Cartilage progenitor cells derived extracellular vesicles-based cell-free strategy for osteoarthritis treatment by efficient inflammation inhibition and extracellular matrix homeostasis restoration.

Osteoarthritis (OA) is a common degenerative joint disease which currently lacks of effective agents. It is therefore urgent and necessary to seek an effective approach that can inhibit inflammation and promote cartilage matrix homeostasis. Cartilage progenitor cells (CPCs) are identified as a cell population of superficial zone in articular cartilage which possess strong migration ability, proliferative capacity, and chondrogenic potential. Recently, the application of CPCs may represent a novel cell therapy strategy for OA treatment. There is growing evidence that extracellular vesicles (EVs) are primary mediators of the benefits of stem cell-based therapy. In this study, we explored the protective effects of CPCs-derived EVs (CPCs-EVs) on IL-1ß-induced chondrocytes. We found CPCs-EVs exhibited chondro-protective effects in vitro. Furthermore, our study demonstrated that CPCs-EVs promoted matrix anabolism and inhibited inflammatory response at least partially via blocking STAT3 activation. In addition, liquid chromatography-tandem mass spectrometry analysis identified 991 proteins encapsulated in CPCs-EVs. By bioinformatics analysis, we showed that STAT3 regulatory proteins were enriched in CPCs-EVs and could be transported to chondrocytes. To promoting the protective function of CPCs-EVs in vivo, CPCs-EVs were modified with cationic peptide ε-polylysine-polyethylene-distearyl phosphatidylethanolamine (PPD) for surface charge reverse. In posttraumatic OA mice, our results showed PPD modified CPCs-EVs (PPD-EVs) effectively inhibited extracellular matrix catabolism and attenuated cartilage degeneration. Moreover, PPD-EVs down-regulated inflammatory factors expressions and reduced OA-related pain in OA mice. In ex-vivo cultured OA cartilage explants, PPD-EVs successfully promoted matrix anabolism and inhibited inflammation. Collectively, CPCs-EVs-based cell-free therapy is a promising strategy for OA treatment.

Incidence and Characteristics of Knee Ligament and Meniscal Injuries in Patients With Posterolateral Tibial Plateau Fractures.

Background: Anterior cruciate ligament (ACL) tears are commonly seen with concomitant injuries to the posterolateral tibial plateau, while the occurrence of ACL injuries in posterolateral tibial plateau fractures (PTPFs) remains unclear. Purpose: To (1) explore the incidence of knee ligament (anterior or posterior cruciate ligament, medial or lateral collateral ligament) and medial or lateral meniscus injuries in patients with PTPF and (2) find reliable PTPF-related parameters to predict the risk of knee ligament and meniscal injuries. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients diagnosed with PTPF who had computed tomography and magnetic resonance imaging (MRI) data were identified. Morphological parameters of the PTPF were measured on sagittal computed tomography images. Knee ligament and meniscal injuries were assessed using MRI. The association of ACL injuries with meniscal injuries was analyzed. Receiver operating characteristic (ROC) analysis was used to determine the value and cutoff point of the PTPF morphological parameters for diagnosing complete in-substance ACL tears. Results: Overall, 113 patients with PTPF were included. ACL injuries were present in 94 (83.2%) patients, including 43 (38.1%) avulsion fractures and 28 (24.8%) complete in-substance tears. Patients with in-substance ACL tears had a higher incidence of lateral meniscus posterior horn tears compared with the other patients (PBonferroni < .001). ROC analysis revealed that both the fracture depression angle (cutoff point, 25.5°) and the posterior articular surface loss percentage (cutoff point, 37.5%) had a sensitivity >90% and a specificity >80% for the diagnosis of complete in-substance ACL tears. Conclusion: ACL injuries were seen in 83.2% of the study patients. Complete in-substance ACL tears were associated with an increased incidence of lateral meniscus posterior horn tears. Among PTPF parameters, fracture depression angle and posterior articular surface loss percentage showed a high predictive value for the presence of complete in-substance ACL tears, thereby reducing delays in diagnosis and treatment.

Editorial Commentary: High Tibial Osteotomy Lateral Hinge Fracture Is More Common in Patients With Posterolateral Tibial Condylar Protrusion.

