Partial-thickness rotator cuff tears (PTRCTs) are one of the leading causes of shoulder pain and dysfunction in middle/older patients. Ellman classified PTRCTs arthroscopically according to the location (articular, bursal, or interstitial) and depth of the tear. Ellman grade III tears, which involve more than 6 mm or 50% of the tendon thickness, are also known as high-grade PTRCTs. Most of these tears require rotator cuff repair surgery. There is no consensus on the optimal treatment of Ellman grade III tears under arthroscopy. How to effectively promote tenon-bone healing, reduce rotator cuff retear rate, and improve clinical efficacy is still the focus of attention. Platelet-rich plasma (PRP) has received increasing attention in musculoskeletal system research in recent years. PRP contains essential growth factors that promote tenon-bone healing and can promote tendon healing. However, few clinical studies have reported PRP's potential role in treating bursal-side PTRCTs, and even fewer studies have reported the combined use of PRP in arthroscopic rotator cuff repair.

To explore the clinical effect of a single injection of PRP during arthroscopic rotator cuff repair to treat bursal-side PTRCTs.

From July 2016 to July 2018, 54 patients of Ellman grade III bursal-side PTRCTs were treated by arthroscopic rotator cuff repair, and the data was collected and retrospectively analyzed. According to whether PRP was combined with intraoperative treatment, it was divided into two groups. The experimental group (27 cases) received arthroscopic rotator cuff repair combined with PRP treatment, while the control group (27 cases) received arthroscopic rotator cuff repair without PRP injection. Before the operation and at the last follow-up, the visual analog scale (VAS) was used to assess the pain, American shoulder and elbow surgeons score (ASES), the Constant-Murley shoulder score (CSS), University of California at Los Angeles scores (UCLA) were used to evaluate the pain and functional recovery of the affected shoulder. Meanwhile, the range of motion of anteflexion, abduction, lateral external rotation, and internal rotation were assessed and compared between the two groups. At the final follow-up, the integrity of the rotator cuff was evaluated according to the MRI image of the shoulder, and the postoperative efficacy and rotator cuff retear rate of the two groups were further discussed and analyzed.

All the patients were followed up. There were no significant differences in VAS score, ASES score, CSS score, UCLA score, and the shoulder range of motion between the two groups before operation (P>0.05). At the final follow-up, the two groups' VAS score was lower than before the operation, and the difference between the preoperative and last follow-up in the same group was statistically significant (P<0.05). The VAS score of the patients in the experimental group was significantly lower than that of the control group, and the difference between the groups was statistically significant (P<0.05). At the last follow-up, the ASES score, CSS score, UCLA score, and shoulder range of motion of the two groups were higher than that before the operation, and the differences between the same group before the operation and at the last follow-up were statistically significant (P<0.05). In contrast, the difference between the groups was insignificant (P>0.05). Due to the UCLA grading evaluation of the curative effect, the excellent and good rate was 96.3% in the experimental group, and the acceptable rate was 92.6% in the control group. At the final follow-up, MRI showed retears in 7.4% of the experimental group and 18.5% of the control group. The rate of rotator cuff retearing in the experimental group was lower than that in the control group, and there was a trend of reducing postoperative rotator cuff retearing in the experimental group. However, the difference was not statistically significant (P>0.05) .

A single injection of PRP during arthroscopic rotator cuff repair to treat Ellman grade III bursal-side PTRCTs can achieve satisfactory clinical efficacy, with an excellent and good rate of more than 95%. The application of platelet-rich plasma can significantly relieve postoperative shoulder pain, improve shoulder joint function, promote shoulder range of motion, and reduce postoperative rotator cuff retear.