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Partial-thickness articular cartilage defects (PTCDs) do not heal spontaneously and are thought to be a predisposing factor for the development of osteoarthritis. Younger and smaller animals have a better healing capacity for many types of injuries including those to articular cartilage. Our aim was to examine the longitudinal histological changes of immature murine articular cartilage after the creation of small PTCDs and to compare them to PTCDs in mature cartilage. Single linear PTCDs were created in 3-week-old and 16-week-old rats in the direction of joint motion. At 6 and 12 weeks after PTCD creation, histological changes were examined in the defect sites and surrounding cartilage. Immature cartilage showed a higher repair capability than mature cartilage. Although repaired immature cartilage had fibrocartilage, it exhibited better quality than any PTCD model, except for a fetus model and comparable quality to full-thickness cartilage defects (FTCD) after bone marrow stimulation. Elucidation of the underlining mechanisms that immature cartilage possesses for repairing PTCDs is necessary in order to aid the prevention or develop treatment for osteoarthritis.

Twenty cementless total hip revision arthroplasties using Anatomic BR stems were performed in 20 patients. Fourteen patients, with a mean age of 62.6 years (range 41-74 years) at time of revision surgery, were followed retrospectively for a minimum of 10 years (range 11-15 years). Clinical function and radiographic evidence of implant stability were evaluated. Preoperative femoral deficiencies were evaluated radiographically and classified according to Paprosky type as follows: four Type-II, four Type-IIIA, four Type-IIIB, and two Type-IV femurs. Mean preoperative Harris hip score was 46.3 points (range 29-58 points) and improved to 68.8 points (range 45-90 points) at the most recent follow-up examination. Of the 14 patients followed, six had radiographic evidence of subsidence (axial shift of more than 2 mm after revision with long-stem components). Component fixation showed bone ingrowth in three (21%) patients, inconclusive evidence of ingrowth in six (43%) patients, suboptimal but stable fixation in three (21%) patients, and unstable fixation in two (14%) patients. Based on these we results, we conclude that even with circumferential proximal porous coating and improved proximal geometry, nonmodular femoral implant stability remains unpredictable following total hip arthroplasty revision.

The purpose of this study was to test if radial shock waves could enhance the introduction of nuclear factor-kappa B (NF-kB) decoy oligodeoxynucleotides, which is reported to markedly inhibit NF-kB activation and suppress pro-inflammatory cytokine gene expression, using rat Achilles tendon cells. In the presence of NF-kB decoy labeled with or without fluorescein isothiocyanate (FITC) in culture media, radial shock waves were applied to the tendon cells in variable conditions and cultivated for 24 h. The transfection rate was assessed by counting FITC-positive cells, and IL-1-induced NF-kB activation in the cells was assessed. Radial shock waves significantly enhanced introduction of NF-kB decoy-FITC into the tendon cells. IL-1-induced NF-kB activation was significantly inhibited by pretreatment of the cells with NF-kB decoy combined with radial shock wave exposure. The present study demonstrated the effectiveness of radial shock waves on introduction of NF-kB decoy into tendon cells. Radial shock wave treatment combined with local NF-kB decoy administration could be a novel therapeutic strategy for chronic tendinopathy. ß

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