Suture Slippage After Arthroscopic Cuff Repair: Medial Displacement of Suture Knots on Follow-up Ultrasonography

Facile and rapid fabrication of a novel 3D-printable, visible light-crosslinkable and bioactive polythiourethane for large-to-massive rotator cuff tendon repair

Facile and rapid 3D fabrication of strong, bioactive materials can address challenges that impede repair of large-to-massive rotator cuff tears including personalized grafts, limited mechanical support, and inadequate tissue regeneration. Herein, we developed a facile and rapid methodology that generates visible light-crosslinkable polythiourethane (PHT) pre-polymer resin (∼30 min at room temperature), yielding 3D-printable scaffolds with tendon-like mechanical attributes capable of delivering tenogenic bioactive factors. Ex vivo characterization confirmed successful fabrication, robust human supraspinatus tendon (SST)-like tensile properties (strength: 23 MPa, modulus: 459 MPa, at least 10,000 physiological loading cycles without failure), excellent suture retention (8.62-fold lower than acellular dermal matrix (ADM)-based clinical graft), slow degradation, and controlled release of fibroblast growth factor-2 (FGF-2) and transforming growth factor-β3 (TGF-β3). In vitro studies showed cytocompatibility and growth factor-mediated tenogenic-like differentiation of mesenchymal stem cells. In vivo studies demonstrated biocompatibility (3-week mouse subcutaneous implantation) and ability of growth factor-containing scaffolds to notably regenerate at least 1-cm of tendon with native-like biomechanical attributes as uninjured shoulder (8-week, large-to-massive 1-cm gap rabbit rotator cuff injury). This study demonstrates use of a 3D-printable, strong, and bioactive material to provide mechanical support and pro-regenerative cues for challenging injuries such as large-to-massive rotator cuff tears.

Biomechanical effect of increased number of suture strands on rotator cuff repair in a bovine model

OBJECTIVE

This study aimed to investigate if there was a link between the biomechanical properties and the number of suture strands in repairing a rotator cuff (RC) tear in a bovine model using the transosseous technique.

METHODS

Fifty-four fresh tendons from bovine (mean age: 7.1 ± 0.5 months; range 6.5-7.5 months) and 1 humeral head from porcine (8.5 months) were used in this study. All the specimens had no apparent abnormalities. Using the transosseous structure, the RC tendon was detached from the greater tuberosity and randomly assigned to 3-strand, 4-strand, 5-strand, and 6-strand groups, with the glenohumeral abducted at 0° and 90°. Biomechanical tests were conducted to compare the groups' differences in the failure mode, pull-toextension load in the 1-, 2-, and 3-mm formations, and the maximum load. The analysis of variance test was performed to compare the results. Statistical significance was set at P < .05.

RESULTS

No significant difference was observed among the groups concerning the tendon characteristics (all P ≥ .05). At 90° shoulder abduction, a significant difference was detected in the load between 3- and 5-strand groups for 1-mm gap formation (P=.049). No statistical differences were noted in the load at the gap displacements in the 1-, 2-, and 3-mm formations at 0° and 90° shoulder abduction (all P > .05). The maximum failure load and extension in maximal tension increased with the number of sutures.

CONCLUSION

The maximum load and ultimate extension increase with the number of sutures at both positions. The number of sutures was not an influencing factor of gap formation. Regarding the tear size and tension of the RC, choosing the appropriate number of strands individually instead of excessively increasing the number of sutures is advocated for RC repair.

The imaging features of tape suture: a contemporary surgical material

OBJECTIVE

To offer an adjunctive imaging tool to MRI for evaluating tape suture related rotator cuff repairs.

MATERIALS AND METHODS

A two-part pilot study was performed to assess visibility of tape suture following imaging with various modalities. Institutional research ethics board approval was obtained prior to cadaveric studies. Two tape sutures, FiberTape® and TigerTape®, were evaluated in each experiment. The first experiment assessed the tape suture's presence in a gelatin mold following exposure to X-ray, ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) without contrast. The second experiment assessed tape suture's visibility in a cadaveric shoulder model following a standard of care, double-row, transosseous equivalent rotator cuff repair. The same imaging protocols and equipment were used for each part of the study with the addition of MR arthrography-tailored images on the cadaveric specimen. All images were assessed by a musculoskeletal trained radiologist.

RESULTS

The gelatin study demonstrated that the tape suture was visible via ultrasound only. X ray, CT, and MRI did not show tape suture material. In the ultrasound component of the cadaveric study, distinct echogenic textural detail of the tape suture was easily identified, compatible with the simulated rotator cuff repair. X ray and unenhanced CT did not show the tape suture material or the rotator cuff. MRI without intraarticular gadolinium contrast did not adequately image the suture tape; however, faint artifact in the repair region was visualized. MRI with intra-articular contrast did not show the tape suture material in detail; however, the intraarticular gadolinium did provide an advantageous background of high T1 signal that contrasted with the cuff/suture construct.

CONCLUSION

Ultrasound proved to be an effective imaging modality to visualize tape suture in both the gelatin and cadaveric parts of the pilot study. Ultrasound may be a useful tool to evaluate post-operative tape suture-related repairs in patients that cannot obtain MRIs or when the MRI findings are equivocal.