Quadriceps Tendon With Bone Autograft Has Better Stability and Magnetic Resonance Imaging Maturation Than Hamstring Tendon Autograft After Anterior Cruciate Ligament Reconstruction in Patients With Knee Hyperextension.

PURPOSE: To compare the clinical outcomes of anterior cruciate ligament (ACL) reconstruction between methods using quadriceps tendon with bone (QTB) and hamstring tendon (HT) in patients with hyperextension of the knee. METHODS: The medical records of patients with knee hyperextension greater than 8° who underwent arthroscopic ACL reconstruction between October 2010 and October 2020 with follow-up for at least 2 years (median, 3 years; interquartile range [IQR], 2.0-4.6 years) were retrospectively reviewed. Side-to-side difference in anterior translation, pivot-shift test grade, Lysholm score, and graft intensity using the Howell grade on magnetic resonance imaging at final follow-up were compared between the QTB and HT groups. RESULTS: The HT and QTB groups consisted of 42 patients and 21 patients, respectively. The overall mean age was 21.5 years (range, 14-48 years), and the median Tegner Activity Scale score was 6 (range, 3-9). Postoperatively, the median side-to-side difference in anterior translation was 1.75 mm (IQR, 1-3 mm) in the HT group and 1.0 mm (IQR, 0-1.75 mm) in the QTB group (P = .01). Pivot-shift testing showed grade 0 in 74.7%, grade 1 in 18.7%, and grade 2 in 6.6% of patients in the HT group and grade 0 in 85.7% and grade 1 in 14.3% of those in the QTB group (P = .03). The median postoperative Lysholm score was 99 in both groups. Graft signal intensity showed a significant between-group difference: grade I in 52%, grade II in 36%, and grade III in 12% of patients in the HT group versus grade I in 85.7%, grade II in 9.5%, and grade III in 4.8% of those in the QTB group (P = .03). CONCLUSIONS: In patients who underwent ACL reconstruction for hyperextension of the knee, QTB yielded better clinical outcomes than HT with respect to anterior stability, rotational stability, and graft signal intensity on median 2-year follow-up magnetic resonance imaging. LEVEL OF EVIDENCE: Level III, retrospective case-control study.

Male elite soccer players have a higher incidence of accessory ossicles in the foot and ankle.

PURPOSE: Accessory ossicles are caused by the failure of the fusion of secondary ossification centres and are more likely to occur due to heavy loading during the growth period or improper treatment after injury. This study aimed to investigate the incidence of foot and ankle accessory ossicles in male professional soccer players. METHODS: This study included male professional soccer players who underwent medical checkups at our hospital between 2017 and 2023 as the soccer group. Medical checkups included radiographs of bilateral anteroposterior and oblique foot, as well as bilateral anteroposterior and lateral ankle. Male patients age-matched with the soccer group who visited our hospital undergoing anteroposterior and oblique foot or anteroposterior and lateral ankle radiography were included in the control group. The incidence of accessory ossicles was investigated and compared between the soccer and control groups. RESULTS: In this study, 276 ankles and 276 feet, as well as 121 ankles and 79 feet, were included in the soccer and control groups, respectively. The incidence of accessory ossicles in the soccer and control groups was as follows: accessory navicular 35.9%, 24% (P = .049), os peroneum 8.0%, 2.5% (P = .09); os supranaviculare 7.6%, 1.3% (P = .039); os infranaviculare 1.4%, 1.3% (P = .090); os calcaneus secundarius 4.3%, 0% (P = .059); os vesalianum 0%, 0%; os subfiblare 12.7%, 2.5% (P < .001); os subtibiale 18.1%, 2.5% (P = .001); and os trigonum 89%, 24% (P < .001). CONCLUSIONS: Male professional soccer players had a higher incidence of accessory navicular, os supranaviculare, os subfiblare, os subtibiale, and os trigonum.

Age-based comparison of meniscal dimensions between an asymptomatic complete discoid lateral meniscus and normal meniscus: MRI evaluation.

