Four-Part Proximal Humerus Fractures.

OBJECTIVE: In complicated Neer three- and four-part proximal humerus fracture (PHF), greater tuberosity (GT) fragments are often comminuted, and the currently widely used locking plate may not fix GT fragments effectively. A further understanding of morphological characteristics of the GT fragments may help explore new fixation devices. This study aimed to determine the fracture line morphology of the GT fragment of Neer three- or four-part PHF and analyze the location relationship between the locking plate and the GT fragment. METHODS: Seventy-one three-dimensional computed tomography scans of Neer three- and four-part PHF were retrospectively reviewed between January 2014 and June 2019. Fracture fragments were reconstructed and virtually reduced in the Mimics software, and fracture lines of GT fragments were depicted on a humerus template in the 3-matic software and then were superimposed altogether. The common sites of the GT fracture were identified, and the location relationship between the locking plate and GT fragments was analyzed in a computer-simulated scenario. RESULTS: The fracture line morphology of GT fragments was similar between Neer three- and four-part PHF. The overall morphology of GT fragments was in a fan shape, which could be summarized as anterior, superior, posterior, and middle lines. Of these, we identified 51 split and 29 avulsion type GT fragments based on the Mutch classification, and they could occur simultaneously in a PHF. The overall morphology of split type fragments was in a fan shape, and avulsion type fragments showed a quite distinguishable distribution pattern. A GT fragment could be classified as anterior-split, posterior-split, complete-split, anterior -avulsion, and posterior-avulsion type based on its morphology and location. The median percentage of fragment area covered by the plate was 32.3% in all of the fragments, and it was 69.4%, 23.0%, 37.2%, 21.8%, 0.0% in anterior-split, posterior-split, complete-split, anterior-avulsion, and posterior-avulsion type GT fragments. We defined the posterior-split, anterior-avulsion, and posterior-avulsion type GT fragments as the risky GT fragments, and they occurred in 43 (60.6%) Neer three- and four-part PHFs. CONCLUSION: The fracture line morphology of GT fragments of Neer three- and four-part PHF was in a fan shape. GT fragments could be classified based on their location and morphology. The extent of GT fragment coverage provided by the locking plate differed in various fragment types, and we identified the anterior-avulsion, posterior-avulsion, and posterior-split type fragments as the risky GT fragments with a high incidence rate in Neer three- and four-part PHFs.

Delay between admission and surgery as a potential risk factor for postoperative morbidity and mortality in elderly patients with hip fractures: A retrospective study.

BACKGROUND: This study aimed to assess the impact of delay between admission and surgery on the postoperative outcomes such as mortality and related complications in elderly patients with acute hip fractures. METHODS: 840 patients aged ≥65 years from January 2009 to September 2015 were included in this retrospective study. According to the interval from admission to surgery, the patients were divided into four groups: group A (surgery within 24 h), group B (surgery within 24 h-48 h), group C (surgery within 48 h-72 h), and group D (surgery later than 72 h). Postoperative complications during hospitalization and mortality at different follow-up time points were compared. RESULTS: A total of 763 cases were successfully followed up, with an average follow-up time of 30.4 ± 13.1 months. The mean age of the patients was 79.4 ± 6.8 years. The difference in gross postoperative complications among groups was statistically significant in terms of pressure sore (P = 0.02), respiratory complications (P = 0.001), and urological complications (P < 0.001). The multivariate logistic regression analysis identified 3 factors independently associated with the postoperative morbidity, including age (odds ratio [OR] = 1.040), postoperative drainage volume (OR = 1.002) and time from admission to surgery (OR = 1.108). The difference in postoperative mortality among groups was statistically significant at 1 year (P = 0.046) after operation. The multivariate logistic regression analysis identified that age, postoperative drainage volume and time from admission to surgery were independently associated with mortality at 1 year postsurgery. CONCLUSION: The incidence of postoperative morbidity and mortality in elderly patients with hip fracture is usually the result of multiple factors, surgeons should pay attention to the patient's age, postoperative wound status and surgical delay time, which may significantly affect the outcome of the treatment.

Establishment of a finite element model and stress analysis of intra-articular impacted fragments in posterior malleolar fractures.

