Biologic enhancement of a common arthroscopic suture.

PURPOSE: The purpose of this study was to investigate the in vitro effects of an arginine-glycine-aspartic acid (RGD) coating on a high-strength nonabsorbable polyester/polyethylene (PE/PEE) suture material commonly used in orthopaedic procedures. METHODS: Human bone and tendon specimens were isolated and cultured. The cells were then plated in known densities in the presence of RGD-coated and uncoated PE/PEE suture and allowed to adhere for predetermined time periods. The RGD-coated and uncoated control sutures were then removed and assayed for cell osteoblast and tenocyte adhesion and proliferation. RESULTS: The RGD-modified suture showed a statistically significant increase in both adhesion and proliferation of human tenocytes when compared with uncoated controls (P < .05). CONCLUSIONS: The RGD peptide sequence can be effectively coupled with commercially available PE/PEE suture. RGD-coated suture is able to stimulate the adhesion and proliferation of human tenocyte cells in vitro, as well as withstand standard sterilization and storage conditions. Furthermore, the acid hydrolysis process did not affect the strength of the suture material. CLINICAL RELEVANCE: RGD-modified suture materials have the potential to create favorable biologic responses when used in common orthopaedic procedures.

Material properties and composition of soft-tissue fixation.

Surgical interference screws and suture anchors for attaching soft tissue, such as ligaments and tendons, to bone are routinely used in arthroscopic surgery and sports medicine. Interference screw fixation provides a press fit between bone, graft/tendon, and screw and is frequently used to attach replacement ligaments in tunnels drilled for anterior and posterior cruciate ligament reconstruction. Suture anchors are used in surgical procedures wherein it is necessary for a surgeon to attach (tie) tissue to the surface of the bone, for example, during joint reconstruction and ligament repair or replacement. The composition of these implants ranges from metals to polymers and composites. Typically, because of the relatively large amount of torque that must be applied during insertion, these screws are constructed from metal. However, interference screws and suture anchors have also been constructed from bioabsorbable polymers and composites. The ideal material would (1) provide adequate mechanical fixation, (2) completely degrade once no longer needed, and (3) be completely replaced by bone. Because no material has been shown to be superior for all applications, the surgeon must weigh the advantages and disadvantages of each to evaluate the optimum material for a given application and patient. The purpose of this article is to present a comprehensive review of the commercially available interference screws and suture anchors, with an emphasis on implant composition, interaction, and design. This article provides the orthopaedic surgeon with a background on biomaterials, specifically those used in interference screws and suture anchors. Because there is no material that is perfect for all surgical situations, this review can be used to make educated decisions on a case-by-case basis.

Tendon and bone responses to a collagen-coated suture material.

Tendon to bone integration after rotator cuff repair is not a reproducible process. During repair, bioabsorbable and nonabsorbable suture material is universally used to facilitate the procedure. Improving the biological architecture of inert suture might aid in overall tendon to bone healing. The objective of our study is to enhance the bone to tendon union by absorbing type I collagen onto high strength nonabsorbable polyester/polyethylene suture commonly used in rotator cuff surgery. Our purpose was to evaluate the tendon and bone cellular response to this novel coated suture compared to uncoated suture. Primary human osteoblasts (HOBs) and tenocytes were plated onto polyester/polyethylene suture that was either uncoated or coated with type I bovine collagen. Cell adhesion to the sutures was assayed at 24 hours. Proliferation was determined at 48 hours by measuring [3H]- Thymidine incorporation in cells attached to the sutures. At 24 and 48 hours, respectively, cells grown on the collagen-coated suture showed a significantly greater response measured by adhesion and proliferation than cells grown on uncoated suture. At five days of culture, alkaline phosphatase activity and protein synthesis was significantly greater on the collagen-coated suture compared to uncoated. Collagen-coated polyester/polyethylene suture appears to stimulate adhesion, proliferation alkaline phosphatase, and protein synthesis more than uncoated sutures, and therefore may aid in the tendon to bone incorporation process critical to rotator cuff repair.

