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Purpose of Review: As reverse total shoulder arthroplasty indications have expanded and the incidence of its use has increased, developments in implant design have been a critical component of its success. The purpose of this review is to highlight the recent literature regarding the effect of implant design on reverse total shoulder arthroplasty biomechanics. Recent Findings: Implant design for reverse total shoulder arthroplasty has evolved considerably from the modern design developed by Paul Grammont. The Grammont design had a medialized center of rotation and distalized humerus resulting from a 155° humeral neck shaft angle. These changes intended to decrease the forces on the glenoid component, thereby decreasing the risk for implant loosening and improving the deltoid moment arm. However, these features also led to scapular notching. The Grammont design has been modified over the last 20 years to increase the lateral offset of the glenosphere and decrease the prosthetic humeral neck shaft angle to 135°. These changes were made to optimize functional range of motion while minimizing scapular notching and improving active external rotation strength. Lastly, the introduction of preoperative planning and patient-specific instrumentation has improved surgeon ability to accurately place implants and optimize impingement-free range of motion. Summary: Success and durability of the reverse total shoulder arthroplasty has been contingent upon changes in implant design, starting with the Grammont-style prosthesis. Current humeral and glenoid implant designs vary in parameters such as humeral and glenoid offset, humeral tray design, liner thickness, and neck-shaft angle. A better understanding of the biomechanical implications of these design parameters will allow us to optimize shoulder function and minimize implant-related complications after reverse total shoulder arthroplasty. [ABSTRACT FROM AUTHOR]

Background: Most orthopaedic journals currently require reporting outcomes of surgical interventions for at least 2 postoperative years, but there have been no rigorous studies on this matter. Various patient-reported outcome (PRO) measures (PROMs) have been used to assess the status of the shoulder after rotator cuff repair (RCR). Hypothesis: We hypothesized that the mean shoulder-specific PROMs at 1 year improve substantially over baseline but that there is no clinically meaningful difference between the mean 1- and 2-year PROMs after RCR. Study Design: Meta-analysis; Level of evidence, 2. Methods: We conducted a systematic review of published randomized controlled trials (RCTs) and prospective cohort studies (level of evidence 1 and 2) reporting the shoulder-specific American Shoulder and Elbow Surgeons (ASES), the Constant, or the Western Ontario Rotator Cuff (WORC) Index scores at baseline, 1 year, and 2 years after RCR. The methodologic quality of studies was assessed. Also, the random effects meta-analyses of changes in PROMs for each of the first and second postoperative years were conducted. Results: Fifteen studies (n = 11 RCTs; n = 4 cohort studies) with a total of 1371 patients were included. Studies were highly heterogeneous, but no visual evidence of major publication bias was observed. The weighted means of the baseline PROMs were 46.2 points for the ASES score, 46.4 points for the Constant score, and 38.8 points for the WORC Index. The first-year summary increments were 41.1 (95% CI, 36.0-46.2) points for the ASES score, 34.2 (95% CI, 28.8-39.6) points for the Constant score, and 42.9 (95% CI, 37.3-48.4) points for the WORC Index. In contrast, the second-year summary increments were 2.3 (95% CI, 1-3.6) points for the ASES score, 3.2 (95% CI, 1.9-4.4) points for the Constant score, and 2 (95% CI, -0.1 to 4) points for the WORC Index. Conclusion: All PROMs improved considerably from baseline to 1 year, but only very small gains that were below the minimal clinically important differences were observed between 1 year and 2 years after RCR. This study did not find any evidence for requiring a minimum of 2 years of follow-up for publication of PROs after RCR. Our results suggest that focusing on 1-year PROMs after RCR would foster more timely reporting, better control of selection bias, and better allocation of research resources. [ABSTRACT FROM AUTHOR]

Glenoid component loosening remains a common complication following anatomic total shoulder arthroplasty (TSA); however, plain radiographs are unable to accurately detect early implant migration. The purpose of this study was to validate the accuracy of a method of postoperative, three‐dimensional (3D) computed tomography (CT) imaging with metal artifact reduction (MAR) to detect glenoid component migration following anatomic TSA. Tantalum bead markers were inserted into polyethylene glenoid components for implant detection on 3D CT. In‐vitro validation was performed using a glenoid component placed into a scapula sawbone and incrementally translated and rotated, with MAR 3D CT acquired at each test position. Accuracy was evaluated by root mean square error (RMSE). In‐vivo validation was performed on six patients who underwent anatomic TSA, with two postoperative CT scans acquired in each patient and marker‐based radiostereometric analysis (RSA) performed on the same days. Glenoid component migration was calculated relative to a scapular coordinate system for both MAR 3D CT and RSA. Accuracy was evaluated by RMSE and paired Student's t‐tests. The largest RMSE on in‐vitro testing was 0.24 mm in translation and 0.11° in rotation, and on in‐vivo testing was 0.47 mm in translation and 1.04° in rotation. There were no significant differences between MAR 3D CT and RSA measurement methods. MAR 3D CT imaging is capable of quantifying glenoid component migration with a high level of accuracy. MAR 3D CT imaging is advantageous over RSA because it is readily available clinically and can also be used to evaluate the implant‐bone interface. [ABSTRACT FROM AUTHOR]

We present the design and development of an organic package that is compatible with fully released RF microelectromechanical systems (MEMS). The multilayer organic package consists of a liquid-crystal polymer film to provide near hermetic cavities for MEMS. The stack is further built up using organic thin-film polyimide. To demonstrate the organic package, we have designed and implemented a 2-bit true-time delay X-band phase shifter using commercially available microelectromechanical switches. The packaged phase shifter has a measured insertion loss of 2.45 [+ or -] 0.12 dB/bit at 10 GHz. The worst case phase variation of the phase shifter at 10 GHz is measured to less than 5[degrees]. We have also conducted temperature cycling (-65[degrees]C to 150[degrees]C) and 85/85 to qualify the packaging structures. Index Terms--Cavities, chip-on-flex, liquid-crystal polymer (LCP), microelectromechanical systems (MEMS), microwave, packaging, phase shifter.

We present the development of an ultrahigh moisture-resistant enclosure for RF microelectromechanical system (MEMS) switches using liquid-crystal polymer (LCP). A cavity formed in LCP has been laminated, at low temperature, onto a silicon MEMS switch to create a package. The LCP-cap package has an insertion loss of less than 0.2 dB at X-band. E595 outgas tests demonstrate that the LCP material is suitable for constructing reliable packages without interfering with the operation of the MEMS switch. The package also passes Method 1014, MIL-STD-883 gross leak, and fine leak hermeticity tests. Index Terms--Cavities, chip-on-flex, liquid-crystal polymer (LCP), microelectromechanical system (MEMS), microwave, packaging.