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T Torisu

Publications and source records attributed to T Torisu.

At least 19 recordsLinked to original sources
PubMed2005

Three-dimensional finite element analysis of unicompartmental knee arthroplasty--the influence of tibial component inclination.

Aseptic loosening and failure of a tibial component are recognized problems in unicompartmental knee arthroplasty (UKA). Excessive stress on the supporting cancellous bone is thought to contribute to the loosening and failure. Of factors that could influence supporting cancellous bone stresses, we focused on the inclination of a unicompartmental tibial component by analyzing the effect of coronal plane and sagittal plane inclination. Detailed geometrically accurate, three-dimensional finite element models were constructed from computed tomography (CT) data of a typical adult male proximal tibia. The material properties for the models were obtained directly from the CT data to simulate the inhomogeneous distribution of cancellous bone properties. Placing the component in slight valgus inclination in the coronal plane reduced the cancellous bone stresses. Posterior inclination in the sagittal plane caused a moderate increase in the stresses. Our results suggest that slight valgus inclination of a UKA tibial component may be preferable to varus or square inclination in the coronal plane. An excessive posterior slope of a tibial component should be avoided.

Arthroplasty, Replacement, Knee↗
PubMed2005

Changes in masseter muscle blood flow during voluntary isometric contraction in humans.

The effect of jaw clenching on local blood flow in the masseter muscle was measured using the hydrogen clearance method in 13 healthy subjects. Sustained isometric masseter-muscle contraction levels of 25 and 50% of maximum voluntary contraction (MVC) were investigated. The blood flow at 25% MVC before contraction, during contraction and after contraction was 12.3 +/- 10.9, 19.2 +/- 12.1 and 78.8 +/- 63.9 mL min(-1) (100 g)(-1) (mean +/- s.d.), respectively. At 50% MVC, it was 14.2 +/- 12.9, 18.6 +/- 10.0 and 80.1 +/- 61.8, respectively. The volume of blood flow was significantly greater after contraction as compared with before contraction at both levels (P < 0.0001) and there was no significant difference between before and during contraction periods (P = 0.17: 25% MVC; P = 0.38: 50% MVC). At 50% MVC blood flow before contraction and the difference in blood flow before and during contraction showed significant negative correlation (r = -0.636, P < 0.02). When the volume of blood flow was low before contraction it tended to increase during contraction and decreased when it was high before contraction. These findings indicate that blood flow in the masseter muscle during sustained isometric contraction is affected by the condition of contraction and may be influenced by the muscle region. It was also indicated that the blood flow during high level contraction was influenced by the volume of blood flow before contraction. Clinically, our findings may help to understand pathological changes which may lead to chronic masticatory muscle pain.

Adult↗
PubMed2005

Does the self-centering mechanism of bipolar hip endoprosthesis really work in vivo?

PURPOSES: To examine radiographically the component motion in a bipolar prosthesis and to determine whether the self-centering mechanism really works in vivo. METHODS: 38 patients with 41 bipolar hip endoprostheses (30 for coxarthrosis and 11 for osteonecrosis of femoral head) were included in this study. Two radiographs of each case were taken to evaluate the self-centering mechanism. The first anteroposterior radiograph of both hip joints was taken at the maximum abduction while the patient standing on the endoprosthetic leg. The second radiograph was taken after the patient returned to neutral position while standing on 2 legs. In the present study, the order in which the radiographs were taken differed from previously reported studies. The radiographs were analysed using the method similar to that of Drinker and Murray. The adductive motion from abduction to a neutral position is within the range of inner bearing oscillation. RESULTS: The outer head alignment changed from 23 degrees to 12 degrees in the patients with osteonecrosis. However, the valgus position of the outer head (36 degrees) remained unchanged in the patients with coxarthrosis standing on 2 legs in the neutral position. CONCLUSION: The self-centering mechanism of the bipolar endoprosthesis functioned in the patients with osteonecrosis, but did not work in the coxarthrosis group.

Arthroplasty, Replacement, Hip↗
PubMed2005

Debridement and continuous irrigation for the treatment of pyogenic arthritis caused by the use of intra-articular injection in the osteoarthritic knee: indications and outcomes.

