Robust Proton Conduction against Mechanical Stress in Flexible Free-Standing Membrane Composed of Two-Dimensional Coordination Polymer.

Introduction of mechanical flexibility into proton-conducting coordination polymers (CPs) is in high demand for future protonic applications such as fuel cells and hydrogen sensors. Although such mechanical properties have been primarily investigated in one-dimensional (1D) CPs, in this study, we successfully fabricated highly flexible free-standing CP membranes with a high surface-to-volume ratio, which is beneficial for enhanced performance in the aforementioned applications. We fabricated a layered CP, Cu2 (NiTCPP) (H4 (H2 TCPP); 5,10,15,20-tetrakis(4-carboxyphenyl) porphyrin), in which a two-dimensional (2D) square grid sheet composed of tetradentate nickel porphyrins and paddlewheel-type copper dimers was connected to each other by weak van der Waals forces. The mechanical flexibility was evaluated by bending and tensile tests. The flexural and Young's moduli of the membrane were significantly higher than those of conventional Nafion membranes. Electrochemical impedance spectroscopy analysis revealed that the in-plane proton conductivity of the membrane was maintained even under applied bending stress. Because the X-ray diffraction analysis indicates that the proton-conducting pathway through the hydrogen bonding network remains intact during the bending operation, our present study provides a promising strategy for the fabrication of new and advanced 2D CPs without using substrates or additional polymers for protonic devices.

Power Autonomy and Agility Control of an Untethered Insect-Scale Soft Robot.

It is still challenging to achieve agility and trajectory control for untethered soft robots on an insect scale given their low mechanical impedance and compact structures. In this study, fast translational movements and swift turning motions are demonstrated on a power autonomous soft robot with a piezoelectric-thin-film-actuated body and electrostatic turning footpads. A high relative running speed of 2.5 body length per second compared with existing untethered robots is realized on a 24-mm-long untethered prototype integrated with power source, control, and wireless communication modules. An arc-shaped leg structure is adopted to self-regulate the frication forces on different footpads during turning by an inclination-induced redistribution of the payload gravity on legs and footpads. The trajectory maneuverability is demonstrated by navigating a 380 mg robot prototype with an 1810 mg payload to pass through a 58-cm-long S-shaped path with wireless control in 43.4 s. Due to the flexibility of the all-polymer body structure, the robustness of the untethered robot to large strain is demonstrated when compressed by 91 times the weight of the robot. A maximum travel distance of 58.6 m is achieved for the robot equipped with a 40 mA·h lithium battery, corresponding to the cost of transport of 261. This work provides a feasible solution to achieve high agility and advance the practicability of untethered soft robots on an insect scale.

Complex Three-Dimensional Terrains Traversal of Insect-Scale Soft Robot.

This article proposes a piezoelectric-driven insect-scale soft robot with ring-like curved legs, enabling it to traverse complex three-dimensional (3D) terrain only by body-terrain mechanical action. Relying on the repeated deformation of the main body's n and u shapes, the robot's leg-ground mechanical action produces an "elastic gait" to move. Regarding the detailed design, first, a theoretical curve of the front leg with a fixed angle of attack of 75° is designed by finite element simulation and comparative experiments. It ensures no increase in drag and no decrease in the lift when climbing steps. Second, a ring-like leg structure with 100% closed degree is proposed to ensure a smooth pass through small-sized uneven terrain without getting stuck. Then, the design of the overall asymmetrical structure of the robot can improve the conversion ratio of vibration to forward force. The shape of curved legs is controlled by pulling the flexible leg structure with two metal wires working as spokes. The semirigid leg structure made of fully flexible materials has shape stability and structural robustness. Compared with the plane-legged robot, the curved-legged robot can smoothly traverse different rugged 3D terrains and cross the terrain covering obstacles 0.36 times body height (BH) at a speed of >4 body lengths per second. Moreover, the curved-legged robot shows 100% and 64% chances of climbing steps with 1.2- and 1.9-times BH, respectively.

