A definition for each contextual factor in hand OA should be formulated

Performance of a literature review to assess the level of evidence for the different candidate contextual factors

Identification or development of potential instruments to assess contextual factors, where applicable

Disease-specific instruments have to be developed for the (sub)domains HRQOL, aesthetic damage, bony damage, deformity, and hand mobility

Development and testing of VAS/NRS questions to measure the domain pain

Development of a new measure for hand pain in analogy to knee and hip pain (Intermittent and Constant OA Pain for the hand)

Evaluation of instruments that are commonly used by hand therapists, such as the DASH, PRWHE, and Michigan Hand Outcome Questionnaire, for use in hand OA.

Investigation what hand OA contributes to grip strength or pinch strength relative to other conditions that affect hand strength or function

Performance of qualitative interviews: how to measure patient global assessment

Investigation of the subdomain tender joints

Further evaluation of the instrument to assess tender joints (Doyle index), with respect to validation in OA — e.g., what is the added value of joint count to other domains, like pain. How many joints and which ones should be incorporated in the tender joint count? How should the tender joint count be performed? Is there a floor effect?

To develop instruments to assess soft swollen joints and bony damage

Investigation of the value of patient-performed joint count (e.g., self-complete homunculus) versus physician-performed joint count

Investigation of the metric properties of US and MRI

Investigation of the value of CT