The aim of this study is to describe macro- and micro anatomical structures, including investigating vessels running in osseous pores in finger joints from participants with rheumatoid arthritis (RA) using histology and different imaging modalities. The perspectives are to increase understanding of the macro- and micro anatomic basis for bone erosions in RA, and possibly to provide new insights to the monitoring of patients with RA.

This study is a descriptive, cross-sectional pilot study. The trial subjects will have their hands imaged by conventional radiography. The 2nd and 3rd digit metacarpophalangeal (MCP) joint will be scanned by high-resolution peripheral quantitative computed tomography (HR-pQCT). Patients with RA (n = 10) will be included and bone samples from MCP joints analyzed using microcomputed tomography (µCT) and histology.

ELIGIBILITY CRITERIA

Inclusion criteria:

• Age > 18 years.
• Participants diagnosed with RA according to the ACR/EULAR (2010) classification criteria or American Rheumatism Association 1987 revised criteria for the patients who were diagnosed before 2010.
• Indication for prosthesis surgery with total joint replacement of the MCP joint according to the clinical procedure (often radiological signs of osteoarthrosis (OA) in the MCP joint, joint pain, angular deformity and/or impairment of daily functions).

RA Participants:

Inclusion Criteria:

• Age > 18 years
• Participants diagnosed with RA according to the ACR/EULAR (2010) classification criteria or American Rheumatism Association 1987 revised criteria for the patients who were diagnosed before 2010.
• Indication for prosthesis surgery with total joint replacement of the MCP joint according to the clinical procedure (often radiological signs of OA in the MCP joint, joint pain, angular deformity and/or impairment of daily functions).

Exclusion Criteria:

• Unable to give written informed consent.
• Active malignant disease, hypercalcemia, poor kidney function (estimated glomerular filtration rate < 35 mL/min), untreated hypo-/hyperthyroidism, pregnancy or wish thereof, previously fracture/dislocation of the investigated joint or metal prosthesis in joints of the investigated hand.

Bone sample will be excluded from analysis, if the following is present:

- Bone not adequate for analysis (fractured bone samples).

Participants with RA are recruited in conjunction with a routine visit at the Department of Orthopedic Surgery at Aarhus University Hospital or at the Regional Hospital Holstebro for assessment of surgical indication for joint replacement surgery on MCP joints by a specialist in orthopedic surgery.