High-Performance All-Solid-State Proton Rectifier Using a Heterogeneous Membrane Composed of Coordination Polymer and Layered Double Hydroxide.

Rational control of unidirectional proton transport is highly challenging, primarily owing to the difficulty in introducing an asymmetric factor into proton conducting media. In this study, free-standing membranes of a proton-conducting two-dimensional porous coordination polymer, Cu2 (CuTCPP) (H2 TCPP: 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin) and a hydroxide ion-conducting layered double hydroxide, Mg-Al-LDH(NO3 ), were combined to generate a pH gradient in the conducting media. The current-voltage measurements revealed that the heterogeneous membrane exhibits a significant unidirectional proton transport with a proton rectification ratio exceeding 200 under 90 % relative humidity in the initial voltage scan. This value is the highest among the reported all-solid-state proton rectifiers. The high designability of both components with well-defined structures, which is in contrast to the organic polymers used so far, provides a new avenue for developing and understanding the proton-rectifying behavior in the solid state.

Clinical Outcomes of Cannulated Screws versus Ring Pin versus K-Wire with Tension Band Fixation Techniques in the Treatment of Transverse Patellar Fractures: A Case-Control Study with Minimum 2-Year Follow-Up.

Purpose: K-wire with tension band (KTB) technique has long been the primary surgical method for transverse patella fractures; however, it also has shortcomings. This study is aimed at evaluating the three different techniques to see whether the cannulated screw tension band (CSTB) or ring pin tension band (RPTB) techniques could decrease complications and achieve better knee function compared with KTB. Methods: We conducted a retrospective comparison of the KTB, CSTB, and RPTB fixation techniques. We selected and reviewed 90 patients (30 patients in each fixation group) with follow-up at least 2 years. Duration of operation, intraoperative blood loss, mean healing time, visual analog scale score, range of motion, Böstman score, Iowa knee score, modified Lysholm rating scale, and postoperative complications were compared. Multivariate analyses were performed to identify the independent risk factors for fracture healing time, postoperative complications, and knee function recovery. Results: After adjusting for confounding factors, multivariate regression analysis revealed that CSTB was 0.26 times (95% CI: 0.08-0.86, p = 0.027) less likely to prolong fracture healing time, 0.20 times (95% CI: 0.06-0.64, p = 0.007) lesser risk of postoperative complications, and more than four times (95% CI: 1.41-13.56, p = 0.011) as likely to improve the knee function score compared with KTB. Besides, RPTB were also superior to KTB in reducing the incidence of postoperative complications (OR: 0.21, 95% CI: 0.07-0.64, p = 0.006) and improved knee function score (OR: 3.96, 95% CI: 1.30-12.08, p = 0.016); however, the CSTB group being more superior. In addition, AO/OTA C2 fractures (OR, odds ratio: 10.68, 95% CI: 1.30-87.70, p = 0.027) and high-energy fracture (OR: 8.78, 95% CI: 1.57-49.17, p = 0.013) were also associated with prolonged fracture healing time but not with postoperative complications and knee function. No significant differences in related indicators such as gender, age, BMI, AO/OTA classification, fracture side, injury mechanism, duration of operation, and intraoperative blood loss were detected among the three groups. Conclusion: This study demonstrated that the CSTB technique is superior to KTB and RPTB techniques in reducing the incidence of postoperative complications, and it also has advantages in accelerating fracture healing, achieving better VAS, ROM, and functional recovery. Further long-term large-sized prospective randomized trials are needed to evaluate the efficacy of the KTB in treating transverse patellar fractures.

Experimental study of the effects of hypoxia simulator on osteointegration of titanium prosthesis in osteoporotic rats.

