Effect of the Starting Point of Half-Pin Insertion on the Insertional Torque of the Pin at the Tibia

PURPOSE: The authors have observed a failure to achieve secure fixation in elderly patients when inserting a half-pin at the anteromedial surface of the tibia. The purpose of this study was to compare two methods for inserting a half-pin at tibia diaphysis in elderly patients. MATERIALS AND METHODS: Twenty cadaveric tibias were divided into Group C or V. A half-pin was inserted into the tibias of Group C via the conventional method, from the anteromedial surface to the interosseous border of the tibia diaphysis, and into the tibias of Group V via the vertical method, from the anterior border to the posterior surface at the same level. The maximum insertion torque was measured during the bicortical insertion with a torque driver. The thickness of the cortex was measured by micro-computed tomography. The relationship between the thickness of the cortex engaged and the insertion torque was investigated. RESULTS: The maximum insertion torque and the thickness of the cortex were significantly higher in Group V than Group C. Both groups exhibited a statistically significant linear correlation between torque and thickness by Spearman's rank correlation analysis. CONCLUSION: Half-pins inserted by the vertical method achieved purchase of more cortex than those inserted by the conventional method. Considering that cortical thickness and insertion torque in Group V were significantly greater than those in Group C, we suggest that the vertical method of half-pin insertion may be an alternative to the conventional method in elderly patients.

Establishment of Efficacy and Safety Assessment of Human Adipose Tissue-Derived Mesenchymal Stem Cells (hATMSCs) in a Nude Rat Femoral Segmental Defect Model

Human adipose tissue-derived mesenchymal stem cell (hATMSC) have emerged as a potentially powerful tool for bone repair, but an appropriate evaluation system has not been established. The purpose of this study was to establish a preclinical assessment system to evaluate the efficacy and safety of cell therapies in a nude rat bone defect model. Segmental defects (5 mm) were created in the femoral diaphyses and transplanted with cell media (control), hydroxyapatite/tricalcium phosphate scaffolds (HA/TCP, Group I), hATMSCs (Group II), or three cell-loading density of hATMSC-loaded HA/TCP (Group III-V). Healing response was evaluated by serial radiography, micro-computed tomography and histology at 16 weeks. To address safety-concerns, we conducted a GLP-compliant toxicity study. Scanning electron microscopy studies showed that hATMSCs filled the pores/surfaces of scaffolds in a cell-loading density-dependent manner. We detected significant increases in bone formation in the hATMSC-loaded HA/TCP groups compared with other groups. The amount of new bone formation increased with increases in loaded cell number. In a toxicity study, no significant hATMSC-related changes were found in body weights, clinical signs, hematological/biochemical values, organ weights, or histopathological findings. In conclusion, hATMSCs loaded on HA/TCP enhance the repair of bone defects and was found to be safe under our preclinical efficacy/safety hybrid assessment system.

The First Korean Case of Camurati-Engelmann Disease (Progressive Diaphyseal Dysplasia) Confirmed by TGFB1 Gene Mutation Analysis

Camurati-Engelmann disease (CED) is an autosomal dominant progressive diaphyseal dysplasia caused by mutations in the transforming growth factor-beta1 (TGFB1) gene. We report the first Korean family with an affected mother and son who were diagnosed with CED. The proband is a 19-yr-old male with a history of abnormal gait since the age of 2. He also suffered from proximal muscle weakness, pain in the extremities, and easy fatigability. Skeletal radiographs of the long bones revealed cortical, periosteal, and endosteal thickenings, predominantly affecting the diaphyses of the upper and lower extremities. No other bony abnormalities were noted in the skull and spine and no remarkable findings were seen on laboratory tests. The patient's mother had a long-standing history of mild limb pain. Under the impression of CED on radiographic studies, we performed mutation analysis. A heterozygous G to A transition at cDNA position +653 in exon 4 of the TGFB1 gene (R218H) was detected in the patient and his mother.