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Background The purpose of the present study was to measure the intraoperative joint gap using tensor device and pre- and, postoperative joint stability at 0, 30 and 90° of flexion using stress radiography and to identify whether these factors influence patient-reported outcome measurement (PROM) in anatomical bi-cruciate retaining (BCR) knee arthroplasty (TKA). Methods Fifty-three knees with preoperative varus osteoarthritis of the knee underwent anatomical BCR TKA with oblique 3° angle femorotibial joint line. The intraoperative medial and lateral joint gap using a tensor device and gap difference (lateral minus medial; varus laxity) were also calculated. Postoperative joint stability was measured using stress radiographs. PROM was also evaluated at 1.5 years postoperatively. The effect of intraoperative and postoperative joint stabilities on PROMs were analyzed using Spearman’s rank correlation analysis. Results Intraoperative greater difference between medial joint gap at 140° and 0° of flexion showed significant positive correlation with postoperative function of patellofemoral joint. Intraoperative varus laxity at extension improved postoperative symptoms in 2011 Knee Society Score (2011 KSS); greater postoperative lateral stability at 30 and 90° of flexion with the varus stress test was associated with the better patient expectation in 2011 KSS. Postoperative medial laxity at 90° of flexion with the valgus stress test positively correlated with the patient expectation and satisfaction in 2011 KSS. Conclusion Surgeons should notice that the postoperative lateral stability and medial laxity at 90° of flexion improved PROM in anatomical BCR TKA.

Background The purpose of the present study was to measure the intraoperative joint gap using tensor device and pre- and, postoperative joint stability at 0, 30 and 90° of flexion using stress radiography and to identify whether these factors influence patient-reported outcome measurement (PROM) in anatomical bi-cruciate retaining (BCR) knee arthroplasty (TKA). Methods Fifty-three knees with preoperative varus osteoarthritis of the knee underwent anatomical BCR TKA with oblique three-degree angle femorotibial joint line. The intraoperative medial and lateral joint gap using a tensor device and gap difference (lateral minus medial; varus laxity) were also calculated. Postoperative joint stability was measured using stress radiographs. PROM was also evaluated at 1.5 years postoperatively. The effect of intraoperative and postoperative joint stabilities on PROMs were analyzed using Spearman's rank correlation analysis. Results Intraoperative greater difference between medial joint gap at 140° and 0° of flexion showed significant positive correlation with postoperative function of patellofemoral joint. Intraoperative varus laxity at extension improved postoperative symptoms in 2011 Knee Society Score (2011 KSS); greater postoperative lateral stability at 30 and 90° of flexion with the varus stress test was associated with the better patient expectation in 2011 KSS. Postoperative medial laxity at 90° of flexion with the valgus stress test positively correlated with the patient expectation and satisfaction in 2011 KSS. Conclusions Surgeons should notice that the postoperative lateral stability and medial laxity at 90° of flexion improved PROM in anatomical BCR TKA.

Background: Hamstring tendon graft diameters < 8 mm are considered a risk factor for graft failure. There is a lack of data regarding the prediction of double-bundle (DB) hamstring graft diameter using magnetic resonance imaging (MRI). This study aimed to evaluate whether preoperative MRI can be a predictor of DB hamstring graft diameter and to determine the minimum hamstring tendon cross-sectional area (CSA) on MRI required to produce a hamstring graft equivalent to 8 mm of a single-bundle (SB) graft, in the case of a DB graft.Methods: A retrospective study was performed on patients who underwent anterior cruciate ligament (ACL) reconstruction between 2017 and 2020. The inclusion criteria were (1) patients aged 20 years or older and (2) operation with DB reconstruction. The exclusion criteria were (1) multiple ligament injuries, (2) previous hamstring injury, and (3) patients who underwent revision surgery. The correlation between preoperative MRI CSA and anthropometric data and graft size was calculated, and the factors most associated with graft size were calculated using multiple regression analysis. The receiver operating characteristic (ROC) curve was also used to calculate the threshold for creating a thicker DB graft.Results: Based on the inclusion and exclusion criteria, we selected 69 patients for this study. There was a positive correlation between intra-operative graft size and height (r = 0.590, P < 0.001), weight (r = 0.485, P < 0.001) and preoperative MRI semitendinosus tendon + gracilis tendon CSA (r = 0.591, P < 0.001). Multiple regression analysis showed that preoperative MRI CSA was the most influential factor on intra-operative graft size (β = 0.366, 95% CI 0.237-0.946, P = 0.001). Based on the ROC analysis, the optimal cut-off value of MRI CSA for determining the CSA of DB graft corresponding to an SB diameter of 8 mm was 19.1 mm2 (sensitivity 96.3%, specificity 80.0%).Conclusions: MRI CSA was found to be the most relevant factor for graft size. The ability to predict graft diameter by preoperative MRI is beneficial for surgical planning and graft selection and may reduce the risk of failure.Level of Evidence: Level IV, case series

