Efficacy of extracorporeal shockwave therapy and lowintensity pulsed ultrasound in a rat knee osteoarthritis model: A randomized controlled trial

Objective: This study aims to assess the efficacy of extracorporeal shockwave therapy (ESWT) and low-intensity pulsed ultrasound (LIPUS) on osteoarthritic rat knees.

Material and Methods: Twenty-four rats were divided into 3 groups: group 1-control (n=8), group 2-LIPUS (n=8) and group 3-ESWT (n=8). Cartilage degeneration was provided using mono-iodo-asetate (MIA). One milligram of MIA was delivered to the right knees in group 1 and both knees in group 2 and 3. A 0.09% saline solution was delivered to the left knees in group 1 for control. Twenty-four hours after the delivery, ESWT was applied once on the right knees in the group 2 rats to the medial tibia plateu with a 1 Hz frequency and 800 impulses. LIPUS was applied to the right knees in the group 2 rats to the medial tibia plateu with a 3 mHz frequency and 40 mW/cm2 intensity for 20 minutes over a period of 15 days. Pain scores were measured with a knee bend test. Bone mineral density measurements and scintigraphic bone scans were performed. Histopathological examination was done using a modified Mankin scale.

Results: There was no difference among the right knee subchondral bone osteoblastic activities (p>0.05). The left knee osteoblastic activities in the LIPUS and extracorporeal shockwave therapy (ESWT) groups were higher than those in the control group (p<0.05), but there was no difference between the LIPUS and ESWT groups. There was no difference among the groups for both knee subchondral bone BMD values (p>0.05). The modified Mankin scores of both the right and left knees of the ESWT and LIPUS groups were lower than those of the control group (p<0.05), but there was no difference between the ESWT and LIPUS groups. The pain scores of both knees of the ESWT and LIPUS groups at day 7 were higher than those of the control group (p<0.05), but there was no difference between the ESWT and LIPUS groups. There was no difference among the pain scores of the right knees at day 14 (p<0.05).

Conclusion: ESWT and LIPUS have systemic proliferative and regenerative effects on cartilage and tissue.