Dai-Soon Kwak

Microscopic Age Estimation from the Anterior Cortex of the Femur in Korean Adults

Abstract:  The purpose of this study was to develop age‐predicting equations from the anterior cortex of the femur of Korean adults. Seventy‐two femoral samples (44 male and 28 female) were obtained from Korean cadavers and used to develop the equations. The thin sections (<100‐μm thick) were prepared by manual grinding; the sections were not decalcified and were stained with Villanueva bone stain reagent. Analysis of covariance showed no significant differences in age‐adjusted histomorphological variables between sexes. In stepwise regression analysis, osteon population density, average osteon area, and the most anterior cortical width were selected for an age‐predicting equation which produced a high regression correlation (R2 = 0.789). The average Haversian canal area was not significantly related to age for any specimen.

Determination of sex for the 12th thoracic vertebra by morphometry of three-dimensional reconstructed vertebral models.

Abstract:  Thirty‐three linear measurements and two ratios were derived from 102 12th thoracic vertebrae of the Digital Korean database at the Catholic Institute for Applied Anatomy. Of 35 linear traits, 23 were sexually dimorphic. We created 23 discriminant function equations that predicted sex with 62.7–85.3% accuracy. The analysis using combinations of two factors gave higher accuracies: most equations with accuracies over 80% included at least one measurement involving the coronal diameter of the vertebral endplate. Using stepwise method of discriminant function analysis, three variables predicted sex with 90.0% accuracy: the coronal diameter of the superior endplate of the vertebral body, the ratio of anterior to middle height of the body, and the length of the left mammillary process and pedicle. Coronal dimensions of the vertebral body represented the major sex difference. These equations will help forensic discrimination of the sex of this vertebra among Koreans.

How Effective Is Multiple Needle Puncturing for Medial Soft Tissue Balancing During Total Knee Arthroplasty? A Cadaveric Study

We investigated the quantitative effect and risk factors for over-release during multiple needle puncturing (MNP) for medial gap balancing in varus total knee arthroplasty (TKA). Of the ten pairs of cadaveric knees, one knee from each pair was randomly assigned to undergo MNP in extension (E group), while the other knee underwent MNP in flexion (F group). The increased extension and 90° flexion gaps after every five needle punctures were measured until over-release occurred. The extension gap (< 4mm) and the 90° flexion gap (< 6mm) gradually increased in both groups. The 90° flexion gaps increased more selectively than did the extension gaps. MNP in the flexed knee, a narrow MCL, and severe osteoarthritis were associated with a smaller number of MNPs required to over-release.

Resected femoral anthropometry for design of the femoral component of the total knee prosthesis in a Korean population

We measured the mediolateral (ML) and anteroposterior (AP) length, height and widths of the anterior, posterior and inferior section of the resected distal femurs using three dimensional computer tomographic measurements in 200 knees from 100 cadavers. We also calculated the aspect ratio (ML/AP) and compared the measured parameters with that of six conventionally used total knee femoral prostheses. We found that the average ML (70.2±5.5 mm) and AP (53.9±3.8 mm) dimensions from our study were lower than those reported from Western populations. The aspect ratio showed a progressive decline with an increasing antero-posterior dimension. All of the compared designs showed undersizing for the mediolateral dimension distally and for the widths of the resected medial and lateral posterior femoral condyles. But some of the compared designs showed oversizing for the height of the resected medial and lateral posterior femoral condyles. This study provides guidelines for designing a suitable femoral component for total knee prostheses that fit Asian populations.

Sex determination using discriminant analysis of the medial and lateral condyles of the femur in Koreans

The proximal and distal parts of the femur show the differences between the sexes. Head diameter and the breadth of the epicondyle of the femur are known to distinguish males from females. The proximal end of the femur is studied to determine sex using discriminant analysis but; its distal end is not done. This study aims to develop an equation specific to Koreans by using the medial and lateral condyles of the femur, and to demonstrate the usefulness of equations for specific population groups. We used three-dimensional images from 202 Korean femurs. Twelve variables were measured with a computer program after the femurs were in alignment. Eleven variables showed a statistically significant difference between the sexes (P<0.01). The most accurate equation used width of the medial and lateral condyles (WDC), with of the medial condyle (WMC), depth of the lateral condyle (DLC), and depth of the intercondylar notch (DIN) (94.1%), and is as follows: D = 0.336 × WDC + (-0.097) × WMC + (-0.153) × DLC + 0.372 × DIN - 20.912. The second highest accuracy was 90.1% for the width dimensional group and WDC. This study shows that the medial and lateral condyles of the femur should be helpful for sex determination in situations where the skull and pelvis are missing and part of the femur is available. The study also demonstrates the need for different equations for different population groups.

Quantitative anatomy of the endplate of the middle and lower cervical vertebrae in Koreans.

Study Design. Assessment of the size and shape of cervical vertebral endplates in Koreans. Objective. To obtain data regarding cervical vertebrae and propose an appropriate size for artificial discs in Koreans. Summary of Background Data. The use of various types of cervical artificial discs has increased in recent years; hence, it is important to develop endplate implants of appropriate size. In this study, we determined the quantitative anatomy of cervical endplates in Koreans and proposed a new angular parameter. Methods. This study details the quantitative surface anatomy of the middle and lower cervical vertebral endplates based on the study of 272 cervical vertebrae in Korean cadavers. Computed tomographic images were obtained from 57 Korean cadavers (28 males and 29 females). The mean age and height were 51.14 years (range, 21–60 years) and 161 cm (range, 146–175 cm), respectively. The images were reconstructed, and linear parameters (EPWu, upper endplate width; EPDu, upper endplate depth; EPWl, lower endplate width; and EPDl, lower endplate depth) and an angular parameter (AUA, anterior wall to uncovertebral joint angle) were measured. Results. The width and depth of both the upper and lower endplates increased from C3 through C7. The EPDu, EPWl, and EPDl values of Koreans were similar to those reported in whites, while the EPWu value in this study were smaller than those reported in whites. The AUA for C4 differed significantly between the sexes. The linear parameter values obtained using Korean cadavers were compared with those obtained using white and Singaporean subjects. The EPWu values of Koreans were smaller than those reported in whites, while the values for all the parameters were considerably larger than those reported in Singaporeans. The AUA indicated the existence of various relationships between the endplate and the uncovertebral joint. Conclusions. This data can be used to develop cervical devices for Koreans. The AUA should be studied in other populations.