The most common adverse event during opening-wedge high tibial osteotomy is lateral hinge fracture. It may be caused by a variety of factors, including an insufficient osteotomy, a large opening gap, an inappropriate hinge position, and early weight bearing with compromised fixation. In addition, particularly in men, posterolateral protrusion of the proximal tibial condyle often results in an insufficient posterior cortical osteotomy owing to surgical overprotection in an effort to avoid popliteal vessel injury. An insufficient posterolateral osteotomy shifts the hinge point posteriorly, resulting in an unstable hinge fracture during opening of the osteotomy wedge, as well as undesirable changes in the mechanical axis. A solution in patients with a large posterolateral proximal tibial condyle could be to shift the osteotomy slightly distally. Surgeons should be mindful of individual proximal tibial morphology in the area of the lateral hinge.

Multi-planar fixation of displaced, multi-fragmentary patella fractures in elderly patients with anterior locking plates and cerclage wires: preliminary results.

PURPOSE: The purpose of this study was to evaluate the outcomes of displaced, multi-fragmentary patella fractures in elderly patients treated with anterior plating and cerclage wires. PATIENTS AND METHODS: Between 2018 and 2020, patients aged at least 60 years old undergoing anterior plating and circumferential wiring for displaced, multi-fragmentary patella fractures with a minimum of 12 months follow-up were included. Fragments were reduced and circumferentially stabilized by loop wires, followed by multi-planar fixation with an anterior locking plate and multi-directional screws. Postoperative outcomes were evaluated with the Böstman scores and range of motion. Patients were also asked about symptomatic hardware as well as satisfaction with postoperative outcomes. RESULTS: Sixteen patients with an average age of 71.8 ± 9.3 years old were followed up for an average follow-up was 25.1 ± 8.2 months. At the latest follow-up, the average Böstman scores were 27.2 ± 3.4, and active knee flexion was 123 ± 14°. Two patients complained pinpoint implant irritation and underwent implant removal. Another underwent implant removal due to cultural reasons. Fifteen patients were satisfied with the operative outcomes, and one was unsatisfied due to intermittent patellofemoral pain. Cerclage wire breakage was noted in nine patients on postoperative radiographs, but none elicited pinpoint pain. No wound complications, infections, nonunion or loss of reduction were observed. CONCLUSIONS: Anterior locking plates and cerclage wires in tandem provide reliable multi-planar fixation for displaced, multi-fragmentary patellar fractures in elderly patients and resulted in favorable clinical outcomes.

A fractional gradient descent algorithm robust to the initial weights of multilayer perceptron.

For multilayer perceptron (MLP), the initial weights will significantly influence its performance. Based on the enhanced fractional derivative extend from convex optimization, this paper proposes a fractional gradient descent (RFGD) algorithm robust to the initial weights of MLP. We analyze the effectiveness of the RFGD algorithm. The convergence of the RFGD algorithm is also analyzed. The computational complexity of the RFGD algorithm is generally larger than that of the gradient descent (GD) algorithm but smaller than that of the Adam, Padam, AdaBelief, and AdaDiff algorithms. Numerical experiments show that the RFGD algorithm has strong robustness to the order of fractional calculus which is the only added parameter compared to the GD algorithm. More importantly, compared to the GD, Adam, Padam, AdaBelief, and AdaDiff algorithms, the experimental results show that the RFGD algorithm has the best robust performance for the initial weights of MLP. Meanwhile, the correctness of the theoretical analysis is verified.

Combined Proximal Tibial Osteotomy for Adult Kashin-Beck Disease with Severe Varus Knee Osteoarthritis: Case Report and Literature Review.

BACKGROUND: Kashin-Beck disease (KBD) is an endemic, chronic osteoarthropathy that seriously affects joint function and can lead to severe knee deformity. Osteotomy is considered to be one of the effective methods for the treatment of this disease. Therefore, we designed a novel type of osteotomy named combined proximal tibial osteotomy (CPTO), which combines the characteristics of opening-wedge high tibial osteotomy and tibial condylar valgus osteotomy. CASE PRESENTATION: We report the case of a 48-year-old male with knee pain and varus deformity who was diagnosed with KBD and varus knee osteoarthritis (Kellgren-Lawrence stage IV). Considering the patient's relatively young age, a varus deformity of the right knee of 16.79°, and an intra-articular instability, we performed a CPTO treatment. In this procedure, we performed an L-shaped osteotomy from the medial edge of the proximal tibia to the intercondylar eminence and an osteotomy from the medial side of the proximal tibia to the lateral side through the same incision, to adjust the leg alignment and the congruity of the joint by valgus correction. At 29 months follow-up, this patient achieved satisfactory results, with a varus right knee of 2.87°. There was significant improvement in his right knee function, pain, and joint stability. CONCLUSIONS: CPTO may be an acceptable treatment for KBD patients with severe knee varus deformity and intra-articular instability. It can be considered as an alternative treatment, especially for patients with advanced osteoarthritis needing knee preservation.

