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Objective: To evaluate long-term loading patterns using subchondral bone density (SBD) distribution of the tibial plateau after tibial plateau leveling osteotomy (TPLO) and tibial tuberosity advancement (TTA)., Study Design: Cross-sectional study., Animals: Adult (> 2 years), medium to large breed dogs (>20 kg) that had been treated with TPLO or TTA at least 1 year prior to the study were recruited. A normal cohort of similar age and weight dogs with normal physical and orthopedic examinations served as control., Methods: Dogs were sedated for computed tomography (CT) of the stifle, and DICOM (digital imaging and communications in medicine) files were processed for CT osteoabsorptiometry (CTOAM). Tibial plateaus were sampled at 6 zones, and CTOAM was used to determine regional and maximal areas of SBD as a marker of joint loading., Results: Data were collected on 48 stifles in 31 dogs (15 TPLO, 11 TTA, 22 control). Lower Hounsfield unit (HU) values were measured in the caudal and mid-region of the lateral tibial plateau after TPLO and compared to normal. HU values did not differ between joints treated with TTA and those in the control group., Conclusion: TPLO may alter stifle load distribution relative to the normal control group. There were no differences between TTA and the control group., Clinical Significance/impact: Despite ongoing osteoarthritis (OA) in dogs after surgical intervention for cranial cruciate disease, changes in tibial SBD are minor and may not correlate with clinical function., (© 2018 The American College of Veterinary Surgeons.)

It is shown how stable, nonaqueous suspensions of fully exfoliated smectite clays such as Laponite and montmorillonite can be obtained. Suspensions in toluene and in a branched aliphatic solvent (polydecene) were characterized using elemental analysis, rheometry, and small-angle X-ray scattering. For Laponite, stable suspensions were obtained by adsorbing a dichain poly(isobutylene) based stabilizer to the particles. This approach did not result in full exfoliation for montmorillonite particles, possibly because the stabilizer was able to connect individual clay sheets at the edges during the treatment process. Instead, a quaternary ammonium surfactant, dimethyl dioctadecylammonium bromide (DODAB), was first adsorbed to the clay. Subsequently, adsorption of the poly(isobutylene) based stabilizer to this pretreated clay resulted in fully exfoliated suspensions of montmorillonite. Suspensions of clay particles treated only with DODAB have been studied by several authors before and are included in this study for comparison. A detailed discussion of the suspension behavior of the different clay samples is given. The suspension routes presented here may enable further studies of the structure and flow behavior of suspensions of thin, flexible clay platelets as a function of aspect ratio.