Hyaluronic acid and proteoglycan link protein 1 suppresses platelet­derived growth factor-BB-induced proliferation, migration, and phenotypic switching of vascular smooth muscle cells.

The development of atherosclerotic cardiovascular disease is associated with the phenotypic switching of vascular smooth muscle cells (SMCs) from a contractile to a synthetic state, leading to cell migration and proliferation. Platelet­derived growth factor­BB (PDGF­BB) modulates this de-differentiation by initiating a number of biological processes. In this study, we show that gene expression of hyaluronic acid (HA) and proteoglycan link protein 1 (HAPLN1) was upregulated during differentiation of human aortic SMCs (HASMCs) into a contractile state, but downregulated upon during PDGF-BB-induced dedifferentiation. This is the first study showing that the treatment of HASMCs with full-length recombinant human HAPLN1 (rhHAPLN1) significantly reversed PDGF-BB-induced decrease in the protein levels of contractile markers (SM22α, α-SMA, calponin, and SM-MHC), and inhibited the proliferation and migration of HASMCs induced by PDGF-BB. Furthermore, our results show that rhHAPLN1 significantly inhibited the phosphorylation of FAK, AKT, STAT3, p38 MAPK and Raf mediated by the binding of PDGF-BB to PDGFRß. Together, these results indicated that rhHAPLN1 can suppress the PDGF-BB-stimulated phenotypic switching and subsequent de-differentiation of HASMCs, highlighting its potential as a novel therapeutic target for atherosclerosis and other vascular diseases. [BMB Reports 2023; 56(8): 445-450].

HDAC Inhibitor, CG-745, Enhances the Anti-Cancer Effect of Anti-PD-1 Immune Checkpoint Inhibitor by Modulation of the Immune Microenvironment.

Histone deacetylase inhibitors (HDACis) are well-known epigenetic regulators with therapeutic potential in various diseases. Recent studies have shown that HDACis are involved in immune-mediated anti-cancer effects and may modulate the activity of immunotherapy agents. CG-745, a histone deacetylase inhibitor, has shown anti-cancer effects in pancreatic cancer, colorectal cancer, and non-small cell lung cancer. However, the exact role of CG-745 within the immune system is largely unknown. In this study, we have shown that CG-745 induces microenvironment changes promoting anti-cancer effect of anti-PD-1 antibody in syngeneic mouse models. Specifically, CG-745 induces or extends IL-2 and IFN-γ expression with or without additional stimulation, and increases proliferation of cytotoxic T cells and NK cells, while inhibiting proliferation of regulatory T cells. The analysis of immune cell distribution in the tumor microenvironment and spleen reveals that CG-745 suppresses M2 macrophage polarization and decreases the myeloid-derived suppressor cells. Recent advances in immunotherapy highlight the anti-cancer effects of immune checkpoint inhibitor despite a relatively limited clinical benefit in the subset of patients. Our results indicate that CG-745 enables the synergistic effects of the immune checkpoint inhibitor combination therapy in various cancers by suppressing tumor microenvironment.

Interaction of Synaptosomal-Associated Protein 25 with Neutral Sphingomyelinase 2: Functional Impact on the Sphingomyelin Pathway.

Neurotransmitter release is mediated by ceramide, which is generated by sphingomyelin hydrolysis. In the present study, we examined whether synaptosomal-associated protein 25 (SNAP-25) is involved in ceramide production and exocytosis. Neutral sphingomyelinase 2 (nSMase2) was partially purified from bovine brain and we found that SNAP-25 was enriched in the nSMase2-containing fractions. In rat synaptosomes and PC12 cells, the immunoprecipitation pellet of anti-SNAP-25 antibody showed higher nSMase activity than the immunoprecipitation pellet of anti-nSMase2 antibody. In PC12 cells, SNAP-25 was colocalized with nSMase2. Transfection of SNAP-25 small interfering RNA (siRNA) significantly inhibited nSMase2 translocation to the plasma membrane. A23187-induced ceramide production was concomitantly reduced in SNAP-25 siRNA-transfected PC12 cells compared with that in scrambled siRNA-transfected cells. Moreover, transfection of SNAP-25 siRNA inhibited dopamine release, whereas addition of C6-ceramide to the siRNA-treated cells moderately reversed this inhibition. Additionally, nSMase2 inhibition reduced dopamine release. Collectively, our results indicate that SNAP-25 interacts with nSMase2 during ceramide production, which mediates exocytosis and neurotransmitter release.