BACKGROUND: Intra-articular impacted fragments (IAIFs) are considered articular surface fragments resulting from impact and compressive forces. The malreduction of IAIFs in posterior malleolar fractures has been associated with talar subluxation and long-term post-traumatic arthritis. In this study, we establish IAIF defect finite element models of different sizes in posterior malleolar fractures and explored how IAIF defects predict the onset of post-traumatic arthritis. METHODS: A reliable three-dimensional finite element model of the normal ankle was established. Finite element models with different sizes of IAIF defects were created to calculate ankle joint contact stress. The finite element data were recorded and analyzed. RESULTS: There was a linear relationship between the size of the IAIF defect and MCS with IAIF defects in the posterolateral region. The result of Pearson linear correlation analysis was r = 0.963, P = 0.009. The regression equation was MCS = 0.087*AI + 2.951 (AI, area of IAIF) by simple linear regression analysis. When the IAIF defect was in the posteromedial region, there was also a linear relationship between the size of the IAIF defect and MCS. The result of Pearson linear correlation analysis was r = 908, P = 0.033. The regression equation was MCS = 0.065*AI + 1.841. The MCS was increased mainly in the border of the IAIF defect. CONCLUSIONS: A small IAIF defect in the posterior malleolus will result in a high MCS, and the MCS in the posterolateral region is larger than the MCS in the posteromedial region when the size of the IAIF defect is the same. We obtain the regression equation of MCS and area of IAIF defect. This indicates that patients are more prone to post-trauma arthritis when the size of IAIF defects is more than 17.8 mm2 in the posterolateral region and more than 40.9 mm2 in the posteromedial region. Trial registration Retrospectively registered.

Morphological analysis of posterior malleolar fractures with intra-articular impacted fragment in computed tomography scans.

BACKGROUND: Intraarticular impacted fragment (IAIF) of posterior malleolar fractures has been reported by a few studies. However its location, morphology, and the correlation of posterior malleolar fractures have not been described in detail. The aim of this study was to describe the morphology of IAIF in posterior malleolar fractures, to analyze the related factors between IAIF and posterior malleolar fragments, and explore the treatment of IAIF. MATERIALS AND METHODS: Between January 2013 and December 2018, 108 consecutive patients with unilateral posterior malleolar fractures were managed in our hospital. Basic demographic and computed tomography (CT) data were collected and classified by Lauge-Hansen, OTA/AO, Haraguchi, and Mason classification. Additional radiographic data, including the length and area of posterior malleolar fragment, IAIF, and stable tibial plafond were measured. The location of IAIF was described, and involvement of the fibular notch and medial malleolus was also observed. Statistics were analyzed based on univariate analysis (Chi-square test, t-test, Mann-Whitney U test, Fisher's test) and Spearman's correlation test. RESULTS: Among the 108 cases of posterior malleolar fractures, 75 (69.4%) were with IAIF and 33 (30.6%) cases were without. There were 74 (68.5%) females and 34 (31.5%) males, and the average age of the patients was 49 years (18-89 years). The average LIFN/(LIFN + LSFN) [length of involving fibular notch/(length of involving fibular + length of stable notch fibular notch)] was 32.9% (11.6-64.9%). The APMF/(APMF + ASTP + AIAIF) [area of posterior malleolar fragment/(area of posterior malleolar fragment + area of IAIF + area of stable tibial plafond)] and AIAIF/APMF (area of IAIF/area of posterior malleolar fragment) were 13.1% (0.8-39.7%) and 52.6% (1.2-235.4%), respectively. Involvement of medial malleolus (fracture line extended to medial malleolus, P = 0.022), involvement of fibular notch (P = 0.021), LIFN/(LIFN + LSFN) (P = 0.037), LMPMF (P = 0.004), and APMF were significantly related to the occurrence of IAIF. CONCLUSION: Our research indicates a high incidence of IAIF in posterior malleolar fractures. All IAIFs were found in posterior malleolar, and the most common location was within the lateral area A. Posterior malleolar fracture lines that extend to medial malleolus or fibular notch herald the incidence of IAIF. LIFN/(LIFN + LSFN), LMPMF and APMF are also associated with the incidence of IAIF. CT scans are useful for posterior malleolar fractures to determine the occurrence of IAIF and make operational plans. Operation approach selection should be based on the morphology of posterior malleolar fragments and the location of IAIF. LEVEL OF EVIDENCE: Level III, retrospective case analysis.

Characteristics and classification of medial malleolar fractures.

