Extracorporeal Shockwave Shows Regression of Osteoarthritis of the Knee in Rats

Background. This study investigated the effects of extracorporeal shockwave technology (ESWT) in osteoarthritis of the knee in rats. Materials and Methods. Thirty-six Sprague-Dawley rats were randomly divided into three groups with 12 rats in each group. Group I was the control group and received neither anterior cruciate ligament transection (ACLT) nor ESWT. In groups II and III, ACLT was performed in left knee and osteoarthritis (OA) was verified at 12 wk. Group II received no ESWT, and group III received ESWT at 12 wk after ACLT. Radiographs and bone mineral density (BMD) were obtained at 0, 12, and 24 wk. The animals were sacrificed at 24 wk. One half of the animals were subjected to bone strength test, and the other half for histomorphologic examination and immunohistochemical analysis. Results. Radiographs of the left knee showed progressive OA changes at 12 and 24 wk in group II, whereas, very subtle OA changes were noted in group I and group III. BMD and bone strength were significantly lower in group II compared with groups I and III, but no difference was noted between group I and group III. The cartilage degradations were significantly higher in group II compared with groups I and III, but no difference was noted between group I and group III. The subchondral bone remodeling was significantly less pronounced in group II compared with groups I and III, but no difference was noted between group I and group III. Conclusions. Application of ESWT to the subchondral bone of the medial tibia condyle showed regression of osteoarthritis of the knees in rats. (C) 2011 Elsevier Inc. All rights reserved.