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Background and Objective: Weight bearing position is considered as a functional condition. However, available data about it and also knee position sense is little. This study aimed to compare knee joint position sense in weight bearing and non weight bearing positions in men and women, and to determine the effect of target angle on knee joint position sense. Materials and Methods: This interventional study was performed in Zahedan University of medical sciences, Zahedan, Iran in 2006. Forty-four healthy subjects (22 women, 22 men) participated in this study through simple non-probability sampling. Subjects were asked to flex their knees in prone or in standing position, while their eyes closed. Three target angles (45, 60, 90 degrees of knee flexion) were reproduced by each subject. Angle matching errors were measured using an electrogoniometer. Outcomes were collected in form of relative, absolute and variable errors. Data were analyzed using MANOVA test. Results: There was significant difference between weight bearing and non weight bearing positions in terms of angle matching error (P<0.05), while no significant difference was seen between women and men, and also in three target positions. Conclusion: This study showed that subjects are more capable of recognition and identification of the angles during weight bearing position. A larger amount of proprioceptive afferent data may result from sources other than examined knee and lower extremity.

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Background and Objective: Rheumatoid arthritis is an autoimmune-inflammatory disease with possible joint destruction and disability. Persica plant, seems contain anti-inflammatory capabilities. This study was done to determine the effect of hydroalcoholic extract of Ferula persica resin on induced rheumatoid arthritis by Freund's complete adjuvant in rat.
Methods: In this experimental study, 36 male Wistar rats (200-250 g) and 8 weeks old were randomly allocated in 6 groups including normal group, positive control, negative control, and groups treated with the hydroalcoholic extract of persica resin with 25, 50 and 75 mg/kg/bw doses. The resin of persica was extracted by Maceration method. On the first day, inflammation was induced with injection of 0.2 ml of Freund's complete adjuvant into the right knee joint of rats and from the fifteenth day hydroalcoholic extract was injected intraperitoneally and daily for 15 days. On the 30^th day, blood samples were taken from hearts for rheumatoid factor measurement. Histological slides were prepared from knee joint.
Results: The level of RF in the three treatment groups was significantly reduced compared to the negative control group (p<0.05). Destruction of cartilage were observed in treated group with dose of 25 mg/kg/bw in comparision with positive control group, treated group with 50 and 75 mg/kg/bw doses. Also in the negative control group, synovial hyperplasia, pannus and the destruction of cartilage were observed.
Conclusion: It seems that hydroalcoholic extract of Ferula persica resin can causes dose dependent reduction of inflammation and destruction of cartilage result from induced rheumatoid arthritis in the rats.

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Background and Objective: Sodium levothyroxine is one of the common medicines used for treatment of hypothyroidism and thyroid cancer. The study was done to determine the effect of sodium levothyroxine on knee articular cartilage tidemark integrity, plateau tibia cartilage thickness (calcified and non-calcified) and liver enzymes in induced hypothyroidism rats.
Methods: In this experimental study, 50 adult female BALB/c mice, weighting 25-30 grams were randomly allocated into one control and four experimental groups. Animals in control did not receive any medicine. Animals in the second group were received different increasing doses of sodium levothyroxine daily for 8 weeks. Animals in the third group were received constantly high dose of levothyroxine daily for 8 weeks. In the fourth group, the animals became hypothyroid with propylthiouracil (PTU). In the fifth group, animals with hypothyroidism were received sodium levothyroxine by gavage same as group 2. After 8 weeks serum samples were taken to determine ALT, AST and ALP. The plateau tibia cartilage stained with hematoxylin-eosin. Histologic changes evaluated by light microscopy. Using a light microscope equipped with camera, the samples were photographed and using a computer equipped with axiovision software. Cartilage (calcified and non-calcified) thickness measured in micrometer. The integrity of tidemark line on hematoxylin-eosin staining also evaluated.
Results: The results of the present study showed separation, disruption and destruction in tidemark line in group 3 (the group with high dosage of sodium levothyroxine from the beginning of the treatment). The total cartilage and non-calcified part thickness in groups 3, 4, 5 were reduced and in group 3 showed significant reduction (P<0.05). Calcified cartilage thickness in all groups were reduced and in group 3 showed significant reduction (P<0.05). ALT level decreased in all groups compared to control group but only in the second and third groups, the decrease of ALT was significant (P<0.05). AST serum level in all groups significantly increased in compared to control group (P<0.05). ALP serum level in all groups increased compared to the control group, but this increase was significant only in the groups 4, 5.
Conclusion: Consumption of sodium levothyroxine with constantly high dose can cause severe alteration in knee joint cartilage in hypothyroidism rats.

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Background and Objective: One of the most common malalignments of the knee joint is valgus. This study was done to determine the effect of using graded knee brace at two angles of 60 and 30 degrees on the ground reaction force components in males with genu valgus during landing.
Methods: This clinical trial study was done on twenty males with genu valgus with age range of 21.70±2.12 years. The graded knee brace was used in two flexion angles of 60 and 30 degrees. Landing from a platform with 40 cm height on a force plate was done during three conditions including without brace, with a brace at flexion angles of 30 and 60 degrees.
Results: A significant reduction was observed in the vertical force during contact phase while landing with brace at a 60-degree angle compared with landing without brace by 15.21% (P<0.05). Also, the peak of medio-lateral force during the heel contact phase while landing with knee brace at 30 degree was significantly greater than that landing with knee brace at 60 degree by 27.18 % (P<0.05).
Conclusion: By reducing the knee flexion angle, the forces of the lower extremities increase and this issue could possibly increase the risk of injury in the knee joint. Therefore, the use of this type of brace is recommended for individuals with genu valgum at a 60 degrees limiting angle.

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Background and Objective: Using lumbar orthoses changes the running mechanics. An essential biomechanical factor in rehabilitation and injury prevention is the co-contraction of the knee and ankle joints. Therefore, this study aimed to investigate the effect of 2 types of thoracolumbosacral braces on ankle and knee joint co-contraction in people with kyphosis during running.
Methods: This quasi-experimental study was conducted on 15 men aged 18-25 years suffering from kyphosis greater than 40 degrees in the Biomechanics Laboratory of the University of Mohaghegh Ardabili Health Center during the summer of 2020. Each participant randomly performed 3 running tests in each condition: without a brace, with a sensor brace, and with a simple brace. The test consisted of electromyographic data of the selected lower limb muscles, which also recorded the contraction of the knee and ankle muscles in the right leg when running at a constant speed.
Results: The results showed a reduction of the general knee co-contraction while using a sensory brace compared to without the brace by 6% during the loading phase (P<0.05). Additionally, using a simple brace compared to the condition without a brace, the ankle-directed contraction during the push-off phase decreased by 38% (P<0.05). Directed vastus medialis and lateralis co-contraction while using a sensory brace increased by about 49% compared to without the brace at the loading phase and increased by about 47% at the mid-stance phase without a brace condition compared to the simple brace condition (P<0.05).
Conclusion: General knee co-contraction after using a sensory brace was lower than when a simple brace was used.