Ultra-Short Bone Conserving Cementless Femoral Stem / 대한고관절학회지

Excellent long-term results have been reported with conventional length cementless femoral stems in total hip arthroplasty; however, proximal stress shielding and thigh pain are still a concern. Metaphyseal engaging bone conserving short stems provide theoretical benefits compared with conventional length cementless stems, including avoiding proximal-distal mismatch, decreasing proximal stress shielding, and limiting perioperative fractures. The purpose of the ultra-short bone conserving cementless stem was to reproduce natural load transfer with an ultra-short stem obtaining optimal stability using the morphology of the proximal femur. Loss of stability of the stem and failure of osseous ingrowth is a potential concern with the use of ultra-short proximal loading cementless femoral stems. Ultra-short, metaphyseal-fitting anatomic or non-anatomic cementless femoral stems provided stable fixation without relying on diaphyseal fixation in young and elderly patients, suggesting that metaphyseal-fitting alone is sufficient in young and elderly patients who have good bone quality.

Finite Element Analysis and Torsional Stability Testing of Reference (Metaphyseal and Diaphyseal Fixation) and Experimental (Metaphyseal Fixation Only) Cementless Femoral Stems / 대한정형외과학회잡지

PURPOSE: To report the details of the findings of finite element analysis and torsional stability testing of a reference stem (fixation in both metaphysis and diaphysis) and an experimental stem (fixation in the metaphysis only). MATERIALS AND METHODS: Finite element ABAQUS software (version 5.5) was used for all analyses. A Newton Raphson iterative solution scheme was used to calculate the nodal displacements and to solve the contact equations. Finite element models of the reconstructed proximal femur were developed. A model of bone geometry was developed from the digitized sections of a right adult human femoral specimen. Two femoral stems (reference and experimental stems) were designed in accordance with the bone geometry. Rotational micromotion of the implant relative to the proximal femoral cortical surface was measured using a single, linearly variable differential transducer (LVDT). Three piezoelectric transducers were used to detect the displacement of the stem in the femur. RESULTS: Under all interface conditions, the compressive stresses of the coating surface were below 1.5 MPa. Shear stresses in the two friction models were below 0.5 MPa, and below 1 MPa in the bonded model. The stress exerted over the cortex in the experimental model was 50% of that in the reference model. The relative displacement of the stem in the coated region was less than 0.05 mm, but it increased distally in a linear fashion and was 0.45 mm at the stem tip. A stress concentration in the proximal femoral cancellous bone was noticeably higher in the experimental model than in the reference model. However, the overall characteristics of stress transfer were not changed by stem shape modification. Experimental stem was found to have significantly less rotational micromotion and total permanent rotational displacement values (between 10 and 29 N.m) than the reference stem. CONCLUSION: The torsional stability of the experimental stem is enhanced by: increasing stem thickness in the anteroposterior plane; adding a lateral flare to the stem; and a congruent fit between the proximal medial portion of the stem and calcar femorale. A role of short and tapered distal stem of the experimental stem was negligible in providing with the stem stability and, therefore, the femoral distal stem can be removed. Distal stem removal can minimize stress shielding related bone resorption and can avoid thigh pain.

The smoking habits among the OPD patients and the success rates of the physician's cessation order / 결핵

No abstract available.

Relationship between the sphericity of femoral head-acetabulum and the low incidence of primary osteoarthritis of the hip joint in Koreans

I examined the sphericity and the congruity of the femoral head and the acetabulum in 172 Korean fetuses and in 655 Korean adults. I found that Korean fetal acetabuli and femoral heads are spherical and that the proportion of the head contained in the acetabulum remains constant and congruous throughout the fetal life. Adult actabuli and femoral heads are also spherical in both gender and are there are no visible changes in the shape of the acetabuli and the femoral heads with respect to age. No evidence was found that the congruity of the hip joint is a cause of osteoarthritis of the hip joint. Clinical Relevance: Stable hip joints at the time of birth provide an explantation for the low incidence of congenital dislocation of the hip joint in Koreans. The spherical femoral head and acetabulum (congruous hip joint) seem to be a contributing factor to the low incidence of primary osteoarthritis of the hip in Koreans.