Ability of modern proximal tibial lateral plates to capture posterolateral tibial plateau fracture fragments.

Background: The surgical treatment of posterolateral tibial plateau fractures involves a challenging and diverse set of considerations, one of which is the lack of proper and satisfactory internal fixations to purchase posterolateral fragments. Evaluating the configuration of internal fixations is often overlooked, despite it being important to outcomes of fracture fixation. This study aimed to (I) propose a new digital methodology of internal fixation evaluation that based on actual fracture cases and (II) evaluate the fixation effectiveness of four commercially available proximal tibial lateral plate-screw constructs for posterolateral fragments. Methods: Tibial plateau fractures involving the posterolateral column were retrospectively reviewed. The reconstructed three-dimensional (3D) fracture models were virtually reduced, and targeted internal fixations were modeled digitally in specialized software. Four implants from three manufacturers (DePuy Synthes, Westchester, NY, USA; Zimmer, Warsaw, IN, USA; and Biomet, Warsaw, IN, USA) were placed on each fracture in an optimal position to simulate surgical fixation and quantitatively evaluate fixation effectiveness. The fragment was considered to be "captured" if it was purchased by at least two screws. The 3D fracture maps and heat maps were created by graphically superimposing all uncaptured fracture fragments onto a tibia template. Results: This study included 144 posterolateral tibial plateau fractures. When not using screws in a variable angle (VA) manner, the fixation effectiveness for posterolateral fragments was 58.3% for the DePuy Synthes locking compression plates (LCP), 47.9% for the DePuy Synthes VA-LCP, 50.7% for the Zimmer plate, and 43.8% for the Biomet plate. In contrast, the capturing rates boosted to 76.4% and 71.5% when utilizing VA screws in the DePuy Synthes VA-LCP and the Biomet plate. The high-frequency uncaptured areas tended to concentrate on the rim of the posterolateral wall and were mainly distributed in the posterior 1/2 to 3/4 of the parallel position of the fibula head. Conclusions: The proposed new digital methodology was demonstrated feasible and may improve the quantitative evaluation of the implants and optimize the design of implants. The commercially available proximal tibial lateral plate-screw constructs were insufficient in capturing posterolateral fragments, and design-improved or additional implants may be necessitated.

Three-dimensional computed tomography mapping and analysis of distal femur fractures (AO/OTA types 33A, 33B, and 33C).

Background: Distal femur fractures are complex injuries with a high rate of fracture healing problems. Since the widespread of computed tomographic imaging in the diagnosis of distal femur fractures, many fracture characteristics have been discovered. This study aimed to depict the location and frequency of distal femur fracture lines and further analyze the morphological characteristics using the 3-dimensional computed tomography (CT) mapping technique, thus providing more information to solve this challenging clinical problem. Methods: In total, 217 distal femur fractures in 216 patients were retrospectively reviewed. Fracture fragments on CT were digitally reconstructed and virtually reduced to match a template model. The contour of every fracture fragment was then marked with smooth curves, and the overlap of all fracture lines allowed for the creation of 3-dimensional fracture maps and heat maps. Fracture characteristics were summarized based on these maps. Results: This study included 114 left knee injuries, 101 right knee injuries, and 1 case with bilateral injury. Distal femur fractures were most likely to occur among patients aged 61 to 70 years. On the heat map of all 217 fractures, fracture line hot zones were mainly concentrated around the metaphysis, the lateral part of the intercondylar notch, and the patellofemoral joint. Distal femur fractures with three Arbeitsgemeinschaft für Osteosynthesefragen Foundation/Orthopaedic Trauma Association (AO/OTA) types demonstrated distinct fracture characteristics. In total, there were 58 coronal plane fractures (41.1%) in 141 intercondylar fractures. Conclusions: The intercondylar fracture patterns in AO/OTA type B and type C fractures were similar, while the supracondylar characteristics in AO/OTA type A and type C were different. The findings in this study can help orthopaedic surgeons better understand the fracture morphology on the basis of AO/OTA classification. Further studies are needed to establish a standard biomechanical fracture model and new fixation strategy for better clinical outcomes.