Local Stabilization of Hypoxia-Inducible Factor-1α Controls Intestinal Inflammation via Enhanced Gut Barrier Function and Immune Regulation.

Intestinal epithelial cells are adapted in mucosal hypoxia and hypoxia-inducible factors in these cells can fortify barrier integrity to support mucosal tissue healing. Here we investigated whether hypoxia-related pathways could be proposed as potential therapeutic targets for inflammatory bowel disease. We developed a novel hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitor, CG-598 which stabilized HIF-1α in the gut tissue. Treatment of CG-598 did not affect extra-intestinal organs or cause any significant adverse effects such as erythropoiesis. In the experimental murine colitis model, CG-598 ameliorated intestinal inflammation with reduction of inflammatory lesions and pro-inflammatory cytokines. CG-598 treatment fortified barrier function by increasing the expression of intestinal trefoil factor, CD73, E-cadherin and mucin. Also, IL-10 and IL-22 were induced from lamina propria CD4+ T-cells. The effectiveness of CG-598 was comparable to other immunosuppressive therapeutics such as TNF-blockers or JAK inhibitors. These results suggest that CG-598 could be a promising therapeutic candidate to treat inflammatory bowel disease.

Effect of Robinia pseudoacacia Leaf Extract on Interleukin-1ß-mediated Tumor Angiogenesis.

BACKGROUND/AIM: Interleukin (IL)-1ß is a pro-inflammatory cytokine that has recently been established as a stimulator of angiogenesis via regulation of proangiogenic factor expression in the tumor microenvironment. This study aimed to demonstrate the inhibitory effects of Robinia pseudoacacia leaf extract (RP) on IL-1ß-mediated tumor angiogenesis. MATERIALS AND METHODS: Secreted embryonic alkaline phosphatase (SEAP) reporter gene assay, ex vivo and in vitro tube formation assay, western blot, and quantitative PCR were used to analyze the inhibitory effect of RP on IL-1ß-mediated angiogenesis. RESULTS: RP inhibited secretion of SEAP, blocked IL-1ß signaling, and inhibited IL-1ß-mediated angiogenesis in ex vivo and in vitro assays. RP inhibited nuclear translocation of NF-ĸB by suppressing phosphorylation of IL-1ß signaling protein kinases and inhibited mRNA expression of IL-1ß-induced pro-angiogenic factors including VEGFA, FGF2, ICAM1, CXCL8, and IL6. CONCLUSION: RP suppressed IL-1ß-mediated angiogenesis and, thus, could be a promising agent in anticancer therapy.

Development of a Label-Free LC-MS/MS-Based Glucosylceramide Synthase Assay and Its Application to Inhibitors Screening for Ceramide-Related Diseases.

Ceramide metabolism is known to be an essential etiology for various diseases, such as atopic dermatitis and Gaucher disease. Glucosylceramide synthase (GCS) is a key enzyme for the synthesis of glucosylceramide (GlcCer), which is a main ceramide metabolism pathway in mammalian cells. In this article, we developed a liquid chromatography-tandem mass spectrometry (LCMS/MS) method to determine GCS activity using synthetic non-natural sphingolipid C8-ceramide as a substrate. The reaction products, C8-GlcCer for GCS, could be separated on a C18 column by reverse-phase high-performance liquid chromatography (HPLC). Quantification was conducted using the multiple reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z 588.6 → 264.4 for C8-GlcCer at positive ionization mode. The calibration curve was established over the range of 0.625-160 ng/mL, and the correlation coefficient was larger than 0.999. This method was successfully applied to detect GCS in the human hepatocellular carcinoma cell line (HepG2 cells) and mouse peripheral blood mononuclear cells. We also evaluated the inhibition degree of a known GCS inhibitor 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) on GCS enzymatic activity and proved that this method could be successfully applied to GCS inhibitor screening of preventive and therapeutic drugs for ceramide metabolism diseases, such as atopic dermatitis and Gaucher disease.