Porous tantalum tibial component is durable with excellent bone ingrowth, higher knee scores, and long-term survivorship. However, to our knowledge, the effect of posterior cruciate-retaining (CR) and posterior cruciate-substituting (PS) porous tantalum tibial component has not been reported. The aim of the current study was to investigate the prosthetic bone quality between CR porous tantalum tibial component and PS using three-dimensional multi-detector-row computed tomography (3D-MDCT). Porous twenty-two (22) CR total knee arthroplasties and 22 PS received 3D-MDCT at every 6 months up to 5.5 years postoperatively to assess prosthetic bone quality (bone marrow contents/tissue volumes [BMC/TV, mg/cm3]) underneath the pegs of porous tantalum modular tibial component. Clinical outcomes (Knee Society score [KSS], Western Ontario and McMaster Universities (WOMAC), FJS-12, Patella score) were evaluated at a minimum follow-up period of 5.5 years. No statistically significant differences were found in age, gender, body mass index, KSS, and BMC/TV volumes in the proximal tibia between the two groups before total knee arthroplasty (TKA). There were also no significant differences between the CR and PS groups with regard to BMC/TV at every 6 months up to 5.5 years after TKA. At 5.5 years postoperatively, there was no significant difference between the two groups in terms of the KSS, WOMAC, forgotten joint score (FJS-12), and Patella score. The present study revealed that the prosthetic bone quality of the CR porous tantalum tibial component and PS were equivalent at every 6 months up to 5.5 years after TKA. This study reflects level II evidence.

Purpose Numerous surgical techniques and fixation methods have been described in medial patellofemoral ligament (MPFL) reconstruction such as choice of graft, graft fixation method of patella/femur and initial tension. We describe short term clinical results of MPFL reconstruction by using soft suture anchor and adjustable cortical fixation system. Methods Twenty-four patients who underwent isolated MPFL reconstruction by using soft suture anchor and adjustable cortical fixation system were included in this study. All patients were followed up for at least 2 years, and pre-operative and 2 years post-operative Kujala score, IKDC score and Knee Injury and Osteoarthritis Outcome Score were used to assess clinical outcome. Radiographic evaluation included the Q angle, congruence angle and patellar tilt angle. Pre- and post-operative changes were evaluated by Mann–Whitney U test. Results There were no complications including re-dislocation, patella fracture, infection, and joint contracture. The apprehension test was positive in 4.2% post-operatively. A statistically significant improvement in clinical scores and radiographic evaluation were evident after surgery. Conclusions Isolated MPFL Reconstruction using soft suture anchor and adjustable cortical fixation system led good restoration of patellar stability and significant improvement of knee function in short-term results. This surgical technique can reduce complications such as patella fractures, and can be done safely. Clinical relevance This technique may be a treatment option with little associated complications in the treatment for patellar instability. Level of Evidence Case series, Level IV.