AIMS: The morphology of medial malleolar fracture is highly variable and difficult to characterize without 3D reconstruction. There is also no universally accepeted classification system. Thus, we aimed to characterize fracture patterns of the medial malleolus and propose a classification scheme based on 3D CT reconstruction. METHODS: We retrospectively reviewed 537 consecutive cases of ankle fractures involving the medial malleolus treated in our institution. 3D fracture maps were produced by superimposing all the fracture lines onto a standard template. We sliced fracture fragments and the standard template based on selected sagittal and coronal planes to create 2D fracture maps, where angles α and ß were measured. Angles α and ß were defined as the acute angles formed by the fracture line and the horizontal line on the selected planes. RESULTS: A total of 121 ankle fractures were included. We revealed several important fracture features, such as a high correlation between posterior collicular fractures and posteromedial fragments. Moreover, we generalized the fracture geometry into three recurrent patterns on the coronal view of 3D maps (transverse, vertical, and irregular) and five recurrent patterns on the lateral view (transverse, oblique, vertical, Y-shaped, and irregular). According to the fracture geometry on the coronal and lateral view of 3D maps, we subsequently categorized medial malleolar fractures into six types based on the recurrent patterns: anterior collicular fracture (27 type I, 22.3%), posterior collicular fracture (12 type II, 9.9%), concurrent fracture of anterior and posterior colliculus (16 type III, 13.2%), and supra-intercollicular groove fracture (66 type IV, 54.5%). Therewere three variants of type IV fractures: transverse (type IVa), vertical (type IVb), and comminuted fracture (type IVc). The angles α and ß varied accordingly. CONCLUSION: Our findings yield insight into the characteristics and recurrent patterns of medial malleolar fractures. The proposed classification system is helpful in understanding injury mechanisms and guiding diagnosis, as well as surgical strategies. Cite this article: Bone Joint J 2021;103-B(5):931-938.

A clinical nomogram predicting unplanned intensive care unit admission after hip fracture surgery.

BACKGROUND: Despite the improvement of surgical procedures and perioperative management, a portion of patients were still at high risk for intensive care unit admission owing to severe morbidity after hip fracture surgeries. The purpose of this study was to analyze influencing factors and to construct a clinical nomogram to predict unscheduled intensive care unit admission among inpatients after hip fracture surgeries. METHODS: We enrolled a total of 1,234 hip fracture patients, with 40 unplanned intensive care unit admissions, from January 2011 to December 2018. Demographics, chronic coexisting conditions at admission, laboratory tests, and surgical variables were collected and compared between intensive care unit admission and nonadmission groups using univariate analysis. The optimal lasso model was refined to the whole data set, and multivariate logistic regression was used to assign relative weights. A nomogram incorporating these predictors was constructed to visualize these predictors and their corresponding points of the risk for unplanned intensive care unit admission. The model was validated temporally using an independent data set from January 2019 to December 2019 by receiver operating characteristic area under the curve analysis. RESULTS: In the development group, we identified age, chronic heart failure, coronary heart disease, chronic obstructive pulmonary disease, Parkinson disease, and serum albumin and creatinine concentration were associated with unscheduled intensive care unit admission using multivariate analysis. The final model had an area under the curve of 0.854 (95% confidence interval, 0.742-0.966). The median calculated odds ratio of intensive care unit admission based on the nomogram was significantly higher for patients in the intensive care unit admission group than in the non-intensive care unit admission group (65.93% vs 0.02%, P < .01). The validation group proved its high predictive power with an area under the curve of 0.96 (95% confidence interval, 0.91-0.99). CONCLUSION: In this study, we identified several independent factors that may increase the risk for unexpected intensive care unit admission after hip fracture surgery and developed a clinical nomogram based on these variables. Preoperative evaluation using this nomogram might facilitate advanced intensive care unit resource management for high-risk patients whose conditions might easily deteriorate if not closely monitored in general wards after surgeries.

Heparin-induced thrombocytopenia and acute colonic pseudo-obstruction after therapeutic anticoagulation in a very elderly patient with hip fracture: a case report.