INTRODUCTION: This study aimed to evaluate the meniscal size of asymptomatic discoid lateral meniscus (DLM) and compare it with that of normal lateral meniscus (LM) and to compare changes in meniscal dimensions with age among patients with asymptomatic DLM and those with normal LM using magnetic resonance imaging (MRI). MATERIALS AND METHODS: We retrospectively reviewed the medical records, including MRI data, of patients with asymptomatic DLM (DLM group) or normal LM (control group). Width and extrusion of both DLM and normal LM and tibial length were measured and compared using mid-coronal and mid-sagittal MR images. Meniscal size and sagittal and coronal meniscal ratio according to age, as well as differences between DLM and normal menisci, were also evaluated. RESULTS: Thirty-four knees were included in the DLM group, whereas the control group comprised of 50 patients. The DLM group showed significantly less meniscal extrusion, greater coronal width, posterior capsule distance, sagittal meniscal length, and sagittal meniscal ratio than the control group (DLM: 0.1 ± 0.3 mm, 23.3 ± 2.2 mm, 5.4 ± 2.4 mm, 25.1 ± 2.8 mm, 61 ± 6%, and control: 0.4 ± 0.4 mm, 9.5 ± 2.3 mm, 2.5 ± 1.2 mm, 30.2 ± 2.6 mm, 71 ± 4%, respectively). The coronal meniscal ratio decreased with age in both the control (p = 0.001) and DLM (p = 0.037) groups. The sagittal meniscal ratio (p = 0.001) and minimum height (p = 0.04) decreased and the anterior capsule distance (p = 0.035), posterior capsule distance (p = 0.026), and entire sagittal length (p = 0.005) increased with age in the DLM group, while the distance between the meniscal inner margins (p = 0.019) increased with age in the control group. CONCLUSIONS: The meniscal ratio in the sagittal plane of the DLM group was significantly lower than that of the control group. The sagittal meniscal ratio of asymptomatic DLM decreased with age, indicating that the size of asymptomatic DLM does not change with age. LEVEL OF EVIDENCE: III: Retrospective comparative study.

Bone Marrow-Derived Fibrin Clots Stimulate Healing of a Knee Meniscal Defect in a Rabbit Model.

PURPOSE: To determine the in vivo effectiveness of bone marrow aspirate-derived (BMA) fibrin clots for avascular meniscal defect healing in a rabbit model. METHODS: In 42 Japanese white rabbits, a 2.0-mm cylindrical defect was introduced into the avascular zone of the anterior part of the medial meniscus in the bilateral knees. The rabbits were grouped according to implantation of a BMA fibrin clot (BMA group) or a peripheral blood (PB)-derived clot (PB group) into the defect and nonimplantation (control group). Macroscopic and histological assessments were performed using a scoring system at 4 and 12 weeks after surgery. At 12 weeks after surgery, compressive stress was analyzed biomechanically. RESULTS: The meniscal score in the BMA group (12.1) was greater than that in the PB group (5.5; P = .031) and control group (4.4; P = .013) at 4 weeks. The meniscal score in the BMA group (13.1) was greater than that in the control group (6.4; BMA = 13.1; P = .0046) at 12 weeks. In the biomechanical analysis, the BMA group demonstrated significantly higher compressive strength than the PB group (6.6 MPa) (BMA = 15.4 MPa; P = .0201) and control group (3.6 MPa; BMA = 15.4 MPa; P = .007). CONCLUSIONS: Implantation of BMA fibrin clots into the meniscal defect of the avascular zone in a rabbit model improved the meniscal score at 4 weeks and strengthened the reparative meniscal tissue at 12 weeks compared with the implantation of PB fibrin clots. CLINICAL RELEVANCE: Healing in the avascular zone of the meniscus can be problematic. Approaches to improving this healing response have had variable results. This study provides additional information that may help improve the outcomes in patients with these injuries.

Comparative analysis of discoid lateral meniscus size: a distinction between symptomatic and asymptomatic cases.

