Patients Prospectively Recruited in Knee and Hip Arthroplasty

A: Hip and knee replacement arthroplasties relieve pain and improve physical
functioning and quality of life. However, some patients suffer from persisting
pain or are not satisfied with the outcome. Several studies have suggested risk
factors for poor outcome after hip and knee replacement arthroplasty; however,
most studied cohorts are relatively small (n<800), which makes correcting for
confounding factors problematic. This larger cohort (n=3000) enables us to
study all suggested risk factors and the possible correlations between them,
while correcting for confounding factors.
By determining risk factors for poor outcome after hip and knee replacement
arthroplasty, it will be possible to influence these factors, in order to
optimalise the outcome of hip and knee replacement arthroplasty.

B: Aseptic loosening is the main cause of failure of hip and knee replacement
arthroplasty in the long term. Several studies have suggested variances in
immunomodulating genes as a possible contributor to aseptic loosening; however,
group sizes were too small to draw any firm conclusions (n<90). In this current
study, we aim to study the influence of immunomodulating genes on aseptic
loosening in a larger patient cohort (n=3000) A better understanding of the
underlying process of aseptic loosening will make it possible to determine the
prognosis of prosthesis loosening more accurately.

C: Osteoarthritis is the most frequent indication for hip and knee
arthroplasty. Conversely, the indication for hip and knee replacement
arthroplasty can be viewed as the final stage in the pathophysiology of
osteoarthritis. Recent studies showed that genetics play an important role in
the pathophysiology of osteoarthritis. By comparing genetic variations between
patients in final stage osteoarthritis and matched controls with a less severe
clinical manifestation of osteoarthritis, a better understanding of the
pathophysiology of osteoarthritis can be obtained.

A. What are the determinants of quality of life of hip and knee replacement
arthroplasty at long term follow-up?
B. Which genetic factors are associated with aseptic loosening in hip and knee
replacement arthroplasty?
C. Which genetic determinants predispose to hip or knee replacement
arthroplasty due to osteoarthritis?

Prospective cohort study:
- Measures for quality of life, hip and knee function and illness perception
will be measured and repeated annually, until revision surgery is performed.
The exact nature of the revision surgery will be examined in the clinical
charts.

Case-control study:
- Gene frequencies will be compared between cases of aseptic loosening and
controls.
- Genetic association studies will be performed, comparing patients who
underwent hip or knee replacement with matched controls with a less severe
manifestation of osteoarthritis.

Filling in the questionnaires will take approximately 20 minutes. These
questionnaires will be sent to the patients, and will be returned by post-free
envelope.

The genetic material will be isolated from a saliva sample. Patients will
receive a special saliva container and will return the filled container by
post-free envelope.