The purpose of this study is to investigate the effect of the ball-cone contact interface variation on the ceramic ball stress which is the dominant factor of the design of the moldular artificial hip joint. A contact stress analysis problem is formulated using the optimization principle and finite element analysis technique on the ball-cone system of three dimensional axi-symmetrical model, Numerical procedure is employed to get the solution for varying angles of cones and angular mismatches between the ball and cone interfaces. There is a fair amount of friction in the interface and included in the analysis model.
Ceramics ; Finite Element Analysis ; Friction ; Hip Joint ; Hip

PURPOSE: This paper is proposing an improved CT-free registration method which may provide us an accurate and reliable placement of acetabular cup without CT/MRI images. DESIGN AND METHODS: The proposed method employs a T-bar shaped gauge placed on the anatomical landmarks of the pelvis for the registration. The T-bar shaped gauge has its own LED markers and the position of the gauge is obtained through OPTOTRAK3020 system. These landmark points are the anterior superior iliac spines and the symphysis pubis defining anterior pelvic plane. Two subjects were tested to compare the landmark based registration and the proposed T-bar based registration. RESULTS: The measurement deviations of the pelvic obliquity in the frontal plane, tilt in the sagittal plane, and rotation in the transverse plane were 2.08, 1.41, and 2.51 degrees respectively in the point based registration. The T-bar based registration produced 40% smaller deviations(p<0.05): the pelvic obliquity in the frontal plane, tilt in the sagittal plane, and rotation in the transverse plane were 0.84, 0.81, and 1.17 degrees respectively in the T-bar based registration. There was no outlier exceeding 5 degrees in measurement deviation by the T-bar based registration while the outliers were found by the landmark based registration. CONCLUSIONS: We found that T-bar based CT free registration method is more reliable and accurate than the landmark based registration for the acetabular cup navigation. Also, the new method produced more precise registration(p<0.05). We are expecting some offset error of the new registration method due to the skin thickness existing between the T-bar frame and the bony pelvic frame, which may be compensated if we may accumulate sufficient database of the offset.
Acetabulum ; Arthroplasty, Replacement, Hip* ; Pelvis ; Skin ; Spine

PURPOSE: Interface between bone and implant is one of the crucial factors that influence the implant longevity. We proposed an implant fixation method that could induce osseointegration. MATERIALS AND METHODS: Buffer which had polished inner surface and roughed outer one was inserted between femoral head and femoral cup. To verify the effect of proposed fixation method, we made buffered implant with composite femur, applied normal walking force with universal test machine and measured principle strain at the medial region of femoral head. Also we estimated contact stress and compared mechanical characteristics to conventional fixation method by FEM. RESULTS: Experimental results showed compressive stress at the medial region was occurred and maintained. Contact stress was estimated to 0.9 MPa by FEM. As using buffer, tensile stress regions were reduced from 10% to 4.5% and after osseointegration to 6.7%. The regions that had micromotion less than 28 micrometer were about 95%. Fracture risks at the interface and inside the buffer were low. CONCLUSION: We found that the fixation method we proposed reduced tensile stresses and micromotion which separate implant from bone, so that osseointegration at the interface would be possible.
Femur ; Head ; Hip* ; Longevity ; Osseointegration ; Walking

Our purpose is to describe a successful twin pregnancy and delivery after intracytoplasmic sperm injection (ICSI) followed by calcium ionophore with spermatozoa from a globozoospermic man. On the second attempt of ICSI, all of eight metaphase II oocytes were fertilized with treatment with calcium ionophore. Day 3 transfer of six normally developing embryos resulted in an ongoing twin pregnancy, and two preterm healthy babies were born in the 33th week of gestation. To the best of our knowledge, this is the first report of pregnancy and delivery after ICSI followed by calcium ionophore with spermatozoa from a globozoospermic man in Korea.
Calcium* ; Embryonic Structures ; Humans ; Metaphase ; Oocytes ; Pregnancy ; Pregnancy, Twin* ; Sperm Injections, Intracytoplasmic* ; Spermatozoa*