A prospective, randomized evaluation of arthroscopic stabilization versus nonoperative treatment in patients with acute, traumatic, first-time shoulder dislocations.

BACKGROUND: Nonoperative treatment of traumatic shoulder dislocations leads to a high rate of recurrent dislocations. HYPOTHESIS: Early arthroscopic treatment for shoulder dislocation will result in a lower recurrence rate than nonoperative treatment. STUDY DESIGN: Prospective, randomized clinical trial. METHODS: Two groups of patients were studied to compare nonoperative treatment with arthroscopic Bankart repair for acute, traumatic shoulder dislocations in young athletes. Fourteen nonoperatively treated patients underwent 4 weeks of immobilization followed by a supervised rehabilitation program. Ten operatively treated patients underwent arthroscopic Bankart repair with a bioabsorbable tack followed by the same rehabilitation protocol as the nonoperatively treated patients. The average follow-up was 36 months. RESULTS: Three patients were lost to follow-up. Twelve nonoperatively treated patients remained for follow-up. Nine of these (75%) developed recurrent instability. Six of the nine have required subsequent open Bankart repair for recurrent instability. Of the nine operatively treated patients available for follow-up, only one (11.1%) developed recurrent instability. CONCLUSIONS: Arthroscopic stabilization of traumatic, first-time anterior shoulder dislocations is an effective and safe treatment that significantly reduces the recurrence rate of shoulder dislocations in young athletes when compared with conventional, nonoperative treatment.

Stability of double-row rotator cuff repair is not adversely affected by scaffold interposition between tendon and bone.

BACKGROUND: Rotator cuff reconstructions may be improved by adding growth factors, cells, or other biologic factors into the repair zone. This usually requires a biological carrier (scaffold) to be integrated into the construct and placed in the area of tendon-to-bone healing. This needs to be done without affecting the constructs mechanics. Hypothesis/ PURPOSE: The hypothesis was that scaffold placement, as an interposition, has no adverse effects on biomechanical properties of double-row rotator cuff repair. The purpose of this study was to examine the effect of scaffold interposition on the initial strength of rotator cuff repairs. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-five fresh-frozen shoulders (mean age: 65.5 ± 8.9 years) were randomly assigned to 5 groups. Groups were chosen to represent a broad spectrum of commonly used scaffold types: (1) double-row repair without augmentation, (2) double-row repair with interposition of a fibrin clot (Viscogel), (3) double-row repair with interposition of a collagen scaffold (Mucograft) between tendon and bone, (4) double-row repair with interposition of human dermis patch (ArthroFlex) between tendon and bone, and (5) double-row repair with human dermis patch (ArthroFlex) placed on top of the repair. Cyclic loading to measure displacement was performed to 3000 cycles at 1 Hz with an applied 10- to 100-N load. The ultimate load to failure was determined at a rate of 31 mm/min. RESULTS: There were no significant differences in mean displacement under cyclic loading, slope, or energy absorbed to failure between all groups (P = .128, P = .981, P = .105). Ultimate load to failure of repairs that used the collagen patch as an interposition (573.3 ± 75.6 N) and a dermis patch on top of the reconstruction (575.8 ± 22.6 N) was higher compared with the repair without a scaffold (348.9 ± 98.8 N; P = .018 and P = .025). No significant differences were found for repairs with the fibrin clot as an interposition (426.9 ± 103.6 N) and the decellularized dermis patch as an interposition (469.9 ± 148.6 N; P = .73 and P = .35). CONCLUSION: Scaffold augmentation did not adversely affect the zero time strength of the tested standard double-row rotator cuff repairs. An increased ultimate load to failure was observed for 2 of the augmentation methods (collagen patch as an interposition and decellularized dermis patch on top of the reconstruction) compared with the nonaugmented repairs. CLINICAL RELEVANCE: Scaffolds intended for application of growth factors or cellular components in a repair situation did not adversely jeopardize the stability of the operative construct.