Cadaveric-biomechanical study on medial retinaculum: its stabilising role for the patella against lateral dislocation

Background: The aim of this study was to analyse the biomechanical role of medial retinaculum, as a stabilising factor against lateral patellar dislocation. Materials and methods: This cadaveric-biomechanical study included the patellae of 10 cadaveric knees, which were surgically exposed and the medial retinaculum of each one was located. A stable 24.51 N force was applied to the four parts of the quadriceps, and an increasing lateral displacing force was applied to the patella, up to 5 mm dislocation. The study was repeated for 0o, 45o, and 90o of knee flexion, with the medial retinaculum intact and dissected. The Wilcoxon signed rank test was used for data analysis. A p value < 0.05 was considered as statistical significant. Results: After the dissection of medial retinaculum, the lateral displacement force was lower at every angle of knee flexion (p = 0.005, p = 0.007, p = 0.005, respectively). The lateral displacement force increased as the flexion angle increased (p = 0.005), regardless of medial retinaculum integrity. Conclusions: Medial retinaculum acts as a stabilising factor for the patella, against its lateral dislocation in lower flexion angles. Therefore, methods of surgical reinforcement or repair of medial retinaculum could provide protection againstrecurrent patellar dislocation

Phosphorus and potassium recovery from anaerobically digested olive mill wastewater using modified zeolite, fly ash and zeolitic fly ash: a comparative study

BACKGROUND: Nutrient recovery from wastewater is gaining attention in the frame of circular economy. In this study, Ca(OH)2-treated zeolite (CaT-Z), lignite fly ash (FA) and zeolitic fly ash (ZFA) were primarily used to adsorb phosphate phosphorus (PO4-P) from anaerobically digested olive mill wastewater (ADOMW). The simultaneous recovery of potassium (K) was also examined based on adsorption and desorption data. The fractionation of adsorbed P was determined as an important parameter for its plant availability. RESULTS: More P was adsorbed from ADOMW on ZFA and FA (up to 4.35 and 5.21 mg g−1, respectively) than on CaT-Z (2.62 mg g−1). An increased P adsorption on ZFA and FA was observed between incubation times of 7 and 14 days. The sequential desorption procedure verified the trend of P adsorption capacities and showed that the plant-available P (NaHCO3-P) amounted to 1.34, 2.34 and 1.69 mg g−1 CaT-Z, ZFA and FA, respectively. After 14 days, CaT-Z and ZFA adsorbed much more K (19.2 and 20.5 mg g−1, respectively) than FA (4.3 mg g−1). The desorption of exchangeable K confirmed this difference. Scanning electron microscopy–energy dispersive spectrometry analyses indicated P adsorption and surface precipitation as Ca–P phases as well as K+ for Ca2+ ion exchange on the loaded adsorbents. CONCLUSIONS: ZFA was more efficient for dual adsorption combining the properties of the zeolitic fraction (enhanced K adsorption) and pristine FA (P adsorption on Ca-bearing phases). The sufficient concentrations of plant-available P and K on the three adsorbents suggest their potential use as soil amendments. © 2022 Society of Chemical Industry (SCI). © 2022 Society of Chemical Industry (SCI)