Analysis of the pathomechanics in patients with painful early onset of osteoarthritis in the CMC-1 joint.

Osteoarthritis of the carpometacarpal (CMC) joint of the thumb is a significant
clinical problem with a large impact on society, the individual patient and
health economics. Currently there is no reliable diagnostic tool for the
diagnosis of CMC-1 joint osteoarthritis and are patients being diagnosed and
treated based on their clinical symptoms and 2D or 3D imaging. This research
project intends to create a new diagnostic protocol which helps in decision
making concerning treatment and will lead to more efficient use of therapy,
better functional outcome, prevention of progression of the disease and less
costs for care.

This project focuses on detection of predisposing factors (e.g. instability of
the joints) for the onset of early CMC-1 joint osteoarthritis based on CMC-1
joint kinematics. For this purpose we need to develop a new diagnostic 4D
imaging tool.
The aim of the first part of this project is to select common movement and
loading patterns in daily life that cause complaints of pain in patients with
early onset of osteoarthritis in the CMC-1 joint. Second we will analyse CMC-1
joint pathomechanics in patients with osteoarthritis of the CMC-1 joint with
tailor made 4D imaging methods under loading conditions and motions patterns of
the thumb that give complaints.

For the selection of common painful movement patterns we will use an already
existing instrument as a starting point: the Sequential Occupational Dexterity
Assessment (SODA) and will investigate the usefulness of the different ADL
subtest within the SODA test for scoring patients with CMC-1 joint
osteoarthritis. The 4D imaging protocol and design of the dynamic loading
system will be guided by the outcome of the ADL activity related parts of the
SODA tests. Patients with only pain or mild (early) CMC-1 joint osteoarthritis
and their matched controls will be asked to perform these standardised movement
and loading patterns during 4D imaging of the CMC-1 joint. Center of rotation
of the MCP-1 bone and joint space thickness will be analyzed with respect to
their usefulness as parameters to differentiate between the pathomechanical
mechanisms of different patient groups. We will also examine CMC-1 joint
kinematics of these patients again with their MCP-1 joint in fixed flexion to
investigate the possible benefit of splinting this joint.

The effective radiation dosis due to CT-imaging is estimated and calculated to
be around 0.8mSv. This is qualified bij de IRCP as a minor risk.