Joint distraction in treatment of knee osteoarthritis: a comparison with a presently applied surgical alternative: total knee prosthesis

Knee Joint Distraction (KJD) is proven to be beneficial in patients with
endstage osteoarthritis of the knee in comparison with their own baseline
profile. Following, this experimental procedure will be compared with currently
used surgical techniques in treatment of osteoarthritis of the knee, namely
total knee prosthesis (TKP). It is expected that KJD has equivalent or better
clinical outcome.

Primary:
- To test the hypothesis that the clinical effect of KJD (determined by WOMAC)
is not (clinically relevant) different from TKP at 2 years post treatment
(equivalence hypothesis).


Secondary:
- To describe and compare the clinical efficacy over 2 years of treatment by a
questionnaire (KOOS) for pain, other symptoms, function in daily living,
function in sports and recreation, and knee related quality of life) and by a
VAS for pain.
- The study will also be used to gather preliminary data on medical consumption
and non-medical costs related to disease and treatment as well as quality of
life.
- For the KJD group, tissue structure repair over 2 year follow-up compared to
baseline will be evaluated, to increase the number of patients in a KJD cohort
(ms added) in which structure modification has been evaluated. Extending this
KJD cohort with data on structure modification provides a basis for future
analyses on prediction of tissue structure repair after KJD.

This, multi-center, randomised controlled, non-blinded prospective 2 years
follow-up trial will be accomplished at the Maartenskliniek Woerden (MK-W).
Patients with severe OA of the knee, for whom conservative therapy fails and
are indicated for a TKP by a orthopaedic surgeon and meet the inclusion
criteria can be included. Patients will be randomised between TKP en KJD (2:1).
Clinical outcome parameters are evaluated over time up to 2 years.

Data on direct and indirect costs as well as change in quality of life are
gathered by use of questionnaires.

Additionally, the KJD patients are monitored for tissue structure repair. Blood
and urine will be collected before and up to 2 years after surgery. Samples are
used for evaluation of biochemical markers of cartilage and bone synthesis and
breakdown. Moreover, at baseline and over time up to 2 years, X-ray and MRI
images are evaluated for cartilage and bone changes.

KJD is performed according to the methodology as used in previous knee
distraction studies, using 2 monotubes, one laterally and one medially.
Intra-operative the tubes are distracted 2 mm. During hospitalization the frame
is further distracted, 1mm a day, until in total 5 mm is reached. Distraction
lasts for 6 weeks whereby fully load bearing is encouraged, with crutches for
stability. After 6 weeks the frame is removed at day-care surgery. TKP is
performed as usual according to the clinical protocol.

All patients included will visit the outpatient clinic more frequently, namely
ten times in two years. At this visit questionnaires have to be filled in. For
patients treated with KJD, additionally 10 ml of blood and 5 ml of urine will
be collected, an X-ray will be taken and 3 times a MRI examination will be
performed, at baseline, 1yr and 2yr evaluation. Patients treated with KJD have
the chance of developing pin-tract infections; this is a known complication of
a *fixateur externe*. These skin infections can be effectively treated with
antibiotics. Another possible disadvantage of KJD is that there is a higher
risk for knee joint contracture, aimed to prevent by adequate physiotherapy.
Rehabilitation will not be significantly different from TKP.