Activation of neutral sphingomyelinase 2 by starvation induces cell-protective autophagy via an increase in Golgi-localized ceramide.

Autophagy is essential for optimal cell function and survival, and the entire process accompanies membrane dynamics. Ceramides are produced by different enzymes at different cellular membrane sites and mediate differential signaling. However, it remains unclear which ceramide-producing pathways/enzymes participate in autophagy regulation under physiological conditions such as nutrient starvation, and what the underlying mechanisms are. In this study, we demonstrate that among ceramide-producing enzymes, neutral sphingomyelinase 2 (nSMase2) plays a key role in autophagy during nutrient starvation. nSMase2 was rapidly and stably activated upon starvation, and the enzymatic reaction in the Golgi apparatus facilitated autophagy through the activation of p38 MAPK and inhibition of mTOR. Moreover, nSMase2 played a protective role against cellular damage depending on autophagy. These findings suggest that nSMase2 is a novel regulator of autophagy and provide evidence that Golgi-localized ceramides participate in cytoprotective autophagy against starvation.

Dopamine transporter trafficking is regulated by neutral sphingomyelinase 2/ceramide kinase.

Dopamine (DA) reuptake is the primary mechanism to terminate dopaminergic transmission in the synaptic cleft. The dopamine transporter (DAT) has an important role in the regulation of DA reuptake. This study provides anatomical and physiological evidence that DAT recycling is regulated by ceramide kinase via the sphingomyelin pathway. First, the results show that DAT and neutral sphingomyelinase 2 (nSMase2) were successfully co-precipitated from striatal samples and were colocalized in the mouse striatum or PC12 cells. We also identified a protein-protein interaction between nSMase2 and DAT through in situ proximity ligation assay experiments in the mouse striatum. Second, dopamine (DA) stimulated the formation of ceramide and increased nSMase activity in PC12 cells, while treatment with a cell-permeable ceramide-1-phosphate (C1P) increased DA uptake. Third, we used inhibitors and siRNA to inhibit nSMase2 and ceramide kinase and observed the effects on DAT recycling in PC12 cells. Treatment with ceramide kinase inhibitor K1, or nSMase inhibitor GW4869, decreased DA uptake in PC12 cells, although the application of FB1, a ceramide synthase inhibitor, did not affect DA uptake. Transfection of nSMase2 and CERK siRNA decreased DAT surface level in PC12 cells. These results suggested that SM-derived C1P affects cell surface levels of DAT.

DA-9801 promotes neurite outgrowth via ERK1/2-CREB pathway in PC12 cells.

