Knee osteoarthritis (KOA) is a kind of degenerative osteoarthrosis, which usually involves articular cartilage, subchondral bone, meniscus and quadriceps femoris, which is equivalent to the change of "tendon" in traditional Chinese medicine. The occurrence and development of the change of "tendon" can be explained by the theory of "bone-restoration and tendon-softening" in traditional Chinese medicine. If the force line of the lower limb of the knee joint is normal, it can be indicated by "bone-restoration" in traditional Chinese medicine, that is, the blood around the knee joint runs smoothly, and the "tenons" such as meniscus, ligaments, cartilage, etc. are softened by the blood. This condition of the knee joint can be manifested by the balance of the surrounding soft tissue state. If the force line of the lower limb of the knee joint changes, showing a medial offset and misalignment of the knee joint, it can be indicated by "bone is out of alignment" in traditional Chinese medicine, that is, the structure of the soft tissue around the knee joint and its mechanical characteristics have changed. This condition of the knee joint can be manifested by "the tendons lose their flexibility". In this paper, the theories of modern biomechanics and "bone-restoration and tendon-softening" in traditional Chinese medicine were comprehensively analyzed, the characteristics of the "tenons" when knee osteoarthritis occurs were analyzed, and the characteristics of the occurrence and development of knee osteoarthritis from the perspective of Chinese and Western medicine were discussed.

Objective To explore the potential correlation between fluoride levels of urine and influencing factors in water-high-fluoride areas.Methods In 2010,based on plain area,mountainous area and mixed area (altitudes were 898,2 200,1 460 m,respectively),3 villages of water-high-fluoride areas were selected by purpose sampling;pupils' family members were selected as survey population by cluster sampling.Questionnaire was conducted to collect general information;fluoride contents in urine and drinking water were measured using ionselective electrode.A linear multiple regression was used to examine which factors affected urinary fluoride.Results Totally there were 968 people distributed in plain area (444),mixed area (368) and mountainous area (156),medians of urinary fluoride level were 0.71,1.59 and 1.67 mg/L,respectively,the difference was significant (F =203.90,P ＜0.01);medians of water fluoride level in the three different habitats were 0.50,1.00 and 3.50 mg/L,respectively,the difference was significant (F =331.98,P ＜ 0.01).Age,gender,fluoride contents in drinking waters and habitat explained 33.1％ of urinary fluoride variation.Male had higher urine fluoride than female,older age and higher level fluoride in drinking water contributed to higher fluoride level in urine,higher altitude contributed to higher urinary fluoride.Conclusion Once fluoride content in urine is used to estimate fluoride exposure level among people in high fluoride area,gender and age must be taken in consideration.