Sex determination using discriminant analysis of upper and lower extremity bones: New approach using the volume and surface area of digital model

This study used 110 CT images taken from donated Korean cadavers to create 3-D models of the following upper and lower limb bones: the clavicle, scapula, humerus, radius, ulna, hip bone (os coxa), femur, patella (knee cap), tibia, talus, and calcaneus. In addition, the bone volume and surface area were calculated to determine sex differences using discriminant analysis. Significant sex differences were found in all bones with respect to volume and surface area (p<0.01). The order of volume was the same in females and males (femur>hip bone>tibia>humerus>scapula), although the order of surface area was different. The largest surface area in men was the femur and in women was the hip bone (p<0.01). An interesting finding of this study was that the ulna is the bone with the highest accuracy for sex determination (94%). When using the surface area of multiple bones, the maximum accuracy (99.4%) was achieved. The equation was as follows: (discriminant equation of surface area; female<0<male)=0.060×clavicle+0.020×scapula+0.045×humerus+(-0.049)×radius+0.093×ulna+(-0.023)×hip bone+0.091×patella+(-0.052)×fibula+0.043×talus-11.548. These results show that bone volume and surface area of extremity bones can be used for sex determination.

Morphometric Evaluation of Korean Femurs by Geometric Computation: Comparisons of the Sex and the Population

We measured 28 parameters of 202 femurs from Koreans by an automated geometric computation program using 3D models generated from computed tomography images. The measurement parameters were selected with reference to physical and forensic anthropology studies as well as orthopedic implant design studies. All measurements were calculated using 3D reconstructions on a computer using scientific computation language. We also analyzed sex and population differences by comparison with data from previous studies. Most parameters were larger in males than in females. The height, head diameter, head center offset, and chord length of the diaphysis, most parameters in the distal femur, and the isthmic width of the medullary canal were smaller in Koreans than in other populations. However, the neck-shaft angle, subtense, and width of the intercondylar notch in the distal femur were larger than those in other populations. The results of this study will be useful as a reference for physical and forensic anthropology as well as the design of medical devices suitable for Koreans.

Anatomic Consideration of the C1 Laminar Arch for Lateral Mass Screw Fixation via C1 Lateral Lamina : A Landmark between the Lateral and Posterior Lamina of the C1

Objective To clarify the landmark for deciding the entry point for C1 lateral mass screws via the posterior arch by using 3-dimensional (3D) computed images. Methods Resnick insisted that the C1 posterior arch could be divided into pure posterior and lateral lamina (C1 pedicle). Authors studied where this transition point (TP) is located between the posterior lamina and the C1 pedicle and how it can be recognized. The 3D computed images of 86 cadaver C1s (M : F=45 : 41) were used in this study. Results The superior ridge of the C1 posterior arch had 2 types of orientation. One was in the vertical direction in the C1 posterior lamina and the other was in the horizontal direction in the C1 pedicle. The TP was located at the border between the 2 areas, the same site as the posterior end of the groove of the vertebral artery. On posterior-anterior projection, the posterior arch was sharpened abruptly at TP. We were unable to identify the TP in 6.4% of specimens due to complete or partial osseous bridges. A total of 93.8% of the TP were located between the most enlarged point of the spinal canal and the medial wall of the vertebral artery. Conclusion The anatomic entry zone of C1 lateral laminar screws was clarified and identified based on the TP by using preoperative 3D computed images.

Biomechanical comparison of three techniques for fixation of tibial avulsion fractures of the anterior cruciate ligament.

PurposeTo evaluate the initial stability of a suture anchor fixation and to compare this with a screw fixation and pull-out suture fixation for anterior cruciate ligament tibial avulsion fracture.MethodsThe initial fixation strength of 3 different fixation techniques, antegrade cannulated screw fixation, pull-out suture fixation with Ethibond and bioabsorbable knotless suture anchor fixation, was evaluated. Using 14 fresh cadavers (28 knees), the strength to failure, initial displacement and mode of failure were measured.ResultsThe strength to failure of the suture anchor fixation was not significantly different from that of the screw fixation and was higher than that of the pull-out suture fixation. The initial displacement of the suture anchor fixation was lower than that of the screw fixation and the pull-out suture fixation. The majority of the suture anchor fixations and the screw fixations were failed by pull-out from the bone. Eight of the 56 suture anchor fixations failed by pull-out of the suture from the ligament proper. And, one of the 7 screw fixations failed due to fracture of the avulsed bony fragment. All of the pull-out suture fixations failed by suture material rupture.ConclusionsThese biomechanical results suggest that the initial fixation strength of suture anchor fixation was not less than that of screw fixation or pull-out suture fixation. And, the initial displacement of suture anchor fixation was lower than that of screw fixation or pull-out suture fixation. The suture anchor fixation appears to be a good alternative fixation technique for repair of anterior cruciate ligament tibial avulsion fracture.