Queen's University in accordance with the guidelines of the Canadian Council of Animal Care. Eight 10e12 month old Sprague-Dawley rats were used in this study. Growth plate closure was radiographically confirmed to ensure skeletal maturity. Two impact loads were tested in this study design: 31N (18MPa), reported to be the injury threshold inducing physiological response in joints; and 53N (30MPa), reported to induce joint damage with limited matrix alteration, representing a moderate trauma such as sport injury. The impacts were induced to the periosteum close to the synovial junction of the medial femoral condyles with a 1.5mm diameter probe mounted onto an Electronic Force biodynamic test instrument (Bose 5500, Bose Co., Minnesota, USA). Loads were applied at a speed of 15mm/sec with a peak load maintained for 0.05 seconds. The right knee was used as the experimental side and the left as the control. Isoflurane inhalation was used for general anaesthesia during surgery. Subcutaneous injections of Bupivacaine (2mg/kg) and Tramadol (20mg/ kg) were administered for analgesia. The knee capsule was surgically exposed by a skin incision on the medial knee and through an opening of the medial intermuscular septum. The capsule was carefully cut to expose the medial femoral condyle. The same surgical approach was applied on both knees. On the experimental side, the region of interest (ROI) of the exposed condyle was positioned under the probe and preloaded with 2N force to ensure its stability during impaction. After impact, the intermuscular septum and skin were sutured independently. Animals were sacrificed at 3 or 6 weeks post-surgery. Distal femurs were harvested and fixed in 4% formaldehyde. Tissues were decalcified in 10% EDTA and prepared for histology. Serial 5 mm-thick sections were SHBG, sex hormone binding globin; Results are generated from linear mixed-effect model adjusted for age, body mass index and 25-hydroxyvitamin D.Bold values indicate statistical significance at a ¼ 0.05.
Abstracts / Osteoarthritis and Cartilage 24 (2016) S63eS534S359
subregions), and fast progression (an increase of more than one WORMS grade in at least one of the ten subregions). Co-variance analysis was performed to test if there were differences between atrophic vs. non-atrophic knee OA phenotypes, using both (radiographs and MRI) definitions, regarding no progression, slow, and fast progression of JSN and cartilage loss. Logistic regression analysis with generalized estimated equations was performed to assess the association of atrophic knee OA with any progression of JSN and cartilage loss, compared to non-atrophic OA knees (reference group). The results were adjusted for age, gender, body mass index, tibiofemoral malalignment, progression of meniscal damage and extrusion. Results: A total of 450 knees from 398 participants were included. Using the radiographic definition, there were 77 (17.1%) atrophic OA and 373 (82.9%) non-atrophic OA knees at baseline. Using the MRI definition, there were 50 (11.1%) atrophic OA and 400 (88.9%) non-atrophic OA knees. There were no significant differences between both groups (atrophic vs. non-atrophic) regarding fast progression of JSN or cartilage damage (Table 1). Logistic regression analysis using both definitions showed that the atrophic phenotype of knee OA was not at increased risk for progression of disease compared to the non-atrophic phenotype (Table 2). Using the radiographic definition, a modest protective effect against progression of MRI cartilage loss was demonstrated for atrophic OA knees when compared to the non-atrophic group (OR ¼ 0.6 (95%CI 0.3, 1.0); p¼0.04).
(2 levels) and month (2 levels [months 3, and 12]) and the corresponding interactions, adjusted for baseline values. ClinicalTrials.gov registration: NCT01164111 Results: Eighty patients (70% women, 70.4 ± 7.6 years, BMI of 27.8 ± 4.6) were randomized to IG (n ¼ 40) or CG (n ¼ 40); data from 85% (33 and 35 patients respectively) were available at follow-up. For all HOOS subscales (including ADL) and functional tests (except ascending stairs (between-group change score and 95%CI) (1.3 sec [0.3; 2.3], P ¼ 0.01), descending stairs (1.6 sec [0.3; 2.9], P ¼ 0.01) and Hip extension of unaffected side (12.0 Nm [0.0; 24.0], P ¼ 0.05) no between-group differences were observed at 12 months. At 3 months statistically significant and clinical relevant between-group difference in change score of HOOS-Sport/Rec was observed, where IG scored 10.5 points [1.4; 19.6] higher compared to CG (P ¼ 0.02). Furthermore, IG had higher muscle strength (knee extension of the affected side (14.6 Nm [6.3; 22.9], P < 0.001)) and better function (chair stand (2.6 sec [1.
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