The aim of this study was the objective control of the therapeutic effect of weak pulsing magnetic fields (series of periodically repeating square pulses increasing according to an e-function, frequencies of 10, 20, 30, and 200-300 Hz) by means of a double-blind study on osteoarthritis of the knee. Measured parameters were the Knee Society score, pain sensation, blood count and cardiocirculatory values.
36 placebo and 35 verum test persons (all with a knee gap smaller than 3 mm) were exposed daily for 16 minutes over 6 weeks to a low frequency magnetic field (flux densities increasing gradually from 3.4 up to 13.6 microT) encompassing the whole body. The last data collection was made 4 weeks after the end of treatment.
Principally, the statistically ensured results exclusively favour the used magnetic field therapy; by far the greatest number of at least significant differences was found at the end of the whole treatment, lasting 6 weeks. In particular, it is striking that all 4 questioned pain scales showed at least significant improvements in favour of the verum collective; also the walking distance was increased. As another confirmed fact, even after 4 weeks without therapy the persistence of several functional and analgesic effects could be documented.
Predominantly, on the one hand, pain relief in osteoarthritis patients was confirmed by a double-blind trial, on the other hand, increases in mobility could be proven. Furthermore, we describe mainly the modes of action of low frequency magnetic energy and 3 physical concepts that are seen as the connecting link between electromagnetic fields coupled into connective tissue and biochemical repair and growth processes in bones and cartilage. Proceeding from the results of this and preceding studies, one has to consider seriously whether this kind of magnetic field application should not be employed as cost-effective and side effect-free alternative or adjuvant form of therapy in the field of orthopaedic disorders.
Institut für Hygiene an der Universität Graz, Osterreich.