Efficacy of leg swing versus quadriceps strengthening exercise among patients with knee osteoarthritis: study protocol for a randomized controlled trial.

BACKGROUND: Knee osteoarthritis (OA) is a leading cause of global disability. According to current guidelines, exercise is the most recommended and important non-surgical treatment for knee OA. However, the best type of exercise for this condition remains unclear. Evidence has shown that traditional Chinese exercises may be more effective. Therefore, the current prospective, two-armed, single-center randomized controlled trial (RCT) aimed to identify an effective physiotherapy for knee OA. METHODS/DESIGN: In total, 114 patients with painful knee OA will be recruited from the orthopedic outpatient department of Shanghai Jiao Tong University Affiliated Sixth People's Hospital. To compare the therapeutic effect of two different home-based exercise programs, the participants will be randomly assigned into the experimental group (leg swing exercise) or the control group (quadriceps strengthening exercise). Each participant in both groups will be required to attend five individual sessions with a physiotherapist who will teach the exercise program and monitor progress. Participants will be instructed to perform the exercises at home every day for 12 weeks. Clinical outcomes will be assessed at baseline and 12 and 24 weeks after starting the intervention. The primary outcomes are average overall knee pain and physical function in daily life. The secondary outcomes include other measures of knee pain, physical function, patient-perceived satisfactory improvement, health-related quality of life, physical activity and performance, muscle strength of the lower limb, and adherence. DISCUSSION: This study will provide more evidence on the effects of traditional Chinese exercise on improving physical function and relieving joint pain among patients with knee OA. If proven effective, leg swing exercise can be used as a non-surgical treatment for knee OA in the future. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2000039005 . Registered on 13 October 2020.

[Research progress of osteotomy around knee in the treatment of valgus knee osteoarthritis].

OBJECTIVE: To review the research progress of surgical methods of osteotomy around the knee in the treatment of valgus knee osteoarthritis. METHODS: The relevant literature on the surgical treatment of valgus knee osteoarthritis at home and abroad in recent years was reviewed, and the advantages, disadvantages, and effectiveness of different surgical methods of osteotomy around the knee were summarized. RESULTS: For young and active patients with symptomatic valgus knee osteoarthritis, osteotomy around the knee is a safe and reliable treatment option. At present, the main surgical methods include medial closing wedge distal femoral osteotomy, lateral opening wedge distal femoral osteotomy, medial closing wedge high tibial osteotomy, and lateral opening wedge high tibial osteotomy. The indications, advantages, and disadvantages of different osteotomies are different, and the selection of appropriate surgical method is the key to achieve good effectiveness. CONCLUSION: There are many osteotomies in the treatment of valgus knee osteoarthritis. In order to achieve good results, improve survival rate, and reduce postoperative complications, the most reasonable surgical strategy needs to be developed according to different situations.

Three-dimensional fracture mapping of multi-fragmentary patella fractures (AO/OTA 34C3).

BACKGROUND: Multi-fragmentary patella fractures (MFPFs) are common patella fracture type. Low-profile plate fixation seems to be promising advancement in the treatment of such difficult fractures. There is no systematic morphologic study specifically for MFPFs to provide objective reference for the improvement of future implants and biomechanical models. This study aimed to delineate and quantify the location and spatial frequency of fracture lines, comminution zones, and coronal plane fragments in MFPFs using three-dimensional (3D) CT mapping technique. METHODS: A total of 187 MFPFs were retrospectively reviewed and analyzed. Fractures were digitally reconstructed from CT data, and fracture lines, comminution zones, and coronal fragments were graphically overlaid onto a 3D patella template. Fracture characteristics were summarized qualitatively based on the fracture maps and quantitatively on the counts and volume of each fragment. Furthermore, according to the classic fracture patterns concerning MFPFs, subgroup analysis was conducted. RESULTS: On average, we observed 7 fragments in each fracture, 3 of which were <1 cm3. Most fractures (81.2%) had coronal fragments on the anterior and/or posterior patella surfaces. We identified three classic patella fracture patterns: transverse with comminution, stellate, and "displaced comminuted" in 104, 54, and 29 knees, respectively. 3D maps demonstrated distinct distribution fracture patterns of fracture lines, comminution zones, and coronal fragments. CONCLUSIONS: Supero-medial corner of the patella was seldomly involved, and might be used as the cornerstone for fixation. Coronal fragments were common on both anterior and posterior patella surfaces, justifying the application of anterior plate osteosynthesis characterized by multi-planar fixation. Comminution areas mainly concentrated in the lower half of the patella, potentially suitable for an implant in combination with sutures or circumferential cerclage wiring. The described 3D features of MFPFs could provide reference for the design of future implants and biomechanical models.

