Single knotless-anchor with two ethicon 2# for Ellman grade III bursal-side partial thickness rotator cuff tears: a cadaveric biomechanical study and short-term clinical evaluation

BACKGROUND: Several surgical techniques are used to treat bursal-side partial thickness rotator cuff tears (PTRCTs). However, use of single knotless-anchor with two Ethicon 2# repair technique for PTRCTs has not been reported. MATERIALS AND METHODS: Bursal-side PTRCTs (Ellman grade III, 75% thickness of tears) were created in the supraspinatus tendon in 16 fresh-frozen cadaveric shoulders. The specimens were randomly assigned to two equal groups: (1) Group A (Transtendon repair), a single knotless-anchor repair with two Ethicon 2#; (2) Group B, Conversion repair (Double-row, DR). Post-repair, each specimen was subjected to cyclic loading test from 5 to 100 N (50 cycles), followed by an ultimate failure test. The displacement of greater tuberosity (mm) and ultimate (N) were recorded. In the clinical study, 12 patients diagnosed with Ellman grade III Bursal-side PTRCTs (using a single knotless anchor with two Ethicon 2# repair techniques) were operated on and analyzed. Visual analog scale (VAS), American Shoulder and Elbow Surgeons Score (ASES), Constant-Murley Score (CMS), and range of motion (ROM) were assessed before surgery and at final minimum follow-up (>1year). RESULTS: There was no significant between-group difference with respect to load-to-failure test (Group A, 359.25 ± 17.91 N; Group B, 374.38 ± 13.75 N, P > 0.05). There were no significant differences with respect to rotator cuff displacement of 10 mm (Group A, 190.50 ± 8.52 N; Group B, 197.25 ± 6.84 N, P > 0.05) and 15 mm (Group A, 282.25 ± 12.20 N; Group B, 291.13 ± 14.74 N, P > 0.05). However, there was significant between-group difference with respect to displacement of 3 and 5 mm (P < 0.05). In the clinical trial, all patients were followed up for an average of 20.4 months (12–29 months). At the last follow-up after surgery(minimum>1year), the VAS score was 0.50 ± 0.67 (0–2), the ASES score was 86.50 ± 3.96 (79–92), the CMS score was 85.08 ± 5.65 (74–93), the mean Forward flexion ROM was 154.00°± 12.48° (131°-169°), and the abduction ROM was 165.00°±13.26° (138°-173°). There was a statistically significant difference between the results of the preoperative and the last postoperative follow-up. The results of the last postoperative follow-up were statistically different from those of the preoperative follow-up (P < 0.05). Regarding complications, stiffness (2 cases) and shoulder impingement (1 case) occurred in 3 cases (25%). CONCLUSION: A single knotless anchor with two Ethicon 2# may provide a biomechanically and clinically feasible option for the treatment of bursal-side Ellman grade III PTRCTs, particularly in resource-constrained settings. MESH KEYWORDS: Bursal-side Ellman Grade III; Single Knotless-anchor; Double-row repair; Biomechanical study; Short-term clinical evaluation.