Tadami Matsumoto

Chordoma in the cervical spine managed with en bloc excision.

STUDY DESIGN En bloc resection of a chordoma in the midcervical vertebral spine was performed. OBJECTIVES To document the surgical technique used for en bloc excision of a chordoma arising in the midcervical spine. SUMMARY OF BACKGROUND DATA Malignant tumors arising in long bones are excised en bloc. The authors recently designed a technique for en bloc resection of malignant tumors in the thoracolumbar spine using the T-saw. However, this technique is difficult in tumors of the cervical spine, and there are no previous reports of successful en bloc resection of such tumors. METHODS Using an anterior approach, the ipsilateral vertebral artery was ligated. This was followed by sharply cutting the pedicle of the cervical vertebra with a specially designed T-saw. RESULTS En bloc excision of chordomas in the cervical spine was achieved using the T-saw. CONCLUSION Although the surgical margin was intralesional in a small area, the technique used in this case study indicates that en bloc excision of such tumors can be used with a safety margin even in the cervical spine.

Early magnetic resonance imaging and histologic findings in a model of femoral head necrosis

The authors examined early magnetic resonance images and histologic findings of avascular necrosis of the femoral head in a canine model. The avascular necrosis of the femoral head model was surgically induced. Animals were euthanized at 3 days, 1, 2, and 4 weeks, and the proximal femurs were retrieved. Magnetic resonance images and histologic sections were performed on each of the specimens obtained. Twenty-five mongrel dogs were studied, 4 dogs at 3 days and 7 dogs at each of the other intervals. Findings suggest that histologic changes may be seen as early as 3 days, with marrow edema and hemorrhage as early findings, and fibrous marrow transformation and appositional bone growth as later findings. Magnetic resonance imaging abnormalities did not occur until 1 week after injury and were seen in all animals by 4 weeks.

A new cementless total hip arthroplasty with bioactive titanium porous-coating by alkaline and heat treatment: Average 4.8-year results

A method has been developed for creating a bioactive coating on titanium by alkaline and heat treatment, and shown that it forms a thin layer of hydroxyapatite (HA) on the surface of implants when soaked in simulated body fluid. A series of 70 cementless primary total hip arthroplasties using this coating technique on a porous titanium surface was performed, and followed up the patients for a mean period of 4.8 years. There were no instances of loosening or revision, or formation of a reactive line on the porous coating. Although radiography just after operation showed a gap between the host bone and the socket in over 70% of cases, all the gaps disappeared within a year, indicating the good osteoconduction provided by the coating. Alkaline-heat treatment of titanium to provide a thin HA coating has several advantages over plasma-spraying, including no degeneration or absorption of the HA coating, simplicity of the manufacturing process, and cost effectiveness. In addition, this method allows homogeneous deposition of bone-like apatite within a porous implant. Although this was a relatively short-term study, treatment that creates a bioactive surface on titanium and titanium alloy implants has considerable promise for clinical application.

Minimum ten-year results of a porous acetabular component for Crowe I to III hip dysplasia using an elevated hip center.

We conducted a retrospective study of the placement of porous-coated acetabular components using screws at more than 20 mm above the teardrop without structural bone graft for dysplastic hips to determine long-term outcome. Thirty hips (29 patients) were monitored for a mean of 15.2 years (range, 10.4-18.3 years) after surgery. Compared with 12 contralateral normal hips, the distance of the hip center from the teardrop was significantly high (26.8 +/- 4.8 and 13.4 +/- 2.7 mm P < .001); however, it was not laterally different (31. 5 +/- 5.1 and 31.7 +/- 5.0 mm). No acetabular components showed loosening. One metal shell was revised for wear and osteolysis. Morselized bone grafted in 25 hips was incorporated in all cases. Slight elevation of the hip center without lateralization in cementless cups fixed with screws was well tolerated for dysplastic hips.

