The phenotypic and functional heterogeneity of synovial tissue fibroblasts are well described, whereas the cellular and molecular mechanisms that establish this diverse fibroblast repertoire in the adult joint have remained unclear. When is the fate of synovial fibroblast repertoire determined, and what are the consequences for arthritis development as adults?

In this Review, the authors discuss the similarities and differences between intervertebral disc degeneration and osteoarthritis of the facet joint and argue that both diseases should be viewed as being part of the same molecular disease spectrum.

Bone regeneration is a dynamic and tightly regulated process, but various mechanisms can disrupt this process and cause healing impairment. This Review discusses the complex processes that occur during the early phases that might be targeted to prevent bone healing disorders.

Although elegant work has detailed the clinical presentation, immune response and disease outcome of multisystem inflammatory syndrome in children, many questions remain. Studies in 2022 have explored the nature of the vascular injury, the role of the SARS-CoV-2 spike protein and the association with the current variants of the virus.