The purpose of this study was to perform medial meniscus (MM) centralization for medial meniscus extrusion (MME) associated with medial meniscus posterior root tear (MMPRT) and to examine the short-term results. The hypothesis is that arthroscopic centralization as an augmentation of MMPRT repair improves clinical outcomes and the extrusion distance of MM in short-term results. Twenty-six patients (mean age 62.1 ± 6.0 years) who underwent arthroscopic centralization as an augmentation of MMPRT repair were included. Clinical evaluation was performed before and 2 years after surgery using Lysholm score and knee injury and osteoarthritis outcome score (KOOS). Image evaluation used MRI and plain X-ray images. The extrusion distance and MME ratio were compared on MRI images before and 2 years after surgery. The degree of osteoarthritis (OA) was evaluated using Kellgren–Lawrence classification. The degree of OA and hip–knee–ankle (HKA) angle were compared by plane X-ray images before and 2 years after surgery. In clinical results, both Lysholm score and KOOS improved significantly after surgery. In image evaluation, the extrusion distance decreased significantly from 4.8 ± 0.7 mm before surgery to 2.7 ± 0.3 mm 2 years after surgery (p

Objective: Insall advocated that a successful clinical outcome of total knee arthroplasty (TKA) depends on soft tissue balance procedure. Spacer blocks, balancer, and instrumented tibial sensor (VERESENSE, OrthoSensor, Dania, Florida, USA) are the current methods of soft tissue balancing during TKA. The purpose of the study is to assess intraoperative medial and lateral tibiofemoral compressive force (TFCF) using novel insert sensor and investigate the relationship between TFCF and patient-reported outcome measurements (PROMs). Methods: Twenty-five patients who underwent bicruciate stabilized (BCS) TKA were evaluated retrospectively. We measured intraoperative medial and lateral TFCF in neutral position as well as the force ratio (FR %:medial TFCF/medial + lateral TFCF) in varus and valgus position using the novel insert sensor throughout the range of motion (ROM) and assessed the relationship between intraoperative medial and lateral TFCF and PROM at 6 months after TKA. Results: Medial TFCF increased and lateral TFCF decreased throughout ROM. The mean FR was 0.44% ± 0.22 throughout ROM. Medial and lateral TFCF differences at 60° of ROM in neutral position showed a positive correlation with physical function in Western Ontario and McMaster Universities scores ( r = 0.60, p < 0.05). Medial and lateral TFCF differences at 30° and 140° of ROM in valgus stress test showed a positive correlation with symptoms in 2011 Knee Society Scores ( r = 0.49, p < 0.05; r = 0.51, p < 0.05). Conclusion: The present study revealed that BCS TKA reproduces the coronal laxity, which is similar to healthy knee. These results suggest that intraoperative medial stability is important for function and symptoms, therefore, surgeons should not release medial soft tissue for achieving better clinical outcomes after BCS TKA. Level of Evidence: II

BACKGROUND: Although many studies have evaluated the success of porous tantalum component in primary and revision cementless total knee arthroplasty (TKA) cases, few studies have reported the breakage of porous tantalum monoblock patella component (PTMP). The purpose of this study was to investigate the radiographic outcomes of breakage of PTMP at short-term follow up. METHODS: This was a retrospective study of 49 consecutive knees in 43 patients who underwent TKA surgery between September 2012 and March 2014. Bone marrow contents/tissue volumes (BMC/TV. mg/cm(3)) were evaluated using 2-dimensional osteomorphometry software with 2D- multi-detector-row computed tomography (2D-MDCT) to measure fixation of the bone-prosthesis interface with patella at 6, 12, and 24 months after surgery. Clinical follow up was obtained by reviewing each patient at orthopedic record. RESULTS: We experienced a case that resulted in breakage of PTMP without traumatic episode at 26 months after surgery. Relative changes of Bone Mineral Contents per Tissue Volume. (BMC/TV mg/cm(3)) at ROI. 1 (superior border of the patella) and ROI. 2 (peg of patella) were significantly higher than ROI.3 (inferior border of patella) at 6, 12 and 24 months after surgery (p

