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Biomedical subjects

T Muneta

Publications and source records attributed to T Muneta.

54 records · Page 3Linked to original sources
PubMed1989

[The effect of exercise on the normal and reconstructed anterior cruciate ligament in rabbits].

The effects of exercise on the biomechanical properties of the normal anterior cruciate ligament and bone specimen were investigated in two groups of rabbits: the one group with seven rabbits aged 7-8 months and the other with nine rabbits of 13-14 months. Four weeks of exercise produced significant increases in the maximum failure load, total absorbed energy to failure and stiffness in group of younger rabbits, but these changes were not seen in the older rabbits. Exercise effects on the remodelling of the reconstructed ACL were further studied in the two groups of rabbits, by observing macroscopic, histological, and biomechanical changes. While histologically normally structured ligament-bone junctions were seen partially in all the specimens, the specimen of the group with four weeks of exercise after 21 weeks after reconstructive surgery, showed a significant increase in stiffness of the reconstructed ACL. Macroscopically a glittering appearance was seen more frequently in the reconstructed ligament when compared to that of a cage-confined non-exercised group of rabbits.

Animals↗
PubMedDate not supplied

Relation between the painful shoulder and the cervical spine with narrow canal in patients without obvious radiculopathy.

It is well known that cervical radiculopathy sometimes causes shoulder pain. Hypothesizing that the cause of painful shoulder is related to the cervical spine in the absence of obvious radiculopathy, we measured the anteroposterior diameter of the spinal canal and the range of motion of the cervical spine in patients with painful shoulder on lateral cervical radiographs of the spine. Painful shoulder was diagnosed in 76 patients (24 men and 52 women; mean age 57.6 years). Patients who reported neck pain or numbness of the upper limbs and patients with neurologic abnormalities were excluded from this study. A control group of 54 asymptomatic volunteers (27 men and 27 women; mean age 55.5 years) was formed. The difference in age between the patient group and the control group was not significant. The anteroposterior diameter of the spinal canal at C5 and C6 in the painful-shoulder group (C5: 12.74 mm; C6: 12.76 mm) was significantly narrower than in the control group (C5: 13.60 mm; C6: 13.79 mm). The range of motion was greatest at C4-5 and smallest at C2-3 in both groups; and there was no significant difference in the range of motion between the painful-shoulder group and the control group. When women only or men only were assessed, the results were nearly the same between groups. The cervical spine without obvious radiculopathy appears to be involved in patients with a painful shoulder. We speculate that the shoulder is affected by irritation of a cervical nerve root or referred pain.

Adult↗
PubMedDate not supplied

Cause of toe-in gait after posteromedial release for congenital clubfoot.

Eighteen children with 24 congenital clubfeet were examined for their foot-progression angle and radiographic angles before and after Turco's posteromedial release. The foot-progression angle was -12.9 degrees before surgery and 1.6 degrees after surgery. The ratio of correction of the foot-progression angle was 58%. Using multiple regression analysis, this ratio was mostly related to the ratio of correction of the anteroposterior talo-first metatarsal and lateral talocalcaneal angles. These results suggest that it is important in correction of toe-in gait of congenital clubfoot to correct adduction deformity of the forefoot and equinus deformity of the hindfoot.

Child↗
PubMedDate not supplied

Relationship between changes in length and force in in vitro reconstructed anterior cruciate ligament.

The effect of tibial and femoral attachment site on the length change and force of an anterior cruciate ligament graft during unloaded flexion in eight cadaver specimens was examined. Two tibial sites (anteromedial and central portion of the anterior cruciate ligament attachment) and three femoral sites (anterior and central portions of the anterior cruciate ligament attachment, and over-the-top) were evaluated. Graft length changes between all combinations of attachment sites were measured from full extension to 150 degrees of passive flexion at 15 degrees intervals using the displacement of a 2-mm inextensible cord. The anterior cruciate ligament was then reconstructed using a Kennedy Ligament Augmentation Device, and graft forces at the same angles of passive flexion were measured with a buckle transducer. Graft length change and force were more affected by the femoral attachment site than the tibial site. There was a close correlation between length change and force measurements in flexion, but not near extension. The pattern of force and length change versus flexion angle for a given combination of attachment sites sometimes varied over the knees tested. Our results suggest that intraoperative isometry measurements are worthwhile for indicating an overloaded graft in flexion; however, length changes near extension may not adequately reflect graft force, creating the possibility that a graft may be more highly loaded than realized.

