Septic joint replacement: an orthopedic perspective.
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Arthroplasty, Replacement, Knee↗
Biomedical subjects
K Krackow
Publications and source records attributed to K Krackow.
Activity level and wear in total knee arthroplasty: a study of autopsy retrieved specimens.
We assessed the correlation between activity level, length of implantation (LOI), and wear in total knee arthroplasty. Twenty-eight implants were retrieved at autopsy from 8 men and 15 women. Linear, volumetric, and visual wear and the presence or absence of creep were quantitated. Functional level was classified using the Knee Society, the standard Charnley classification, and the UCLA activity level scale. The average age at surgery was 68 years +/- 14.0 SD and average LOI was 74 months +/- 38 SD. The average linear and volumetric wear rates were 0.127 mm/y +/- 0.104 SD and 31.80 mm3/y +/- 42.8 SD. LOI (B coefficient = -0.656 +/- 0.0 SE; P<.001) correlated with linear, volumetric, and visual wear rates. Charnley C patients showed decreased volumetric wear in the lateral compartment (P=.01). Decreased activity level (UCLA) correlated with areas of less extent and severity of creep (P=.001 and P<.001).
Aged↗
Preincubation of human synovial cells with IL-1 modulates prostaglandin E2 release in response to bradykinin.
Kinins are vasoactive peptides whose potent inflammatory and bone resorbing properties suggest a role for these autacoids in the pathogenesis of inflammatory arthritis. We used cultured human synovial cells as a model to evaluate the effects of bradykinin on articular tissue. In resting synovial cells, bradykinin was a relatively ineffective stimulus for PGE2 production. However, after a period of preincubation with the cytokine, IL-1, which is itself a stimulus for PGE2 production, synovial cells exhibited a further striking time- and dose-dependent response to bradykinin. Maximal release of PGE2 was observed in response to 10(-7) to 10(-6) M bradykinin after first pretreating the cells for 24 h with 5 to 10 U/ml of IL-1. rIL-1 alpha and IL-1 beta, as well as rTNF-alpha, induced a similar response to bradykinin in synovial cells, whereas recombinant IL-2 did not. The bradykinin analog, lysylbradykinin, was equipotent in inducing PGE2 release from IL-1 pretreated synovial cells, whereas des(Arg9) bradykinin, substance P, and neurokinins A and B were ineffective in this regard in both IL-1-pretreated and in resting cells. Synovial cells derived from patients with rheumatoid arthritis and osteoarthritis responded similarly to bradykinin. The synergistic response in PGE2 production induced by IL-1 and bradykinin was significantly inhibited by pretreatment with 1 microM indomethacin or dexamethasone (96 and 94% inhibition, respectively). In addition, the response was abrogated by pretreatment with 10 micrograms/ml of cycloheximide or actinomycin D (81 and 97% inhibition, respectively). These data provide the first description of synergism of IL-1 with a noncytokine peptide in human synovial cells. The ability of IL-1 to increase the responsiveness of synovial tissues to bradykinin may play an important role in potentiating inflammatory responses within the joint.
Adjuvants, Immunologic↗