The mid-term outcome of total ankle arthroplasty and ankle fusion in rheumatoid arthritis: a systematic review.

BACKGROUND: While arthrodesis is the standard treatment of a severely arthritic ankle joint, total ankle arthroplasty has become a popular alternative. This review provides clinical outcomes and complications of both interventions in patients with rheumatoid arthritis. METHODS: Studies were obtained from Pubmed, Embase and Web of Science (January 1980-June 2011) and additional manual search. INCLUSION CRITERIA: original clinical study, > 5 rheumatoid arthritis (population), internal fixation arthrodesis or three-component mobile bearing prosthesis (intervention), ankle scoring system (outcome). The clinical outcome score, complication- and failure rates were extracted and the methodological quality of the studies was analysed. RESULTS: 17 observational studies of 868 citations were included. The effect size concerning total ankle arthroplasty ranged between 1.9 and 6.0, for arthrodesis the effect sizes were 4.0 and 4.7. Reoperation due to implant failure or reoperation due to non-union, was 11% and 12% for respectively total ankle arthroplasty and arthrodesis. The methodological quality of the studies was low (mean 6.4 out of a maximum of 14 points) and was lower for arthrodesis (mean 4.8) as compared to arthroplasty (mean 7.8) (p = 0.04). CONCLUSIONS: 17 observational and no (randomized) controlled clinical trials are published on the effectiveness of arthroplasty or arthrodesis of the ankle in rheumatoid arthritis. Regardless of the methodological limitations it can be concluded that both interventions show clinical improvement and in line with current literature neither procedure is superior to the other.

Communication between human mast cells and CD4(+) T cells through antigen-dependent interactions.

Mast cells (MCs) are immune cells residing in tissues where pathogens are first encountered. It has been indicated that MCs might also be involved in setting the outcome of T-cell responses. However, little is known about the capacity of human MCs to express MHC class II and/or to capture and present antigens to CD4(+) T cells. To study the T-cell stimulatory potential of human MCs, CD34(+) stem cell derived MCs were generated. These cells expressed HLA-DR when stimulated with IFN-γ, and, importantly, presented peptide and protein for activation of antigen-specific CD4(+) T cells. The interplay between MC and T cell led to increased HLA-DR expression on MCs. MCs were present in close proximity to T cells in tonsil and expressed HLA-DR and CD80, indicating their ability to present antigens to CD4(+) T cells in T-cell areas of human LNs. Our data show that MCs can present native antigens to human CD4(+) T cells and that HLA-DR expressing MCs are present in tonsil tissue, indicating that human MCs can directly activate T cells and provide a rationale to study the potential of MCs to prime and/or skew human T-cell responses.