Anterior Cruciate Ligament↗
PubMedDate not supplied

Effects of postoperative immobilization on the reconstructed anterior cruciate ligament. An experimental study in rabbits.

To investigate the effects of postoperative immobilization and limited motion on reconstructed anterior cruciate ligaments, 28 rabbits received an anterior cruciate ligament reconstruction using autogenous Achilles tendon and were then divided into three groups: fully immobilized, 4 weeks immobilized, and limited motion. Two rabbits from each group were evaluated macroscopically, histologically and microangiographically at 4-week intervals until 12 weeks postoperatively. An additional six rabbits in the 4 weeks immobilized and limited motion groups were studied biomechanically at 12 weeks postoperatively. Macroscopically, both immobilized groups showed more proliferation of the infrapatellar fat pad, which was adherent to the reconstructed anterior cruciate ligament. Histology revealed more rapid regeneration of reconstructed anterior cruciate ligaments in the limited motion group, with no findings of necrosis in the mid-substance. Microangiography indicated faster normalization of vascularity in the limited motion group. The biomechanical study showed no significant difference in laxity between the 4 weeks immobilized and limited motion groups. The graft stiffness and maximum load to failure were greater for the limited motion group, although the increase was not statistically significant. The histologic and microangiographic results from the limited number of animals in this study support limited postoperative motion in the anterior cruciate ligament reconstructed knee. However, there were no differences in terms of the biomechanical parameters at 12 weeks postoperatively between the immobilized and limited motion treatment modes.

Animals↗
PubMedDate not supplied

Computerized tomographic analysis of tibial tubercle position in the painful female patellofemoral joint.

We used computerized tomography to evaluate the position of the tibial tubercle and to determine if the tibial tubercle is positioned more laterally in female patients with patellofemoral pain. We also wanted to determine the relationship of the tibial tubercle to tibial external rotation and patellar tilt. Sixty female patients and 19 healthy female controls were evaluated. To evaluate the position of the tibial tubercle, the tibial tubercle rotation angle (the angle formed by the line between the posteriormost edges of the medial and lateral femoral condyle and the line between the central point of the intercondylar space and the central point of the patellar tendon at the level of the tibial tubercle) was measured by superimposing the images from the level of the distal femoral condyle and the tibial tubercle. The relationship between the tibial tubercle rotation angle and patellar tilt was then assessed by dividing the patients into 3 subgroups according to the patellar tilt. The tibial tubercle rotation angle was significantly different between the patellofemoral pain patients and the controls. There were also significant differences between the patients with moderate patellar tilt (10 degrees to 20 degrees) and the controls, and between the patients with high patellar tilt (> 20 degrees) and the controls.

Adolescent↗
PubMedDate not supplied

Immunohistologic analysis of synovium in infrapatellar fat pad after anterior cruciate ligament injury.

To clarify the natural course of synovitis after anterior cruciate ligament injury, we took synovial tissues at various periods after injury and analyzed them immunohistologically. Twelve patients with isolated anterior cruciate ligament injuries participated in the study. Inflammation intensity was graded semiquantitatively based on the following parameters: synovial lining cell depth, synovial hyperplasia, vascular hyperplasia, lymphocyte infiltration, and the expression of cell adhesion molecules. The expression of fibrogenic cytokines and the degree of fibrosis were also investigated to elucidate the mechanisms of arthrofibrosis. The results demonstrated that synovitis in the infrapatellar fat pad subsides within 3 months after injury with the progression of fibrosis. Fibrogenic cytokines, platelet-derived growth factor and transforming growth factor-beta, were detected at fibrotic sites, suggesting their involvement in arthrofibrosis. An increased incidence of arthrofibrosis recently has been recognized to occur when anterior cruciate ligament reconstruction is performed within several weeks after injury. We speculate that when anterior cruciate ligament reconstruction is performed during the stage of acute synovitis, the operation may further promote the synovitis, accelerating the arthrofibrotic reaction. Waiting to perform the anterior cruciate ligament reconstruction until the synovitis resolves may possibly decrease the motion problems seen postoperatively.

Adipose Tissue↗
PubMedDate not supplied

Anterior knee laxity and loss of extension after anterior cruciate ligament injury.

