[Effect of low-intensity pulsed ultrasound on regeneration of joint cartilage in patients with second and third degree osteoarthritis of the knee].

OBJECTIVE To determine if the application of low intensity pulsed ultrasound (LIPUS) therapy has a positive effect over the cartilage repair, functional status and reduction of pain in patients with grade 2 or 3 osteoarthrosis of the knee. DESIGN This trial was an observational, before and after study without a control group, in which 10 patients (eleven knees) were studied. We applied LIPUS therapy with an intensity of 0.3W/cm(2), duty cycle of 50%, giving a total of 36J/cm(2) per session during 36 sessions (three months). The clinical measures were obtained before the first session and at the end of the 36th session, and were: cartilage thickness by the analysis of magnetic resonance images (MRI) measured by two rheumatologists and a radiology specialist, pain by a visual analog scale (1-10cm) and function/severity by the Lequesne index. We used the non parametric tests of Wilcoxon for comparing medians and the Spearmans rho for the correlation of the inter observer cartilage thickness measurements defining a p value of<0.05 as significant. RESULTS We observed an effect on pain (VAS mean before 7.09+-2.54 mean after 4.18+-2.22 p 0.005) and on the function/severity index (Lequesne mean before 10.55+-5.42 mean after 5+-4.45 p 0.008). There was poor consistency regarding the cartilage thickness measures by resonance imaging between the three observers (2 rheumatologists and 1 radiologist) so we were not able to define the presence or absence of effect on cartilage thickness augmentation. CONCLUSIONS LIPUS has a benefic effect over pain and functionality/severity in patients with Kellgren and Lawrence grade 2 and 3 osteoarthritis of the knee. Unfortunately in this study we did not count with a reliable measure method to conclude on its effect over cartilage thickness measured by MRI.