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Down C.,Laboratory for Mineralized Tissue Research | Xu Y.,Laboratory for Mineralized Tissue Research | Osagie L.E.,Laboratory for Mineralized Tissue Research | Bostrom M.P.G.,Laboratory for Mineralized Tissue Research
Journal of Arthroplasty | Year: 2011

Total knee arthroplasty is a common treatment of osteoarthritis, although unicompartmental knee arthroplasties are frequently used to retain unaffected compartments. Joint space width (JSW) is a major factor in determining treatment. We examined the relationship between JSW and cartilage quality in 60 patients undergoing total knee arthroplasty to assess its accuracy in representing cartilage degradation. Radiographic JSW was recorded, whereas the unaffected compartment of each tibial plateau was examined postoperatively using Collins, Mankin, and Kellgren and Lawrence scores. No correlation was seen between visual or histologic grading and JSW. Histology more accurately represented cartilage quality, yet it is impractical to obtain preoperatively; thus, JSW is the main mode of assessment. However, using JSW solely to indicate unicompartmental knee arthroplasty may overlook disease in apparently unaffected compartments. © 2011 Elsevier Inc..

Grosso M.J.,Laboratory for Mineralized Tissue Research | Grosso M.J.,Cleveland Clinic | Courtland H.-W.,Laboratory for Mineralized Tissue Research | Yang X.,Laboratory for Mineralized Tissue Research | And 9 more authors.
Journal of Orthopaedic Research | Year: 2015

The purpose of this study was to determine the individual and combined effects on periprosthetic cancellous bone of intermittent parathyroid hormone administration (iPTH) and mechanical loading at the cellular, molecular, and tissue levels. Porous titanium implants were inserted bilaterally on the cancellous bone of adult rabbits beneath a loading device attached to the distal lateral femur. The left femur received a sham loading device. The right femur was loaded daily, and half of the rabbits received daily PTH. Periprosthetic bone was evaluated up to 28 days for gene expression, histology, and μCT analysis. Loading and iPTH increased bone mass by a combination of two mechanisms: (1) Altering cell populations in a pro-osteoblastic/anti-adipocytic direction, and (2) controlling bone turnover by modulating the RANKL-OPG ratio. At the tissue level, BV/TV increased with both loading (+53%, p < 0.05) and iPTH (+54%, p < 0.05). Combined treatment showed only small additional effects at the cellular and molecular levels that corresponded to a small additive effect on bone volume (+13% compared to iPTH alone, p > 0.05). This study suggests that iPTH and loading are potential therapies for enhancing periprosthetic bone formation. The elucidation of the cellular and molecular response may help further enhance the combined therapy and related targeted treatment strategies. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Hernandez-Soria A.,Laboratory for Mineralized Tissue Research | Yang X.,Laboratory for Mineralized Tissue Research | Grosso M.J.,Laboratory for Mineralized Tissue Research | Reinhart J.,Laboratory for Mineralized Tissue Research | And 2 more authors.
Journal of Biomaterials Science, Polymer Edition | Year: 2013

A calcium phosphate - hydroxyapatite (HA) bone cement was loaded with varying concentrations of tobramycin and vancomycin and the elution properties of these antibiotics were evaluated. Nine groups of antibiotic loaded cement cylinders (N = 6 in each group) were prepared and placed in saline for 28 days. Elution rates of tobramycin and vancomycin from the HA cement were evaluated at high, medium, and low doses of incorporated antibiotic. Tobramycin elution rates did not vary according to dose (0.36, 0.18, and 0.09g). Vancomycin elution rates were also not significantly affected by dose (0.1, 0.05, and 0.025 g). The combination of tobramycin and vancomycin increased the elution rate of vancomycin for the medium and low dose of tobramycin. The dose of tobramycin did not affect its elution rate from the cement in the combined groups. Importantly, the concentration of antibiotic eluent stayed above the minimum inhibitory concentration for the entire 28 days for all groups except the medium and low dose of vancomycin alone. Overall, elution rates of both tobramycin and vancomycin in the calcium phosphate-HA cement were comparable to those from polymethylmethacryltate beads In vitro. © 2012 Taylor & Francis.

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