Influence of exercise and rest on pseudotumors.
MRI scanning of Metal-on-Metal total hip arthroplasy.

Although Metal-on-Metal (MoM) hip arthroplasty gained huge popularity in the
beginning of this century, critical reports about Adverse Reactions to Metal
Debris (ARMD) were published, eventually leading to a recall of some MoM
designs1, and a stop of its use in some countries due to too many questions
about its value and safety. Manifestations of ARMD include the occurrence of
pseudotumors, which may cause severe symptoms, can be locally destructive and
might require revision surgery in a proportion of patients. Pseudotumours,
defined as a peri-articular mass caused by an immunological delayed
hypersensitivity response to metal particles and characterised by a
lymphocyte-dominated histological pattern. These pseudotumors usualy have an
intra-articular connection.
MRI is used to noninvasively detect, monitor, and quantify the (chronic)
synovitis and progressive destruction of soft tissue and bone in RA (Jacobson
et al 1999).

Recent pilot study on measuring volumes in pseudotumours showed that estimating
pseudotumor volume in clinical practice using maximum diameter in three
different planes is easily attainable, has a strong correlation with a 3D-ROI
method, and can be used for monitoring pseudotumor volume over time.

The influence of activity level right before the MRI is made is unknown. I
seems clear that more activity results in more hydrops and so results in a
larger pseudotumor.
The objective of this study is to investigate the possible influence of timing
of day on making of MRI. Or to be more specific, what is the influence of
exercise on the outcome of pseudotumour diagnositics with MRI?

This is an observational case-control study in patients with a pseudotumor in
which the characteristics of this pseudotumor are compared with imaging
followin two different conditions.

All subjects will be scanned in MRI after a period of rest. Then all subjects
will perform a excersise program followed by a second MRI scan.

Time burden:
Visit 1: A questionaire is taken for current hip performance. Physical exam and
information on how to use the activity sensor. Time est. 1 hour.
In the period between the first and second visit the subject will carry the
activity sensor on their upper leg. Time est. 4 days, 10 hours a day.
Visit 2: Rest for 30 minutes. MRi scanning 30 minutes. Blood samples. Excersise
with fysiotherapist 60 minutes. (total time est 3 hours).
Visit 3: Excersise program 20-30 minutes. MRI scanning 30 minutes. Blood
samples.

Riscs:
MRI scanning: Minimal risks as standard precautions and contraindications are
taken in account.
Blood samples: Minimal risk. Haematoma
Excersise program: The subjects are asked to excersise tot their own maximum
tollerance. During excersise the subjects are under supervison of the
fysiotherapist to minimise the risk of excersise related complaints and
minimize the rist of a fall.