This study was performed to examine the relationship between knee extension loss and the length of time after injury. We also wanted to compare anterior laxity in anterior cruciate ligament-injured knees in the early and late stages of injury. Loss of knee extension was measured in 81 patients with anterior cruciate ligament injury using lateral radiography with the injured leg relaxed and elevated. Extension loss was defined as the difference in maximal extension angle between the injured and uninjured knees. Average loss of extension was 3.6 degrees in the 17 knees in which the anterior cruciate ligament had been torn 3 weeks or less before examination (the acute injury group) and 0.6 degree in the 64 knees in which the anterior cruciate ligament had been torn more than 3 weeks before examination (the chronic injury group). The extension loss in the acutely injured knees was significantly greater compared with that in the uninjured knees and in the chronically injured knees. Arthrometric measurements using the KT-1000 arthrometer were reliable to diagnose an acute tear. There was no correlation between the degree of extension loss and arthrometric anterior knee laxity measurements. In 12 patients, the initial extension deficit in the early stage of injury significantly resolved with time, and manual maximum arthrometric measurements of anterior knee laxity improved spontaneously with time.

Acute Disease↗
PubMedDate not supplied

Quantitative analysis of synovial fibrosis in the infrapatellar fat pad before and after anterior cruciate ligament reconstruction.

We performed quantitative analysis of synovial fibrosis in the infrapatellar fat pad in 26 patients who underwent arthroscopically assisted anterior cruciate ligament reconstructions. Twelve patients underwent reconstruction with patellar tendon autografts, and 14 had reconstructions with semitendinosus and gracilis tendon autografts. Synovial samples were obtained at the time of reconstruction from 10 patients and at second-look arthroscopy from all 26 patients. Sections from quick-frozen samples were stained with either hematoxylin and eosin or Fast green and Sirius red. We used sodium hydroxide in absolute methanol to elute the Fast green and Sirius red stains, and the total collagen content of each section was estimated by measuring the optical density of the eluted solution. The volume of each section was determined on a computer using an imaging program, and collagen content per unit of tissue was calculated. Median collagen content was 15.3 micrograms/mm3 for the preoperative samples, 25.1 micrograms/mm3 for the group with patellar tendon autografts, and 27.1 micrograms/mm3 for the group with hamstring tendons autografts. Analysis of preoperative and postoperative paired samples revealed a significant increase in synovial collagen after anterior cruciate ligament reconstruction. We observed increased fibrosis in patients who had pain on exertion or stiffness in squatting after the reconstructive surgery.

Adipose Tissue↗
PubMedDate not supplied

Intercondylar notch width and its relation to the configuration and cross-sectional area of the anterior cruciate ligament. A cadaveric knee study.

If a narrow intercondylar notch contains a smaller anterior cruciate ligament, that may explain why people with narrow notches have a higher incidence of anterior cruciate ligament injuries. To investigate the significance of notch width measurement, we used 16 embalmed cadaveric knees. A positive mold of the entire anterior cruciate ligament, including its femoral and tibial insertions, was created with silicone rubber and plaster commonly used for dental molding. We had two hypotheses to test from this study. One was that the dimensions of the anterior cruciate ligament can be predicted by the notch width. The other was that the size of a person's anterior cruciate ligament can be predicted by a caliper measurement of the intercondylar notch. The width, sagittal length, and cross-sectional area of the midsubstance and the femoral and tibial insertions of the anterior cruciate ligament were measured. The notch width index, the ratio of notch width to width of the femoral condyle, showed a positive correlation only to the ratio of width to sagittal length of the tibial insertion. None of the parameters showed any differences between the knees with a notch width index less than or equal to 0.2 and those with a notch width index greater than 0.2. The knees with small notch width indexes did not have thinner anterior cruciate ligaments in them. These findings may not be applicable to knees obtained from other races, i.e., not Japanese.

Aged↗
PubMedDate not supplied

Significance of the single-legged hop test to the anterior cruciate ligament-reconstructed knee in relation to muscle strength and anterior laxity.

We investigated the significance of the single-legged hop test to the anterior cruciate ligament-reconstructed knee as it specifically relates to knee muscle strength recovery and residual anterior laxity. The hop test was conducted on 107 patients with unilateral anterior cruciate ligament-reconstructed knees (78 semitendinosus tendon autografts and 29 bone-patellar tendon-bone autografts). Patients were tested an average of 2 years after surgery. Correlation coefficient analyses determined whether the relationship between knee muscle strength recovery and the hop test was invariant across all levels of residual anterior laxity and whether the relationship between residual anterior laxity and the hop test was invariant across levels of quadriceps muscle strength recovery. Furthermore, we examined the effect of graft harvest site on the hop index. Positive correlations were found between the hop index and muscle strength index at all levels of residual anterior laxity (P < 0.05), but these correlation coefficients were relatively low. There were no apparent correlations between the hop index and residual anterior laxity at all levels of quadriceps muscle strength recovery. There was no significant difference in the average hop index between the semitendinosus tendon autograft group and the bone-patellar tendon-bone autograft group.