Reversing the surface charge of MSC-derived small extracellular vesicles by εPL-PEG-DSPE for enhanced osteoarthritis treatment.

Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) possess a great therapeutical potential for osteoarthritis (OA) treatment. However, the steric and electrostatic hindrance of cartilage matrix leads to very limited distribution of MSC-sEVs in cartilage and low bioavailability of MSC-sEVs after intra-articular injection. To overcome this, a strategy to reverse the surface charge of MSC-sEVs by modifying the MSC-sEVs with a novel cationic amphiphilic macromolecule namely ε-polylysine-polyethylene-distearyl phosphatidylethanolamine (PPD) was developed in this study. Through incubation with 100 µg/ml PPD, positively charged MSC-sEVs (PPD-sEVs) were obtained, and the modification process showed nearly no disturbance to the integrity and contents of sEVs and exhibited good stability under the interference of anionic macromolecules. A more effective cellular uptake and homeostasis modulation ability of PPD-sEVs than unmodified MSC-sEVs to chondrocytes was demonstrated. More importantly, PPD-sEVs demonstrated significantly enhanced cartilage uptake, cartilage penetration, and joint retention capacity as compared to MSC-sEVs. Intra-articular injection of PPD-sEVs into a mouse OA model showed significantly improved bioavailability than MSC-sEVs, which resulted in enhanced therapeutic efficacy with reduced injection frequency. In general, this study provides a facile and effective strategy to improve the intra-articular bioavailability of MSC-sEVs and has a great potential to accelerate the clinical practice of MSC-sEVs based OA therapy.

A global neural network learning machine: Coupled integer and fractional calculus operator with an adaptive learning scheme.

Find the global optimal solution of the model is one promising research topic in computational intelligent community. Dependent on analogies to natural processes, the evolutionary swarm intelligent algorithms are widely used for solving global optimization problems which directed by the fitness values. In this paper, we propose one efficient fractional global learning machine (Fragmachine) which includes two stages (descending and ascending) to determine the optimal search path. The neural network model is used to approach the given fitness value. Specifically, for the descending stage, the integer gradient of the network output with respect the current location is employed to find the next descending point, while for the ascending stage, the fractional gradient is implemented to climb and escape from the local optimal point. We further propose one adaptive learning rate during training which relies on both the current gradient (integer or fractional) information and the fitness value. Finally, a series of numerical experiments verify the effectiveness of the proposed algorithm, Fragmachine.

Biomechanical evaluation of different types of lateral hinge fractures in medial opening wedge high tibial osteotomy.

BACKGROUND: Lateral hinge fractures are common complications in the medial opening wedge high tibial osteotomy for treatment of knee osteoarthritis. The rehabilitation protocols are decided depending on the remaining stability following these fractures. This study aimed to evaluate the biomechanical properties of different types of lateral hinge fractures in medial opening wedge high tibial osteotomy. METHODS: Twenty synthetic tibia models were used as test samples. A 10-mm bone wedge was removed from the medial side of the proximal tibias to create the bone defect. The samples were then divided into 4 groups: (1) intact lateral hinge; (2) Takeuchi type I fractures; (3) type II fractures; and (4) type III fractures. After fixation with a locking plate, the stability parameters including construct stiffness, wedge displacement, and construct strength were tested under compressive forces and compared among the 4 groups. FINDINGS: No statistical difference was found in the construct stiffness among the 4 groups (P = 0.78). The type III fractures had the largest wedge displacement compared with the other 3 groups. The failure loads on average were significantly reduced in the type III fractures compared with those with intact hinge (P < 0.01) and in type I fractures (P = 0.04). No statistical difference was observed between the type I fractures and the intact hinge in terms of wedge displacement or failure loads. INTERPRETATION: The type III fractures were the most unstable and patients with these fractures should be managed cautiously. Delayed weightbearing and/or additional fixation should be considered.