Multiinstitutional epidemiological study regarding osteoarthritis of the hip in Japan

Background. Osteoarthritis (OA) of the hip is a major disease that affects the healthy lifespan of a population. It is necessary to fully understand the patients’ conditions before a systematic treatment can be applied. However, a nationwide epidemiological study regarding hip OA has not yet been conducted in Japan. The present study examined the current status of patients with hip OA, including the disease etiology. Methods. This is a multiinstitutional study of new patients presenting with hip OA at the orthopedic outpatient clinics of 15 institutions in fi ve geographical areas of Japan. The collected data from each patient included the sex, age, treatment history for developmental dysplasia of the hip (DDH), the clinical score of the hip joints based on the Japanese Orthopaedic Association (JOA) scoring system, and the pelvic inclination according to anteroposterior radiographs. In addition, the etiology was determined from the following 17 options: primary OA, acetabular dysplasia, intragluteal dislocation, osteonecrosis, trauma, Perthes disease, slipped capital femoral epiphysis, infection, rheumatoid arthritis, ankylosing spondylitis, neuroarthropathy, endocrine diseases, metabolic diseases, hereditary bone diseases, synovial chondromatosis, generalized OA, and others. Results. There were a substantially larger number of female patients than male patients. This difference regarding sex was present in each generation. The mean age of the patients was 58 ± 14 years. The peak age at presentation was approximately 50 years. Most patients had no history of therapy for DDH. The older patients had lower gait and activities of daily living scores. The etiology was assessed to be acetabular dysplasia in most of the patients. A lower frequency of elderly patients demonstrated acetabular dysplasia. The patients who had a pelvic posterior inclination increased with increasing age. Conclusions. The patients with hip OA in Japan were unique in regard to age distribution, sexual heterogeneity, and disease

Osteoarthritis hip joints in Japan: involvement of acetabular dysplasia

BackgroundWe conducted a nationwide epidemiologic study regarding hip osteoarthritis (OA) in Japan, and a previous report found these patients to be unique in comparison to Caucasians. This report focused on the data regarding each hip joint, and the involvement of acetabular dysplasia with hip OA was analyzed.MethodsSeven hundred twenty OA hips were examined. Sixty-five joints with osteonecrosis of the femoral head and 215 non-OA contralateral joints of the unilateral patients were examined as controls. The revised system of stage classification for hip OA of the Japanese Orthopedic Association (JOA) was used according to the reproducibility in order to ensure reliable data from the multiple institutions. The acetabular dysplasia indexes were also chosen according to the reproducibility and measured in the radiograph of bilateral hip joints. The clinical score was assessed using the JOA scoring system. The relative risk of the grade of acetabular dysplasia indexes for hip OA was calculated as the odds ratio and the 95% confidence interval.ResultsThe stage of the OA joints deteriorated with increasing age. The clinical scores also decreased. The grade of the acetabular dysplasia indexes of the OA joints was significantly higher than that of the control joints. Each index of acetabular dysplasia demonstrated significantly increased odds ratios for hip OA. Among the OA joints, the deterioration of the OA stage was found to be significantly associated with an increasing grade of acetabular dysplasia. The odds ratio for OA deterioration in the acetabular dysplasia index was also obtained. The joints of females tended to have a higher grade and prevalence of acetabular dysplasia than those of males.ConclusionsThese findings confirmed a high prevalence of acetabular dysplasia in hip OA joints in Japan. Acetabular dysplasia was one of the most important factors associated with hip OA.

Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ): a patient-based evaluation tool for hip-joint disease. The Subcommittee on Hip Disease Evaluation of the Clinical Outcome Committee of the Japanese Orthopaedic Association

BackgroundThe Japanese Orthopaedic Association Hip Score is widely used in Japan, but this tool is designed to reflect the viewpoint of health-care providers rather than that of patients. In gauging the effect of medical therapies in addition to clinical results, it is necessary to assess quality of life (QOL) from the viewpoint of patients. However, there is no tool evaluating QOL for Japanese patients with hip-joint disease.MethodsWith the aim of more accurately classifying QOL for Japanese patients with hip-joint disease, we prepared a questionnaire with 58 items for the survey derived from 464 opinions obtained from approximately 100 Japanese patients with hip-joint disease and previously devised evaluation criteria. In the survey, we collected information on 501 cases, and 402 were subjected to factor analysis. From this, we formulated three categories—movement, mental, and pain—each comprising 7 items, for a total of 21 items to be used as evaluation criteria for hip-joint function.ResultsThe Cronbach’s α coefficients for the three categories were 0.93, 0.93, and 0.95, respectively, indicating the high reliability of the evaluation criteria. The 21 items included some related to the Asian lifestyle, such as use of a Japanese-style toilet and rising from the floor, which are not included in other evaluation tools.ConclusionsThis self-administered questionnaire may become a useful tool in the evaluation of not only Japanese patients, but also of members of other ethnic groups who engage in deep flexion of the hip joint during daily activities.

