Perspective: One and one make three - leveraging the synergy of imaging and biomechanics in osteoarthritis research and care.

Mechanical stress on joint tissues is a central driver of osteoarthritis (OA), yet our understanding of OA pathomechanics remains incomplete, obstructing etiology-driven personalized treatments. Current joint assessment approaches are largely monodisciplinary. In this perspective we aim to advocate for the integration of imaging and biomechanics to assess joint function in OA research, by exploring their relative strengths and limitations and their potential synergy, towards advancing our understanding of pathomechanics in OA. Traditional structural imaging is often static and non-weightbearing, limiting its ability to elucidate pathomechanical pathways of OA. Meanwhile, biomechanical measurement approaches like motion capture are able to measure human movement during dynamic, weightbearing, and functional activities like walking or squatting, but their accuracy and precision is limited by soft tissue artefacts and modeling assumptions and constraints. We argue for the deliberate integration of imaging and biomechanics modalities to overcome their respective limitations towards a comprehensive understanding of the role of pathomechanics in OA. This can done, for example, via videoradiography-based motion analysis and personalized computational models that use additional imaging outputs from radiographs, CT or MRI. Achieving this vision of integrated multimodal analysis requires coordinated, transdisciplinary collaboration and shared resources to move beyond single-modality paradigms toward an integrated framework for pathomechanical joint health assessment, which subsequently can be used to better understand the complex relationships between mechanics, structure and biology within OA. Studies adopting this integrated approach are limited, yet emerging examples showcase the potential for advancing the field of OA research and, eventually, personalized care.