Feasibility study of an orthosis for treatment of Knee Osteoarthritis

Knee osteoarthritis (OA) is the most common joint disorder, and the lifetime
risk of developing symptomatic knee OA has been estimated to be around 45%
(Murphy et al. 2008 Felson et al. 2000). If conservative treatment fails, total
knee replacement (TKR) is a highly effective procedure that provides reliable
relief from pain, improved physical function, and a high level of patient
satisfaction (Hawker et al. 1998, Lutzner et al. 2009). The known limited
lifespan of TKR, the high demand expectation of a prosthesis of relative young
patient with knee osteoarthritis together with the increasing number of TKR*s
constitutes costly healthcare (Blitton et al. 2009, Losina et al. 2009).
Therefore, development of alternative treatments for knee OA, specifically
those that can postpone a prosthesis, are needed.

A promising new treatment is the Knee Joint Distraction (KJD) treatment. Recent
studies suggest that KJD treatment can reverse cartilage tissue structure
damage in severe knee OA and at the same time results in significant clinical
improvement (Intema et al. 2011). Joint distraction in its current form has
some disadvantages, which limit its use. It is an invasive technique involving
an external fixation frame, which patients have to wear for two months. This is
a major psychological burden. It hinders patients during sleep and makes
personal hygiene more difficult. The percutaneous pins of the frame often cause
infection. Finally, after two months of distraction, the joints are very stiff,
which also creates complications (pain and sometimes movement during
anaesthesia).

We have developed an orthosis that takes the entire weight off the affected leg
during walking without the use of percutaneous pins and joint distraction. The
orthosis allows the knee to bend normally. We hypothesize, that this orthosis
will also result in reduction of symptoms and regeneration of cartilage in an
osteoarthritic knee joint.

The primary objective of this study is to examine the effectiveness of the use
of a load-reducing orthosis for two months on functioning (using a validated
osteoarthritis function questionnaire (WOMAC)) in ten patients with
osteoarthritis of the knee.

Observational pilot study.

during two months patients use an non-weight bearing orthosis

The burden for patients involves wearing the orthosis and a sole on the other
foot, difficulties manoeuvring with the orthosis, pain experienced and other
discomforts during the phase in which the orthosis is adjusted to the patient.
Furthermore patients have to visit the hospital several times (questionnaires,
X rays and MRI) in the follow-up period of 24 months. During a two month
intervention period a log should be kept daily to monitor the use of the
orthosis during daily activities. The major risk while using the orthosis is
the change in balance experience which may result in falling and possibly in a
bone fracture. The use of crutches may help, but can also be seen as an
additional burden. The major benefit may be the improvement of OA symptoms and
the curing of this disabilitating disorder in the long run.