In the present study, we examined the mechanisms underlying the effect of DA-9801 on neurite outgrowth. We found that DA-9801 elicits its effects via the mitogen-activated protein kinase (MEK) extracellular signal-regulated kinase (ERK)1/2-cAMP response element-binding protein (CREB) pathway. DA-9801, an extract from a mixture of Dioscorea japonica and Dioscorea nipponica, was reported to promote neurite outgrowth in PC12 cells. The effects of DA-9801 on cell viability and expression of neuronal markers were evaluated in PC12 cells. To investigate DA-9801 action, specific inhibitors targeting the ERK signaling cascade were used. No cytotoxicity was observed in PC12 cells at DA-9801 concentrations of less than 30 µg/mL. In the presence of nerve growth factor (NGF, 2 ng/mL), DA-9801 promoted neurite outgrowth and increased the relative mRNA levels of neurofilament-L (NF-L), a marker of neuronal differentiation. The Raf-1 inhibitor GW5074 and MEK inhibitor PD98059 significantly attenuated DA-9801-induced neurite outgrowth. Additionally, the MEK1 and MEK2 inhibitor SL327 significantly attenuated the increase in the percentage of neurite-bearing PC12 cells induced by DA-9801 treatment. Conversely, the selective p38 mitogen-activated protein kinase inhibitor SB203580 did not attenuate the DA-9801 treatment-induced increase in the percentage of neurite-bearing PC12 cells. DA-9801 enhanced the phosphorylation of ERK1/2 and CREB in PC12 cells incubated with and without NGF. Pretreatment with PD98059 blocked the DA-9801-induced phosphorylation of ERK1/2 and CREB. In conclusion, DA-9801 induces neurite outgrowth by affecting the ERK1/2-CREB signaling pathway. Insights into the mechanism underlying this effect of DA-9801 may suggest novel potential strategies for the treatment of peripheral neuropathy.

Identification of Heat Shock Protein 60 as a Regulator of Neutral Sphingomyelinase 2 and Its Role in Dopamine Uptake.

Activation of sphingomyelinase (SMase) by extracellular stimuli is the major pathway for cellular production of ceramide, a bioactive lipid mediator acting through sphingomyelin (SM) hydrolysis. Previously, we reported the existence of six forms of neutral pH-optimum and Mg(2+)-dependent SMase (N-SMase) in the membrane fractions of bovine brain. Here, we focus on N-SMase ε from salt-extracted membranes. After extensive purification by 12,780-fold with a yield of 1.3%, this enzyme was eventually characterized as N-SMase2. The major single band of 60-kDa molecular mass in the active fractions of the final purification step was identified as heat shock protein 60 (Hsp60) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometric analysis. Proximity ligation assay and immunoprecipitation study showed that Hsp60 interacted with N-SMase2, prompting us to examine the effect of Hsp60 on N-SMase2 and ceramide production. Interestingly, Hsp60 siRNA treatment significantly increased the protein level of N-SMase2 in N-SMase2-overexpressed HEK293 cells. Furthermore, transfection of Hsp60 siRNA into PC12 cells effectively increased both N-SMase activity and ceramide production and increased dopamine re-uptake with paralleled increase. Taken together, these results show that Hsp60 may serve as a negative regulator in N-SMase2-induced dopamine re-uptake by decreasing the protein level of N-SMase2.

Effect of rice cell-derived human granulocyte-macrophage colony-stimulating factor on 5-fluorouracil-induced mucositis in hamsters.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is an important regulator of the maturation and function of cells in the granulocyte and macrophage lineages, and also plays a significant role in wound healing. In a previous study, we expressed human GM-CSF in rice cells (rice cell-derived human GM-CSF; rhGM-CSF). The purpose of the present study was to evaluate its effect on wound healing in oral mucositis. Oral mucositis was induced in Syrian hamster cheek pouches by 5-fluorouracil treatment and mechanical scratching. Ulcerated areas were treated from days 3 to 14 with an application of 200 µL saline, or of the same volume of a solution containing 0.04, 0.2, or 1 µg/mL rhGM-CSF. Treatment of hamsters with rhGM-CSF reduced the ulcerated areas of the oral mucosa, compared with the control. Early in the healing process, the mucositis tissue layer of the rhGM-CSF-treated group showed significantly decreased myeloperoxidase activity and increased numbers of proliferating cell nuclear antigen (PCNA)-positive cells. Treatment with rhGM-CSF also affected expression of inflammatory cytokines in the ulcerative mucosal tissue. These results demonstrate the efficacy of plant-produced rhGM-CSF in wound healing and have significant implications for the development of rhGM-CSF as a therapeutic agent for ulcerative oral mucositis.

A novel magnetic resonance imaging classification of discoid lateral meniscus based on peripheral attachment.

