Kompendium 2020 Forschung & Klinik

TOP-Studien
32
Figure 1: Time integrated SDAI was significantly
higher in patients with RCL (median; 25th and 75th
percentile: 10.8; 8.6 and 15.8) than in controls
without RCL (7.0; 2.7 and 15.5) (Figure 1; p=0.043).
DMARDs had a protective effect on such risk. This link between inflammation
and RCL was further substantiated in the comparison between RA and OA,
being particularly evident for TKA.
Priv.-Doz. DDr. Christoph Böhler
Author:
Christoph Böhler is a specialist
for Orthopaedics and Traumatology
at the Medical University of
Vienna. His clinical and scientific
focus are on primary and
revision arthroplasty. In August
2021 he will start a clinical
Adult Reconstruction Fellowship
at the University of Toronto,
Canada.
Local inflammation plays a pivotal role in the pathogenesis of aseptic loosening,
by which generation of wear debris between the bearing surfaces
leads to activation of macrophages and immune cells, which then release
pro-inflammatory cytokines like TNF-alpha and IL-6. These induce osteoclast
activation and lead to increased bone resorption, osteolysis and eventually to
aseptic loosening. The systemic inflammation of RA may play a role in enhancing
the local inflammation underlying the described processes leading to
aseptic loosening. The implication of these findings for clinical practice are
potentially substantial, at least for individuals with RA and TJA: no patients
in remission showed RCL. Analogously to the observation that in sustained
remission of RA joint damage does not progress, this makes the case that
in the presence of TJA even stricter disease control should be pursued, with
clinical remission being the clear treatment target. Biological DMARDs had
a protective effect on the risk of RCL. Previously, it has been shown that
TNF-inhibitors are able to stop the progression of joint destruction. The
majority of the patients in the biological DMARDs group were treated with
TNF-inhibitors, potentially also suggesting a role of TNF alpha in the mediation
of the inflammatory process leading to aseptic loosening.
Conclusion
Taken together, inflammation in RA patients, as evidenced by higher levels
of disease activity, increases the risk for radiographic loosening after TJA. In
OA patients, as a control disease without systemic inflammation, the risk is
significantly lower. Biological DMARDs may reduce the risk of RCL, although
this would need prospective evaluation. Our data suggest that RA patients
with TJA should regularly undergo orthopaedic and radiographic evaluation
and, in the context of treating RA to target, might be considered for a more
stringent control of disease activity.