PURPOSE: This study evaluated the differences in meniscal sizes and occupancy between symptomatic and asymptomatic patients diagnosed with discoid lateral meniscus (DLM) using magnetic resonance imaging (MRI) to understand how these variations relate to the presence of symptoms and the patients' age. METHODS: A retrospective review of 98 patients with DLM was conducted, excluding those with meniscal displacement. Both the width and extrusion of DLM and the percentage of the meniscus to the tibia were measured using mid-coronal and mid-sagittal MRI and compared between symptomatic and asymptomatic DLM groups. The relationships among each parameter, meniscal size, and patient age were evaluated. Symptomatic cases were divided into those with and without horizontal tears on MRI to compare the differences in meniscal morphology. RESULTS: A total of 92 knees from 74 patients were included. Sixty-one knees required surgical intervention for symptomatic DLM, while 31 were asymptomatic and included the contralateral side of symptomatic knees. The symptomatic group exhibited larger morphological variations than the asymptomatic group. Moreover, the sagittal meniscal ratio reduced with age in the asymptomatic group (r = - 0.54, p = 0.002) but remained constant in the symptomatic group. The symptomatic cases with horizontal tears demonstrated larger meniscal dimensions and smaller posterior capsule distances than those without tears. CONCLUSION: Symptomatic patients with DLM had larger knee morphological changes than asymptomatic ones. Age affected the meniscal occupancy in the sagittal plane only in asymptomatic patients. LEVEL OF EVIDENCE: III.

Intrameniscal degeneration and meniscotibial ligament loosening are associated factors with meniscal extrusion of symptomatic discoid lateral meniscus.

PURPOSE: This study aimed to compare the amount of extrusion of the discoid lateral meniscus (DLM), which was symptomatic and required surgery, with normal meniscuses and asymptomatic DLMs and examine factors associated with the extrusion of symptomatic DLM. METHODS: Medical records of participants with DLM or normal lateral meniscus (LM) were retrospectively reviewed using magnetic resonance imaging (MRI). DLM cases were divided into symptomatic and asymptomatic groups. The midbody meniscal extrusion was measured using mid-coronal MRI. The association between meniscal extrusion and MRI findings, including the meniscofemoral ligament, meniscotibial ligament (MTL), intrameniscal signal intensity of the peripheral rim, meniscal shift, and skeletal maturity, was evaluated. RESULTS: Eighty-six knees with DLM (63 symptomatic) were included. The control group included 31 patients. The symptomatic group showed significantly greater meniscal extrusion (mean ± standard deviation symptomatic DLM: 1.0 ± 1.1 mm, asymptomatic DLM: 0.1 ± 0.4 mm, and normal LM: 0.3 ± 0.6 mm, P < 0.001) and had a significantly higher incidence of MTL loosening (P = 0.02) and intrameniscal signal (P < 0.001) than the other two groups. In the symptomatic group, multivariable linear regression analysis showed that MTL loosening [ß = 1.45, 95% confidence interval (CI) 1.03-1.86, P < 0.001] and intrameniscal signal (ß = 0.49, 95% CI 0.09-0.90, P = 0.002) were independent associated factors. CONCLUSIONS: LM extrusion was significantly more common in patients with symptomatic DLM than in those with asymptomatic DLM or a normal LM. MTL loosening and intrameniscal high-signal intensity on MRI were independently associated with meniscal extrusion. These findings help explain the pathogenesis and diagnosis of symptomatic DLM. LEVEL OF EVIDENCE: III.

Evaluation of the knee joint morphology associated with a complete discoid lateral meniscus, as a function of skeletal maturity, using magnetic resonance imaging.

INTRODUCTION: A discoid lateral meniscus (DLM) is associated with increased risk for meniscal tears and progression of knee joint osteoarthritis. Our aim was to differentiate knee joint morphology between patients with and without a DLM, as a function of skeletal maturity, using magnetic (MR) imaging. MATERIALS AND METHODS: This was a retrospective analysis of MR images of the knee for 110 patients, 6-49 years of age. Of these, 62 were in the open physis group (38 with a DLM) and 48 in the closed physis group (23 with a DLM). The following morphological parameters were measured: anterior obliquity of the lateral tibial plateau (AOLTP), posterior obliquity of the lateral tibial plateau (POLTP), the lowest point of the lateral femoral condyle (LPLFC), and the posterior lateral condylar angle (PLCA). RESULTS: Regardless of skeletal maturity, a DLM was associated with a greater inclination of the POLTP, lateralization of the LPLFC, and smaller PLCA (p < 0.001 for all compared to that of the control group). In the DLM group, the inclination of the AOLTP and the POLTP were significantly smaller (p < 0.001) and the LPLFC was more lateral (p < 0.001) in the closed physis group than in the open physis group. In the control group, the inclination of the POLTP was larger (p < 0.001) and the PLCA smaller (p = 0.019) in the open than in the closed physis group. CONCLUSIONS: We identified a characteristic knee morphology among patients with a complete DLM using MR imaging, which was observed before physeal closure and persisted after skeletal maturity was attained. We also noted lateralization of the LPLFC in the presence of a DLM, with an increase in lateralization with skeletal maturation. LEVEL OF EVIDENCE: Case-control study, III.