BACKGROUND: Poor osseointegration is the key reason for implant failure after arthroplasty,whether under osteoporotic or normal bone conditions. To date, osseointegration remains a major challenge. Recent studies have shown that deferoxamine (DFO) can accelerate osteogenesis by activating the hypoxia signaling pathway. The purpose of this study was to test the following hypothesis: after knee replacement, intra-articular injection of DFO will promote osteogenesis and osseointegration with a 3D printed titanium prosthesis in the bones of osteoporotic rats. MATERIALS AND METHODS: Ninety female Sprague-Dawley rats were used for the experiment. Ten rats were used to confirm the successful establishment of the osteoporosis model: five rats in the sham operation group and five rats in the ovariectomy group. After ovariectomy and knee arthroplasty were performed, the remaining 80 rats were randomly divided into DFO and control groups (n = 40 per group). The two groups were treated by intraarticular injection of DFO and saline respectively. After 2 weeks, polymerase chain reaction (PCR) and immunohistochemistry were used to evaluate the levels of HIF-1a, VEGF, and CD31. HIF-1a and VEGF have been shown to promote angiogenesis and bone regeneration, and CD31 is an important marker of angiogenesis. After 12 weeks, the specimens were examined by micro-computed tomography (micro-CT), biomechanics, and histopathology to evaluate osteogenesis and osseointegration. RESULTS: The results of PCR showed that the mRNA levels of VEGF and CD31 in the DFO group were significantly higher than those in the control group. The immunohistochemistry results indicated that positive cell expression of HIF-1a, VEGF, and CD31 in the DFO group was also higher. Compared with the control group, the micro-CT parameters of BMD, BV/TV, TB. N, and TB. Th were significantly higher. The maximal pull-out force and the bone-to-implant contact value were also higher. CONCLUSIONS: The local administration of DFO, which is used to activate the HIF-1a signaling pathway, can promote osteogenesis and osseointegration with a prosthesis in osteoporotic bone.

Preparation of Amino-Functional UiO-66/PIMs Mixed Matrix Membranes with [bmim][Tf2N] as Regulator for Enhanced Gas Separation.

Development of mixed matrix membranes (MMMs) with excellent permeance and selectivity applied for gas separation has been the focus of world attention. However, preparation of high-quality MMMs still remains a big challenge due to the lack of enough interfacial interaction. Herein, ionic liquid (IL)-modified UiO-66-NH2 filler was first incorporated into microporous organic polymer material (PIM-1) to prepare dense and defect-free mixed matrix membranes via a coating modification and priming technique. IL [bmim][Tf2N] not only improves the hydrophobicity of UiO-66-NH2 and facilitates better dispersion of UiO-66-NH2 nanoparticles into PIM-1 matrix, but also promotes the affinity between MOFs and polymer, sharply reducing interface non-selective defects of MMMs. By using this strategy, we can not only facilely synthesize high-quality MMMs ignoring non-selective interfacial voids, but also structurally regulate MOF nanoparticles in the polymer substrate and greatly improve interface compatibility and stability of MMMs. The method also gives suitable level of generality for fabrication of versatile defect-free MMMs based on different combination of MOFs and PIMs. The prepared UiO-66-NH2@IL/PIM-1 membrane exhibited outstanding gas separation behavior with large CO2 permeation of 8283.4 Barrer and high CO2/N2 selectivity of 22.5.

Anatomical Medial Patellofemoral Ligament Reconstruction for Recurrent Patella Dislocation: Two-Strand Grafts versus Four-Strand Grafts.

The purpose of this study was to describe two anatomical medial patellofemoral ligament (MPFL) reconstruction methods: reconstruction with two-strand grafts and reconstruction with four-strand grafts and to evaluate the clinical and radiological results. From January 2010 to January 2013, patients who sustained recurrent patella dislocation and met inclusion criteria were included in the study and divided into two groups randomly to undergo MPFL reconstruction either by two-strand grafts (T group) or four-strand grafts (F group). Patients were followed up 1 month, 1 year, 2 years, and 3 years postoperatively. The apprehension test was applied to test patella stability. The Kujala score, Lysholm score, and Crosby-Insall grading were used to evaluate the function of the affected knee. The patellar congruence and patellar tilt angle were used to measure the morphology of the patellofemoral joint. In addition, patients' subjective assessments and complications were recorded. Thirty-eight patients in T group and 38 patients in F group were followed for at least 36 months. The apprehension test was positive in all patients preoperatively but was negative at follow-up. The Kujala score, Lysholm score, patellar congruence angle, and the patellar tilt angle of patients in both groups improved significantly at 36-month follow-up when compared with those assessed preoperatively. However, patients in the F group achieved better clinical results in terms of Kujala score, patellar congruence angle, patellar tilt angle, and Crosby-Insall grading when compared with those in the T group 3 years after the operation. Most patients (92% of patients in the T group and 97% of patients in the F group) were satisfied with the surgery. The anatomical MPFL reconstruction with two-strand grafts or four-strand grafts were both safe techniques for recurrent patella dislocation with satisfactory clinical outcomes. The anatomical fixation with four-strand grafts achieved better clinical and radiographic results in the follow-up, which may be a better reconstruction method.

