Mechanical properties of femoral cortical bone following cemented hip replacement.

Femoral bone remodeling following total hip replacement is a big concern and has never been examined mechanically. In this study, six goats underwent unilateral cemented hip hemiarthroplasty with polymethyl methacrylate (PMMA) bone cement. Nine months later animals were sacrificed, and the femoral cortical bone slices at different levels were analysed using microhardness testing and microcomputed tomography (micro-CT) scanning. Implanted femurs were compared to contralateral nonimplanted femurs. Extensive bone remodeling was demonstrated at both the proximal and middle levels, but not at the distal level. Compared with the nonimplanted side, significant decreases were found in the implanted femur in cortical bone area, bone mineral density, and cortical bone hardness at the proximal level, as well as in bone mineral density and bone hardness at the middle level. However, no significant difference was observed in either variable for the distal level. In addition, similar proximal-to-distal gradient changes were revealed both in cortical bone microhardness and bone mineral density. From the mechanical point of view, the results of the present study suggested that stress shielding is an important mechanical factor associated with bone adaptation following total hip replacement.

Ganoderma lucidum polysaccharide peptide reduced the production of proinflammatory cytokines in activated rheumatoid synovial fibroblast.

The aim of the current study was to elucidate the potential therapeutic effect of Ganoderma lucidum polysaccharide peptide (GL-PP) in rheumatoid arthritis (RA). The effects of GL-PP on cell proliferation and cytokine production were studied in RA synovial fibroblasts (RASF). GL-PP significantly inhibited the proliferation of RASF. Following the incubation with GL-PP, production of interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1 in RASF were significantly increased as expressed as percentage change from basal values. However, the actual effects were minimal due to the low basal values. When RASF were activated by IL-1beta or lipopolysaccharides, IL-8 and MCP-1 production increased many folds. GL-PP significantly suppressed their productions. The inhibitory effects of GL-PP on cytokine production in RASF were at least in part, by inhibiting the nuclear factor-kappa B (NF-kappaB) transcription pathway. Our results demonstrated that GL-PP had the unique ability to modulate cytokine production in RASF and warrants further investigation into its mechanism of action.

Arthroscopic treatment of patellar symptoms in posterior stabilized total knee replacement.

Twenty-one patients with patellar symptoms had arthroscopic treatment. Symptoms included frank patellar clunk and painful patellofemoral crepitus. All patients had posterior stabilized total knee replacement (TKR). The average onset of symptoms following TKR was 17 (range 3-75) months. All patients were referred to physiotherapy treatment before arthroscopic treatment. The average duration of symptoms prior to arthroscopic treatment was 23 (range 4-92) months. All patients were satisfied with resolution of symptoms at average follow-up of 32 (range 12-52) months. No complications were encountered; however, one patient had recurrence of a painful patellar crepitus 8 months after arthroscopy.