PURPOSE: To discuss the indications and therapeutic outcomes of synovectomy, debridement, and continuous irrigation for the treatment of pyogenic arthritis caused by intra-articular injection used in the treatment of osteoarthritis of the knee. METHODS: Records of 41 patients with infectious arthritis of the knee who presented to our hospital from 1981 were reviewed. 11 of them had a history of intra-articular injection. They underwent synovectomy, debridement, and continuous irrigation using a Salem double-lumen tube after confirmation that one side of the femorotibial joint cartilage was basically healthy. RESULTS: The infection was successfully treated in 9 of the 11 patients. Of these 9 patients, one died after 3 years and 2 underwent total knee arthroplasty after 3 and 8 years. The remaining 6 patients were followed up for 5 to 15 years. Five of them had deteriorating arthropathy, and the condition was unchanged in the others. Two of these 6 patients had pain while walking, and their Japanese Orthopaedic Association scores were 70. The remaining 4 had good knee function and reduction of pain, with a mean Japanese Orthopaedic Association score of 91 and a mean range of motion of 131 degrees. CONCLUSION: Arthrodesis is frequently considered the treatment for osteoarthritis if the joint destruction has affected the weight-bearing surface. However, in our experience, even when inflammatory granulation develops in the cartilage surface of one side of the femorotibial joint, good results can still be obtained by synovectomy, debridement, and continuous irrigation. After the pyogenic arthritis has subsided, if osteoarthritis has advanced and bowleg has exacerbated, further treatment options are available, such as tibial resection and even joint replacement. Continuous irrigation should be considered a feasible treatment option for pyogenic arthritis.

Adrenal Cortex Hormones↗
PubMed2003

Menatetrenone (vitamin K2) acts directly on circulating human osteoclast precursors.

It is still not certain what the direct effect of menatetrenone is on osteoclast precursors. In the present study, we investigated whether menatetrenone has a direct effect on circulating osteoclast precursors to influence osteoclast differentiation. Monocytes isolated from human peripheral blood were cultured with receptor-activated NF-kappaB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF). Menatetrenone or vitamin K1 was then added to the cultures. Geranylgeraniol or phytol (the respective side chain) was also added to the cultures instead of menatetrenone or vitamin K1, respectively. After 7 and 14 days incubation, cultures were evaluated for cytochemical and functional evidence of osteoclast formation. The number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs) and the percentage area of lacunar resorption induced by RANKL and M-CSF were decreased when menatetrenone or geranylgeraniol was added to the cultures. Dose-dependent inhibition of osteoclast formation and lacunar resorption was seen when the cultures were treated with menatetrenone or geranylgeraniol. In contrast, vitamin K1 or phytol did not affect the number of TRAP-positive MNCs nor the percentage area of lacunar resorption. These results indicate that menatetrenone not only influences osteoclast formation via bone stromal cells but also acts directly on circulating osteoclast precursors to influence osteoclast differentiation. These findings also suggest that geranylgeraniol, the side chain of menatetrenone, plays an important role in this inhibitory effect.

Acid Phosphatase↗
PubMed2003

3M integral bipolar cup system for dysplastic osteoarthritis. Clinical and radiographic review with five- to seven-year follow-up.

Between 1995 and 1997 we undertook 40 bipolar hip arthroplasties in 35 patients with dysplastic osteoarthritis. The steep and shallow acetabulum was excavated and the bipolar socket was placed high with an adjustment of leg-length. At follow-up of between five and seven years, there were 19 excellent, 16 good and five fair results according to the scoring system of Merle d'Aubigné and Postel. The mean radiographic superior migration of the bipolar socket was 2.1 mm (0 to 10). Osteolysis was noted in three hips within three years of the operation. Abduction on weight-bearing was recorded in 24 hips and the bipolar system was found to be functioning predominantly between the inner bearing and the metal femoral head in 20.

Adult↗
PubMed2002

An assessment of histopathological criteria for infection in joint arthroplasty in rheumatoid synovium.