Changes in cartilage and subchondral bone in a growing rabbit experimental model of developmental trochlear dysplasia of the knee.

Purpose: Trochlear dysplasia is one of the most frequent lower extremities deformities. Aim of this research was to investigate the changes in cartilage and subchondral bone of trochlea after patellar dislocation in growing rabbits. Materials and Methods: Ninety-six knees from 48 one-month-old rabbits were divided into two groups (experimental, control). Lateral patellar dislocation was established in the experimental group and distal femurs were collected at 4, 8, 12 and 24-week time points, respectively. General examination and histological observations were conducted to research the anatomical structure of the trochlear cartilage and subchondral bone. Structural parameters of trochlear subchondral bone were measured by MicroCT. Subsequently, the expression of TRPV4, collagen II and MMP-13 in cartilage were detected by western blot and RT-PCR analysis, respectively.Results: Subchondral bone loss was found in experimental group from 4 weeks after patellar dislocation, accompanied by increased TRAP-positive osteoclasts in subchondral bone. The trochlear dysplasia model was well established from 8 weeks after patellar dislocation. In addition, degeneration of cartilage was found from 8 weeks, accompanied by decreased expression of mechanically sensitive TRPV4 and collagen II, and increased expression of MMP-13.Conclusions: This study proved that trochlear dysplasia can be caused by patellar dislocation in growing rabbits, accompanied by significant subchondral bone loss. What is more, this study also shows that degenerative cartilage changes occur in the patellar dislocation model and become aggravated with time, accompanied by decreased TRPV4 and collagen II, but increased MMP-13.

Attentional bias effect on post-traumatic outcomes in children after earthquake: Mediation role of rumination.

After traumatic events, children with different types of attentional biases produce different psychological reactions with the help of the rumination process. A sample of 909 middle school students was taken from the Yunnan Ludian earthquake-affected area. Measurement scales of the Chinese version of the Attention to Positive and Negative Information Scale (APNI), the Chinese version of the Children's Revised Impact of Event Scale (CRIES), and the Revised Post-traumatic Growth Inventory for Children (PTG-C) were used to assess the attentional bias, risk of post-traumatic stress disorder (PTSD), and post-traumatic growth (PTG), respectively. The effect of self-reported attention bias was explored by using a structural equation model and bias-corrected bootstrap test on children's psychological reaction after trauma. The results show that there is a positive relationship between self-reported negative attentional bias and PTSD symptoms partially mediated by intrusive rumination and the negative relationship between self-reported positive attentional bias and PTSD symptoms. On the other hand, the relationship between self-reported positive attentional bias and PTG was positive and partially mediated by deliberate rumination. Furthermore, intrusive rumination did not affect PTG indirectly but mediated the relation of deliberate rumination.

The effect of increased femoral anteversion on the morphological and trabecular microarchitectural changes in the trochlea in an immature rabbit.