BACKGROUND: In the symptomatic discoid lateral meniscus, the effectiveness of preoperative magnetic resonance imaging (MRI) is not well documented. HYPOTHESIS: Magnetic resonance imaging classification will provide more information to the surgeon in choosing the appropriate treatment methods with the help of arthroscopic findings. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Sixty-seven patients (82 knees) were reviewed. The preoperative MRI was checked in 76 of 82 knees. The Lysholm and Ikeuchi grading scales were evaluated. Images were analyzed from MRI, and findings were classified into 4 categories: no shift, anterocentral shift, posterocentral shift, and central shift. Tear pattern classifications were based on arthroscopic findings: horizontal tear, peripheral tear, horizontal and peripheral tear, posterolateral corner loss, and others. The correlations between MRI classification tear patterns and surgical methods were analyzed using the chi-square test or the Fisher exact test. The sensitivity, specificity, and accuracy of shift in preoperative MRI-according to the existence of peripheral tear when corroborated with arthroscopy-were also analyzed with the chi-square test. Inter- and intraobserver reliability was statistically analyzed by producing the inter- and intraclass correlation coefficient. RESULTS: The mean preoperative Lysholm score was 77.3 (range, 43-97), and the last follow-up Lysholm score had increased to 96.8 (range, 84-100; P < .001). At last follow-up (100% follow-up), the Ikeuchi grading scale scored 48 knees as excellent, 30 as good, and 4 as fair. According to the MRI classification, 43 knees were no shift; 6, anterocentral shift; 15, posterocentral shift; and 12, central shift. Shift-type knees had a significantly larger number of peripheral tears, and repairs were performed in the shift-type knees (55%) more frequently than in the no-shift-type knees (28%). Among 82 knees, 31 were repaired simultaneously after a central partial meniscectomy. CONCLUSION: Magnetic resonance imaging classification provides more information to surgeons in choosing the appropriate treatment methods, although the final decision regarding procedure is made during arthroscopy after thorough analysis of the tear.

Modular cementless total hip arthroplasty for multiple epiphyseal dysplasia.

We analyzed a consecutive series of 23 total hip arthroplasties that had been performed using modular cementless prostheses in 13 patients with a confirmed diagnosis of multiple epiphyseal dysplasia and end-stage osteoarthritis of the hip. The average Harris hip score improved from 40.6 to 93.8 points. Postoperatively, all hips demonstrated favorable alterations in the biomechanical parameters including hip center of rotation, femoral offset, femoral neck length, and limb length. At a mean follow-up of 4.8 years, no hip required revision because of aseptic loosening of the acetabular or femoral component. One patient (1 hip, 4.3%) underwent reoperation for polyethylene wear and osteolysis 8 years after index arthroplasty. This study shows encouraging clinical and radiographic outcomes of modular cementless total hip arthroplasties for this technically difficult condition.

Anterior cruciate ligament reconstruction with preservation of remnant bundle using hamstring autograft: technical note.

During an arthroscopic examination for an anterior cruciate ligament (ACL) reconstruction, there is a relatively thick remnant ACL tibial stump attached to the posterior cruciate ligament (PCL) or rarely remained between the femur origin and the tibia insertion. We thought that preservation of the remnant ACL original bundle might promote graft healing or be helpful in preserving the proprioception and function to stabilize the knee. Therefore, we established a remnant preservation procedure without additional instruments during an ACL reconstruction using a bio-cross pin (RIGIDfix system: Mitek, Johnson & Johnson, USA) for the femoral tunnel fixation. The remnant ACL was sutured (usually three stitches) using a suture hook (Linvatec, Largo, FL), and both ends of the sutures were pulled to the far anteromedial (AM) portal. These sutures protected the remnant tissue during the ACL reconstruction because medial traction of these sutures can provide a wide view during the reconstruction. After the femoral and tibial tunnel formation, these sutures were pulled out to the inferior sleeve of the cross pin using a previously inserted wire loop via an inferior sleeve. After graft passage, a superior cross pin was first fixed and tibial fixation was then performed. Finally, inferior cross pin fixation was performed and ties were made at the entrance of the inferior cross pin.

