Objective:To compare the clinical efficacy of arthroscopic debridement, transtendon repair and tear completion and repair in treating Ellman II partial articular surface tendon avulsions.Methods:A retrospective case control study was conducted on 45 patients with partial articular surface tendon avulsions admitted to East Division of Shanghai Sixth Hospital Affiliated to Shanghai Jiao Tong University from December 2017 through December 2019. There were 18 males and 27 females, with a mean age of (56.4±5.0)years (range, 38-66 years). The patients were assigned to arthroscopic debridement group ( n=15), arthroscopic transtendon repair group ( n=15), and arthroscopic tear completion and repair group ( n=15). Operation time and complications were recorded. American Shoulder and Elbow Surgeons (ASES) score and University of California, Los Angeles (UCLA) score were measured preoperatively, at postoperative 3 months and at the latest follow-up. Results:All the patients were followed up for 8-32 months [(18.2±6.3)months]. In arthroscopic debridement group, arthroscopic transtendon repair group and arthroscopic tear completion and repair group, the operation time was (43.7±3.1)minutes, (89.1±5.4)minutes, (62.2±3.6)minutes, respectively ( P<0.05). No complications such as nerve injury, infection and arthrofibrosis were observed after operation. In arthroscopic debridement group, arthroscopic transtendon repair group and arthroscopic tear completion and repair group, the ASES score was preoperative (48.7±2.9)points, (49.1±3.0)points, (48.3±3.6)points, respectively ( P>0.05); the UCLA score was preoperative (15.5±1.3)points, (15.4±1.8)points, (15.2±1.4)points, respectively ( P>0.05). In arthroscopic debridement group, arthroscopic transtendon repair group and arthroscopic tear completion and repair group, the ASES score at the latest follow-up was (90.1±1.6)points, (89.3±1.0)points, (89.4±1.0)points, respectively ( P>0.05); the UCLA score at the latest follow-up was (30.3±2.1)points, (29.0±2.3)points, (28.9±2.7)points, respectively( P>0.05). In arthroscopic debridement group, arthroscopic transtendon repair group and arthroscopic tear completion and repair group, the ASES score at postoperative 3 months was (84.4±2.3)points, (73.5±3.6)points, (73.6±3.2)points, respectively; the UCLA score at postoperative 3 months was (26.9±1.4)points, (21.4±1.0)points, (21.1±1.0)points, respectively. In comparison, no significant difference was found between arthroscopic transtendon group and arthroscopic tear completion and repair group ( P>0.05). However, ASES score and UCLA score in arthroscopic debridement group were significantly higher than those in arthroscopic transtendon group and arthroscopic tear completion and repair group ( P<0.05). Conclusions:Arthroscopic debridement, transtendon repair and tear completion and repair are effective techniques for treatment of Ellman II partial articular surface tendon avulsions. However, the operation time and early efficacy of arthroscopic debridement are better than other two techniques.