Intraoperative frozen section is reported to be a reliable means of identifying occult infection for preoperative evaluation of arthroplasty. The aim of this study was to determine whether the reported histopathological criteria--the existence of more than 10 polymorphonuclear cells (PMN) per high-power field--is valuable for determination of infection during the arthroplasty of patients with rheumatoid arthritis (RA). The permanent histological sections of RA synovium were analysed to study the degree of infiltration of PMNs. Furthermore, in order to examine the penetrative distribution of PMNs within the synovial tissues, immunohistochemical staining of PMNs was performed. In addition, the clinical history, from the postoperative period to the present, was investigated in 46 patients (60 joints). The presence of early- and/or late-stage postoperative infection, the development of postoperative fever, the progression of erythrocyte sedimentation rate (ESR) (more than 30 mm per hour) and the changes in CRP (more than 10 mg per litre) were further examined and compared with the histopathological tissue analyses and findings. The results demonstrated the presence of more than five PMNs per high-power field, excluding surface fibrin and inflammatory exudate in at least five separate microscopic fields in 10 joints (16.7%) of nine patients, out of 60 joints of 46 patients, in which no postoperative infection was evident. As to the magnitude of penetrative distribution of PMNs in 10 joints, there was a trend of deepening infiltration among the patients with intensive PMN infiltration. In addition, no development of postoperative fever, CRP or continuous indications of high ESR values were evident in this group. As the existence of more than 10 PMN per high-power field was not absolutely indicative of occult infection, investigation of frozen section during arthroplasty should be carefully managed.

Adult↗
PubMed2002

The effects of tibial component inclination on bone stress after unicompartmental knee arthroplasty.

Unlike the case with total knee arthroplasty, the femorotibial angle (FTA) after unicompartmental knee arthroplasty (UKA) does not directly depend on the inclination of the tibial component when the height of the joint line is maintained. This study analyzed the effects of the inclination of the tibial component in the coronal plane on the contact pressure of the implant-bone surface and the stresses on the proximal tibia. A two-dimensional, coronal plane model of the proximal tibia was subjected to finite-element analysis. Sixteen patterns of finite-element models of equal FTA were developed in which the inclination of tibial components ranged from 5 degrees valgus to 10 degrees varus in increments of 1 degrees. Stress concentration at the proximal medial diaphyseal cortex gradually increased as the inclination changed from valgus to varus. Maximum contact pressure on the metal-bone interface similarly changed and shifted from the lateral edge to the medial edge of the implant as the inclination changed to varus. It was found that even without changing FTA, the inclination of the tibial component might affect stress concentration and contact pressure in the proximal tibia after UKA. The results suggested that slight valgus inclination of the tibial component might be preferable to varus and even to 0 degrees (square) inclination so far as the stress distribution is concerned.

Arthroplasty, Replacement, Knee↗
PubMed2002

Anticipatory and reflexive neck muscle activities during voluntary rapid jaw opening and passive jaw depression in humans.

The characteristics of head movement during voluntary rapid jaw opening movement and passive jaw depression were investigated using accelerometers and electromyographs (EMG) on eight healthy examinees. Passive depressions were executed by means of load on the lower jaw, initiated either by examinees themselves or an experimenter. In the depression initiated by examinees, a head-extension movement that preceded the load to the lower jaw and anticipatory activities in the nuchal region of the trapezius muscle were observed. In the depression initiated by the experimenter, the anticipatory activities were not observed. In both of these cases, stretch reflexes were induced in the trapezius muscle. During voluntary rapid jaw opening, a head-extension movement nearly synchronized with the opening movement in the lower jaw acceleration, and dorsal-neck muscle activities accompanying the synchronized movement were observed. The peak timing of these neck-muscle activities preceded the latencies of the stretch-reflex activities observed in the jaw-depressed tasks, but no anticipatory activities were observed in the dorsal-neck muscles. We conclude that neither the anticipatory activities nor the reflex activities observed in the passive depressions have effects on the initial part of the dorsal-neck muscle activities, which are related to the head-extension synchronized with the voluntary lower-jaw opening movement.

Adult↗
PubMed2001

Effect of particle size on macrophage-osteoclast differentiation in vitro.

