Jung Ho Park

A pull out suture for transection of the posterior horn of the medial meniscus: using a posterior trans-septal portal.

A transection (root tear or complete radial tear) injury of the medial meniscus posterior horn is not rare in the oriental area and needs to be repaired to restore the hoop tension and to reduce the extruded meniscus, which leads to osteoarthritis of the knee. In cases with transection of the medial meniscus posterior horn, the meniscus can be repaired by a pull out suture technique. However, it is difficult to manipulate a suture hook and drill a tibial tunnel in the narrow medial joint space using the traditional anterior arthroscopic technique. This article describes a new pull out suture technique for transection of the medial meniscus posterior horn using a posterior trans-septal portal that provides a safe and wide field of vision. The handling of the suture hook and a guide may reduce the possibility of a chondral or meniscal injury.

Articular cartilage regeneration with microfracture and hyaluronic acid

Microfracture used to treat articular cartilage injuries can facilitate access to stem cells in the bone marrow and stimulate cartilage regeneration. However, the regenerated cartilage is fibrocartilage as opposed to hyaline articular cartilage and is thinner than native cartilage. Following microfracture in rabbit knee cartilage defects, application of hyaluronic acid gel resulted in regeneration of a thicker, more hyaline-like cartilage. The addition of transforming growth factor-β3, an inducer of chondrogenic differentiation in mesenchymal stem cells, to the treatment with microfracture and hyaluronic acid did not significantly benefit cartilage regeneration.

Body fat distribution and insulin resistance: beyond obesity in nonalcoholic fatty liver disease among overweight men.

Objective: The aim of this study was to characterize the relationship between nonalcoholic fatty liver disease (NAFLD) and body fat distribution and insulin resistance in a sample of non-diabetic overweight men. Subjects and Methods: We conducted a cross-sectional survey of 117 overweight men with NAFLD, as well as 117 controls, who were matched with regard to age and body mass index. None of the study subjects exhibited signs of alcohol abuse, hepatitis B or C, diabetes or fasting hyperglycemia, or hypertension. The diagnosis of NAFLD was based on dual findings of elevated alanine aminotransferase levels and sonographically-determined fatty liver. Body fat distribution was assessed via bioelectrical impedance. Insulin resistance was evaluated via homeostasis model assessment (HOMA-IR). Results: The risk of developing NAFLD was found to be profoundly associated with elevated measurements of waist circumference, fat mass, percentage of body fat and abdominal fat, iron, triglycerides, apolipoprotein B, and results of HOMA-IR. Multivariate analysis revealed that NAFLD was significantly associated with elevated measurements of waist circumference, iron, apolipoprotein B, and HOMA-IR. Conclusions: Our study provides evidence for a profound and dose-dependent association of NAFLD with central adiposity, insulin resistance in overweight men lacking complications of metabolic syndrome. Overweight subjects with insulin resistance or central adiposity were at more risk of NAFLD than were those subjects with less insulin resistance or central adiposity, even those with a similar degree of obesity.

Mucosal mast cell count is associated with intestinal permeability in patients with diarrhea predominant irritable bowel syndrome

Background/Aims Although mucosal mast cell tryptase is known to significantly increase intestinal permeability, the relationship between mucosal mast cells and intestinal permeability remains unclear. The objective of this study was to evaluate the correlation among intestinal permeability, tryptase activity and mucosal mast cell count. Methods Rectal biopsies from 16 patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and 7 normal subjects were assessed for tryptase activity and macromolecular permeability using horseradish peroxidase in Ussing chambers. In addition, mucosal mast cell levels were immunohistochemically quantified via image analysis. Results Rectal biopsy of tissues from IBS-D patients showed significantly increased permeability compared with those from normal controls (0.644 ± 0.08 and 0.06 ± 0.00 ng/2 hr/mm2, P < 0.01). Tryptase activity was also substantially higher in rectal biopsy samples from IBS-D patients than those from normal controls (0.86 ± 0.18 and 0.28 ± 0.04 mU/mg protein, P < 0.05). Mucosal mast cell counts were not significantly different between the 2 groups (P > 0.05). However, correlation analysis revealed that only mucosal mast cell count was significantly correlated with intestinal permeability in IBS-D patients (r = 0.558, P < 0.05). Conclusions This study demonstrated a positive correlation between the number of mucosal mast cells and intestinal permeability, suggesting that mucosal mast cells play an important role for increased intestinal permeability in patients with IBS-D.