OBJECTIVE: The aims of this study were to investigate whether fertilization could induce the resumption of meiosis in mouse oocytes arrested at metaphase I (MI) after in vitro maturation (IVM), and to investigate the effect of Ca²⁺ chelator treatment at the time of fertilization on the transition from MI to metaphase II (MII). METHODS: MII-stage and arrested MI-stage mouse oocytes after IVM were fertilized, and then embryonic development was monitored. Blastocysts from each group were transferred into 2.5 days post-coitum pseudo-pregnant ICR mice. MI oocytes after IVM were treated with a Ca²⁺ chelator to investigate the effect of Ca²⁺ oscillations on their maturation. RESULTS: As insemination time increased, the number of oocytes in the MI group that reached the MII stage also increased. The blastocyst rates and total cell numbers in the MII group were significantly higher than in the MI group. No pregnancy occurred in the MI group, but 10 pregnancies were achieved (10 of 12) in the MII group. The proportion of MI oocytes that matured to MII oocytes after fertilization was significantly higher in the non-treated group than in the Ca²⁺ chelator-treated group. CONCLUSION: The findings that a higher proportion of MI-arrested oocytes progressed to MII after fertilization and that the MI-to-MII transition was blocked by Ca2+ chelator treatments before fertilization indicate that the maturation of MI oocytes to MII oocytes is associated with intracellular Ca²⁺ oscillations driven by fertilization.
Animals ; Blastocyst ; Calcium Signaling ; Cell Count ; Embryonic Development ; Female ; Fertilization ; In Vitro Oocyte Maturation Techniques ; In Vitro Techniques* ; Insemination* ; Meiosis ; Metaphase* ; Mice* ; Mice, Inbred ICR ; Oocytes* ; Pregnancy ; Spermatozoa*

OBJECTIVE: Since IVF program was first established, various types of media and culture systems have been developed either in-house or commercially. The aim of this study was to compare the efficacy of in-house Maria Research Center (MRC) media to that of commercially available Sydney IVF media in human day 3 embryo transfer cycles. METHODS: Three hundred sixty nine couples were included in this prospective, randomized, and comparative study. All couples undergoing IVF treatment at the Maria Fertility Hospital were randomly assigned to either Sydney IVF (n=178) or MRC (n=191) media. RESULTS: No difference was observed between the MRC media and Sydney IVF media groups with respect to fertilization rate (74.4% vs. 75.5%). The clinical pregnancy and implantation rates of MRC media (47.1% and 20.0%, respectively) were also similar to those of Sydney IVF media (44.4% and 19.4%, respectively). However, the proportion of embryos with good quality on day 3 was significantly higher in the MRC media group than the Sydney IVF media group (50.2% vs. 43.2%) (p<0.05). CONCLUSION: MRC media were as effective as Sydney IVF media for sustaining embryo development and pregnancy rates. The present study implies that MRC media can be a suitable alternative to commercially available media for human IVF-ET program.
Embryo Transfer ; Embryonic Development ; Embryonic Structures ; Family Characteristics ; Female ; Fertility ; Fertilization ; Humans ; Pregnancy ; Pregnancy Rate ; Prospective Studies