An Injectable Fibrin Scaffold Rich in Growth Factors for Skin Repair.

Platelet aggregates, such as PRP, PRF, and CGF, have been used alone or in combination with other grafting materials to enhance restoration outcomes. The process for preparing these autografting materials requires two-step centrifugation or specific centrifuges. In this study, we obtained an injectable fibrin scaffold (IFS) rich in growth factors by one-step centrifugation of whole blood from rabbits. The purpose of this study is to introduce some characteristics of IFS. This scaffold was characterized using various techniques, including Masson's trichrome staining, scanning electron microscopy, porosity measurements, and cell counting. The sustained release of growth factors, including PDGF, VEGF, TGF-ß1, IGF, FGF, and EGF, was quantified using ELISA assay. The obtained IFS was tested for its effects on cell proliferation, extracellular matrix deposition, and full-thickness skin defect repair. The prepared IFS is characterized by a loose fibrin network structure with white blood cells and platelets that slowly release growth factors and can promote the healing of skin defects via the promotion of cell proliferation, collagen deposition, and tissue revascularization. In addition, its liquid properties and porous structure are conducive to its application as a therapeutic component in tissue engineering.

Combined proximal tibial osteotomy for varus osteoarthritis of the knee: Biomechanical tests and finite-element analyses.

BACKGROUND: A special combined proximal tibial osteotomy (CPTO) was designed to correct varus osteoarthritis of the knee with severe intra-articular pathologies, which could not be fully corrected by opening-wedge high tibial osteotomy (OWHTO). The biomechanical strength of the CPTO bone-implant construct was evaluated and compared with those of existing osteotomy methods. METHODS: Three variations of osteotomy including OWHTO, tibial condylar valgus osteotomy (TCVO), and CPTO were performed on synthetic bones with locking plate and screws. Wedge stiffness, wedge displacement, and load failure were measured by biomechanical tests. Three types of numerical tibial models were also constructed by three-dimensional model reconstruction software. The stability parameters of the three variations including wedge stiffness, wedge displacement, and stress distribution were further measured by finite-element analyses. RESULTS: The biomechanical testing results revealed that the wedge stiffness, wedge displacement, and failure load of the CPTO construct were very close to those of the OWHTO construct. The numerical results of wedge stiffness and displacement showed good conformity to the previous biomechanical results. The stress distribution at the lateral hinge, the plate corner, and the holes of the CPTO construct were close to those of the OWHTO counterpart, while the stress distribution at the inter-condylar eminence of the tibia and at the middle region of the screws was close to those of the TCVO counterpart. CONCLUSIONS: The CPTO construct can provide comparable strength for early mobilization and rehabilitation to that of the OWHTO construct.

Comparative Analysis of Mechanism-Associated 3-Dimensional Tibial Plateau Fracture Patterns.

BACKGROUND: The association between tibial plateau fracture morphology and injury force mechanism has not been well described. The aim of this study was to characterize 3-dimensional fracture patterns associated with hypothesized injury force mechanisms. METHODS: Tibial plateau fractures treated in a large trauma center were retrospectively reviewed. Three experienced surgeons divided fractures independently into 6 groups associated with injury force mechanisms proposed from an analysis of computed tomographic (CT) imaging: flexion varus, extension varus, hyperextension varus, flexion valgus, extension valgus, and hyperextension valgus. The fracture lines and comminution zones of each fracture were graphically superimposed onto a 3-dimensional template of the proximal part of the tibia. Fracture characteristics were then summarized on the basis of the fracture maps. The association between injury force mechanism and ligament avulsions was calculated. RESULTS: In total, 353 tibial plateau fractures were included. The flexion varus type pattern was seen in 67 fractures characterized by a primary fracture apex located posteromedially and was frequently associated with concomitant anterior cruciate ligament (ACL) avulsion (44.8%). The extension varus pattern was noted in 60 fractures with a characteristic medial fragment apex at the posteromedial crest or multiple apices symmetrically around the crest and was commonly completely articular in nature (65%). The hyperextension varus pattern was seen in 47 fractures as noted by anteromedial articular impaction, 51% with a fibular avulsion and 60% with posterior tension failure fragments. The flexion valgus pattern was observed in 51 fractures characterized by articular depression posterolaterally, often (58.9%) with severe comminution of the posterolateral cortical rim. The extension valgus patterns in 116 fractures only involved the lateral plateau, with central articular depression and/or a pure split. The hyperextension valgus pattern occurred in 12 fractures denoted by anterolateral articular depression. A moderate positive association was found between flexion varus fractures and ACL avulsions and between hyperextension varus fractures and fibular avulsions. CONCLUSIONS: Tibial plateau fractures demonstrate distinct, mechanism-associated 3-dimensional pattern characteristics. Further research is needed to validate the classification reliability among other surgeons and to determine the potential value in the diagnosis and formulation of surgical protocols.

