Suspensory fixation for bone transfer procedures in shoulder instability is superior to screws in an angled construct: a biomechanical analysis.

Background: The Latarjet procedure is a common bony augmentation procedure for anterior shoulder instability. Historically, screw fixation is used to secure the coracoid graft to the anterior glenoid surface; however, malpositioning of the graft leads to oblique screw insertion that contributes to complications. Suture buttons (SBs) are a more recent fixation technique that have not been studied alongside standard screw fixation in the context of biomechanical models of angulated fixation. This study aims to compare the biomechanical strength of single and double, screw and SB fixation at various levels of angulation. Methods: Testing was performed using polyurethane models from Sawbones. The graft piece was secured with screw fixation (Arthrex, Naples, FL, USA) or suspensory button (ABS Tightrope, Arthrex, Naples, FL, USA). Single or double constructs of screws and SBs were affixed at 0°, 15°, and 30° angles to the face of the glenoid component. An aluminum testing jig held the samples securely while a materials testing system applied loads. Five constructs were used for each condition and assessed load to failure testing. Results: For single fixation constructs, suspensory buttons were 60% stronger than screws at 0° (P < .001), and 52% stronger at 15° (P = .004); however, at 30°, both were comparable (P = .180). Interestingly, single suspensory button at 15° was equivalent to a single screw at 0° (P = .310). For double fixation, suspensory buttons (DT) were 32% stronger than screws at 0° (P < .001) and 35% stronger than screws at 15° (P < .001). Both double fixation methods were comparable at 30° (P = .061). Suspensory buttons at 15° and 30° were equivalent to double screws at 0 (P = .280) and 15° (P = .772), respectively. Conclusion: These measurements indicate that the suspensory button has a significantly higher load to failure capacity over the screw fixation technique, perpendicularly and with up to 15° of angulation. These analyses also indicate that the suspensory button fixation offers superior strength even when positioned more obliquely than the screw fixation. Therefore, suspensory button fixation may confer more strength while offering greater margin for error when positioning the graft.

Impact of Sling Use on Functional Mobility in a Geriatric Population.

OBJECTIVES: Sling immobilization is commonly used following rotator cuff repair. The purpose of this study was to determine the detrimental impact of sling usage on mobility and balance in an older adult population through validated gait and balance testing. The authors hypothesize that sling use will negatively affect balance and stability. METHODS: This institutional review board-approved and registered randomized prospective clinical trial enrolled patients from 2019 to 2021. Following informed consent, patients were randomized into two groups: a sling worn (group 1) and no sling worn (group 2). Participants were assessed via the Edmonton Frail Scale as well as Tinetti gait and balance scoring. RESULTS: Fifty patients were included in the study, 23 (46%) men and 27 (54%) women, with a mean age of 72.2 years. The balance score median was 16.00 for participants not wearing a sling and 15.00 for participants wearing a sling. The gait score median was 12.00 for participants not wearing a sling and 11.50 for participants wearing a sling. The balance and gait scores were significantly greater when patients were not wearing a shoulder sling with P values of 0.006 and 0.011, respectively. The overall combined gait and balance score was significantly greater, with median values of 27.00 for participants not wearing a sling and 26.00 for participants wearing a sling (P = 0.001). Patients reported little to no anxiety about falling while wearing the sling, with a score of 0.16. CONCLUSIONS: Postoperative sling immobilization negatively affects balance and gait in the geriatric population, potentially increasing the risk of postoperative falls in an already at-risk population.

A Systematic Review of Screw and Suture Button Glenoid Augmentation Constructs.

Background: Glenohumeral dislocations often lead to glenoid bone loss and recurrent instability, warranting bony augmentation. While numerous biomechanical studies have investigated fixation methods to secure a graft to the glenoid, a review of available constructs has yet to be performed. Purpose: To synthesize the literature and compare the biomechanics of screw and suture button constructs for anterior glenoid bony augmentation. Study Design: Systematic review. Methods: A systematic review was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. There were 2 independent reviewers who performed a literature search using the PubMed, Embase, and Google Scholar databases of studies published between 1950 and 2020. Studies were included that compared the biomechanical outcomes of fixation for the treatment of anterior shoulder instability with glenoid bone loss. Results: Overall, 13 of the 363 studies screened met the inclusion criteria. The included studies measured the biomechanical strength of screws or suture buttons on a cadaveric or synthetic Latarjet construct. Screws and suture buttons were biomechanically similar, as both constructs exhibited comparable loads at failure and final displacement. Screw type (diameter, threading, or composition) did not significantly affect construct strength, and double-screw fixation was superior to single-screw fixation. Additionally, 2 screws augmented with a small plate had a higher load at failure than screws that were not augmented. Unicortical double-screw fixation was inferior to bicortical double-screw fixation, although construct strength did not significantly decrease if 1 of these screws was unicortical. Further, 2 screws inserted at 15° off axis experienced significantly higher graft displacement and lower ultimate failure loads than those inserted at 0° parallel to the glenoid. Conclusion: Suture buttons provided comparable strength to screws and offer an effective alternative to reduce screw-related complications. Augmentation with a small plate may clinically enhance construct strength and decrease complications through the dispersion of force loads over a greater surface area. Differences in screw type did not appear to alter construct strength, provided that screws were placed parallel to the articular surface and were bicortical.