Bony Ingrowth of Coil-Type Open-Architecture Anchors Compared With Screw-Type PEEK Anchors for the Medial Row in Rotator Cuff Repair: A Randomized Controlled Trial

Purpose: To evaluate outcomes of screw-type and coil-type open-architecture suture anchors with respect to bony ingrowth, release of biological markers, and patient-reported outcome measures when used in rotator cuff repair (RCR). Methods: Forty patients undergoing arthroscopic RCR for full-thickness rotator cuff tears were enrolled and prospectively randomized to receive a screw-type (19 patients) or coil-type (21 patients) suture anchor for the medial row during repair. All repairs used a transosseous-equivalent configuration with footprint anchors laterally. Marrow elements released during surgery were evaluated for 9 cytokine markers (insulin-like growth factor 1, fibroblast growth factor 2, bone morphogenetic proteins 7 and 2, platelet-derived growth factors AA and BB, epidermal growth factor, transforming growth factor beta1, and vascular endothelial growth factor). Postoperative computed tomography scans were performed at 6 months. Range of motion, strength, and validated patient-reported outcome measures (Simple Shoulder Test, Single Assessment Numeric Evaluation, visual analog scale, and American Shoulder and Elbow Surgeons scores) were gathered before the operation and at 6 months and 1 year postoperatively. Results: Bone mineral density surrounding the coil-type anchor was significantly greater than that surrounding the screw-type anchor (P =.005). Bone mineral density values within the coil-type and screw-type anchors were comparable (P =.527); however, a larger amount of total bone mineral mass (in milligrams) was shown within the coil-type anchor owing to its larger volume (P <.01). Marrow elements released at the repair site were similar between groups (P >.05). Postoperatively, no statistically significant difference was found between groups for clinical outcome measures at 6 months or 1 year. Retear and complication rates were similar between groups (P >.05). Conclusions: Both the coil-type and screw-type anchors can be reliably used for RCR and produce similar clinical outcomes. The coil-type anchor resulted in superior bony growth surrounding the anchor and a larger total bone mineral mass within the anchor owing to its larger volume. Level of Evidence: Level II, randomized prospective comparative study.