Joint distraction (KJD) in treatment of knee osteoarthritis: cartilage changes in a comparison with a presently applied surgical alternative: high tibial osteotomy (HTO)

Knee Joint Distraction (KJD) is proven to be beneficial in patients with
endstage osteoarthritis of the knee in comparison with their own baseline
profile. In the present study, KJD will be used for unicompartmental
osteoarthritis of the knee, another indication. In the study KJD will be
compared with currently used surgical techniques in treatment of
unicompartmental osteoarthritis of the knee, namely high tibial osteotomy
(HTO).

1. To compare cartilage changes after KJD and after HTO, based on MRI,
radiographs and biomarkers, evaluated 2 years post treatment.
2. To compare clinical efficacy after KJD and after HTO during 2 year follow-up
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.
3. To gather preliminary data on medical consumption and non-medical costs
related to disease and treatment as well as quality of life.

A multicenter (Maartenskliniek te Woerden (MK-W) and University Medical Center
Utrecht (UMC), randomised controlled, 2 years follow-up trial will be
accomplished. Patients with severe unicompartimental OA of the knee, for whom
conservative therapy fails and are indicated for a HTO by a orthopaedic surgeon
and meet the inclusion criteria will be asked to participate. After informed
consent, patients will be randomised between HTO en KJD (2:1). Structural and
clinical outcome parameters are evaluated over time up to 2 years and compared
between two treatmentstrategies. Data on direct and indirect costs as well as
change in quality of life are gathered by use of questionnaires.

HTO is performed according to regular clinical practice. KJD is performed
according to a standard protocol. An external fixator bridging the joint by use
of two Stryker monotubes is placed. Intra-operatively 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. After 6 weeks the frame is removed at day-care surgery,
followed by sstandard care physical therapy.

All patients included will visit the outpatient clinic more frequently, namely
a total of 7 times in two years. At this visit questionnaires have to be filled
in. 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
(KJD+HTO), 1yr (KJD) and 2yr (KJD+HTO) 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 HTO.