Histopathologic study of veins in steroid treated rabbits

Although arterial factors have been regarded as playing an important role in the pathogenesis of osteonecrosis, more attention has been given to venous factors because steroids cause an increase in the intraosseous pressure despite a decrease in blood flow in the femoral head. The authors examined changes in the veins of steroid treated rabbits. Forty rabbits were used: 30 rabbits (the steroid treated group) were injected with methylprednisolone acetate (4 mg/kg) weekly and 10 rabbits (the control group) were treated without steroids. The veins around the femoral head, ear veins, femoral veins, and inferior vena cava were obtained after 8 weeks of treatment, and the specimens were examined by immunohistochemical staining and electron microscopy. In the steroid treated group, proliferation of foam cells was observed in the intima of the vein in 7 of 30 rabbits. Immunohistochemical studies, using monoclonal antibodies for smooth muscle cells and macrophages, showed that the foam cells were derived from smooth muscle cells. Electron microscopy showed damage to the endothelial cells and smooth muscle cells. These results indicated that corticosteroids damaged the venous system. It is suggested that steroid induced disturbance of the draining veins causes stasis and that steroids are an important factor in osteonecrosis of the femoral head.

Pathological and hemodynamic study in a new model of femoral head necrosis following traumatic dislocation.

The blood of the femoral head is thought to be supplied by vessels originating from the medial and lateral circumflex femoral arteries and via the marrow cavity of the neck. Therefore, it is difficult to induce osteonecrosis of the femoral head when the marrow cavity of the neck is preserved. In the present study, we established a new model of femoral head necrosis by dislocating the hip joint and ligating the medial and lateral circumflex femoral arteries and veins. Measurement of femoral head blood flow revealed that a marked decrease to 14.7% of the control value was achieved by both hip dislocation and ligation of blood vessels. Pathologic examination showed no necrosis with either dislocation or ligation alone, whereas at 2 and 4 weeks 80% of the animals subjected to both procedures showed widespread necrosis. These pathologic findings considered in the light of results of the blood flow measurements suggest that a decrease in femoral head blood flow below 20% of the control value is needed to cause osteonecrosis. In addition, magnetic resonance images (MRI) of the model were evaluated in the combined dislocation and ligation group at 4 weeks (n = 5). Changes on MRI were seen in 3 of 5 dogs. The necrotic changes of the femoral head are thought to be detectable on MRI within 4 weeks after ischemia without enhancement.

Analysis of interobserver reliability for radiographic staging of coxarthrosis and indexes of acetabular dysplasia : a preliminary study

BackgroundWe are planning a multicenter survey on coxarthrosis and acetabular dysplasia in Japan. To collect reliable data, we performed a preliminary study to elucidate the observer agreement on assessment items.MethodsWe collected radiographs of hip joints in eight patients with various findings of coxarthrosis. Twelve registered orthopedic specialists evaluated them regarding the roentgenographic stage of coxarthrosis and five indexes of acetabular dysplasia (acetabular angle, center-edge angle, acetabular roof obliquity, acetabular head quotient, approximate acetabular quotient). To assess observer agreement, we calculated the value of the kappa statistic for stages and the coefficient of variation for the indexes. The same 12 specialists then assessed the coxarthritis stage on the same radiographs 1 month after the first evaluation based on our own descriptions of the roentgenographic stages.ResultsFor the first evaluation of the roentgenographic stage, the value of the kappa statistic was 0.448; and for the second evaluation it was 0.600. The results of the coefficient of variation for the indexes of acetabular dysplasia, ranked in ascending order, were as follows: acetabular angle, acetabular head quotient, acetabular roof obliquity, center-edge angle, approximate acetabular quotient.ConclusionsFor the upcoming multicenter survey, clear descriptions of the stages of coxarthrosis and selection of appropriate indexes can be helpful for collecting dependable results.