The quadrant method was described by Bernard et al. and it has been widely used for postoperative evaluation of anterior cruciate ligament (ACL) reconstruction. The purpose of this research is to further develop the quadrant method measuring four points, which we named four-point quadrant method, and to compare with the quadrant method. Three-dimensional computed tomography (3D-CT) analyses were performed in 25 patients who underwent double-bundle ACL reconstruction using the outside-in technique. The four points in this study’s quadrant method were defined as point1—highest, point2—deepest, point3—lowest, and point4—shallowest, in femoral tunnel position. Value of depth and height in each point was measured. Antero-medial (AM) tunnel is (depth1, height2) and postero-lateral (PL) tunnel is (depth3, height4) in this four-point quadrant method. The 3D-CT images were evaluated independently by 2 orthopaedic surgeons. A second measurement was performed by both observers after a 4-week interval. Intra- and inter-observer reliability was calculated by means of intra-class correlation coefficient (ICC). Also, the accuracy of the method was evaluated against the quadrant method. Intra-observer reliability was almost perfect for both AM and PL tunnel (ICC > 0.81). Inter-observer reliability of AM tunnel was substantial (ICC > 0.61) and that of PL tunnel was almost perfect (ICC > 0.81). The AM tunnel position was 0.13% deep, 0.58% high and PL tunnel position was 0.01% shallow, 0.13% low compared to quadrant method. The four-point quadrant method was found to have high intra- and inter-observer reliability and accuracy. This method can evaluate the tunnel position regardless of the shape and morphology of the bone tunnel aperture for use of comparison and can provide measurement that can be compared with various reconstruction methods. The four-point quadrant method of this study is considered to have clinical relevance in that it is a detailed and accurate tool for evaluating femoral tunnel position after ACL reconstruction. Case series, Level IV.

Mechanically planar chiral [2]rotaxanes were synthesized by the introduction of bulky pyrrole moieties into the axle component of an achiral [2]rotaxane. The enantiomers were separated by chiral HPLC. The shuttling of the ring component between the two compartments at high temperature induced the stereoinversion of the mechanically planar chiral [2]rotaxane. The rate of the stereoinversion was studied quantitatively, and the kinetic parameters were determined.

Appropriate medio-lateral (ML) stability is an important factor of good clinical outcome following total knee arthroplasty (TKA). We hypothesized that a newly introduced Bi-Cruciate Stabilized substituting (BCS) prosthesis reduces the medio-lateral instability in mid-flexion range. The purpose of this study was to measure the ML stability (varus ligament balance) using a new tensor device after implantation of BCS TKA and to analysis the association between varus ligament balance and clinical results after TKA.We evaluated 33 patients who underwent 39 Journey. 2. BCS TKA using the measured resection technique. We measured the gaps after implantation from extension to full flexion with reduced patella by constant distraction force with 120N. The varus ligament balance gap was defined as the gap calculated by subtracting from Lateral to medial component gap. The clinical results at 2years after operation was compared with intraoperative varus ligament balance.Varus ligament balance showed its maximum gap at full knee extension and 120° flexion. Varus ligament balance at 30°, 60° and 90° of flexion were significant differences in the varus ligament balance at full extension. (* p 0.05). The varus ligament balance gap was negatively corrected with postoperative 2011 Knee society score (patient's satisfaction) (r = 0.661, p = 0.001).The most important findings of the present study are that BCS TKA can reduces the ML instability in mid-flexion range, and improve simultaneously the patient's satisfaction.Therapeutic study, Level III.

Heterogeneously integrated nanomaterial devices show interesting characteristics for transistors and sensors due to their band diagram or steep material junctions. If these junctions and band alignments can be tuned by an electrical input bias, the device platform not only could be expanded but also could be used to explore fundamental characteristics. However, most reports on hetero-nanomaterial junctions use a global back-gate voltage, which makes it difficult to control band alignment at an interface. To explore device junctions, this study reports a laterally integrated heterojunction of graphene and a carbon nanotube (CNT) network film with individual gate electrodes to tune the band alignment corresponding to the Fermi level shift of graphene in contact with the semiconducting CNT network film. By developing the fabrication process, multiple gate structures are designed to apply a gate bias to CNTs and graphene separately. The threshold voltage shift of the CNT transistor depends on the gate voltage of graphene. Based on the thermionic emission theory, the barrier height between graphene and CNTs for both the conduction and valence band sides varies from 70 to 85 meV, with a linear change as a function of the applied gate voltage to graphene. Although the current Fermi level shift is small, this device platform may realize the exploration of fundamental properties and device concepts.