Adolescent↗
PubMedDate not supplied

Intermediate-term results of meniscal repair in anterior cruciate ligament-reconstructed knees.

We investigated the incidence of and risk factors for recurrent tears of repaired menisci in anterior cruciate ligament-reconstructed knees. We observed 63 patients whose menisci had been evaluated at second-look arthroscopy as healed (N = 50) or incompletely healed (N = 13) for an average of 4 years (range, 2 to 9.5). Of the 13 patients with incompletely healed menisci, 6 (46%) required additional meniscal surgery and 2 (15%) had recurrence of meniscal symptoms such as catching or locking. Among the 50 patients with healed menisci, 5 (10%) required additional meniscal surgery and 9 (18%) had recurrence of meniscal symptoms after second-look arthroscopy. The timing of the recurrence of these symptoms was from 12 to 28 months after surgical repair. Of the 11 patients who had undergone additional surgery, 6 had sustained second injuries during sports activities and the other 5 had no identifiable cause of injury. When comparing age, tear sites, rim width, side-to-side differences with KT-1000 arthrometer testing, and the pivot shift test, there were no differences between the group requiring additional surgery, the symptomatic group, and the asymptomatic group. However, the postoperative Tegner activity score of the group requiring additional surgery was statistically significantly higher than the others.

Adolescent↗
PubMedDate not supplied

A new pain provocation test for superior labral tears of the shoulder.

We prospectively evaluated the usefulness of a new pain provocation test to diagnose superior labral tears in 32 patients with diagnosed throwing injuries of the shoulder. Results of the pain provocation test were compared with findings on magnetic resonance arthrography (all 32 patients) and arthroscopic examination (15 patients). In 22 patients, detachment of the superior labrum was observed on arthrograms, and all of them had positive results on the new pain provocation test. Nine of the other 10 patients had negative results on the new pain provocation test. However, 1 of the 10 patients had a positive result. Eleven of 15 patients were found to have superior labral lesions arthroscopically, and all of them were classified as type II superior labral anterior posterior lesions. All the 11 patients had positive pain provocation tests. The other four patients without superior labral tears on arthroscopic findings had negative results on the new pain provocation test. The new pain provocation test identified all patients with detachment of the superior labrum confirmed by magnetic resonance arthrography, for a sensitivity of 100%, a specificity of 90%, and an accuracy of 97%. Results of the new pain provocation test were in accord with arthroscopic findings in the 15 patients who underwent arthroscopic examination.

Adolescent↗
PubMedDate not supplied

Nonsurgical treatment of lateral ligament injury of the ankle joint.

Between 1986 and 1989, 40 patients with acute lateral ligament injury of the ankle joint were treated by immobilizing their affected feet in a plaster cast with a heel for 4 weeks, followed by a brace for the next 2 months. The average follow-up time was 29 months. Ninety-eight percent of the patients were rated as having satisfactory functional results. Stress radiographs at the latest follow-up showed good stability even in ankles that were severely unstable at injury. Posttreatment stress radiographs taken periodically showed that stability was maintained 6 months after treatment.

Adolescent↗
PubMedDate not supplied

Nonsurgical treatment of congenital clubfoot with manipulation, cast, and modified Denis Browne splint.

Between 1974 and 1988, 113 congenital clubfeet in 76 children were consecutively treated by using a modified Denis Browne splint with an aluminum crossbar between a pair of plastic shoe inserts after a few manipulations and a corrective cast. Splintage was followed by surgery in 41 (36%) feet. Sixty-nine feet that did not undergo surgery were evaluated after an average follow-up period of 12 years. Sixty-six (95%) feet were excellent or good, according to the McKay rating system. The success rate of this treatment was 60% when the 41 feet receiving surgery and the three feet with fair or poor outcome were evaluated as failures. The success rate was 42% in severely deformed feet, 70% in moderately deformed feet, and 100% in mildly deformed feet. This treatment was effective for congenital clubfoot with mild or moderate deformity and was sometimes effective for severe deformity.

Casts, Surgical↗