Relationship between the sphericity of femoral head-acetabulum and the low incidence of primary osteoarthritis of the hip joint in Koreans

I examined the sphericity and the congruity of the femoral head and the acetabulum in 172 Korean fetuses and in 655 Korean adults. I found that Korean fetal acetabuli and femoral heads are spherical and that the proportion of the head contained in the acetabulum remains constant and congruous throughout the fetal life. Adult actabuli and femoral heads are also spherical in both gender and are there are no visible changes in the shape of the acetabuli and the femoral heads with respect to age. No evidence was found that the congruity of the hip joint is a cause of osteoarthritis of the hip joint. Clinical Relevance: Stable hip joints at the time of birth provide an explantation for the low incidence of congenital dislocation of the hip joint in Koreans. The spherical femoral head and acetabulum (congruous hip joint) seem to be a contributing factor to the low incidence of primary osteoarthritis of the hip in Koreans.

Cementless Bony lngrowth Total Hip Prosthesis (Anatomical Contact Porous Coated Total Hip Prosthesis) Design using Computed Axial Tomography and Computer Aid Design

The purpose of this study is to design an Anatomical Contact Porous Coated Total Hip Prosthesis(ACP) which can transmit stress to the bone more physiologically and which can also eliminate the shortcomings of the currently available total hip prosthesis as much as possible. In the designing process, we have utilized computed axial tomography(CAT) and computer aid design (CAD). To obtain the shape of the femoral canal nondestructively, computed axial tomography data was obtained from fourteen male and fourteen female cadaver femurs and from twenty male and twenty female patients. To create the medullary canal in the computer, the actual dimension of each CAT-scan image was traced and digitized. For each femur a close-fit prototype of the stem was made with polyester and this was inserted into the corresponding femur in usual surgical manner. To test the accuracy of the fit of the prototype in the canal, an image of the cross-section of the canal with the polyester stem was obtained by CAT-scan in the same way that the original CAT-scan of the canal of the femur was done. We then had our computer display fit ratio between the prototype and the canal. We made sure all of the prototypes fit in the canal anatomically, especially around the defined regions (proximal medial and distal lateral regions). Further improvement was made on the fit of the stem in the canal by optimized computer programming. From studies on the shape and the size of the femoral canals of the sixty-eight femurs, eight sizes of ACP femoral stems were designed for each side. Also, on the basis of the anthropometric measurement of the acetabuli in twenty-eight cadaver hips and in the hips of forty patients with femoral neck fracture, different sizes of ACP hemispheric acetabular components were designed, ranging from 40 and 70 millimeters with 2 millimeter increments.

Incidence and Clinical Significance of Deep Vein Thrombosis after Cementless Total Hip Replacement in Korean Patient Population

We studied the incidence of deep vein thrombosis in the 110 Korean patients who had Porous Coated Anatomic (P.C.A.) cementless total hip replacement. The diagnosis of deep vein thrombosis was made by roentgenographic venography. The perfusion lung-scanning was done to make a diagnosis of pulmonary embolism. Our findings showed that there was an unusually low incidence (7 per cent) of deep vein thrombosis in our unprotected patient group. They also revealed that some factors that are believed to be relevant to thrombosis were conspicuously rare in this series. In view of this fact, we re-evaluated the so-called risk factors and came to a conclusion that some of them-such as advanced age, venous valve number; coagulation assay data, orthopedic diagnosis, preoperative limitation of mobility, hypertension and blood group-that have been claimed to be relevant in fact seem to be irrelevant to deep vein thrombosis.

