• Journal of the Korean Orthopaedic Association
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• v.54 no.3
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• pp.281-286
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• 2019

Avascular necrosis (AVN) is defined as the cellular death of bone and bone marrow components due to the loss of blood supply, and associated with post-traumatic or non-traumatic events. AVN usually involves the epiphysis of a long bone, such as the femoral and humeral heads, which are susceptible to osteonecrosis. Many studies have been conducted but they were restricted to investigations of femoral head avascular necrosis. The presence of osteonecrosis in the proximal femur may impair biological fixation after total hip arthroplasty. We report a 56-year-old male patient with avascular necrosis located not only at the femoral head, but also in the entire femur, including the medullary cavity, who underwent total hip arthroplasty 2 years earlier along with a review of the relevant literature.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.2
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• pp.133-144
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• 1995

After resection of intraarticular, periacetabulum(P2) and pubic rami(P23) and extraarticular, proximal femur(P2-H12) by Enneking classification, reconstruction is very difficult. We experienced three cases of saddle prostheses for reconstruction after P2, P23, and P2-H12 resection in pelvic malignancies. Case 1 was a high grade chondrosarcoma in 36 year-old-man and P2 resection was done. But he died of disease 19 months after operation. Case 2 was a malignant giant cell tumor in 32 year-old-woman. P23 resection was given and she is disease-free 32 months after operation. Case 3 was an osteosarcoma of 27-year-old-man and P2-H12 resection was performed and he is disease-free postoperative 12 months now. According to MSTS functional evaluatin system, all three patients showed no pain(5), intermediate function(2), emotinally satisfied(3), one cane or crutch supported(1), limited walking(3), and minor cosmetic gait(3). There was no significant complication and no dislocation except intermittent inguinal hernia in case 2. All patients started crutch walking 3 weeks after operation. Around 6 months postoperatively, the preserved iliac wing(P1 component) was hypertrophied enough to endure the full weight bearing. All could have squating and kneeling positions. In conclusion, saddle prosthesis would be a very useful method of reconstruction after P2, P23, and/or H1-2 resection to shorten the operation time and to reduce the infection rate without significant loss of function.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.7
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• pp.703-708
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• 2013

Conventional total hip joint replacement(THR) surgery requires a long incision and long rehabilitation time. The stem used in THR is inserted into the cancellous bone of the femur where it plays the role of the artificial joint. Minimally invasive surgery(MIS) has been devised to reduce muscle damage to patients. In this study, a mechanical stem was developed on the basis of MISto reduce the incision length through the principle of the gear. The mechanical stem consists of six components. A prototypical model for a mechanical stem was fabricated using an acryl-based polymer, and its workability was confirmed. To actualize the mechanical stem, a three-dimensional Bio-CAD modeling technique was applied. The hip joint area based on computed tomography(CT) was reconstructed. The safety of the mechanical stem by applying more load than the weight of a man under virtual surgery environment conditions was confirmed by finite element analysis.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.951-955
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• 2001

The experimental comparison between bonded and unbonded types stem-cement interface was carried out on axisymmetric stem-cement-aluminum model of the femoral component of a total hip replacement. Human femur was modeled in non-tapered and tapered($7.5^{\circ}$) aluminum hollow cylinders to emulate the diaphyseal and metaphyseal segments of the femur. For unbonded type, we tested stems with three different taper angles($5^{\circ},\;7.5^{\circ},\;10^{\circ}$). In every case, the cement-aluminum interface was designed to endure 8MPa shear strength. (a measured value at cement-bone interface) We tested aluminum models under axial loading for both cases. As an experimental result, it was found that unbonded stem sustained more axial load as bonded stem in both cases, diaphyseal and metaphyseal models. The unbonded types failed in cement mantle under axial compressive load, while the bonded ones failed in shear at cement-aluminum interface. These results suggest that a polished stem will sustain much higher axial load than a roughened stem. And a polished stem will make more stable cement-bone interface that may promote better osteosythesis around the stem.

• Journal of the Korean Orthopaedic Association
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• v.53 no.6
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• pp.490-497
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• 2018

Purpose: To evaluate the utility of ceramic-on-polyethylene articular bearing surface when cementless total hip arthroplasty is performed in patients older than 65 years through an analysis of the minimum five-year follow-up results using the ceramic femoral head and cross-linked polyethylene liner. Materials and Methods: From March 2010 to September 2012, 51 patients (56 hips) who were older than 65 years were enrolled in this retrospective study. The mean age at surgery was $70.9{\pm}5.1years$ old. A clinical assessment was analyzed using the Harris hip score. For the radiographic assessment, the cup inclination and anteversion, stem alignment, and wear amount were measured. The postoperative complications were also determined. Results: The mean Harris hip score was improved from preoperative 48 points to postoperative 87 points (p<0.05). The mean cup inclination was $40.9^{\circ}{\pm}6.4^{\circ}$ and the mean cup anteversion was $20.3^{\circ}{\pm}8.1^{\circ}$. The mean cup anteversion of the elevated liner-used group (16 cases) was $14.3^{\circ}{\pm}7.9^{\circ}$ and the mean cup anteversion of the neutral liner used group (40 cases) was $22.4^{\circ}{\pm}9.1^{\circ}$ (p<0.05). The mean stem alignment angle was $0^{\circ}$ (range, varus $4^{\circ}$-valgus $4^{\circ}$). The mean linear wear amount was $0.458{\pm}0.041mm$ and the average annual linear wear rate was $0.079{\pm}0.032mm/yr$. Six cases (10.7%) of intraoperative periprosthetic femoral fractures were encountered. Conclusion: Based on these results, the use of a ceramic-on-polyethylene articular bearing surface in elderly patients with cementless total hip arthroplasty is beneficial. On the other hand, careful effort is needed to prevent intraoperative periprosthetic femoral fractures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1157-1158
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• 2012

