RESUMEN
Background: Tension band wiring and plate fixation are common internal fixation methods used for olecranon fractures, but complications and reoperations are common. The purpose of this study is to investigate the clinical outcomes of displaced olecranon fractures treated with olecranon sled internal fixation. Methods: The data of 39 patients with olecranon fractures treated with olecranon sled in the Department of Traumatology of Beijing Jishuitan Hospital between May 2018 and April 2020 were retrospectively analyzed. There were 17 males and 22 females; the mean age was 44.0 ± 15.8 (range, 18-68 years). Preoperative olecranon fractures were classified according to the Mayo classification: 24 cases were type IIA and 15 cases were type IIB. Elbow range of motion (extension and flexion) and forearm rotation (protonation and supination) were observed at the last follow-up. The Mayo elbow performance score (MEPS), Disabilities of the arm, shoulder and hand (DASH) and visual analogue scale (VAS) scores were used to evaluate elbow function and pain, and complications were also recorded. Results: Thirty-nine patients were followed up for 33.6 ± 8.3 months (range, 25-51 months) after the operation. At the last follow-up, the mean flexion-extension arc was 137° ± 15° (range, 60°-160°), and the mean pronation-supination arc was 178° ± 4° (range, 160°-180°). The mean MEPS was 94.9 ± 9.9 (range, 50.0-100.0). The mean DASH score was 5.4 ± 4.3 (range, 0-18.3). The mean VAS score was 0.4 ± 0.8 (range, 0-3). Seven patients developed olecranon skin irritation, and 3 of them had the internal fixation device removed. Two patients developed heterotopic ossification, of whom 1 patient suffered elbow stiffness. Conclusion: Olecranon sled internal fixation has good clinical outcomes in the treatment of Mayo type II olecranon fractures with a low rate of reoperations.
RESUMEN
Sound absorbing materials combining millable polyurethane elastomer (MPU) and eucommia ulmoides rubber (EUG) were successfully fabricated via a physical blending process of EUG and MPU. The microstructure, crystallization performances, damping, mechanical and sound absorption properties of the prepared MPU/EUG composites were investigated systematically. The microstructure surface of various MPU/EUG composites became rough and cracked by the gradual incorporation of EUG, resulting in a deteriorated compatibility between EUG and MPU. With the increase of EUG content, the storage modulus (E') of various MPU/EUG composites increased in a temperature range of -50 °C to 40 °C and their loss factor (tanδ) decreased significantly, including a reduction of the tanδ of MPU/EUG (70/30) composites from 0.79 to 0.64. Specifically, the addition of EUG sharply improved the sound absorption performances of various MPU/EUG composites in a frequency range of 4.5 kHz-8 kHz. Compared with that of pure MPU, the sound absorption coefficient of the MPU/EUG (70/30) composite increased 52.2% at a pressure of 0.1 MPa and 16.8% at a pressure of 4 MPa, indicating its outstanding sound absorption properties.