BACKGROUND: Hip fractures have become a severe public health problem, especially in very elderly patients. Most of them are treated with low molecular weight heparin as prophylaxis or treatment of venous thromboembolism. Heparin-induced thrombocytopenia is one of the complications induced by low molecular weight heparin, which may cause poor prognosis. However, there is not enough awareness for heparin-induced thrombocytopenia in very elderly trauma patients. CASE PRESENTATION: We report a case of hip fracture with heparin-induced thrombocytopenia in a very elderly patient. The patient developed heparin-induced thrombocytopenia, digestive hemorrhage and acute colonic pseudo-obstruction after the use of low molecular weight heparin, which eventually led to death. CONCLUSIONS: This is the first case report of digestive hemorrhage and acute colonic pseudo-obstruction in heparin-induced thrombocytopenia patients with major trauma. This case highlights the severity of HIT in very elderly patients with hip fractures using low molecular weight heparin, and the need for platelet monitoring in these patients. We indicate that there may be a correlation of pathogenesis between digestive hemorrhage and acute colonic pseudo-obstruction in heparin-induced thrombocytopenia patients.

Multiple retrograde tracing methods compatible with 3DISCO clearing.

Exploring the spatial relationship of various neuron pools in the spinal cord is crucial and difficult due to its complexity. The single-labelling tracing and sectioning were employed in previous studies exploring the distribution of spinal motor neuron pools, which could only delineate one single motor neuron pool in one specimen and could not achieve intact-tissue observation. Here, with combination of neuroanatomy tracing techniques and the optical clearing technique, we developed a multiple retrograde tracing method compatible with 3DISCO clearing. Fluoro-Gold, Fluoro-Ruby, Cholera Toxin Subunit B, Alexa Fluor 488 and 647 Conjugate were injected intramuscularly in hindlimbs of C57BL/6 adults. After labelling, the harvested spinal cords were optically cleared by 3DISCO method and imaged using confocal microscope. There were positive signals of all four tracers and four motor neurons pools targeting injected muscles were labelled. Three-dimension model of four motor neuron pools was successfully reconstructed based on tomography images showing the spatial relationship of different neuron pools. In conclusion, using this method, we first delineated the spatial relationship of four different motor neuron pools targeting four skeletal muscles in one spinal cord at the same time, which provide a holistic view of motor neuron pools in the spinal cord.

Treatment of unstable distal clavicle fractures (Neer type II): A comparison of three internal fixation methods.

OBJECTIVE: This study was performed to compare the clinical efficacy of three internal fixation methods for distal clavicle fractures (Neer type II): clavicular hook plate (Group A), anatomical plate (Group B), and arthroscopic Endobutton (Group C). METHODS: From 2001 to 2014, 58 patients with Neer type II distal clavicle fractures were treated at our institution. The clinical results were assessed with the visual analog scale (VAS), Constant score, and Simple Shoulder Test (SST) score. RESULTS: All patients had anatomic reduction and bone healing at the final follow-up. Groups B and C had considerably less intraoperative blood loss than Group A. The incision was significantly shorter in Group C than in Groups A and B. The mean VAS score was significantly higher in the affected than unaffected shoulder. The Constant and SST scores were significantly higher in the unaffected than affected shoulder. The VAS, Constant, and SST scores of the affected shoulders were not significantly different among the three groups. CONCLUSIONS: Arthroscopic Endobutton fixation has long-term clinical results similar to those of other surgical protocols for distal clavicle fractures (Neer type II). We recommend this technique because of less blood loss, shorter incision length, and less shoulder irritation than other methods.

A Biomechanical Study of an Alternative Internal Fixation Method for Transverse Patella Fractures.

Pain and reoperation after fixation using tension band wiring and K-wires is not uncommon. A novel hook plate was designed to improve the treatment of patella fractures. The aim of this study was to compare the stability of the hook plate with that of tension band wiring and K-wires in a simulated patellar transverse fracture model (AO/OTA classification 34-C1.1). The authors tested 16 embalmed cadaver knee joints fixed with the hook plate and tension band wiring and K-wires under cyclic loading. Specimens underwent 100 cycles extending the knee joint from 90° of flexion to full extension at a velocity of 50 mm/min. The fracture gap was measured after the initial and last cycles. Data were assessed statistically using the t test, with significance set as P<.05. The fatigue test showed that the fracture gap after 100 cycles was 2.97±1.39 mm using tension band wiring and K-wires and 1.53±0.93 mm for the hook plate (P=.029). Six of 8 specimens in the tension band wiring and K-wires group met the failure criterion of fracture gap greater than 2 mm vs 1 in the hook plate group (P=.041). From a biomechanical point of view, the hook plate is a valid alternative to tension band wiring and K-wires for fixing patella transverse fractures. Compared with tension band wiring and K-wires, the hook plate may have superior ability in sustaining a reduced transverse patella fracture. [Orthopedics. 2018; 41(5):e643-e648.].

