Determining realistic prognosis of outcome of total knee arthroplasty

Durability of total knee arthroplasty is an important issue for orthopaedic
surgeons as well as patients. General belief is primary total knee
arthoplasties last for ten to fifteen years. It is debatable if this
information is correct. There is a paucity of follow-up studies with at least
15 years follow-up.
With respect to revision total knee arthroplasty, good or excellent clinical
outcomes range from 40% to 89%. Patient expectations are strong predictors of
outcome and functioning of joint replacement as well as satisfaction after
joint replacement. Which clinical factors influence outcome of revision knee
arthroplasty is insufficiently studied. These factors can help giving realistic
prognosis of revision total knee arthroplasty and therefore improve clinical
outcomes and patient satisfaction.

Answer the following questions:

1. What are the long term results (>20y) of patients with a primary total knee
prosthesis (type Total Condylar) for different endpoints:
a. Removal of the prosthesis. (with or without re-implantation)
b. Recommended removal: radiographic loosening
c. Clinical failure

2. Is survival of the prosthesis equal for rheumatoid arthritis in comparison
with osteoarthritis?

3. Which preoperative clinical parameters determine clinical outcome (including
patient satisfaction) of a revision total knee arthroplasty?

This protocol comprises an observational clinical cohort study. Data will be
collected by investigation of medical files, clinical measurements and once
filling in a number of questionnaires by patients. Questionnaires used are
SF-36, EQ5D, OKS, KOOS, IPQ, and SQUASH. For determining clinical knee
functioning we use Knee Society Score (KSS) or Hospital for Special Knee Score
(HSS). Both scores have to be determined by a surgeon, in contrast to the other
questionnaires. Information is collected until failure of the prosthesis or
until patients have died.

For the study which analyses outcomes of revision TKA different models will be
constructed for determining relationships between preoperative data (predictor
variables) and several outcome variables.

Filling in the questionnaires will take approximately 30 minutes. Determining
the HSS/KSS knee score will be performed at the department of Orthopedics in
the LUMC and takes 10 minutes. Radiographic assessment will be done if this was
not done within two years of the end of study. As much as possible will be
tried to combine clinical and radiographic assessment with other appointments
in the LUMC.

Subjects can leave the study at any time for any reason if they wish to do so
without any consequences. Daily practice of follow-up of total knee
arthroplasty is control at the department of Orthopaedics once every 2-3 years.
Reason is early detection of wear of the prosthesis, before patients experience
any discomfort.