Increased femoral anteversion (FA) has been recently demonstrated as one risk factor for recurrent patellar dislocation (RPD). However, it has been still unclear whether the increase of FA can result in patellar dislocation, and subsequent morphological and trabecular microarchitectural changes in the trochlea has not been investigated. Forty knees from 20 rabbits at 3 months of age were included. The right knees underwent surgery with internal rotation of distal femur to increase FA, with the left knees acting as internal controls. The surgical knees were called operated group, and non-operated knees were control group. Micro-CT scans for distal femur were acquired after 4 months of surgery. In the operated group, a boss located proximal to the entrance of the groove was formed. The central trochlear height was significantly greater, sulcus angle was significantly greater, both lateral and medial trochlear slope were significantly lower, and boss height was significantly greater in comparison to the control group. Regarding the microarchitectural changes, the trabecular thickness were increased by 67.5% at the groove, 33.0% and 29.5%, at the medial and lateral femoral condyle, and trabecular number were decreased by 37.8% and 26.5% at the groove and medial femoral condyle. This study provided a novel animal model of trochlea dysplasia by femoral rotational osteotomy and increased FA. These changes were associated with the load redistribution in the patellofemoral joint after the increase of FA.

Changes in Cartilage and Subchondral Bone of Femoral Trochlear Groove After Patellectomy in Growing Rabbits.

OBJECTIVE: To explore the effects of patellectomy on the bony and cartilaginous morphology of the trochlear groove in growing rabbits. METHODS: Forty-eight 4-week-old New Zealand white rabbits were randomly assigned to two groups. The control group underwent a sham surgical procedure, whereas the patellectomy group underwent patella excision surgery. Half of the rabbits in each group were sacrificed 3 months postoperatively; the rest were sacrificed 6 months postoperatively. Hematoxylin and eosin staining was performed on collected samples. Measurements included the bony and cartilaginous sulcus angles of the trochlear groove. In addition, the thickness of the articular cartilage at the deepest sulcus position (central thickness) and at the mid-position of the medial and lateral facets was measured and compared between groups. RESULTS: Three months after surgery, histological images revealed significant differences between the control group and the patellectomy group in cartilaginous sulcus angle (144.2° ± 1.5° vs 151.9° ± 2.4°, respectively; P < 0.001). No obvious difference in bony sulcus angle was found between the groups. Six months after surgery, significant between-group differences were observed in cartilaginous sulcus angle (136.3° ± 2.5° in control group vs 160.7° ± 3.0° in patellectomy group, P < 0.001) and bony sulcus angle (136.2° ± 2.2° in control group vs 160.4° ± 2.6° in patellectomy group, P < 0.001). However, there were no significant intra-group differences between cartilaginous and bony sulcus angles in either group. Three months after surgery, significant between-group differences were detected in articular cartilage thickness at the three different positions (medial facet: 324.3 ± 14.0 µm in control group vs 391.7 ± 98.8 µm in patellectomy group, P = 0.029; central position: 362.1 ± 13.6 µm in control group vs 730.3 ± 76.8 µm in patellectomy group, P < 0.001; lateral facet: 324.6 ± 12.7 µm in control group vs 358.5 ± 38.7 µm in patellectomy group, P = 0.009). No between-group differences in cartilage thickness were found at 6 months. CONCLUSIONS: Abnormal mechanical stress (patellectomy) during a rabbit's development can cause flattening of the femoral trochlear cartilage, followed by changes in the subchondral osseous layer. Abnormal mechanical stress is a crucial factor in the development of trochlear groove dysplasia.

Joint Awareness after Unicompartmental Knee Arthroplasty Evaluated with the Forgotten Joint Score.

