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Biomedical subjects

A Hirooka

Publications and source records attributed to A Hirooka.

11 recordsLinked to original sources
PubMed1999

Evaluation of surgeries for rheumatoid shoulder based on the destruction pattern.

OBJECTIVE: To identify the optimal treatment of rheumatoid shoulder, we analyzed the clinical results of shoulder surgeries according to each type of shoulder destruction pattern. METHODS: Forty-seven shoulder surgeries for rheumatoid arthritis (18 arthroscopic synovectomies, 10 total shoulder replacements, 19 humeral head replacements) were assessed clinically and compared in regard to 5 different destruction patterns of rheumatoid shoulder (nonprogressive, arthrosis-like, erosive, collapse, and mutilating patterns). RESULTS: For nonprogressive-type shoulders, we were able to obtain both pain relief and range of motion (ROM) improvement with arthroscopic synovectomy. For erosive-type shoulders, we could obtain pain relief but no ROM improvement with synovectomy; and we obtained both pain relief and ROM improvement with prosthetic replacement. For the collapse-type shoulders, we could not obtain pain relief or ROM improvement with arthroscopic synovectomy, but did obtain pain relief with prosthetic replacement. For mutilating-type shoulders, we could obtain only pain relief with prosthetic replacement. The results of the various surgeries for rheumatoid shoulder were distinctly different depending on the shoulder destruction patterns. CONCLUSION: These findings could be of value for the selection of treatment, including a surgical procedure, for rheumatoid shoulders. For the nonprogressive-type and for erosive-type shoulders before bone destruction progresses, arthroscopic synovectomy should be selected. For erosive-type shoulders after bone destruction, for the collapse-type, and for mutilating-type shoulders, prosthetic replacement should be selected. In regard to the prosthetic replacement, the humeral component should be cemented because the incidence of migration in noncemented humeral component procedures was high.

Adult↗
PubMed1996

Shoulder destruction in rheumatoid arthritis. Classification and prognostic signs in 83 patients followed 5-23 years.

We studied the natural course and the possibility of making prognoses about shoulder joint destructions in 83 patients with rheumatoid arthritis (RA) (166 shoulder joints). For this purpose, we used radiographic patterns and 2 indices (upward migration and medial displacement). The patterns of joint destruction were classified into 5 groups: 1) non-progressive type (n 74) with normal radiographs, only osteopenia or small erosions even after 15-20 years of RA; 2) erosive type (n 22) showing marginal erosions but no collapse; 3) collapse type (n 34) showing subchondral cysts, followed by collapse; 4) arthrosis-like type (n 12) showing arthrotic features; 5) mutilating type (n 14) showing mutilating bone destructions. From the radiographic findings and the 2 indices determined at 5-10 years, we could predict the prognosis of shoulder joint destruction after 15-20 years of RA. Our findings may be of value for selecting treatment, including surgery, for the rheumatoid shoulder.

Adult↗
PubMed1996

MRI of early osteonecrosis of the femoral head after transcervical fracture.

We have carried out a prospective study of 17 patients (14 women, 3 men) of mean age 48 years (21 to 76) with transcervical fractures of the femur using MRI to detect early evidence of avascular necrosis of the head. Two fractures were Garden stage I, 12 stage II, and three stage III. We performed internal fixation under radiological control at a mean of five days (2 to 15) after injury using a titanium cannulated cancellous screw or a titanium compression hip screw. MRI was performed at one, six and 12 months and then yearly after operation. T1- and T2-weighted images were obtained by a spin-echo technique. The duration of follow-up of patients who did not subsequently require replacement of the head of the femur was from 2 to 5 years (mean 3.2). One month after operation eight of the 17 hips showed a band of low signal intensity on T1-weighted images and high signal intensity on T2-weighted images indicating lesions in the femoral head away from the fracture line. These were of three types: type I was a small infarct at the superolateral region of the femoral head and was seen in three hips; type II was a shallow lesion from the superolateral region to the fovea of the femoral head (three hips); and type III was a large lesion occupying most of the femoral head (two hips). No further changes were seen in the MRI after six months from operation. Collapse of the femoral head did not occur in the three hips with type-I lesions, but two of the three type-II hips and both type-III hips subsequently collapsed. At the final follow-up the three hips with a type-I lesion and one with a type-II were still asymptomatic but radiography showed sclerosis in the femoral head corresponding to the MRI lesions. The nine hips which showed no changes on MRI at one month had no abnormal findings on physical examination, radiography or MRI at final follow-up.

Adult↗
PubMed1991

Arthroscopic stapling for detached superior glenoid labrum.

Superior labral tears of the shoulder involve the biceps tendon and labrum complex which may be detached, displaced inferiorly, and interposed between the glenoid and the humeral head. We have treated ten young athletes with painful shoulders due to this lesion by arthroscopic stapling. Arthroscopy at the time of staple removal, after three to six months, showed that all the lesions had been stabilised. Clinical review at over 24 months showed an excellent or good result in 80%. The two relative failures were due in one to residual subacromial bursitis, and the other to multidirectional shoulder instability. Arthroscopic stapling can restore the shoulder anatomy, and it is recommended for active adolescent athletes with this lesion.

Adolescent↗
PubMed1991

Effect of early synovectomy on the course of rheumatoid arthritis.