Human organic anion transporter 2 is an entecavir, but not tenofovir, transporter.

Entecavir (ETV) and tenofovir (TFV) are essential nucleoside analogues in current hepatitis B virus (HBV) treatments. Since these drugs target the HBV polymerase that is localized within human hepatocytes, determining of their cellular uptake process is an important step in fully understanding their pharmacological actions. However, the human hepatic transporters responsible for their uptake have remained unidentified. Therefore, this study aimed at identifying the primary ETV and TFV uptake transporter(s) in human hepatocytes. In transport assays, temperature-sensitive ETV and TFV uptake by human hepatocytes were observed, and their uptake were strongly inhibited by bromosulfophthalein, which is an inhibitor of organic anion transporters/organic anion transporting polypeptides (OATs/OATPs). Given these results, ETV and TFV uptake activities in several human OAT/OATP expression systems were examined. The results showed that, among the transporters tested, only OAT2 possessed ETV transport activity. On the other hand, none of the transporters showed any TFV uptake activity. To summarize, our results identify that human OAT2 is an ETV transporter, thereby suggesting that it plays an important part in the mechanisms underlying ETV antiviral activity. Furthermore, although the hepatic TFV transporters remain unknown, our results have, at least, clarified that these two anti-HBV drugs have different hepatocyte entry routes.

Incidence of venous thromboembolism and hemorrhage related safety studies of preoperative anticoagulation therapy in hip fracture patients undergoing surgical treatment: a case-control study.

BACKGROUND: Venous thromboembolism is a common postoperative complication following orthopedic surgeries, with morbid and potentially fatal consequences. Perioperative low-molecular-weight heparin (LMWH) therapy can reduce the incidence of venous thromboembolism, but may also increase the risk of bleeding complications. Current literature reflects the need to balance the improved efficacy of early initiating prophylaxis with increased risk of perioperative bleeding. The purpose of this study was to compare the effectiveness and hemorrhage related safety of preoperative versus postoperative LMWH therapy for prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE) in hip fracture patients. METHODS: We retrospectively evaluated 222 patients who underwent surgical treatment at Peking University People's Hospital between January 2009 and December 2010. Patients were allocated to two groups, receiving either preoperative or postoperative initiation of LMWH therapy for venous thromboembolism prophylaxis. Preoperative anticoagulation therapy was initiated 1-12 days prior to surgery (133 patients), and postoperative anticoagulation therapy was initiated 12 h after completion of surgery (89 patients). The preoperative group was further subdivided into four subgroups according to the time of initiation of therapy: 1-3 days before surgery (group A, 54 patients), 4-6 days before surgery (group B, 57 patients), 7-9 days before surgery (group C, 15 patients), and 10-12 days before surgery (group D, 7 patients). Occurrences of DVT, PE, adverse drug effects, intraoperative and postoperative bleeding were recorded, along with concentrations of preoperative and postoperative hemoglobin and length of hospital stay. The above parameters were compared between groups. RESULTS: Among recipients of preoperative anticoagulation therapy, two patients developed postoperative PE (1.5 %), one patient developed DVT (0.75 %). In the group receiving postoperative initiation of anticoagulation therapy, one patient each developed PE and DVT (1.1 %, 1.1 %). There was no difference in the occurrence of PE and DVT between the two groups (P>0.05, Chi-square tests). We identified the incidences of major bleeding, minor bleeding, and intraspinal hematoma after spinal anesthesia, which were 0 %/0 %, 3.76 %/3.37 %, and 0 %/0 %, respectively in preoperative and postoperative anticoagulation groups. There was no significant difference in the incidence of bleeding complications between patients receiving preoperatively initiated LMWH with patients receiving postoperatively initiated LMWH. Spinal anesthesia was administered to 168 patients, with no cases of postoperative intraspinal hematoma. CONCLUSIONS: Preoperative anticoagulation therapy with LMWH may not increase intraoperative or postoperative blood loss, or the rate of intraspinal hematoma after spinal anesthesia, but also does not significantly reduce the risk of postoperative DVT or PE, compared to postoperative initiation.

Differential inhibition features of direct-acting anti-hepatitis C virus agents against human organic anion transporting polypeptide 2B1.