OBJECTIVE: To investigate the temporal relationship of medial unicompartmental knee arthroplasty (UKA) and forgotten joint score (FJS), and to analysis the predictive factors associated with FJS after medial UKA. METHODS: This is a cross-sectional observational study. A total of 188 cases of medial UKA were included in this study, and all the prostheses used were Oxford mobile-bearing UKA from January 2016 to January 2019. All patients have completed the questionnaire of FJS, and the relevant data were obtained for 1 month (n = 38), 6 month (n = 40), 12 month (n = 42), 24 month (n = 34), and 36 month (n = 34) patient subgroups. The score ranged from 0-100, with a higher score indicating a more natural knee joint. In addition, the associations between the potential influencing factors (body mass index [BMI], age, gender, duration of onset before surgery, Kellgren-Lawrence grade of the medial compartment before surgery) with FJS were analyzed using Pearson correlation and multiple linear regression. RESULTS: Postoperative FJSs were 44.5 ± 13.5 at 1 month，63.8 ± 10.1 at 6 months, 77.1 ± 12.2 at 12 months, 78.4 ± 12.2 at 24 months, 78.9 ± 12.5 at 36 months. The postoperative FJSs were lowest at 1 month and highest at 36 month (P < 0.01). The mean value of FJS kept improving until 12 months post-operation, which was slightly lower than that of 24 months and 36 months, but there was no statistical difference between them. Pearson correlation and multiple linear regression analysis showed that gender and Kellgren-Lawrence grade of the medial compartment before surgery had no significant influence on FJS, while age, BMI, and duration of onset before surgery had significant associations with FJS after UKA. BMI was negatively correlated with FJS, while older patients (>60) and with longer duration of onset before surgery (>3 years) were a positive predictor of good outcome for the FJS. CONCLUSION: Patients can expect marked improvement in the natural feel of the prosthesis during the first year after UKA, slight continued improvement at 2 and 3 years. Furthermore, we identified three preoperative patient-related factors (age, BMI, and duration of onset before surgery) that may predict the FJS after medial UKA, which can be used to guide surgical decision making.

Combined medial and lateral patellar retinaculum plasty for skeletally immature patients with patellar dislocation and low-grade trochlear dysplasia.

BACKGROUND: To evaluate the clinical outcomes of combined medial and lateral patellar retinaculum plasty for skeletally immature patients with patellar dislocation and low-grade trochlear dysplasia. METHODS: From December 2014 to December 2016, we reviewed 19 skeletally immature patients who underwent medial and lateral patellar retinaculum plasty at our institution. Clinical evaluations were performed pre- and postoperatively, and included determination of the number of patellar re-dislocation patients, the Kujala and Tegner scores, the patellar tilt angle, lateral patellar shift, and congruence angle. The radiographic evaluation parameters were measured on computed tomography scans. RESULTS: No dislocation or subluxation occurred during the mean follow-up of 35.42 months (24-48 months). Postoperatively, the Kujala score improved from 57.6 ±â€¯4.2 to 86.9 ±â€¯8.1 (P < 0.05), and the Tegner activity score improved from 2.6 ±â€¯1.0 to 5.0 ±â€¯1.3 (P < 0.05). Radiographically, the patellar tilt angle decreased from 32.7 ±â€¯5.9° to 13.4 ±â€¯4.28° (P < 0.05), the lateral patellar shift decreased from 15.9 ±â€¯1.1 mm to 8.4 ±â€¯0.6 mm (P < 0.05), and the congruence angle decreased from 29.9 ±â€¯15.3° to -9.6 ±â€¯15.5° (P < 0.05). CONCLUSIONS: Medial and lateral patellar retinaculum plasty is a promising procedure that has the advantage of being a simple operation that induces little trauma. It is a good treatment option for skeletally immature patients with patellar dislocation who have low-grade trochlear dysplasia.

The dysplastic trochlear sulcus due to the insufficient patellar stress in growing rats.