• Journal of muscle and joint health
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• v.25 no.2
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• pp.122-134
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• 2018

Purpose: The purpose of this study was to develop a 12-week structured exercise program (12-week-SEP) and evaluate its effects on pain, physical function and quality of life in patients with total hip arthroplasty (THA). Methods: A nonequivalent control group non-synchronized design was utilized to examine the effects of the 12-week-SEP on patients' outcomes after THA. A total of 46 adult patients (experimental group=25, control group=21) who had THA were recruited for the study. The 12-week-SEP consisted of education, exercise (muscle strengthening and progressive walking), and feedback. Data were analyzed by SPSS/WIN 21.0 using the $x^2$ test and repeated measures ANOVA. Results: The mean age of the participants was 60.9 years and 25 men (54.5%) and 21 women (45.7%) were included in the study. There were significant intervention effects on pain reduction and increased physical function but no effects on quality of life. Conclusion: The 12-week-SEP provided pain relief and enhanced physical function in patients underwent THA. Clinical application of the 12-week-SEP can improve postoperative nursing practices for patients with THA. Future research with larger sample is of necessity to obtain greater generalizability of the empirical evidences of the 12-week-SEP.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.107-114
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• 2018

Long-term complications such as loosening, wear, osteolytic lesion and granulomatous reaction by foreign bodies can occur, after total hip arthroplasty. The implantation alignment effects dislocation and wear, according to its amount and direction. Wear particles in total hip arthroplasty brings about biochemical complications such as osteolysis or send wear. In this sense, it is important to regularly check wear and alignment of total hip replacement. Because the wear in followup of 10 years may remain in a small amount, like a 1 or 2 mm generally, somewhat precise measurement tool has to be established. The wear and alignment measurement softwares commercially available currently lack in project saving or reproducibility. This study suggests a reliable method for the measurement using an X-ray image and a CAD software. The proposed method can be executed only if having a CAD software under most of current general clinical radiographical environment. The proposed was revealed through tests for the method to have accuracy of 0.06 mm with precision of 0.05 mm for wear measurement, and precision of 0.27 degrees for tilt measurement.

• Journal of Biomedical Engineering Research
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• v.23 no.2
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• pp.119-130
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• 2002

The nonlinear finite element program has been developed to analyze the design performance of an artificial hip prosthesis and long term behavior of a treated femur with stems made of composite material after cementless total hip arthroplasty(THA). The authors developed the three dimentional FEM models of femoral bone with designed composite stem which was taken with elliptic cross section of 816 brick elements under hip contact load and muscle farce in simulating single leg stand. Using the program, density changes, stress distributions and micromotions of the material femoral bone were evaluated by changing fiber orientation of stems for selected manufacturing method such as plate cut and bend mold. The results showed that the composite materials such as AS4/PEEK and T300/976 gave less bone resorption than the metallic material such as cobalt chrome alloy, titanium alloy and stainless steal. It was found that increasing the long term stability of the prosthesis in the femur could be obtained by selecting the appropriate ply orientation and stacking sequence of composite.

• Journal of the Korean Orthopaedic Association
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• v.55 no.2
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• pp.143-153
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• 2020

Purpose: To evaluate the timing of the improvement in surgical skills of the direct anterior approach for hip arthroplasty through an analysis of the clinical features and learning curve in 58 cases. Materials and Methods: From November 2016 to November 2018, 58 patients, who were divided into an early half and late half, and underwent hip arthroplasty by the direct anterior approach, were enrolled in this retrospective study. The operation time and complications (fracture, lateral femoral cutaneous nerve injury, heterotopic ossification, infection, and dislocation) were assessed using a chi-square test, paired t-test, and cumulative sum (CUSUM) test. Results: The mean operation times in total hip arthroplasty (26 cases) and bipolar hemi-arthroplasty were 132.1 minutes and 79.7 minutes, respectively, demonstrating a significant difference between the two groups. CUSUM analysis based on the results revealed breakthrough points of the operation time, decreasing to less than the mean operation time because of the 16th case in total hip arthroplasty and 14th case in bipolar hemiarthroplasty. Complications were encountered in the early phase and late phase: five cases of fractures in the early phase, no case in the late phase; eight and two cases of lateral femoral cutaneous nerve injury, respectively; three and two cases of heterotopic ossification, respectively; and one case of dislocation, one case of infection and three cases of others in the early phase. The CUSUM chart for the fracture rate during operation in the early phase revealed the following: five cases fracture (17.2%) in the early phase and no case in the late phase (0%). This highlights the learning curve and the need for monitoring the inadequacy of operation based on the complications. Conclusion: Hip arthroplasty performed by the direct anterior approach based on an anatomical understanding makes it difficult to observe the surgical field and requires a learning curve of at least 30 cases.