To determine whether particle size affects macrophage-osteoclast differentiation in vitro, latex beads of 0.1, 1, and 10 microm in diameter were added to a murine macrophage-UMR106 osteoblast-like cell coculture system. The extent of osteoclast differentiation was determined by assessing the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells on glass coverslips and the extent of lacunar resorption on dentine slices. The addition of particles, 1 and 10microm in size, to the cocultures resulted in a significant increase in the number of TRAP-positive osteoclast-like cells and in the resorption pit surface area compared with findings in control cultures to which no particles had been added. Particles 0.1 microm in size also stimulated osteoclast formation relative to the control; however, the difference was not significant. These results indicate that particles, particularly these 1 and 10microm in size, sizes which were phagocytosable, significantly enhanced the process of macrophage-osteoclast differentiation and suggest that particle size plays an important role in periprosthetic osteolysis.

Acid Phosphatase↗
PubMed2001

The effect of macrophage-colony stimulating factor and other humoral factors (interleukin-1, -3, -6, and -11, tumor necrosis factor-alpha, and granulocyte macrophage-colony stimulating factor) on human osteoclast formation from circulating cells.

Macrophage-colony stimulating factor (M-CSF) is an essential requirement for human osteoclast formation, but its effect on the proliferation and differentiation of circulating osteoclast precursor cells is unknown. Other growth factors and cytokines are also known to support/stimulate osteoclast formation from mouse marrow precursors, but it is not certain whether these factors similarly influence human osteoclast formation. In this study, human monocytes were cocultured with osteoblast-like UMR-106 cells on coverslips and dentine slices for up to 21 days in the presence of 1,25 dihydroxyvitamin D(3) (10(-7) mol/L), dexamethasone (10(-8) mol/L), and various concentrations of either M-CSF or other humoral factors (interleukin [IL]-1beta, IL-3, IL-6, and IL-11; tumor necrosis factor-alpha [TNF-alpha]; and granulocyte macrophage [GM]-CSF). The effect on osteoclast formation was assessed by tartrate-resistant acid phosphatase (TRAP) and vitronectin receptor staining and lacunar bone resorption. The results of time-course and proliferation studies showed that M-CSF stimulated both the proliferative and differentiation stages of human osteoclast formation from circulating osteoclast precursors in a dose-dependent manner. A high concentration of M-CSF (100 ng/mL) did not inhibit osteoclast formation. IL-3 and GM-CSF were also capable of stimulating human osteoclast formation, although these growth factors were much less potent than M-CSF. IL-3- and GM-CSF-stimulated osteoclast formation was inhibited by an antibody specific for human M-CSF. Osteoclast formation and lacunar resorption was not seen when either TNF-alpha, IL-1beta, IL-6 (+ soluble IL-6 receptor), or IL-11 was substituted for M-CSF during coculture. These results confirm that M-CSF is essential for human osteoclast formation from circulating mononuclear precursors, and also shows that IL-3 and GM-CSF may support osteoclast differentiation via the stimulation of M-CSF production by human monocytes.

Adult↗
PubMed2001

Influence on force curve exerted by jaw tapping force.

The purpose of this study, which made use of visual biofeedback, was to determine how methods of regulating jaw tapping force differed depending on the strength of the tapping, using the force curve as an index. Nine healthy examinees were asked to make 30-35 jaw tapping movements, reproducing the defined target tapping force as accurately as possible. We measured the duration of the tooth contact phase, the time to peak force, the first time derivative of force (peak dF/dt), and the time to peak dF/dt. The results indicated that the duration of the tooth contact phase and the time to peak force increased with the target value (P < 0.01). As the target rose, the peak dF/dt increased significantly (P < 0.01), but the time to peak dF/dt was not significant (P=0.134). We found that the higher the target value, the greater the degree of dependency on feedback information. We also found that both the peak dF/dt and the time to peak dF/dt were determined for each examinee prior to movement.

Adult↗
PubMed2001

Head movement properties during voluntary rapid jaw movement in humans.