Ninety-one patients with rheumatoid arthritis were retrospectively assigned to 3 subsets according to the number of joints with erosion (NJE). The subsets were least erosive (LES); more erosive (MES); most erosive involving multilating disease (MUD). In the early stages of disease the subsets were distinct (p less than 0.001) regarding mean values of annual reduction of carpal height (delta CHR) and serum Clq levels. Patient assessment (radiographic and clinical) continued to deteriorate in the MES and MUD subsets over the 1-5 year interval after synovectomy. Apparent stabilization of knee disease in the LES subset may be a feature of this subset rather than a result of synovectomy. Although synovectomy may offer short term symptomatic relief, we found no evidence that it retards the bony destruction or the disease process.

Adult↗
PubMed1989

Repair of rabbit articular surfaces with allograft chondrocytes embedded in collagen gel.

In an attempt to repair articular cartilage, allograft articular chondrocytes embedded in collagen gel, were transplanted into full-thickness defects in rabbit articular cartilage. Twenty-four weeks after the transplantation, the defects were filled with hyaline cartilage, specifically synthesising Type II collagen. These chondrocytes were autoradiographically proven to have originated from the transplanted grafts. Assessed histologically the success rate was about 80%, a marked improvement over the results reported in previous studies on chondrocyte transplantation without collagen gel. By contrast, the defects without chondrocyte transplantation healed with fibrocartilage. Immunological enhancement induced by transplanted allogenic chondrocytes or collagen was not significant at eight weeks after treatment, so far as shown by both direct and indirect blastformation reactions. Thus, allogenic transplantation of isolated chondrocytes embedded in collagen gel appears to be one of the most promising methods for the restoration of articular cartilage.

Animals↗
PubMed1989

[High strength Ag-Pd-Cu alloys].

Twelve kinds of Ag-Pd-Cu alloy, containing 25, 30, 35, 40 wt% Pd, 20, 25, 30 wt% Cu and the residual quantity 30-55 wt% Ag were melted in an argon atmosphere. These alloys were cast using dental precision casting, subsequently, softening heat treatment (water quenching from 800 degrees C) and hardening heat treatment (450-250 degrees C oven cooling) were applied. After softening heat treatment, the Vickers hardness, tensile strength, and elongation of the experimental alloys ranged from 145 to 200, from 41 to 60 kgf/mm2 and from 11 to 27%, respectively. Therefore, these alloys were very ductile in softening heat treatment condition. After hardening heat treatment, the Vickers hardness of the alloys increased in the range of 241-433 and tensile strength increased in the range of 73-107 kgf/mm2. However, elongation decreased to 0.5-3.5%. Composition of the alloy that had the maximum tensile strength (104 kgf/mm2) was about 45 Ag-35 Pd-20 Cu. Brightness (L*) of the test pieces that were immersed in 0.1% sodium sulfide solution of 37 degrees C for 3 days ranged from 58 to 67. After hardening heat treatment, the Ag-Pd-Cu ternary alloy containing 20-30% Cu, 30-40% Pd had satisfactory high hardness and strength for adhesion bridge, but their elongation and tarnishing resistance were insufficient for clinical application.

Copper↗
PubMed1989

[Repair of rabbit articular surfaces with allografts of chondrocytes embedded in collagen gels].

In an attempt to restore articular cartilage, allogeneic articular chondrocytes embedded in collagen gels were transplanted onto full-thickness defects in rabbit articular cartilage. Within 24 weeks after the transplantation, the defects were filled with hyaline cartilage, specifically synthesizing type II collagen. These chondrocytes were autoradiographically proven to be originated from the originally transplanted chondrocytes. As histologically assessed, success rate was about 80%, a marked improvement over the results (40% success rate) in previous studies reporting chondrocyte transplantation without collagen gels. On the other hand, the defects without chondrocyte transplantation healed with fibrocartilaginous tissue more than 24 weeks after treatment. Immunological enhancement induced by transplanted allogeneic chondrocytes or collagen was not significant for eight weeks after treatment, so far as shown by both direct and indirect blastformation reactions. Thus, allogeneic transplantation of isolated chondrocytes embedded in collagen gels appears to be one of the most promising methods for the restoration of articular cartilage.

Animals↗
PubMedDate not supplied

Indicators of superior glenoid labral detachment on magnetic resonance imaging and computed tomography arthrography.

The magnetic resonance imaging and computed tomography arthrographic findings of 36 shoulders with arthroscopically diagnosed detachment of the superior labrum were compared with those of 40 shoulders with a normal superior labrum to detect any findings specific to the injury. In this study we defined a specific magnetic resonance imaging finding as the presence of a linear, high-to-intermediate intensity area between the superior labrum and the glenoid rim on oblique coronal T2-weighted images. We also defined a specific computed tomography arthrography finding as air entering between the superior labrum and the upper part of the glenoid surface. On the basis of these findings magnetic resonance imaging had a sensitivity of 41%, a specificity of 86%, and an accuracy of 63%, whereas computed tomography arthrography had a sensitivity of 45%, a specificity of 93%, and an accuracy of 73%. Thus both of these procedures were specific for these particular findings, but they were neither sensitive nor accurate.

Adolescent↗