Metal Punch vs. Drill for Rotator Cuff Anchor Socket Creation; Cadaveric and Clinical Comparisons

Background: Arthroscopic rotator cuff repair has been shown to decrease pain and increase function of certain rotator cuff tears. One potential source of pain is the technique used for bone tunnel creation in the humerus prior to suture anchor placement. This study compared the standard metal punch method to a continuous drilling method for tunnel creation prior to subsequent suture anchor placement. Our hypothesis was that the use of a drill would result in less bony trauma and therefore superior resolution of postoperative pain following rotator cuff repair.

Methods: Tunnels were created for six cadaveric (age: 50.83±3.25; male n=3; female n=3) shoulder humeri using a 4-anchor construct to mimic transosseous equivalent rotator cuff repair. Following suture fixation, μCT scans were performed for evaluation of peri-tunnel bone architecture. A tensile force was applied to the anchor through the suture material at a constant displacement rate of 1mm/s until ultimate failure of the construct. All statistical analyses were performed using SPSS (version 25; IBM, Armonk, NY, USA), and significance was set at p≤0.05. A total of 43 subjects between 18 and 80 years old were randomized into the study, with 22 in the drill group and 21 in the punch group. Following surgery, the first 5 patients in each cohort underwent MRI at the 2-week postoperative visit. Pain and other patient reported measures (PROMs) were assessed at all standard of care postoperative visits. Patient demographics and PROMs were assessed for significance within the groups using repeated ANOVA and unpaired t-test. A P-value of <0.05 was set for significance.

Results: Preclinical - There were no statistically significant differences (p>0.05) between punched and drilled anchors with respect to peri-socket bone architecture and material properties. Clinical - There were no statistically significant differences (p>0.05) between punch and drill cohorts for assessments of pain, function, or bone marrow lesion size. However, the punch cohort reported statistically significant and clinically meaningful reductions in pain scores at 2 weeks, 6 weeks, 3 months, and 6 months compared to preoperative scores (p<0.02), whereas the drill cohort reported statistically significant and clinically meaningful reductions in pain scores at 6 weeks, 3 months, and 6 months after surgery (p <0.05). Similarly, the punch cohort reported statistically significant reductions in PROMIS pain interference scores, which were within 1 standard deviation of the healthy adult control population, at 2 weeks, 6 weeks, 3 months, and 6 months compared to preoperative scores (p <0.05), whereas the drill cohort did not report statistically significant improvements in PROMIS PI scores until 3 months postoperatively and were not within 1 standard deviation of the healthy adult control population until 6 months after surgery.

Conclusion: Preclinical and clinical data suggest that it is reasonable to utilize either a punch or drill socket-creation method for suture anchor placement in arthroscopic rotator cuff repair, while considering the potential for earlier pain relief associated with the punch method.