The purpose of the present study was described as the arthroscopically assisted procedure that uses a synthetic conoid ligament reconstruction using Zip Tight (Zimmer biomet, Warsaw, USA) and fracture-site fixation with K-wire. Our hypothesis was that this technique provided a satisfactory functional outcome with minimum complication. 45 patients underwent operation to treat fractures of the distal clavicle between January 2014 and May 2017. The inclusion criteria were as follows: (1) there is an episode of trauma and it is the first fracture (2) distal clavicle fracture of Neer type IIb with dislocation in image findings. The exclusion criteria were as follows: (1) Neer type I, IIa and III of distal clavicle fracture (2) existing injury of rotator cuff, biceps tendon and labral during the arthroscopic procedure. Based on these criteria, 23 patients were included in this study. Clinical outcome assessments were performed using 1-year postoperative Quick DASH score, Constant–Murley score, ASES score. Radiological outcome consisted of antero-posterior and axillary radiographs. Mean clinical outcomes were as follows: Quick DASH score was 3.8 ± 2.8, ASES score was 92.3 ± 3.2 and Constant–Murley score was 94.1 ± 3.0. It was a highly satisfactory result in all of the score at 1-year follow-up. All patients had achieved radiographic union at a minimum 1-year follow-up. There were no cases of nonunion or osteolysis. This study demonstrated that the arthroscopy-assisted treatment using Zip Tight and K-wire provided a satisfactory functional outcome with minimum complication with Neer type IIb fractures of the distal clavicle. IV, Case series, Treatment study.

AimsPatellofemoral problems are a common complication of total knee arthroplasty. A high compressive force across the patellofemoral joint may affect patient-reported outcome. However, the relationship between patient-reported outcome and the intraoperative patellofemoral contact force has not been investigated. The purpose of this study was to determine whether or not a high intraoperative patellofemoral compressive force affects patient-reported outcome.Patients and MethodsThis prospective study included 42 patients (42 knees) with varus-type osteoarthritis who underwent a bi-cruciate stabilized total knee arthroplasty and in whom the planned alignment was confirmed on 3D CT. Of the 42 patients, 36 were women and six were men. Their mean age was 72.3 years (61 to 87) and their mean body mass index (BMI) was 24.4 kg/m2(18.2 to 34.3). After implantation of the femoral and tibial components, the compressive force across the patellofemoral joint was measured at 10°, 30°, 60°, 90°, 120°, and 140° of flexion using a load cell (Kyowa Electronic Instruments Co., Ltd., Tokyo, Japan) manufactured in the same shape as the patellar implant. Multiple regression analyses were conducted to investigate the relationship between intraoperative patellofemoral compressive force and patient-reported outcome two years after implantation.ResultsNo patient had anterior knee pain after total knee arthroplasty. The compressive force across the patellofemoral joint at 140°of flexion was negatively correlated with patient satisfaction (R2= 0.458; β = –0.706; p = 0. 041) and Forgotten Joint Score-12 (FJS-12; R2= .378; β = –0.636; p = 0. 036). The compressive force across the patellofemoral joint at 60° of flexion was negatively correlated with the patella score (R2= 0.417; β = –0.688; p = 0. 046).ConclusionPatient satisfaction, FJS-12, and patella score were affected by the patellofemoral compressive force at 60° and 140° of flexion. Reduction of the patellofemoral compressive forces at 60° and 140° of flexion angle during total knee arthroplasty may improve patient-reported outcome, but has no effect on anterior knee pain.