BACKGROUND: Developmental factors were assumed to be the key factors that influenced the morphology of femoral trochlea. This study investigated the effects of insufficient patellar stress after birth on the morphological development of the femoral trochlea. Effects of insufficient patellar stress on femoral trochlea were investigated using surgical induced patellectomy and patellar dislocation in growing rat model. METHODS: In this study, two experimental groups and one sham group (SG) were established. Thirty-six Wistar rats (female, 28 days of age) were randomly assigned to three groups. The patellectomy group (PG), rats underwent the patellectomy in this group. The dislocation group (DG), rats underwent the surgery-induced patellar dislocation. Histological staining (Safranin-O and fast green), Micro-computed tomographic (Micro-CT) analysis in two experimental endpoints (3, 12 weeks postoperatively) were selected to evaluate morphological changes of the femoral trochlea. RESULTS: Articular cartilage on the trochlear sulcus was remodeled at 3 weeks after the surgery, and degenerated at 12 weeks through the histological staining. The femoral trochlear angle (FTA) did not show a significant difference at 3 week between the experimental groups and the sham group (PG vs SG P = 0.38, DG vs SG p = 0.05), but the FTA was significantly increased in experimental groups at 12 weeks(PG vs SG P = 0.001, DG vs SG p = 0.005). The Bone volume density (BV/TV), Trabecular number (Tb.N) under the trochlea groove were significantly reduced at 3 weeks postoperatively in the experimental groups (PG vs SG p = 0.001, DG vs SG p = 0.002). No significant difference was found in BV/TV and Tb. N among the three groups at 12 weeks postoperatively. CONCLUSION: Surgical induced patellectomy and patellar dislocation leads to the dysplastic trochlear sulcus in growing rats. Besides the bone morphology of trochlear sulcus, the articular cartilage and subchondral trabecula under the trochlear sulcus were remodeled early stage after the surgery.

Functional Regions of the Medial Patellofemoral Ligament.

The purpose of this study was to explore the anatomy and discuss functional regions of the medial patellofemoral ligament (MPFL). Twelve fresh-frozen knees specimens were dissected. All medial surfaces of knees were intact and did not have indication of injury. General feature of the MPFL were observed. All anatomical landmarks were carefully identified and marked. The length of the two functional regions were conducted and recorded. All data were obtained, described, and analyzed in the form of mean ± standard deviation. The MPFL was found in all specimens we dissected. Closed to the patellar insertion, it adheres to the deep surface of the vastus medialis obliquus (VMO). Due to the VMO, the MPFL is divided into two functional regions: overlap region and nonoverlap region. Anatomically, the overlap region and nonoverlap region of 25.43 ± 2.0 and 44.85 ± 3.04 mm, the width of VMO insertion is 13.94 ± 2.03 mm, and the width of patellar insertion is 22.91 ± 3.46 mm. We divide the MPFL into two anatomical functional regions, demarcated by the meshing points of fibers between the MPFL and VMO: overlap region and nonoverlap region. This finding provides the theoretical foundation for the treatment of the MPFL injury and shed lights on the future researches.

Clinical Outcomes of Closing- and Opening-Wedge High Tibial Osteotomy for Treatment of Anteromedial Unicompartmental Knee Osteoarthritis.

This article compares the long-term outcomes of closing-wedge osteotomy (CWO) and opening-wedge osteotomy (OWO) in the treatment of unicompartmental medial osteoarthritis with varus deformity. This study included 79 patients who underwent high tibial osteotomy (HTO) between 2002 and 2008. Pre- and postoperative radiography and computed tomography were used to evaluate the posterior tibial slope, the patellar height, the tibiofemoral angle, and the lateral and medial tibiofemoral joint space. Pre- and postoperative severity of arthritis was assessed with the Kellgren-Lawrence grading system. Pre- and postoperative American Knee Society (AKS) score and Lysholm Knee Score (LKS) were determined to evaluate functional outcomes. The duration of follow-up was 86.1 ± 6.2 months. Postoperatively, at the most recent follow-up, there was a slight increase in the size of the medial tibiofemoral joint space after CWO and OWO, which reflected a decrease in stress on the medial compartment and manifested as a significant improvement in the AKS knee and function scores and the LKS. OWO increased the posterior tibial slope as compared with the preoperative value, while CWO reduced the posterior tibial slope. CWO and OWO for HTO resulted in similar functional outcomes. OWO was associated with patella infera and more severe patellofemoral arthritis, while CWO was associated with a greater severity of lateral tibiofemoral arthritis.

Single- and double-bundle medial patellofemoral ligament reconstruction procedures result in similar recurrent dislocation rates and improvements in knee function: a systematic review.