Cementless Press-Fit and Fibrous or Bony Ingrowth "Asian Total Hip Prosthesis" Design Using Computed Axial Tomography and Computer Aided Design and Computer Aided

The purpose of this study was to design intramedullary femoral stems that will optimally distribute the stresses to the bone. It was postulated that an ideal distribution of stresses would occur if the femoral stem had the same shape as the canal. However, because of the curved nature of the canal it was not possible to insert a canal replica. To make insertion possible, certain areas on the stem must be removed. Cross-section of the femoral canal at 5 and 10mm intervals, were non-destructively obtained by computer assisted tomography and each outline was stored on computer disk. Close-fit stem shapes were generated by computer aided design. These close-fit hip stem designs significantly improved total and priority region stem-canal contact. Further investigation employing both theoretical analysis and laboratory experimentation will examine the strength of these stems and theirs stress distribution to the femur.

A Failure of the Locking System of the Acetabular Assembly in a Total Hip Replacement

In this study, the author presents the case of one patient who had a Harris-Galante total hip replacement for pigmented villonodular synovitis of the left hip joint, the locking system failed and separation of the polyethylene liner from the acetabular metal shell occurred while the closed reduction of the posterior dislocation of the femoral prosthesis was performed. This study indicates that the design of the acetabular assembly should be modified. The gap between the rims of metal shell and polyethylene liner should be reduced or eliminated.

The Reaction of the Acetabular Articular Cartilage to Bipolar Hemiarthroplasty

An evaluation of the acetabular cartilage was performed grossly and histologically in a patient who had a bipolar hemiarthroploasty, which had served satisfactorily for 2 years until the femoral prosthetic head had been separated from the acetabular assembly due to creep deformation of the inner bearing polyethylene cup. This study indicates that the double-bearing bipolar prosthesis dose not necessarily have an advantage over the classical single-piece prosthesis in the prevention of acetabular cartilage wear.

Study of the Pulse Waveform and the Design of the Portable, Non-invasive, Electromagnetic Stimulation for Enhancement of Fracture Healing

Since the concept of bioelectrical potentials in the bone was developed, various electrical systems have been utilized to heal non-united fractures. The asymmetrical and time varied pulsed electromagnetic stimulator was designed and utilized to treat eight fractures of the lower extremity and one congenital pseudoarthrosis of the tibia. Nonunited fractures, neglected old fractures, and a case of congenital pseudoarthrosis responded favorably to our designed pulse waveform. On the other hand, fresh fractures responded equivocally. A new1y designed electromagnetic stimulator which can deliver vascular and calcification pulses, will be developed on an industrial basis to provide various clinical and experimental applications.

Acetabular Dysplasia and Osteoarthritis Developed by an Eversion of the Acetabular Labrum

There is much confusion in orthopedic literature regarding the nature and significance of the so-called acetabular labrum in congenital dislocation of the hip. This experiment describes an animal model in which the relationship between eversion of the acetabular labrum and acetabular dysplasia with degeneration of the articular cartilage was studied. The acetabulum gradually become shallower and more vertically oriented and the femoral head gradually subluxed, but never dislocated. The radiographic appearance of the hip dysplasia was very similar to that seen in human beings. The animals remained asymptomatic without clinically visible signs of hip abnormality throughout the study. It was clearly demonstrated that there was substantial amounts of degenerative change in the articular cartilages of the subluxed hip with no evidence of degenerative change radiologically. It could be concluded that excision of the acetabular labrum should be avoided during open reduction of congenital dislocation of the hip.

Fibrous Dysplasia: Report of Four Cases / 대한정형외과학회잡지

Fibrous dysplasia of bone is a condition affecting one or more bones, usually not disabling, of slow progress, and showing a tendency to become arrested. The etiology of fibrous dysplaia is unknown but it is now believed to be a developmental error in which primitive fibrous tissue proliferates within the bony medulIa and encroaches upon the cortex from within, often producing expansion. The process may be localized to a small segment or may involve almost the entire shaft of the bone, and it may be monostotic, monomelic or polyostotic. In the latter form some patients exhibit a remarkable combination of skin pigmentation and endocrine disturbances. This paper reports the one case of polyostic and three cases of monostotic fibrous dysplasia. The disgnosis was made by clinical, radiological and histological findings.