The Effect of Cefazolin on Mechanical Properties and Antibacterial Reactions of Calcium Phosphate Cement / 대한정형외과학회잡지

PURPOSE: The purpose of this study is to evaluate the change of mechanical properties and the effect of antibacterial reactions in calcium phosphate cement (CPC) mixed with cefazolin. MATERIALS AND METHODS: We made CPC and a sodium alginate solution and we mixed in variable dosages of cefazolin and then we made a standard sized cement mold. With that we performed compression stress tests, drug releasing tests and antibacterial tests. RESULTS: We found the typical appearance of hydroxyapatite (HA) in the cement mixed with cefazolin. The compressive strength of the cement mixed with cefazolin was higher than that of the cement not mixed with cefazolin and the higher strength cement had a smaller pore size and less porosity. The sodium alginate solution showed the maximum compressive strength at 2 & 4 wt%, but this was decreased at 6 wt%. Cefazolin was released in proportion to the concentration for the first 8 days on the drug releasing test and then a similar amount was released until the tenth day. An antibacterial effect was detected at all dosages of cefazolin on the antibacterial test. CONCLUSION: The compressive strength of the cement mixed with cefazolin was higher than that of the cement not mixed with cefazolin. The drug was released from the cement in a proper fashion and the antibacterial effect was preserved.

Solitary Intraosseous Neurofibroma of the Femur Neck: A Case Report / 대한정형외과학회잡지

Whereas neurofibroma is a fairly common soft tissue tumor, solitary intraosseous neurofibroma is a very rare type of bone tumor, and there relatively few cases have been reported worldwide, which were localized to the maxilla and mandible. We experienced a solitary intraosseous neurofibroma and treated it by curettage and bone graft through trochanter osteotomy of the femur. We report a rare case of solitary intraosseous neurofibroma and provide a review of reported cases.

Acetabular Degeneration in Osteonecrosis of the Femoral Head / 대한정형외과학회잡지

PURPOSE: To determine the degree of acetabular cartilage degeneration and factors that influence acetabular cartilage degeneration in osteonecrosis of the femoral head (ONFH). MATERIALS AND METHODS: We obtained acetabular cartilage from weight bearing and non-weight bearing portions, including subchondral bone, from 34 hips in 32 patients with ONFH who underwent total hip arthroplasty. Histologic grading by Hematoxylin & Eosin staining and Safranin O staining, and immunohistochemical staining with chondroitin sulfate antibody and type II collagen antibody were performed. RESULTS: Histological grade had no significant correlation with stage, age, weight, or duration or degree of head depression, by the Wilcoxon rank sum test. The weight bearing and the non-weight bearing portions of acetabular cartilage were divided into two groups according to the existence and non-existence of femoral head depression. A significant difference (p=0.01), by Fisher's exact test, was found between the two weight bearing groups in terms of histologic grade. However no significance (p=0.45) was found between the two non-weight bearing groups. The distribution of type II collagen antibody's stainability score show most values in the normal range, while that of chondroitin sulfate antibody's was mainly in the upper. CONCLUSION: The degeneration of the weight bearing portion of acetabular cartilage in ONFH is considered to be due to local rather than general changes. When head depression in absent, acetabular cartilage degeneration is less severe than previously reported.

Bernese Periacetabular Osteotomy Using Dual Approaches for Hip Dysplasias / 대한정형외과학회잡지

PURPOSE: This study was aimed to evaluate the usefulness of the dual approaches used in Bernese periacetabular osteotomy for hip dysplasias, and also to comparatively evaluate the single anterior approach. MATERIALS AND METHODS: We performed a clinical and radiographic assessment of 15 cases (5 cases by the anterior approach and 10 cases by the dual approaches) of periacetabular osteotomy which had been followed up for more than 1 year. RESULTS: All patients had an improved Harris hip score, CE angle, acetabular angle, acetabular depth, femoral head coverage and medial shift of the femoral head. Gait improvement was confirmed by gait analysis. The mount of correction of the CE angle was more by the anterior approach than by the dual approaches, which was due to overcorrection. There were no statistical differences in the operation times or in the amounts of bleeding of the two approaches. Posterior column fractures occurred in 4 hips, which were due to blind osteotomies by the single approach, but none occurred after the dual approaches. CONCLUSION: We visualized all osteotomy sites and could perform the osteotomies easily and were able to decrease the number of complications associated with the dual approaches.

The Effect of Fluid Flow Induced Shear Stress on the Prostaglandin E2 and Nitric Oxide Production of Osteoblast / 대한정형외과연구학회지

It has been generally known that bone tissue responds to the mechanical stress with an adaptative change in the mass and the structure. Recently, the signal transduction pathways involved in fluid flow have been reported, and several mechanotransduction products were suggested. This study was designed to verify the prostaglandin E2(PGE2) and nitric oxide(NO) involving as the biomechanical transducing material of the osteoblast to the fluid flow stimuli. We have checked changes in PGE2 and NO production after applying fluid flow-induced shearing stress to the primary high-density monolayer cultures of chicken fetus osteoblasts. PGE2 and nitrite which is the stable end-product of nitric oxide oxidationas are measured spectrophotometrically, the former using enzyme immunoassay system and the latter using Griess reaction. As a result, PGE2 and NO production by osteoblast was increased after applying the fluid flow-induced shear stress: PGE2 production was increased accumulatively in response to the duration of stress. There were no significant changes in NO production after 6 hours of the stress, but production of NO was markedly increased only after 24 hours. From the above findings, it was confirmed that osteoblast increased the production of PGE2 and NO in respond to the fluid flow-induced shearing stress and that PGE2 production is an earlier response to mechanical stimuli than the production of NO.