Atomically thin 2-dimensional (2D) mechanical resonators are expected to be highly sensitive force sensor and high performance nano-electro-mechanical systems because of their excellent electrical and mechanical properties. For practical application, the stability of their resonance frequencies against the temperature is very crucial. Here, we demonstrate the manipulation of thermal expansion coefficients (TECs) by making van der Waals heterojunction, graphene and MoS2, which have opposite signs of TECs. The apparent TEC of the 2D heterojunction is greatly suppressed to 1/3 of monolayer graphene without the limitation of tunability of the resonance frequency by application of electrostatic attraction., Comment: 17 pages including 4 figures

This study asked whether differences in coronal alignment after total knee arthroplasty (TKA) affect the load distribution on the tibial plateau. The aim of this study was to investigate the correlation between coronal alignment and the load distribution on the tibial plateau after TKA, using three-dimensional multi-detector-row-computed tomography (3D-MDCT). In this study, we performed 84 cementless TKA with porous tantalum modular tibial component (PTMT) and divided into three groups based on post-operative hip–knee–ankle (HKA) angle: varus alignment group (n = 22), (176° ≧) neutral alignment group (n = 45), (180° ± 3°), and valgus alignment group (n = 17) (184° ≦).The changes in bone quality parameters of trabecular patterns under peg of PTMT were interpreted as load distribution due to changes in alignment. The relationship between HKA angle and load distribution on the tibial plateau was analyzed every 6 months for 4.5 years by measuring Bone marrow contents/tissue volumes (mg/cm3) and bone volumes/tissue volumes (%) under peg of porous tantalum modular tibial component by visualizing three dimensionally with 3D-osteo-morphometry software. There were no correlations between HKA angle and the load distribution on the tibial plateau after TKA at all periods. There was a significantly higher increase in the medial region than the lateral about the BMC/TV and BV/TV values, regardless of the post-operative alignment after TKA for all periods. The relative BMC/TV and BV/TV changes at medial region in varus alignment group were significantly lower than the neutral and the valgus alignment groups of pre-operative medial osteoarthritis of the knee. As far, it can be concluded by the study and the methods used therein that there were no relationships between the load distribution on the tibial plateau and HKA angle after TKA. Therapeutic study, Level III.

The pH effect on the carrier transport of conducting polymer PEDOT:PSS has been studied by terahertz and infrared-visible spectroscopy. The neutralization of conducting polymer poly (3, 4 ethylenedioxythiophene):poly (stylene sulfonate) (PEDOT:PSS) decreased the carrier concentration and mobility, which lowered the electrical conductivity of PEDOT:PSS by five orders of magnitude with increasing pH from 1.7 to 11.7.

An elastic property of biological soft tissue is an important indicator of the tissue status. Therefore, quantitative and noninvasive methods for elasticity evaluation have been proposed. Our group previously proposed a method using acoustic radiation pressure irradiated from two directions for elastic property evaluation, in which by measuring the propagation velocity of the shear wave generated by the acoustic radiation pressure inside the object, the elastic properties of the object were successfully evaluated. In the present study, we visualized the propagation of the shear wave in a three-dimensional space by the synchronization of signals received at various probe positions. The proposed method succeeded in visualizing the shear wave propagation clearly in the three-dimensional space of 35 × 41 × 4 mm3. These results show the high potential of the proposed method to estimate the elastic properties of the object in the three-dimensional space.

An effective one-pot method for the title compounds (III) and (VII) is presented from the easily available alcohols (I).

Single-walled carbon nanotube (SWCNT) field-effect transistors (FETs) were fabricated on strontium titanate (SrTiO3) substrate through a wet-process by using amide-functionalized SWCNT. The SWCNT-FET exhibited good gate-modulation for drain current at low operating voltages (-3 V). The hole mobility was 0.19 cm2/Vs with an on/ off current ratio of 1.3. After immobilization of prostate-specific-antigen (PSA) antibody the SWCNT-FET clearly responded against the PSA. The drain current at -3 V of both drain and gate voltage almost linearly increased with increasing the concentration of the PSA.

Formation characteristics of propane hydrate using fiber layer were investigated experimentally. Water and propane gas contact in the fiber layer, and the propane gas hydrate can be formed continuously. In the experiment, pressure, temperature, the quantity of water and porosity of the fiber layer were varied as the experimental parameters, and the formation ratio and the formation rate were measured. As a result, it was found that the high formation ratio can be obtained by using the fiber layer. Therefore, it can be said that this method is useful to reduce energy consumption and to simplify the apparatus, since it does not need circulation system. Moreover, it was found that the formation rate increases with the subcooling and the quantity of water, and it is slightly affected by the porosity of the fiber layer.