Saucerization of complete discoid lateral meniscus is associated with change of morphology of the lateral femoral condyle and tibial plateau.

PURPOSE: To determine the effect of saucerization surgery on knee joint morphology associated with a complete discoid lateral meniscus (DLM) using magnetic resonance (MR) imaging. METHODS: This retrospective study included cases had undergone saucerization surgery for symptomatic DLM between 2007 and 2022. All cases were divided into two by age group: < 12 (U13) and > 13 (O13). The cases in the match group were randomly selected from preoperative cases in the O13 group matched with the age at the final follow-up (F/U) of cases in the U13 group. The following morphological parameters were evaluated using MR images preoperatively and at the final postoperative F/U in each group: anterior obliquity of the lateral tibial plateau (AOLTP), posterior obliquity of the lateral tibial plateau (POLTP), and the lowest point of the lateral femoral condyle (LPLFC). Each parameter was compared between the U13 preoperative (pre-OP) group and the O13 pre-OP group, the preoperative and final follow-up in the U13, and the U13 group at the final F/U and the match group preoperatively. RESULTS: A total of 77 cases were evaluated. 31 cases were in the U13 pre-OP group and 46 were in the O13 pre-OP group. With a minimal F/U of 2 years, 27 cases in the U13 group and 36 in the O13 group were included. The mean F/U period was 4.6 years in the U13 group and 3.2 years in the O13 group. 32 cases were included in the match group. In the match group, the inclination of the POLTP was significantly larger (P = 0.042) and the LPLFC was more lateral (P = 0.0034) than at the final F/U in the U13 group. CONCLUSIONS: Saucerization surgery for DLM in juvenile patients can prevent progression to the characteristic bone morphology DLM. These results could help the surgeon making the decision when the surgery would be performed for symptomatic DLM patients. LEVEL OF EVIDENCE: Retrospective comparative study; level of evidence, 3.

Room-Temperature Reversible Chemisorption of Carbon Monoxide on Nickel(0) Complexes.

Chemisorption on organometallic-based adsorbents is crucial for the controlled separation and long-term storage of gaseous molecules. The formation of covalent bonds between the metal centers in the adsorbents and the targeted gases affects the desorption efficiency, especially when the oxidation state of the metal is low. Herein, we report a pressure-responsive nickel(0)-based system that is able to reversibly chemisorb carbon monoxide (CO) at room temperature. The use of N-heterocyclic carbene ligands with hemi-labile N-phosphine oxide substituents facilitates both the adsorption and desorption of CO on nickel(0) via ligand substitution. Ionic liquids were used as the reaction medium to enhance the desorption rate and establish a reusable system. These results showcase a way for the sustainable chemisorption of CO using a zero-valent transition-metal complex.

Autologous Platelet-Rich Fibrin Membrane to Augment Healing of Microfracture Has Better Macroscopic and Histologic Grades Compared With Microfracture Alone on Chondral Defects in a Rabbit Model.