PURPOSE: To evaluate medial patellofemoral ligament (MPFL) reconstruction using hamstring tendon autografts using single-bundle (SB) and double-bundle (DB) techniques, and compare the clinical outcomes including the Kujala score, postoperative apprehension, recurrent subluxation or dislocation, and complications. METHODS: The PubMed, Embase, and Cochrane Library databases were searched for relevant literature using the terms ''medial patellofemoral ligament'' and ''MPFL''. The pooled mean values of improvement in the Kujala score were calculated by random effects meta-analysis. Unweighted estimates for the rates of postoperative apprehension, recurrent subluxation or dislocation, and complications were determined by dividing the total number of occurrences by the total number of knees. RESULTS: Thirty-one articles were included, involving 1063 patients (1116 knees). Two hundred and forty-four patients (254 knees) underwent SB reconstruction, while 819 patients (862 knees) underwent DB reconstruction. The pooled mean values of Kujala score improvement were similar in the SB group (30.1; 95% CI 26.6-33.6) and DB group (30.7; 95% CI 27.7-33.7). The SB group had a significantly greater rate of postoperative apprehension (7.9%) than the DB group (4.1%; P = 0.014). There were no significant differences between the two groups in the rates of recurrent subluxation or dislocation (1.2 and 1.6%) and complications (10.6 and 7.7%). CONCLUSION: With variability in patient populations and surgical techniques, the DB procedure for isolated MPFL reconstruction demonstrates similar outcomes to the SB technique regarding improvement of knee function, recurrent subluxation or dislocation, and complications. The SB technique may have a greater risk of postoperative apprehension, whereas the DB technique may cause more stiffness. LEVEL OF EVIDENCE: IV.

[Effect of CDK Inhibitor LS-007 on Acute Lymphoblastic Leukemia and Its Mechanism].

OBJECTIVE: To study the effect of cyclin dependent kinase(CDK) inhibitor LS-007 on acute lymphoblastic leukemia and its mechanism. METHODS: The acute lymphocytic leukemia cell line was cultured and treated by LS-007, flavopiridol and ABT-199, then the changes of apoptosis-related factor mRNA and protein levels were detected by using mRNA quantitative PCR and Werstern blot. RESULTS: quantitative PCR and Western blot detection showed that the levels of antiapoptotic protein decreased significantly in acute lymphoblastic leukemia cells after LS-007 treatment, and the pro-apoptotic effect of LS-007 combined with ABT-199 was much better. CONCLUSION: LS-007 can affect the phosphorylation of RNA polymerase sites and promote cell apoptosis through changing the activities of CDK, thus having some positive significance for relieving acute lymphoblastic leukemia.

Better 4-year outcomes for anterior cruciate ligament reconstruction with double-layer versus single-layer bone-patellar tendon-bone allografts.

PURPOSE: To evaluate the results of anterior cruciate ligament reconstruction using a double-layer bone-patellar tendon-bone (DBPTB) graft. METHODS: Between 2010 and 2011, 98 patients underwent anterior cruciate ligament reconstruction with an allograft. Forty-seven of these patients received a DBPTB allograft and 51 received a traditional monolayer BPTB graft. Outcomes were evaluated at the end of a minimum 4-year follow-up in both groups using KT 1000 arthrometer measurements, Lachman and pivot-shift tests, the International Knee Documentation Committee form, and Lysholm scores. RESULTS: One patient (1/47, 2 %) in the DBPTB allograft group and six patients (6/51, 12 %) in the traditional monolayer BPTB graft were lost during follow-up because of graft rupture (n.s.). The mean side-to-side differences in the DBPTB and monolayer BPTB graft groups 4 years post-operatively were significantly different at 1.4 ± 1.3 and 1.7 ± 1.6 mm, respectively (p < 0.05). The DBPTB group performed significantly better than the BPTB group on the Lachman test, International Knee Documentation Committee knee score, and Lysholm scores (p < 0.05). CONCLUSIONS: The DBPTB allograft group achieved better outcomes than the traditional BPTB allograft group regarding success rate, anterior stability, and knee function. LEVEL OF EVIDENCE: Level II.