Learning Optimized Structure of Neural Networks by Hidden Node Pruning With L1 Regularization.

We propose three different methods to determine the optimal number of hidden nodes based on L1 regularization for a multilayer perceptron network. The first two methods, respectively, use a set of multiplier functions and multipliers for the hidden-layer nodes and implement the L1 regularization on those, while the third method equipped with the same multipliers uses a smoothing approximation of the L1 regularization. Each of these methods begins with a given number of hidden nodes, then the network is trained to obtain an optimal architecture discarding redundant hidden nodes using the multiplier functions or multipliers. A simple and generic method, namely, the matrix-based convergence proving method (MCPM), is introduced to prove the weak and strong convergence of the presented smoothing algorithms. The performance of the three pruning methods has been tested on 11 different classification datasets. The results demonstrate the efficient pruning abilities and competitive generalization by the proposed methods. The theoretical results are also validated by the results.

Conservative treatment for clavicle stress fractures following the clavicular hook plate fixation.

We investigated the outcome of conservative treatment and potential causes for clavicle stress fractures following the clavicular hook plate fixation. Six cases of clavicle stress fractures were retrospectively reviewed. All the stress fractures occurred near the medial end of the hook plates. The average interval between the hook plate fixation and the clavicle stress fractures was 28.3 days (range, 18 to 60 days). The mean follow-up was 27 months (range, 15 to 42 months). Fracture union was achieved in all 6 cases. The most proximal screws in the hook plates were found to be eccentric in the clavicular midshaft in 5 cases. At the final follow-up, the average Constant and Murley scores of the operated shoulders were 91.7 (range, 83 to 96). Clavicle stress fractures could be treated conservatively with satisfactory results. Attention should be paid to the position of the most proximal screws in the hook plates.

Medial Open-wedge Osteotomy with Double-plate Fixation for Varus Malunion of the Distal Femur.

OBJECTIVE: To present our clinical experience of treating varus malunion of the distal femur through a medial open-wedge osteotomy with double-plate fixation. METHODS: A prospective cohort study was performed. From January 2005 to February 2015, 15 consecutive patients with varus malunion following distal femur fractures were surgically treated at a single level I trauma center. The coronal and sagittal deformity were corrected by a medial open-wedge osteotomy of the distal femur. A medial buttress plate was used to maintain the realignment. A lateral locking plate was additionally used as a protection plate. The mean age of patients at the time of the surgery was 35.5 years (range, 22-58 years). The radiographical evaluation included the mechanical femorotibial angle, the mechanical lateral distal femoral angle, the anatomic posterior distal femoral angle, and the leg length discrepancy. Clinical outcome evaluation consisted of the range of motion (ROM) and Hospital for Special Surgery (HSS) score. RESULTS: Mean follow-up was 7.4 years (range, 4-11.5 years). Varus and flexion malalignment and limb discrepancy were adequately corrected in all patients. The mechanical femorotibial angle, the mechanical lateral distal femoral angle, and the anatomic posterior distal femoral angle were restored from 17.5° (range, 13°-25°) to 2.3° (range, - 2°-7°), 102.3° (range, 95°-112°) to 85.2° (range, 81°-92°), and 77.1° (range, 65°-87°) to 82.7° (range, 76°-88°), respectively. The leg length discrepancy was diminished from 3.4 cm (range, 2.4-4.5 cm) to 0.8 cm (range, 0-1.7 cm). The average bone healing time was 4.1 months (range, 2.5-6 months). The average ROM of the affected knees at 24-month follow-up was 3.4°-112.55°. The score of HSS at 4-years follow-up was 76.1 (range, 64-88). No internal fixation failure or secondary operation was noted until the last follow-up. CONCLUSION: Medial open-wedge osteotomy can adequately correct the posttraumatic varus malunion of the distal femur. With fixation of the double plate, non-displaced bone healing and good functional outcome are expected.