PURPOSE: To determine the in vivo effectiveness of a single-stage surgical procedure that combines microfracture and an autologous platelet-rich fibrin (PRF) membrane for cartilage repair in a rabbit model. METHODS: Cartilage defects were created in the trochlear groove of the knees of adult white rabbits. Defects were divided into 2 treatment groups: microfracture only (control group) and microfracture covered by a PRF membrane (PRF group). To evaluate the repair cartilage, assessments were performed at 4, 12, and 24 weeks postoperatively using the International Cartilage Repair Society (ICRS) macroscopic scoring system and modified Wakitani histologic grading system. RESULTS: The mean ICRS macroscopic scores in the control and PRF groups were 4.1 and 5.8, respectively, at 4 weeks (P = .0623); 6.3 and 9.8, respectively, at 12 weeks (P = .006); and 6.5 and 10.3, respectively, at 24 weeks (P = .010). The mean modified Wakitani scores in the control and PRF groups were 4.0 and 3.9, respectively, at 4 weeks (P > .999); 5.3 and 10.4, respectively, at 12 weeks (P = .006); and 2.6 and 7.4, respectively, at 24 weeks (P = .012). CONCLUSIONS: The ICRS macroscopic scores and modified Wakitani scores showed that a single-stage surgical procedure combining microfracture and a PRF membrane was more effective than surgery with only microfracture for promoting cartilage repair. CLINICAL RELEVANCE: A single-stage surgical procedure combining microfracture and an autologous PRF membrane is a potentially beneficial treatment method for cartilage defects that does not require using any xenocollagen membrane.

Serum Cartilage Oligomeric Matrix Protein Detects Early Osteoarthritis in Patients With Anterior Cruciate Ligament Deficiency.

PURPOSE: To investigate the ability of serum cartilage oligomeric matrix protein (COMP) to detect early osteoarthritis (OA) (International Cartilage Research Society [ICRS] grade 1 or 2 cartilage lesions) in patients with anterior cruciate ligament (ACL)-deficient patients. METHODS: Patients with an ACL injury of Kellgren-Lawrence grade 0 or 1 were enrolled. Serum samples for COMP measurement were obtained before surgery. The cartilage surfaces of 6 compartments were classified using the ICRS grading system. The patients were divided into groups with and without early OA according to the cartilage findings and diagnostic criteria for early OA. RESULTS: In total, 98 patients (mean age 23.7 years; range 12 to 49) were included, with 30 patients (30.6%) in the early OA group and 68 (69.4%) in the no early OA group. The 2 groups significantly differed in age, body mass index, preoperative Tegner activity scale, and serum COMP level. The cutoff value of serum COMP for the presence of early OA arthroscopic cartilage lesions was 152.0 ng/mL. Multiple logistic regression analysis revealed age (odds ratio 1.09; 95% confidence interval [CI] 1.02 to 1.16; P = .01) and serum COMP (odds ratio 1.02; 95% CI 1.01 to 1.04; P < .001) to be independent factors for the presence of early OA arthroscopic cartilage findings. CONCLUSIONS: The incidence of early OA arthroscopic cartilage findings was ∼30% in patients with ACL deficiency, and serum COMP levels were significantly higher in the early OA group than in the no early OA group. The optimum cutoff value for serum COMP was 152 ng/mL. Serum COMP can be used to detect early cartilage change in patients with ACL deficiency. LEVEL OF EVIDENCE: Ⅲ, retrospective comparative study.

Biochemical Characteristics and Clinical Result of Bone Marrow-Derived Fibrin Clot for Repair of Isolated Meniscal Injury in the Avascular Zone.

PURPOSE: To characterize bone marrow aspirate-derived fibrin clot (BMA clot) and evaluate the clinical result of meniscal repair with a BMA clot for isolated meniscal injury in the avascular zone. METHODS: Blood counts of total leukocytes, platelets, and concentrations of basic fibroblast growth factor (bFGF), transforming growth factor ß (TGF-ß), and stromal cell-derived factor 1 (SDF-1) were analyzed with BMA, peripheral blood (PB), BMA clot, and PB clot from 5 patients treated for meniscal repair. In addition, a retrospective analysis of 30 patients with isolated avascular meniscal injuries who underwent repair with a BMA clot was performed to assess rate failure. Avascular meniscal injury was identified as horizontal tear, radial tear, and flap tear. Clinical failure was defined as the presence of 1 or more of Barrett's criteria. Anatomic failure was defined as the existence of equivalent signal intensity to intra-articular fluid along the repair area on follow-up magnetic resonance imaging (MRI). Patients' demographic and clinical data were compared between the overall failure group and the success group. RESULTS: The bFGF, TGF-ß, and SDF-1 levels of BMA clots were more highly concentrated compared with PB clots. The Lysholm scores and meniscal status evaluated by MRI were significantly improved from preoperatively to postoperatively (both P < .001). The Kellgren-Lawrence grading of knee radiographs did not significantly differ pre- and postoperatively (P = .140). Rates of clinical failure, anatomic failure, and retear were 10%, 6.7%, and 3.3%, respectively. The demographic characteristics and surgical and postoperative status did not significantly differ between the overall failure group and the success group. CONCLUSIONS: BMA clots had increased levels of cytokines compared to PB clots. The retrospective analysis revealed that the rates of clinical failure and anatomic failure after meniscal repair with a BMA clot for isolated avascular meniscal injury were 10% and 6.7%, respectively. LEVEL OF EVIDENCE: Level IV, case series.