Magnetic resonance imaging appearance of a repaired capsulolabral complex after arthroscopic bankart repair.

BACKGROUND: Revision Bankart operations frequently show capsulolabral buttress loss and recurrent soft tissue Bankart lesion. Capsulolabral augmentation is designed to increase glenohumeral stability by 2 separate mechanisms: deepening the glenoid concavity and reducing capsular laxity. This is accomplished by shifting the capsule to buttress the glenoid labrum. HYPOTHESIS: A retained capsulolabral buttress may show loss of height and slope at a certain period after surgery, regardless of stability. Thus, the authors wanted to confirm the importance of an intraoperative establishment of capsulolabral buttress in terms of stability. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Arthroscopically repaired Bankart lesions in 21 consecutive shoulders that showed no frank dislocation were evaluated using axial and oblique coronal T2-weighted magnetic resonance imaging at 3 timepoints (preoperative period, average postoperative week 6 and a nearly full range of motion recovery, and postoperative month 6 with a return to daily activity). The authors measured 2 parameters (height and slope) on axial (mainly capsulolabral containment) and oblique coronal images (mainly inferior glenohumeral ligament) at the anteroinferior portion of the glenoid (5 mm above the most inferior anchor). In addition, they compared the above-mentioned parameters at postoperative month 6 by magnetic resonance imaging in 21 controls and in 21 patients whose instability recurred after surgery (not included in the prospective study). RESULTS: There was a significant increase between the preoperative period and postoperative week 6 in all 4 parameters (P < .0001). There was also a significant increase between the preoperative period and postoperative month 6 in all 4 parameters (P < .0001). However, no statistically significant difference was observed between postoperative week 6 and postoperative month 6 in all 4 parameters (P > .1). Furthermore, significant differences were observed between normal controls and patients with recurrent instability (P < .001) and between the authors' cases and patients with recurrent instability not in the study (P < .001). However, no difference was observed between their cases and normal shoulders (P > .1). CONCLUSION: After suture anchor Bankart repair, initial capsulolabral buttress property was maintained at 6 months postoperatively. Furthermore, the buttress was more prominent in stable and normal shoulders than in recurrent instability shoulders. Therefore, the authors believe that the establishment of a capsulolabral buttress is meaningful during Bankart repair.

Arthroscopic partial meniscectomy with repair of the peripheral tear for symptomatic discoid lateral meniscus in children: results of minimum 2 years of follow-up.

PURPOSE: This study was undertaken to document the clinical results and technical aspects of arthroscopic partial meniscectomy in conjunction with peripheral tear repair for the treatment of symptomatic discoid lateral meniscus in children. METHODS: From June 1998 to May 2005, the senior author (J.H.A.) performed arthroscopic surgery on 77 children (89 knees) with symptomatic discoid lateral meniscus. Of these patients, we retrospectively studied 23 patients (28 knees) with a peripheral tear that was treated by partial central meniscectomy in conjunction with peripheral suture repair. Mean age at operation was 9.0 years (range, 4 to 15 years), and the mean follow-up period was 50.9 months (range, 24 to 94 months). Arthroscopic findings were categorized into 3 types in terms of peripheral rim stability and tear site: (1) meniscocapsular junction (MC), anterior horn type (MC-A type); (2) MC, posterior horn type (MC-P type); and (3) posterolateral corner (PLC) loss type. These 3 types needed different arthroscopic techniques for saucerization with repair. Clinical results were evaluated using Lysholm knee scores and Hospital for Special Surgery (HSS) scores preoperatively and at final follow-up. RESULTS: All patients were able to return to their previous life activities with little or no limitation, and no reoperation was required after an average follow-up of 51 months. Mean Lysholm knee scores improved from 78.5 (range, 69 to 89) preoperatively to 95.5 (range, 85 to 100) at the final follow-up (P < .0001), and the mean HSS score improved from 80.3 (range, 69 to 89) preoperatively to 95.9 (range, 90 to 100) at the final follow-up (P < .0001). CONCLUSIONS: We believe that the described arthroscopic partial meniscectomy in conjunction with the meniscal repair of the peripheral tear are effective for treating children with a symptomatic discoid lateral meniscus. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Comparison of revision surgery with primary anterior cruciate ligament reconstruction and outcome of revision surgery between different graft materials.

