To observe the change in the status of stresses according to size of the meniscus, a 3-dimensional photoelasticity model of the knee joint was made of epoxy. Three kinds of meniscus models were made of rubber. Through the axial application of a vertical compressive load of 8kg equivalent to the joint reaction of 3,000N in the human knee joint, the peculiar patterns of the isochromatic fringes were observed and stresses around the knee joint were analyzed according to the size of the defect in the medial meniscus. Even distribution of the photoelasticity fringe patterns were observed in the normal knee joint model with both menisci intact. Stress concentration was increased at the margin of the medial side of the knee joint model with the medial menicus removed partially in about 30-50% of its central portion. In addition, the magnitude of stresses were also noted as increased in the lateral part of this type model. In the knee joint model with nearly all of the medial meniscus removed, strssess were concentrated markedly in the central portion of the knee joint just outside of both tibial spines. Stress was increased in its magnitude according to the size of the defect of the meniscus, and was focalized after menisectomy. In the model for partial menisectomy, the maximum stress concentration point of the removed side migrated to the margin of the same side of the joint. But in the model of total menisectomy, maximum stress concentration points of both side were more centralized. Not only an increment of stresses in magnitude but also centralization of the maximum stress concentration point in its location could contribute to the degenerative process of the knee joint after menisectomy. In addition, articular cartilage can be easily damaged with a relatively small amount of external force.
Cartilage, Articular ; Humans ; Joints ; Knee ; Knee Joint ; Menisci, Tibial ; Rubber ; Spine

Epidemilologic information about various syndromes in low back pain has been regarded by Vert Mooney as one of the important sources for establishing prognosis and providing a rationale for therapy. Several risk factors about low back pain and injuries were analyzed through a questionnaire filled out by 172 athletes of various kind of sports including students and professional players. The following results were obtained. 1. Types of sports were associated with the incidence of low back injuries and gymnastics were included in high risk groups (p<0.01). 2. Career is also associated with the incidence of low back injuries (p<0.05). 3. Pain pattern, such as anterior element pain or posterior element pain is also associated with the particular type of sport(p<0.001). 4. Over-use has been suspected as a main cause of sports injury in 37.8% of athletes. Neglect of warming-up, psychologic attitudes and chronic accumulation of micro-trauma have been also suspected (p<0.001). 5. Management of pain was expected to be received from physiotherapists by 34.2%, from coaches or fellow sportsmen by 24.6%, from an acupuncturist by 17.5%, from doctors by 9.7%, and from trainers by 14% of athletes. However 66.7% of the professional players wanted to receive management of pain from trainers (p<0.001).
Athletes ; Athletic Injuries ; Back Injuries ; Epidemiologic Studies ; Gymnastics ; Humans ; Incidence ; Low Back Pain ; Physical Therapists ; Prognosis ; Risk Factors ; Sports

The purpose of this study was to investigate the effects of articular immobilization-induced hindlimb skeletal muscle atrophy on the autophosphorylation of the insulin receptor tyrosine kinase in rats. Rats were divided control, and knee and ankle joint immobilized groups. The experiments were performed on the 3rd, 7th, and 21st day after the immobilization. immobilization was induced by k-wire fixation in knee and ankle joint. The ratio of soleus muscle weight to body weight was decreased in proportion to the duration of the immobilization. The glycogen content of the soleus muscle was decreased significantly (p<0.01) at the 7th day, but this value was recovered to 65% of control at the 21st day after the immobilization. The insulin bindings at various concentrations of insulin to wheat-germ agglutinin purified insulin receptor from red gastrocnemius muscle at the 7th day after immobilization were not changed compared to control. The autophosphorylation of the insulin receptor tyrosine kinase with 10-8 and 10-7 M insulin concentration at the 7th day after immobilization was decreased compared to control. In conclusion, above results showed that insulin resistance of immobilized rat hindlimb skeletal muscle was arised from defect of autophosphorylation of the insulin receptor tyrosine kinase in part.
Animals ; Ankle Joint ; Atrophy* ; Body Weight ; Glycogen ; Hindlimb* ; Immobilization* ; Insulin Resistance ; Insulin* ; Knee ; Muscle, Skeletal* ; Protein-Tyrosine Kinases* ; Rats* ; Receptor, Insulin* ; Tyrosine*

No abstract available.
Humans ; Microcomputers*

Congenital isolated hydronephrosis encompasses a spectrum of physiologic states that spontaneously resolve and pathologic obstruction that necessitates surgical intervention. Distinguishing patients whose condition will resolve, those who will require stringent follow-up, and those who will eventually need surgical intervention present a challenge to clinicians, particularly because no unified guidelines for assessment and follow-up have been established. The recognition of the natural course and prognosis of hydronephrosis and a comprehensive understanding of the currently proposed consensus guidelines may aid in multidisciplinary treatment and in providing proper counseling to caregivers. In this review, we aimed to summarize the literature on the grading systems and management strategies for congenital isolated hydronephrosis.

Purpose: In 2017, the Children’s Hepatic Tumors International Collaboration-Hepatoblastoma Stratification (CHIC-HS) system was introduced. We aimed to evaluate the accuracy of CHIC-HS System for the prediction of event-free survival (EFS) in Korean pediatric patients with hepatoblastoma. Materials and Methods: This two-center retrospective study included consecutive Korean pediatric patients with histopathologically confirmed hepatoblastoma from March 1988 through September 2019. We compared EFS among four risk groups according to the CHIC-HS system. Discriminatory ability of CHIC-HS system was also evaluated using optimism-corrected C-statistics. Factors associated with EFS were explored using multivariable Cox regression analysis. Results: We included 129 patients (mean age, 2.6±3.3 years; female:male, 63:66). The 5-year EFS rates in the very low, low, intermediate, and high-risk groups, according to the CHIC-HS system were 90.0%, 82.8%, 73.5%, and 51.3%, respectively. The CHIC-HS system aligned significantly well with EFS outcomes (p=0.004). The optimism-corrected C index of CHIC-HS was 0.644 (95% confidence interval [CI], 0.561 to 0.727). Age ≥ 8 (vs. age ≤ 2; hazard ratio [HR], 2.781; 95% CI, 1.187 to 6.512; p=0.018), PRE-Treatment EXTent of tumor (PRETEXT) stage IV (vs. PRETEXT I or II; HR, 2.774; 95% CI, 1.228 to 5.974; p=0.009), and presence of metastasis (HR, 2.886; 95% CI, 1.457 to 5.719; p=0.002), which are incorporated as the first three nodes in the CHIC-HS system, were independently associated with EFS. Conclusion The CHIC-HS system aligned significantly well with EFS outcomes in Korean pediatric patients with hepatoblastoma. Age group, PRETEXT stage, and presence of metastasis were independently associated with EFS.