Table 1 Criteria of inclusion and exclusion

• Persons with hand OA according to the ACR classification criteria for clinical OA [26]:

• Persons with a cognitive dysfunction;

   ◦ Pain, aching or stiffness in the hand and 3 of the following:

• Persons who do not understand the Norwegian language;

   ◦ Hard tissue enlargement involving at least 2 of 10 selected joints

• Persons with inflammatory rheumatic diseases (e.g. rheumatoid arthritis, ankylosing spondylitis) or cancer;

   ◦ Hard tissue enlargement of at least 2 DIP joints.

• Persons who have recently experienced severe trauma;

   ◦ Less than 3 swollen MCP joints

• Persons who have recently undergone OA surgery or other major surgery;

   ◦ Deformity of at least 1 of the 10 selected joints

• Persons who have received steroid injections in their hand joints during the previous two months.

OR uni-/bilateral OA in the CMC1 joint

• FIHOA* total score ≥5

• Access to a telephone