The morphometry of soft tissue insertions on the tibial plateau: Data acquisition and statistical shape analysis

This study characterized the soft tissue insertion morphometrics on the tibial plateau and their inter-relationships as well as variabilities. The outlines of the cruciate ligament and meniscal root insertions along with the medial and lateral cartilage on 20 cadaveric tibias (10 left and 10 right knees) were digitized and co-registered with corresponding CT-based 3D bone models. Generalized Procrustes Analysis was employed in conjunction with Principal Components Analysis to first create a geometric consensus based on tibial cartilage and then determine the means and variations of insertion morphometrics including shape, size, location, and inter-relationship measures. Step-wise regression analysis was conducted in search of parsimonious models relating the morphometric measures to the tibial plateau width and depth, and basic anthropometric and gender factors. The analyses resulted in statistical morphometric representations for Procrustes-superimposed cruciate ligament and meniscus insertions, and identified only a few moderate correlations (R 2: 0.37-0.49). The study provided evidence challenging the isometric scaling based on a single dimension frequently employed in related morphometric studies, and data for evaluating cruciate ligament reconstruction strategies in terms of re-creating the native anatomy and minimizing the risk of iatrogenic injury. It paved the way for future development of computer-aided personalized orthopaedic surgery applications improving the quality of care and patient safety, and biomechanical models with a better population or average representation

Canal Transportation and Centring Ratio of Paediatric vs Regular Files in Primary Teeth

Background: During mechanical preparation of the primary root canal, the original anatomy of the tooth should be preserved and the instrument should be perfectly balanced centrally into the canal space for reducing the probability of canal transportation. The aim of this research was to compare canal transportation and canal centring ability in primary root canals using ProTaper Next (Dentsply Mailfair,), AF baby (Fanta), and Kidzo Elephant (Endostar, Poldent Sp.) files. Materials and methods: Eighteen root canals were randomly divided into 3 experimental groups (n = 6 in each group). Instrumentation was performed using ProTaper Next, Fanta AF baby, and Kidzo Elephant files in groups 1, 2, and 3, respectively. During the instrumentation procedure, the irrigation of 2 mL of 1.5% sodium hypochlorite between each file was done, followed by 5 mL of 17% ethylenediaminetetraacetic acid as a final irrigating solution. Cone-beam computed tomography images were obtained before and after instrumentation. Each group was evaluated for transportation and centring ratios. Results: On comparing all the tested groups within each root canal level canal transportation, the results revealed a statistically nonsignificant difference in the buccolingual direction (P > 0.05). Meanwhile, in the mesiodistal direction, group 1 showed a statistically highly significant difference compared to groups 2 and 3 at the cervical level (P 0.05). Regarding the centring ability comparison of the 3 groups within each root canal level, there was a statistically nonsignificant difference amongst all groups (P > 0.05) in both buccolingual and mesiodistal directions. Conclusions: The ProTaper Next regular rotary file and the paediatric rotary files showed no difference in canal transportation and centring ability in the buccolingual direction, while in the mesiodistal direction at the cervical root canal level, the ProTaper Next showed high transportation liability

Age-related changes in the murine larynx: initial validation of a mouse model

OBJECTIVESChanges in voice are commonly associated with aging (presbyphonia). Age-related voice change significantly impairs elderly individuals' ability to communicate meaningfully with others and affects their quality of life. With changing age demographics in our society and increasing emphasis on quality of life, treatment of presbylaryngis is becoming more paramount.METHODSWe used 9 aged and 9 young mice to validate a mouse model for the aging larynx. We stained the larynges with Alcian blue to determine the hyaluronic acid content, trichrome stain to determine the collagen content, and immunohistochemical stain for alpha smooth muscle actin to determine the myofibroblast content. Morphometric measurements were performed for muscle area, muscle thickness, and muscle fiber diameter.RESULTSStatistically significant differences in the density measurements of hyaluronic acid and collagen reflected decreased hyaluronic acid and increased collagen content in the aging larynx. We found alpha smooth muscle actin-labeled myofibroblasts only in the aged larynges. No statistically significant differences were found in the morphometric measurements.CONCLUSIONSAged mice may make a practical model for the age-related changes in the vocal folds that can be used further in studies aiming to correct these changes

Verification of in vivo accuracy of Trumatch™ patient-specific instrumentation in total knee replacement using pin-less computer navigation

Purpose Accurate component alignment in total knee replacement (TKR) is one of the important factors in determining long-term survivorship. This has been achieved by conventional jigs, computer-assisted technology (CAS) and more recently patient-specific instrumentation (PSI). The purpose of the current study was to investigate the in vivo accuracy of Trumatch™ PSI using validated pin-less computer navigation system. Method Twenty consecutive selected patients that fulfilled our inclusion/exclusion criteria underwent TKR using PSI. Coronal alignment, posterior slope, resection thickness and femoral sagittal alignment were recorded using pin-less navigation. The position of the actual cutting block was appropriately adjusted prior to proceeding to definitive resections. Results The coronal alignment using PSI without the assistance of navigation would have resulted in 14 (70 %) within ±3°, 11 (55 %) within ±2° and 6 (30 %) outside acceptable alignment. Thirty-five percentage of proposed femur sagittal alignment and 55 % of posterior tibial slope were achieved within ±3°. Components size was accurately predicted in 95 % of femurs and 90 % of tibia. Conclusion The purported advantages in restoring alignments using Trumatch™ PSI alone over standard equipment are debatable. However, it predicts sizing well, and femoral coronal alignment is reasonable. Combining Trumatch™ PSI with CAS will allow in vivo verification and necessary corrections