This study was carried out to investigate the development rates of human embryos co-cultured with cumulus cells to each blastocyst stage. Human zygotes were co-cultured on cumulus cell monolayer in YS medium supplemented with 20% hFF. On day 2, if patient had four or more 'good' embryos(regular blastomeres without fragmentation), embryos were further cultured for 72hrs. Blastocysts on day 5 were classified into early blastocyst (ErB), early expanding blastocyst (EEB), middle expanding Blastocyst (MEB), and expanded blastocyst (EdB) on the basis of their morphological aspects of trophectoderm cells and blastocoele. Subsequently, maximum 3 of best blastocysts were transferred in 486 cycles. The results in this study were as follows: Patients who had four or more 'good' embryos on day 2 were 498 persons, but patients whose embryos could not be transferred due to failure in development to the blastocyst stage on day 5 were 12 persons (2.4%). The development rate of embryos to the blastocyst stage was 58.2% (2,885/4,957) on day 5, and the rates that developed to the ErB, EEB, MEB, and EdB stage were 15.0% (743/4,957), 14.9% (739/4,957), 14.4% (714/4,957), and 13.9% (689/4,957), respectively. Total 1366 blastocysts were transferred in 486 cycles (mean number=2.81). The implantation rate and the ongoing implantation rate obtained by observing the number of G-sac and FHB were 29.9% (409/1,366) and 22.5% (308/1,366), respectively. The clinical pregnancy rate was 51.2% (249/486), and the ongoing pregnancy rate was 39.1% (190/486). Among women showing ongoing pregnancy, women with singleton were 50% (95/190), women with twin were 37.9% (72/190), and women with triplet were 12.1% (23/190). Although triplet pregnancy rate in this study was high such as 12.1%, because many blastocysts with high viability were produced in our co-culture system using cumulus cells on day 5, we really believe that a multiple pregnancy except twin should not occur by selecting good embryos for maximum two blastocyst transfer. These results demonstrate that autologous cumulus cells may be used for the production of blastocysts with high developmental competence, and the use of autologous cumulus cells to be collected easily, and to be treated conveniently at OPU must be an effective means for obtaining high implantation and pregnancy rate.
Blastocyst* ; Blastomeres ; Coculture Techniques* ; Cumulus Cells* ; Embryo Transfer ; Embryonic Structures* ; Female ; Humans* ; Mental Competency ; Pregnancy ; Pregnancy Rate ; Pregnancy, Multiple ; Pregnancy, Triplet ; Triplets ; Zygote

PURPOSE: Inaccurate femoral canal shaping can result in post-operative complications in hip arthroplasty. We addressed the amount of broach rotation during shaping of the femoral canal and compared it with respect to newly designed broaches which were modified to minimize the rotation. MATERIALS AND METHOD: we designed the broaches that had canal guide which restricts the broach motion such that it is always aligned with the femoral axis while the broach machines the metaphyseal bone. Conventional broaches and the modified broach applied to 5 pair of fresh-frozen cadaver femurs and its spatial motion was measured with motion tracker. Rotations in coronal, saggital and frontal plane during the final 10 mm of broach advance were measured. RESULTS: 2.4..of axial rotation was occurred during final 10 mm advance of broach in the conventional method, which was the largest component of the rotation. Rotation of the broach during machining was decreased to 37% (p=0.075) and 25% (p=0.042) in the sagittal plane and coronal plane, respectively, by proposed method. CONCLUSION: The canal guide in the proposed method significantly reduced the rotation of the broach without any extra incision or measurement devices, resulting in increased accuracy in the femoral canal shaping.
Arthroplasty ; Axis, Cervical Vertebra ; Cadaver ; Femur ; Hip

PURPOSE: To propose a method providing an accurate femoral shaping for cementless total hip arthroplasty to maximize bone contact without femoral bone breakage and make secure correct position of the implant by eliminating the manual broach process MATERIALS AND METHODS: 5-cadaver specimens were tested with this system. A reamer-shaped registration gauge is inserted into the femoral canal. This gauge defines the position of the implant to be inserted. Then, the base frame is attached to the femur and the position of the gauge with respect to the base frame is measured. After removing the gauge, a mini robot is mounted on the frame and shapes the femoral canal. After the milling operation, model implant is inserted and its position and gap are measured. RESULTS: Anteversion angle error was 0.9degrees(S.D.1.7) and Varus/Valgus alignment error was 1.1degrees(S.D.1.5). 95%(S.D. 3.2) of contact surface had less than 0.3mm gap error. CONCLUSIONS: Proposed THA surgery system increased the accuracy of stem position and fitness compared with manual operation. Our mini robot THA surgery provides most of the benefits RobodocR does while operating procedure is much more simplified and economic.
Arthroplasty, Replacement, Hip* ; Cadaver* ; Femur

Catastrophic failure of a zirconia head with Hylamer acetabular component and early failure due to the phase transformation of zirconia ceramic head after total hip arthroplasty have been indebted issues. We report two cases who had failure of the zirconia ceramic head with polyethylene articulations shortly after total hip arthroplasty. Revision retrieval studies were performed subsequently.
Acetabulum ; Arthroplasty, Replacement, Hip* ; Ceramics* ; Head* ; Polyethylene*