Simeprevir (SMV), asunaprevir (ASV), daclatasvir (DCV) and sofosbuvir (SOF), which are direct-acting antiviral (DAA) agents, are expected to become essential pharmaceutical tools in the fight against the hepatitis C virus (HCV). However, because DAAs are taken orally, there is a potential risk of drug-drug interactions (DDIs) at the absorption step with co-administered drugs in the small intestine. Since it is known that organic anion transporting polypeptide 2B1 (OATP2B1) is one of the key transporters contributing to intestinal drug absorption, it is important to thoroughly understand the inhibition profiles of various DAAs in relation to OATP2B1 function in order to avoid unexpected DDIs. Therefore, using a cell-based transport assay, this study aimed at clarifying such DAA inhibition characteristics towards OATP2B1 function. The results of co-incubation inhibition assays showed that SMV and ASV strongly inhibited estrone sulfate (5 nM) uptake by OATP2B1, with half maximal inhibitory concentrations of 0.49 ± 0.12 µM and 0.16 ± 0.06 µM, respectively. Furthermore, it was found that SMV and ASV imposed long-lasting pre-incubation inhibitory effects on OATP2B1 function that enhanced their co-incubation inhibition potencies. On the other hand, no (or much less significant) inhibitory effects were observed for SOF or DCV. To summarise, these results show that SMV and ASV are co-incubation, as well as long-lasting pre-incubation, inhibitors of OATP2B1 function and therefore these inhibitions may lead to clinically relevant DDIs when used with OATP2B1 substrates.

Use of nerve elongator to repair short-distance peripheral nerve defects: a prospective randomized study.

Repair techniques for short-distance peripheral nerve defects, including adjacent joint flexion to reduce the distance between the nerve stump defects, "nerve splint" suturing, and nerve sleeve connection, have some disadvantages. Therefore, we designed a repair technique involving intraoperative tension-free application of a nerve elongator and obtained good outcomes in the repair of short-distance peripheral nerve defects in a previous animal study. The present study compared the clinical outcomes between the use of this nerve elongator and performance of the conventional method in the repair of short-distance transection injuries in human elbows. The 3-, 6-, and 12-month postoperative follow-up results demonstrated that early neurological function recovery was better in the nerve elongation group than in the conventional group, but no significant difference in long-term neurological function recovery was detected between the two groups. In the nerve elongation group, the nerves were sutured without tension, and the duration of postoperative immobilization of the elbow was decreased. Elbow function rehabilitation was significantly better in the nerve elongation group than in the control group. Moreover, there were no security risks. The results of this study confirm that the use of this nerve elongator for repair of short-distance peripheral nerve defects is safe and effective.

Radiological characteristics and anatomical risk factors in the evaluation of hallux valgus in chinese adults.

BACKGROUND: There are no unified theories as to the anatomical changes that occur with hallux valgus, we investigated the radiological characteristics and anatomical risk factors for hallux valgus deformity in Chinese adults. METHODS: We reviewed 141 patients with hallux valgus (206 feet; 15 males, 126 females; mean age, 58.5 years). These patients attended Peking University People's Hospital from April 2008 to March 2014. All feet had intact radiological data, obtained using the Centricity RIS/PACS system. We measured hallux valgus angle (HVA), 1-2 intermetatarsal angle (IMA), proximal articular set angle (PASA), distal articular set angle, hallux interphalangeal angle, metatarsocuneiform angle, size of the medial eminence of the distal first metatarsal, tibial sesamoid position, and joint congruity of the first metatarsophalangeal joint (MTPJ). RESULTS: We found positive correlations between the HVA and IMA (r = 0.279, P < 0.01) and HVA and PASA (r = 0.358, P < 0.01), but not for IMA and PASA (P > 0.05). Feet were divided into three groups based on HVA severity. IMA (P < 0.05) and PASA (P < 0.05) in the mild group were significantly lower than that in the moderate and severe groups, with no significant difference determined for IMA or PASA between the moderate and severe groups (P > 0.05). Feet were then grouped based on the shape of the first metatarsal head. Using this grouping, HVA was significant higher in the rounded shape (19.92°) than in a flat shape (17.66°). The size of the medial eminence of the distal first metatarsal was positively correlated with HVA (r = 0.185, P < 0.01). The medial eminence in the moderate and severe groups was significantly larger than that in the mild group; moderate and severe groups were not significantly different. CONCLUSIONS: PASA enlargement is an adaptive change during early hallux valgus formation, and decompensation leads to subdislocation in the first MTPJ. A rounded first metatarsal head would thus predispose a foot to hallux valgus. Furthermore, bone proliferation at the medial eminence may also lead to early hallux valgus development.