Background
Glenoid defects can be addressed traditionally by asymmetric reaming or by bone-preserving correction to a more lateral joint line by bone or metal augmented baseplates in reverse shoulder arthroplasties. While there is more evidence in literature regarding the outcome and complications of Bony Increased Offset Reversed Shoulder Arthroplasty (BIO-RSA), there is minimal reported experience with the outcome after metal glenoid augments. The aim of this study was to determine whether a metal augment can correct the glenoid deformity in an anatomic manner.
Methods
Glenoid morphology and deformity were determined in 50 patients with Walch type B1, B2, D and Favard type E0–E3 glenoid defects using preoperative radiographic and computed tomography (CT) analysis. All patients received a preoperative planning CT with 3D planning, and measurements of glenoid inclination (in 3 planes proximal, middle, distal), reversed shoulder arthroplasty angle (RSA) and glenoid version were obtained. All patients had a pathologic inclination in the coronal or frontal planes of > 10°. Above the threshold of 10° pathological glenoid version or inclination metal hemi-augments of 10°, 20°, or 30° were used which allow an individual 360° augment positioning according to the patient glenoid deformity.
Results
The mean preoperative numbers of the glenoid version demonstrate that most glenoids were in retroversion and superior inclination. In total 2410° wedges, 1820° wedges and 8 30° wedges were used. In the majority of cases, the wedge was positioned posteriorly and/or cranially between 10:00 and 12:00 o’clock, which allows a correction in a 3D manner of the glenoid inclination and version. The mean RSA angle could be corrected from 22.76 ± 6.06 to 0.19° ± 2.7 (p < 0.0001). The highest retroversion of the glenoid is evidenced in the proximal section and it could be corrected from − 23.32° ± 4.56 to − 6.74° ± 7.75 (p < 0.0001) and in the middle section from − 18.93° ± 3.35 to − 7.66° ± 5.28 (p < 0.0001). A mean sphere bone overhang distance (SBOD) of 5.70 ± 2.04 mm was found in order to avoid or minimize relevant scapular notching.
Conclusion
By using a new 360° metal-augmented baseplate, the preoperative pathological inclination and retroversion can be corrected without medialization of the joint line. Future clinical results will show whether this bone-preserving procedure improves also the clinical outcomes as compared to asymmetric medialized reaming or wedged BIO-RSA.
Level of evidence
Level IV, Case series.
¿Los partidos brasileños responden a una dinámica regional, operando en ciertos espacios del país? ¿Los partidos argentinos se estructuran nacionalmente, hiriendo el federalismo y esfumando las realidades provinciales? ¿Hasta dónde esto es cierto? ¿Qué sucede hoy en estos federalismos? Partidos, sistemas de partidos, sistemas electorales y fenómenos vinculados a estos (como la sobre-representación distrital y su efecto sobre los partidos, etc.) en las esferas federales de Brasil y Argentina se analizan en el presente trabajo. Inicialmente, se realiza un estudio de los sistemas electorales a nivel federal. Luego, se produce un análisis del sistema de partidos en la arena nacional y sobre lo que expresan las constituciones (Constituição da República Federativa do Brasil, de 1988 –CF88; y la Constitución de la Nación Argentina –CN94) sobre estos instrumentos de ejercicio democrático. También se realiza un estudio sobre el presente de los partidos y la forma de clasificarlos. El fenómeno de la sobre-representación distrital (SRD) también es objeto de investigación, por la importancia que cobra en estas federaciones. La forma en que las unidades federativas menores se encuentran sobre-representadas coloca un desafío a estos federalismos: establece pautas del juego político federal.
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