The Efficacy of Bone Morphogenetic Protein-2 Depends on Its Mode of Delivery

Bone morphogenetic protein-2 (BMP-2) induces bone regeneration in a dose-dependent manner, with higher doses of BMP-2 inducing greater bone formation. Previously, we showed that long-term delivery of BMP-2 provides better ectopic bone formation than short-term delivery of an equivalent dose. In the present study, we investigated the efficacy of orthotopic bone formation over a range of BMP-2 doses, using different delivery modes. Heparin-conjugated poly(lactic-co-glycolic acid) nanospheres suspended in fibrin gel were used as a long-term delivery system, and fibrin gel was used as a short-term delivery system. Different doses of BMP-2 were delivered to mouse calvarial defects using either long-term or short-term delivery systems. Eight weeks after treatment, bone regeneration was evaluated by histomorphometry. For both delivery systems, bone regeneration increased as the BMP-2 dose increased up to 1 µg and did not increase beyond this dose. Importantly, at BMP-2 doses higher than 1 µg, long-term delivery resulted in much greater bone formation than short-term delivery. This study shows that long-term delivery of BMP-2 is more effective at enhancing orthotopic bone formation than short-term delivery over a range of doses.

The use of poly(lactic-co-glycolic acid) microspheres as injectable cell carriers for cartilage regeneration in rabbit knees

The use of injectable scaffolding materials for in vivo tissue regeneration has raised great interest because it allows cell implantation through minimally invasive surgical procedures. Previously, we showed that poly(lactic-co-glycolic acid) (PLGA) microspheres can be used as an injectable scaffold to engineer cartilage in the subcutaneous space of athymic mice. The purpose of this study was to determine whether PLGA microspheres can be used as an injectable scaffold to regenerate hyaline cartilage in the osteochondral defects of rabbit knees. A full-thickness wound to the patellar groove of the articular cartilage was made in the knees of rabbits. Rabbit chondrocytes were mixed with PLGA microspheres and injected immediately into these osteochondral wounds. Both chondrocyte transplantations without PLGA microspheres and culture medium injections without chondrocytes served as controls. Sixteen weeks after implantation, chondrocytes implanted using the PLGA microspheres formed white cartilaginous tissues. Histological scores indicating the extent of the cartilaginous tissue repair and the absence of degenerative changes were significantly higher in the experimental group than in the control groups (P < 0.05). Histological analysis by a hematoxylin and eosin stain of the group transplanted with microspheres showed thicker and better-formed cartilage compared to the control groups. Alcian blue staining and Massons trichrome staining indicated a higher content of the major extracellular matrices of cartilage, sulfated glycosaminoglycans and collagen in the group transplanted with microspheres than in the control groups. In addition, immunohistochemical analysis showed a higher content of collagen type II, the major collagen type in cartilage, in the microsphere transplanted group compared to the control groups. In the group transplanted without microspheres, the wounds were repaired with fibro-cartilaginous tissues. This study demonstrates the feasibility of using PLGA microspheres as an injectable scaffold for cartilage regeneration in a rabbit model of osteochondral wound repair.

Correlations of adolescent idiopathic scoliosis and pectus excavatum.

Study Design: Radiologic study of scoliosis in pectus excavatum patients. Objectives: To determine the relation between pectus excavatum deformity and adolescent idiopathic scoliosis (AIS). Summary of Background Data: AIS may be related to other whole body deformities, but few reports have addressed the relation between chest deformity and scoliosis. Methods: A total of 248 patients with a diagnosis of pectus excavatum were enrolled in this study. All study patients underwent whole spine anteroposterior radiographs and chest computed tomography. Severity and type of scoliosis and chest deformity were measured using radiographs, and relations between pectus deformity and AIS were analyzed. Results: Overall, 56 of the 248 study patients had scoliosis (Cobb angle >10 degrees)—a prevalence of 22.58%. The incidence of scoliosis was significantly higher in female patients (38.46%) (P=0.002), and Lenke type 1 predominated in pectus patients (48.2%, P<0.0001). Mean age was greater in the scoliosis group than in the nonscoliosis group (P<0.0001), and the asymmetry of pectus deformity was more prominent in the scoliosis group (P=0.007). However, pectus deformity severity was similar in the 2 groups (P=0.061). Furthermore, although the scoliosis group showed a higher proportion of female patients (P=0.002), the severities of chest and spinal deformities were similar in the 2 groups for both sexes (P=0.314, P=0.227). Conclusions: Pectus excavatum and AIS were found to have a high concomitant incidence. And, the age, sex, and type of disease were significantly different in the scoliosis and pectus excavatum groups. Surgeons should consider these relationships when deciding upon treatment in patients with chest and spinal deformities.

Evaluation of the three-dimensional deformities in scoliosis surgery with computed tomography: efficacy and relationship with clinical outcomes.

