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Background: Monoiodoacetate (MIA)-induced arthritis models are used widely in osteoarthritis (OA) research to develop effective conservative treatments for hip OA, as an alternative to joint replacement surgery. In joint OA models, such as the MIA-induced knee OA model, various doses of MIA are utilized, depending on the purpose of the research. So far, only 2 mg of MIA has been used for MIA-induced hip OA research. We hypothesized that the amount of MIA should be adjusted according to the osteoarthritis model under investigation. We performed radiographic and histological evaluations in rats for hip OA models induced by different doses of MIA.Methods: One hundred and eighty right hips of six-week-old, male Sprague-Dawley rats (n = 30 rats per group) were treated with either a single intra-articular injection of various doses of MIA (0.25, 0.5, 1.0, 2.0, and 4.0 mg) dissolved in 25 μl of sterile saline (MIA group), or with 25 μl of sterile saline alone (Sham group). Radiographic and histological evaluations of the hip joint were performed at one, two, four, eight, and 12 weeks after administration (n = 6 rats per group per time point).Results: OA changes progressed from 1 week after administration in the 1.0-mg, 2.0-mg, and 4.0-mg MIA groups. The degree of OA changes increased as the dose of MIA increased. The 0.25-mg and 0.5-mg MIA groups presented fewer OA changes than the 2.0-mg and 4.0-mg MIA groups during the entire study period (up to 12 weeks). The administration of 0.25 mg and 0.5 mg of MIA-induced both radiographic and histological OA changes in a time-dependent manner, whereas more than 2 mg of MIA provoked end-stage OA at 8 weeks after injection. Absolute, dose-dependent histopathological OA changes were observed 4 weeks after MIA administration.Conclusions: Intra-articular MIA injection to the hip joints of rats induced diverse OA changes dose-dependently. Research for developing novel conservative treatments for hip OA and intractable pain should consider the pathological condition when determining the dose of MIA to be employed. [ABSTRACT FROM AUTHOR]

Background: Femoral neurovascular injury is a serious complication in a direct anterior approach (DAA) total hip arthroplasty. However, dynamic neurovascular bundle location changes during the approach were not examined. Thus, this study aimed to analyze the effects of leg position on the femoral neurovascular bundle location using magnetic resonance imaging (MRI). Methods: This study scanned 30 healthy volunteers (15 males and 15 females) with 3.0T MRI in a supine and 30-degree hip extension position with the left leg in a neutral rotation position and the right leg in a 45-degree external extension position. The minimum distance from the edge of the anterior acetabulum to the femoral nerve (dFN), artery, and vein were measured on axial T1-weighted images at the hip center level, as well as the angle to the horizontal line of the femoral nerve (aFN), artery (aFA), and vein from the anterior acetabulum. Results: The dFN in the supine position with external rotation was significantly larger than supine with neutral and extension with external rotation position (20.7, 19.5, and 19.0; p = 0.031 and 0.012, respectively). The aFA in supine with external rotation was significantly larger than in other postures (52.4°, 34.2°, and 36.2°, p < 0.001, respectively). The aFV in supine with external rotation was significantly larger than in supine with a neutral position (52.3° versus 47.7°, p = 0.037). The aFN in supine and external rotation was significantly larger than other postures (54.6, 38.2, and 33.0, p < 0.001, respectively). Conclusions: This radiographic study revealed that the leg position affected the neurovascular bundle location. These movements can be the risk of direct neurovascular injury or traction. [ABSTRACT FROM AUTHOR]

Background: Diclofenac etalhyaluronate (DF-HA) is a recently developed analgesic conjugate of diclofenac and hyaluronic acid that has analgesic and anti-inflammatory effects on acute arthritis. In this study, we investigated its analgesic effect on osteoarthritis, using a rat model of monoiodoacetate (MIA).Methods: We injected MIA into the right knees of eight 6-weeks-old male Sprague-Dawley rats. Four weeks later, rats were randomly injected with DF-HA or vehicle into the right knee. Seven weeks after the MIA injection, fluorogold (FG) and sterile saline were injected into the right knees of all the rats. We assessed hyperalgesia with weekly von Frey tests for 8 weeks after MIA administration. We took the right knee computed tomography (CT) as radiographical evaluation every 2 weeks. All rats were sacrificed 8 weeks after administration of MIA for histological evaluation of the right knee and immunohistochemical evaluation of the DRG and spinal cord. We also evaluated the number of FG-labeled calcitonin gene-related peptide (CGRP)-immunoreactive(ir) neurons in the dorsal root ganglion (DRG) and ionized calcium-binding adapter molecule 1 (Iba1)-ir microglia in the spinal cord.Results: Administration of DF-HA significantly improved pain sensitivity and reduced CGRP and Iba1 expression in the DRG and spinal cord, respectively. However, computed tomography and histological evaluation of the right knee showed similar levels of joint deformity, despite DF-HA administration.Conclusion: DF-HA exerted analgesic effects on osteoarthritic pain, but did not affect joint deformity. [ABSTRACT FROM AUTHOR]