BACKGROUND: The number of primary anterior cruciate ligament reconstructions is increasing rapidly; the number of failing grafts and need for revision surgery have also risen. HYPOTHESIS: Revision anterior cruciate ligament reconstruction will produce similar results to those of primary reconstruction, and there may be different results according to graft materials. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: Fifty-nine revision surgeries were performed at 1 institution between January 1997 and October 2005. Fifty-five patients (56 operations) were followed. The results of 117 patients (117 knees) treated with arthroscopic primary anterior cruciate ligament reconstruction using double-looped semitendinosus and gracilis autograft from September 2001 to November 2002 were also evaluated. Clinical and stability results between primary and revision anterior cruciate reconstruction were compared. For the revision surgery, 21 (37.5%) knees had revision reconstruction with previously unharvested ipsilateral double-looped semitendinosus and gracilis autograft. Twenty (35.7%) were bone-patellar tendon-bone allograft, and 15 (26.8%) were Achilles allograft. The details of the technique varied according to the original graft choice and the abnormality encountered. Concomitant procedures were necessary in 32 (57.1%) of 56 knees. Clinical and stability results according to the different graft materials were also compared. RESULTS: There were significant improvements in the scores for subjective, objective forms (P < .001), and stability (P < .001). However, the clinical results of revision surgery were inferior to primary reconstruction (P < .001), but as regards stability, the difference between primary and revision cases was not significant (P = .338). There was no difference in clinical and stability results in different groups of graft material (P = .160-.690). CONCLUSION: Revision anterior cruciate ligament reconstruction could improve clinical and stability results, but the clinical results were inferior to those of primary reconstruction. This study also demonstrated that the success of the operation did not depend on the choice of graft materials.

Clearing a blind spot in knee arthroscopy: popliteal bursa.

Each arthroscopic portal to the knee has a blind area that cannot be inspected directly. In particular, visualization of the posterior compartment is difficult to access. Although arthroscopic procedures for the posterior compartment of the knee joint have been developed through posteromedial, posterolateral and posterior trans-septal portal, the popliteal bursa remains as an area that is difficult to access and manipulate. We report a surgical procedure that can examine one of the blind spots in knee arthroscopy, popliteal bursa.

Intraarticular fibroma of the posterior compartment in the knee. A case report.

Posterior knee discomfort and recurrent effusion of the left knee occurred in a 49-year-old man without a history of specific trauma. Magnetic Resonance Imaging (MRI) and an arthroscopic examination revealed a soft tissue mass arising from the posterolateral capsule. The microscopic diagnosis was a fibroma, which is a rare entity in this location. To the best of our knowledge, only four cases of fibroma in the knee have been reported. It was reported that more than 99% of fibromas arise from tendon sheaths or tendons. They sometimes present a diagnostic problem due to their relative rarity in this location and obscure histological features. Fibroma should be included in a differential diagnosis of a soft tissue tumor arising from the knee joint. However, an arthroscopic excision was curative in our case.

Arthroscopic management of the postero-medial or postero-lateral capsule tear in the knee joint: technical note.

We describe the arthroscopic management of the posterior capsule tear using posterior trans-septal portal. This technique is usually used in acute cases where a torn capsule is found but we can also use this technique for reefing of stretched capsule by refreshing the injured capsule. When arthroscopic ligament reconstruction accompanies postero-medial or postero-lateral capsular insufficiency, using the posterior trans-septal portal could ensure better visualization of the capsule and a subsequent more accurate management of the capsule. Since it is helpful in lessening the instability, it could contribute to achieving successful clinical results although this is not a mighty procedure.