Study Design. Prospective radiological and clinical study with scoliosis patients. Objective. To determine the pre- and postoperative differences in the three-dimensional (3D) parameters and relationships with the outcome in scoliosis surgery. Summary of Background Data. Despite a proven important role of the 3D deformities in scoliosis, it is warranted to confirm the efficacy of these measurements, which carry a cost burden and radiation hazard. Methods. Fifty adolescent idiopathic scoliosis patients who underwent correction surgery were enrolled in this study. Pre- and postoperative whole spine radiographs and computed tomography were performed. The vertebral rotation (VR), rib hump index (RH), sternal shift (SS) on computed tomography were measured at the level of the apex in each patient. In addition, the patients described the SRS 30 (scoliosis research society 30) and ODI (owestry disability index) score. And, the differences in the parameter and the relationships between the radiological and clinical outcomes were analyzed. Results. There was significant decrease in the coronal curvature, RH, and SS after surgery (P < 0.0001). In addition, the VR decreased postoperatively but that was not significant (P = 0.236). There were significant relationships between the parameters in the coronal curvature, VR, RH, and SS, pre- and postoperatively (P < 0.05). However, regarding the pre- and postoperative differences, only the changes in the SS were related to changes in the coronal curvature (P = 0.006). In addition, there were significant relationships between the parameters and outcomes. The changes in ODI were related to changes in the coronal curvature, VR, RH, and SS (P < 0.0001, P = 0.039, P < 0.0001, P = 0.019, respectively). However, the changes in the SRS was only related to the changes in SS (P < 0.0001). Conclusion. There were significant correlations between the VR, RH, and SS with the coronal curvature, pre- and postoperatively. In addition, there were significant correlations between the 3D deformities and outcomes. Computed tomography based measurements of 3D deformities can provide useful information in planning, and predicting the outcome of corrective surgery.

Discontinuous release of bone morphogenetic protein-2 loaded within interconnected pores of honeycomb-like polycaprolactone scaffold promotes bone healing in a large bone defect of rabbit ulna

The choice of an appropriate carrier and its microarchitectural design is integral in directing bone ingrowth into the defect site and determining its subsequent rate of bone formation and remodeling. We have selected a three-dimensional polycaprolactone (PCL) scaffold with an interconnected honeycomb-like porous structure to provide a conduit for vasculature ingrowth as well as an osteoconductive pathway to guide recruited cells responding to a unique triphasic release of osteoinductive bone morphogenetic proteins (BMP) from these PCL scaffolds. We hypothesize that the use of recombinant human bone morphogenetic protein 2 (rhBMP2)-PCL constructs promotes rapid union and bone regeneration of a large defect. Results of our pilot study on a unilateral 15 mm mid-diaphyseal segmental rabbit ulna defect demonstrated enhanced bone healing with greater amount of bone formation and bridging under plain radiography and microcomputed tomography imaging when compared with an empty PCL and untreated group after 8 weeks postimplantation. Quantitative measurements showed significantly higher bone volume fraction and trabecular thickness, with lower trabecular separation in the rhBMP2-treated groups. Histology evaluation also revealed greater mature bone formation spanning across the entire scaffold region compared with other groups, which showed no bone regeneration within the central defect zone. We highlight that it is the uniqueness of the scaffold having a highly porous network of channels that promoted vascular integration and allowed for cellular infiltration, leading to a discontinuous triphasic BMP2 release profile that mimicked the release profile during natural repair mechanisms in vivo. This study serves as preclinical evidence demonstrating the potential of combining osteoinductive rhBMP2 with our PCL constructs for the repair of large defects in a large animal model.

The Relationship between Small-Intestinal Bacterial Overgrowth and Intestinal Permeability in Patients with Irritable Bowel Syndrome

Background/Aims Small-intestinal bacterial overgrowth (SIBO) is a frequent finding in patients with irritable bowel syndrome (IBS). Many patients with IBS also have abnormal intestinal permeability, which is probably due to low-grade inflammation in the intestinal mucosa. Our aim was to verify the relationship between SIBO and small-intestinal permeability in IBS patients. Methods A cohort of 38 IBS patients (20 women and 18 men; age range 16-70 years; mean age 40.2 years) with symptoms that fulfilled Rome-II criteria, and 12 healthy controls (5 women and 7 men; age range 25-52 years; mean age: 37.8 years) were recruited. All subjects underwent lactulose breath tests (LBTs) and intestinal permeability tests using the polyethylene glycol (PEG) 3350/400 retrieval ratio. Results A positive LBT was found in 18.4% (7/38) of patients with IBS and 8.3% (1/12) of control subjects. Intestinal permeability was significantly increased in patients with IBS compared with the normal controls (0.82±0.09 vs 0.41±0.05 [mean±SD], respectively; p<0.05). However, the intestinal permeability did not differ significantly between IBS patients with a positive LBT and those with a negative LBT (0.90±0.13 and 0.80±0.11, respectively; p>0.05). Conclusions Intestinal permeability was increased in patients with IBS, but this finding did not correlated with the occurrence of SIBO.