by Osaka Metropolitan University

Left: A bone hole, created in the area where the rotator cuff was originally attached, is irradiated with non-thermal atmospheric pressure plasma. Right: The rotator cuff is sutured in the bone hole. Credit: Osaka Metropolitan University

The human body, filled with muscles and moving parts, is far from indestructible. Injuries are common, especially where tendons and bones connect. In Japan, rotator cuff tears affect approximately one in four people over age 50, and reports state that even after surgery, about 20% of cases result in re-tears. To combat this, new healing methods to bolster current clinical practices are needed.

Graduate student Katsumasa Nakazawa, Associate Professor Hiromitsu Toyoda, and then Professor Hiroaki Nakamura at Osaka Metropolitan University's Graduate School of Medicine, along with Graduate School of Engineering Professor Jun-Seok Oh and colleagues have previously reported positive results using non-thermal atmospheric pressure plasma for bone and tendon repairs.

This time, the team used plasma on rotator cuffs of rabbit models to examine the healing rate and strength of the repair.

The study consisted of two groups, a control and a five-minute plasma irradiation group where rotator cuffs were detached, irradiated, and then sutured. The histology and mechanical strength differences were compared and examined at intervals of two, four, and eight weeks.

The findings were published in the Journal of Shoulder and Elbow Surgery.

The results showed that the plasma irradiation group had a tissue arrangement similar to that of a normal tendon-bone junction after four and eight weeks.

It was also found that more bone tissue was formed than in the control group. In biomechanical testing, the force required to break the plasma irradiated rotator cuff after eight weeks was close to the strength for an undamaged one.

"If the results of this research can be applied to current clinical practices, it may be possible to contribute to more reliable rotator cuff repairs and a reduction in the rate of re-tears," stated Professor Toyoda.

"Furthermore, by introducing this technology to sports medicine, it is expected to speed up athletes' recovery and improve their performance."

More information: Katsumasa Nakazawa et al, Non-thermal atmospheric pressure gas discharge plasma enhances tendon-to-bone junction repair in a rabbit model, Journal of Shoulder and Elbow Surgery (2024). DOI: 10.1016/j.jse.2024.07.039

Provided by Osaka Metropolitan University