Comparison of new and old all-inside suture devices in meniscal cyst formation rates after meniscal repair.

PURPOSE: We compared the magnetic resonance imaging (MRI)-confirmed cyst formation rate after meniscal tear repair using a new all-inside suture device (N group) versus the older all-inside suture device (O group). METHODS: Between October 2008 and July 2017, 94 consecutive menisci of 89 patients were diagnosed with meniscal tears and underwent arthroscopic meniscal repair using the all-inside suture device. Five of these patients were lost to follow-up within 12 months and were excluded from the study. The remaining 89 menisci were followed up for at least 12 months and were included in this retrospective cohort study. Older all-inside suture devices (FasT-Fix, Ultra FasT-Fix) were used until December 2012, while the new all-inside suture device (FasT-Fix 360) was used from January 2013 onwards. Meniscal cysts were detected on T2-weighted fat-suppressed MRI at 12 months postoperatively. Multiple logistic regression analysis was used to identify demographic and clinical factors associated with the use of the new all-inside suture device and cyst formation. RESULTS: In total, 36 and 53 menisci were included in the N and O groups, respectively. The incidence of meniscal cysts was significantly greater in the O group (14 out of 53, 26.4%) than in the N group (two out of 36, 5.56%) (P = 0.012). Two patients in the O group had symptomatic cysts that required removal. Multivariate logistic analyses showed that the cyst formation risk significantly decreased after using the new all-inside suture device than the older all-inside suture devices (odds ratio = 0.139; P = 0.04). CONCLUSIONS: The MRI-confirmed cyst formation rate after meniscal tear repair was significantly lower using the new than the older all-inside suture devices, indicating that the use of a low-profile device may decrease the cyst formation rate.

The Potential of Using an Autogenous Tendon Graft by Injecting Bone Marrow Aspirate in a Rabbit Meniscectomy Model.

Bone marrow aspirate (BMA) is an excellent source of cells and growth factors and has been used successfully for bone, cartilage, and soft-tissue healing. This study aimed to investigate the histological and biomechanical properties of autogenous tendon graft by injecting BMA and its protective effect against degenerative changes in a rabbit model of meniscal defects. Adult white rabbits were divided into untreated, tendon, and tendon + BMA groups, and meniscal defects were created in the knees. The tendon graft and articular cartilage status were evaluated by macroscopic and histological analysis at 4, 12, and 24 weeks postoperatively among the three groups. The tendon graft in the tendon and tendon + BMA groups were used for biomechanical evaluation at 4, 12, and 24 weeks postoperatively. The meniscal covering ratio in the tendon + BMA group was better than that in the tendon and untreated groups at 12 and 24 weeks postoperatively. The matrix around the central portion of cells in the tendon + BMA group was positively stained by safranin O and toluidine blue staining with metachromasia at 24 weeks. The histological score of the tendon graft in the tendon + BMA group was significantly higher than that in the untreated and tendon groups at 12 and 24 weeks postoperatively. In the tendon + BMA group, cartilage erosion was not shown at 4 weeks, developed slowly, and was better preserved at 12 and 24 weeks compared to the untreated and tendon groups. Histological scores for the articular cartilage were significantly better in the tendon + BMA group at 24 weeks. The compressive stress on the tendon graft in the tendon + BMA group was significantly higher than that in the tendon group at 12 weeks postoperatively. Transplantation of autogenous tendon grafts by injecting BMA improved the histologic score of the regenerated meniscal tissue and was more effective than the tendon and untreated group for preventing cartilage degeneration in a rabbit model of massive meniscal defects.