The purpose of this study was to determine whether the start of the synchronized head movement during mandibular movement is evoked by the peripheral reflexes following mandibular movement (i.e. stretch or trigemino-neck reflexes), or, alternatively, is started by pre-programmed central command. Head movement accompanying voluntary rapid jaw opening movement was studied using accelerometers fixed to the upper and lower incisors, as well as electromyographs (EMGs) of the neck muscles. The direction of head acceleration at the upper incisor was towards head extension at the beginning of jaw opening movement in 89.2% of all trials, opposite to the direction of lower jaw acceleration. The onset of head acceleration was later than that of the lower jaw acceleration by averages of 6.2-10.7 ms, and the onset of electromyographic activities of the sternocleidomastoid (SCM) muscle preceded that of head acceleration by an average of 12.5-24.3 ms. These findings suggest that head movement during mandibular movement is not started by peripheral reflexes but by pre-programmed central commands. This may be relevant to muscular discomfort in the neck and shoulder regions of patients with stomatognathic disorders.

Acceleration↗
PubMed2000

Atlantoaxial subluxation associated with ossification of posterior longitudinal ligament of the cervical spine.

STUDY DESIGN: Two case reports. OBJECTIVE: To demonstrate two rare cases of atlantoaxial subluxation associated with ossification of the posterior longitudinal ligament of the cervical spine, in which spastic quadriplegia developed. SUMMARY OF BACKGROUND DATA: There are only two reports of an association of diffuse idiopathic skeletal hyperostosis with atlantoaxial subluxation. This condition often accompanies ossification of the posterior longitudinal ligament of the cervical spine, but there is nothing in the literature about the association of ossification of the posterior longitudinal ligament with atlantoaxial subluxation. METHODS: Clinical and radiographic findings of these two cases were demonstrated. In both cases laminoplasty of the cervical spine was performed with occipitoaxial arthrodesis. RESULTS: The spastic quadriplegia of these two patients caused by myelocompression improved after surgical intervention. CONCLUSION: Ossification of the posterior longitudinal ligament of the cervical spine may cause atlantoaxial subluxation.

Aged↗
PubMed2000

Regulation of human jaw tapping force with visual biofeedback.

The purpose of this study, which made use of visual biofeedback, was to determine whether jaw tapping force reproduction is related to the strength of tapping and to investigate how jaw tapping force affects the tapping movement curve. Nine healthy examinees were asked to reproduce jaw tapping force. We found that the ease and method of regulating jaw tapping force differed depending on the target force. We also found that jaw tapping force was regulated by alteration of the jaw opening distance, the duration of the tooth contact phase, the duration of the jaw closing phase, the maximum jaw opening velocity, and the maximum jaw closing velocity. However, the duration of the jaw opening phase and cycle time was not affected by force regulation under our experimental conditions.

Adult↗
PubMed2000

Role of multinuclear cells in granulation tissue in osteomyelitis: immunohistochemistry in 66 patients.

We investigated the origin of multinuclear cells (MNCs) in the granulation tissue in osteomyelitis by immunohistochemical techniques in 66 patients. 12 samples were analyzed for the presence of CD68, cathepsin K, CD11b and tartrate-resistant acid phosphatase (TRAP) activity. Many MNCs were present in the granulation tissue adjacent to a sequestrum. MNCs in contact with the sequestrum were also noted, however, no osteoblasts were found. Immunohistochemically, CD68, cathepsin K and TRAP were strongly expressed in most of the MNCs, while CD11b positive cells were not found. MNCs remote from and in contact with the sequestrum showed the same immunohistochemical features which are characteristic of osteoclasts. Further, MNCs in contact with the sequestrum had originally developed in the granulation tissue and directly infiltrated towards the sequestrum without cell-to-cell interaction with osteoblasts.

Acid Phosphatase↗
PubMed2000

Delayed paraplegia caused by the gradual collapse of an infected vertebra.

A case of delayed paraplegia caused by a gradual and progressive collapse of a vertebra after healing of pyogenic spondylitis is reported. A 73-year-old man was treated for a hematogenously seeded pyogenic spondylitis of the first lumbar vertebra. Magnetic resonance imaging showed a high signal intensity of the involved vertebra and adjacent discs and a paravertebral abscess without disc space narrowing. Eight months after healing of the infection, the patient had muscle weakness and paresthesia of the lower extremities, which gradually increased. The plane radiographs revealed a kyphotic deformity of 36 degrees with a collapse of the first lumbar vertebra.

Abscess↗