Suture anchors are broadly used for attaching soft tissue (e.g., tendons, ligaments, and meniscus) to the bone and have become essential devices in sports medicine and during arthroscopic surgery. As the usage of suture anchors has increased, various material-specific advantages and challenges have been reported. As a result, suture anchors are continually changing to become safer and more efficient. In this ever-changing environment, it is clinically essential for the surgeon to understand the key characteristics of existing anchors sufficiently.
The use of suture anchors has revolutionized orthopedic surgery because it allows for simple and efficient fixation of soft tissue (e.g., tendons and ligaments) to the bone in both open and arthroscopic surgery around the shoulder, elbow, wrist, and lower limb joints.) Shoulder surgery particularly has experienced a significant change in the type of techniques used from open repair of the rotator cuff and labrum using screws, washers, transosseous sutures, and staples to arthroscopic repair using suture anchors.
The primary function of the suture anchor is to attach tissue at the proper site and maintain its position without loosening or excessive tension until physiologic healing is accomplished. An ideal suture anchor is easy to handle, maintains enough pull-out strength, prevents suture abrasion, and is absorbable without resulting in any reactions as the material dissolves.) Various types of anchors have been developed, and designs of anchors have evolved over the recent decade to maximize their effectiveness in creating a firm tendon-to-bone repair.
The first suture anchor designs were nonabsorbable and metallic. A specific metal can be used combined with other metals to form an alloy or alone. The two most commonly used metal anchors are titanium and stainless steel. Titanium is widely used for orthopedic applications, and it is a strong, light material by itself, but it can also be combined with iron or aluminum (Fig. 1).5) Stainless steel is an alloy of carbon, chromium, and iron. It is more resistant to corrosion than regular steel and stronger than pure iron.5) Stainless steel anchors become encapsulated by a fibrous membrane rich in inflammatory cells, whereas titanium forms a surface layer of calcium and phosphate, which links directly to the bone without evidence of this fibrous layer and with minimal inflammatory response. An oxide layer spontaneously forms, and calcium and phosphate precipitate on this layer. Then, osteoblasts bind to the surface and actively secrete osteoid matrix