Evaluation of knee bone morphology in juvenile patients with complete discoid lateral meniscus using magnetic resonance imaging.

PURPOSE: The characteristic two-dimensional bone morphology in patients with a discoid lateral meniscus (DLM) has been described. However, the associated three-dimensional imaging findings have not been characterized. This study was performed to identify differences in the knee bone morphology between juvenile patients with a DLM and those with a normal meniscus using magnetic resonance (MR) imaging. METHODS: The DLM group comprised 33 consecutive juvenile patients (33 knees) with a complete DLM, and the control group comprised 24 juvenile patients (24 knees) with normal menisci on the basis of MR imaging findings. Each MR image was evaluated to determine the anterior obliquity of the lateral tibial plateau (AOLTP), posterior obliquity of the lateral tibial plateau (POLTP), lowest point of the lateral femoral condyle (LPLFC), posterior lateral condylar angle (PLCA) and posterior medial condylar angle (PMCA). Statistical analyses were performed to determine the differences between the two groups. RESULTS: The POLTP was significantly larger, the LPLFC was significantly more lateral, and the PLCA was significantly smaller in the DLM group than in the control group (p < 0.001, p < 0.001 and p < 0.001 respectively). However, there was no statistically significant difference in the AOLTP or PMCA between the two groups (p = 0.429 and p = 0.148, respectively). CONCLUSIONS: Hypoplasia of the lateral femoral condyle and posterior lateral tibial plateau is recognized in juvenile patients with a complete DLM on coronal and axial MRI images. LEVEL OF EVIDENCE: Diagnostic study, Level III.

Axial Chirality around N-P Bonds Induced by Complexation between E(C6F5)3 (E = B, Al) and an N-Phosphine Oxide-Substituted Imidazolinylidene: A Key Intermediate in the Catalytic Phosphinoylation of CO2.

Complexation-induced axial chirality around an N-P bond occurs upon the predominant coordination of the N-phosphinoyl group in the N-phosphine oxide-substituted imidazolinylidene (SPoxIm) to B(C6F5)3. (Ra) and (Sa) atropisomers of (κ-O-SPoxIm)B(C6F5)3 were observed independently in the single-crystal lattice and the optimized gas-phase structure. Experimental and theoretical studies confirmed that this axial chirality arises from the restricted rotation around the N-P bond, caused by the steric repulsion between the C5-H atoms of the imidazolinylidene ring and the C6F5 rings on the B(C6F5)3 unit. Conversely, this axial chirality was not certainly observed via the complexation between SPoxIm and Al(C6F5)3. The carbene carbon atoms in (κ-O-SPoxIm)E(C6F5)3 (E = B, Al) remain sufficiently nucleophilic to react with CO2, and the phosphinoylation of CO2 with SPoxIm proceeds far more rapidly in the presence of a catalytic amount of Al(C6F5)3 than in the absence of Al(C6F5)3.

Intra-Articular Injection of Stromal Cell-Derived Factor 1α Promotes Meniscal Healing via Macrophage and Mesenchymal Stem Cell Accumulation in a Rat Meniscal Defect Model.

The stromal-cell-derived factor-1α (SDF-1) is well-known for playing important roles in the regeneration of tissue by enhancing cell migration. However, the effect of SDF-1 in meniscal healing remains unknown. The purpose of this study is to investigate the effects of intra-articular injection of SDF-1 on meniscus healing in a rat meniscal defect model. The intra-articular SDF-1 injection was performed at meniscectomy and one week later. Macroscopic and histological assessments of the reparative meniscus were conducted at one, two and six weeks after meniscectomy in rats. In the macroscopic evaluation, the SDF-1 group showed an increase in the size of the reparative meniscus at six weeks after meniscectomy compared to the phosphate-buffered saline (PBS) injection (no-treatment) group. Histological findings showed that intra-articular injection of SDF-1 enhanced the migration of macrophages to the site of the regenerative meniscus at one and two weeks after meniscectomy. CD68- and CD163-positive cells in the SDF-1 group at one week after meniscectomy were significantly higher than in the no-treatment group. CD163-positive cells in the SDF-1 group at two weeks were significantly higher than in the no-treatment group. At one week after meniscectomy, there were cells expressing mesenchymal-stem-cell-related markers in the SDF-1 group. These results indicate the potential of regenerative healing of the meniscus by SDF-1 injection via macrophage and mesenchymal stem cell accumulation. In the present study, intra-articular administration of SDF-1 contributed to meniscal healing via macrophage, CD90-positive cell and CD105-positive cell accumulation in a rat meniscal defect model. The SDF-1-CXCR4 pathway plays an important role in the meniscal healing process. For potential clinical translation, SDF-1 injection therapy seems to be a promising approach for the biological augmentation in meniscal injury areas to enhance healing capacity.

Association Between Interdialytic Weight Gain, Perception About Dry Weight, and Dietary and Fluid Behaviors Based on Body Mass Index Among Patients on Hemodialysis.

OBJECTIVE: This study aimed to identify dietary and fluid behaviors associated with relative interdialytic weight gain (RIDWG) (divided by the respective dry weight [DW]) by stratifying the patients according to body mass index (BMI). DESIGN AND METHODS: This was a cross-sectional, multicenter investigation. Between July 2016 and March 2017, data were collected from 4 Japanese dialysis centers in 3 cities. The patients (n = 577) were asked to reply to a self-completed questionnaire, including questions on perception about DW and dietary and fluid behaviors. The differences in perception about DW and dietary and fluid behaviors were compared between RIDWG nonadherence (average RIDWG ≥5％ a month) and adherence subgroups. RESULTS: The 360 participants were stratified into thin (<20; 28.6%), normal low (≥20 and <22; 22.5%), normal high (≥22 and <25; 31.7%), and overweight (≥25; 17.2%) groups on the basis of BMI. In the thin and normal low BMI groups, the RIDWG nonadherent patients were more likely to identify their DW as "looking to increase." Although the difference was less prominent between the adherence subgroups in the thin BMI group, the RIDWG nonadherent patients in normal low BMI group seemed to generally take less care to intentionally regulate their behaviors as a representative of sodium-intake/fluid management. Although patients with a larger body size (overweight and normal high BMI groups) were not associated with this perception about DW, they were associated with some demographic characteristics; regarding the normal high BMI group, a higher proportion of RIDWG nonadherent patients worked full-time, and they more frequently reported an irregular eating pattern. CONCLUSION: Dietary and fluid behaviors associated with RIDWG differed according to the BMI group. Assessing more specific types of patient behaviors, focusing on the underlying factors associated with dietary and fluid behaviors, and taking BMI into consideration are required.

Main-Group-Catalyzed Reductive Alkylation of Multiply Substituted Amines with Aldehydes Using H2.

Given the growing demand for green and sustainable chemical processes, the catalytic reductive alkylation of amines with main-group catalysts of low toxicity and molecular hydrogen as the reductant would be an ideal method to functionalize amines. However, such a process remains challenging. Herein, a novel reductive alkylation system using H2 is presented, which proceeds via a tandem reaction that involves the B(2,6-Cl2C6H3)( p-HC6F4)2-catalyzed formation of an imine and the subsequent hydrogenation of this imine catalyzed by a frustrated Lewis pair (FLP). This reductive alkylation reaction generates H2O as the sole byproduct and directly functionalizes amines that bear a remarkably wide range of substituents including carboxyl, hydroxyl, additional amino, primary amide, and primary sulfonamide groups. The synthesis of isoindolinones and aminophthalic anhydrides has also been achieved by a one-pot process that consists of a combination of the present reductive alkylation with an intramolecular amidation and intramolecular dehydration reactions, respectively. The reaction showed a zeroth-order and a first-order dependence on the concentration of an imine intermediate and B(2,6-Cl2C6H3)( p-HC6F4)2, respectively. In addition, the reaction progress was significantly affected by the concentration of H2. These results suggest a possible mechanism in which the heterolysis of H2 is facilitated by the FLP comprising THF and B(2,6-Cl2C6H3)( p-HC6F4)2.