Ocean emission of microplastic.

Microplastics are globally ubiquitous in marine environments, and their concentration is expected to continue rising at significant rates as a result of human activity. They present a major ecological problem with well-documented environmental harm. Sea spray from bubble bursting can transport salt and biological material from the ocean into the atmosphere, and there is a need to quantify the amount of microplastic that can be emitted from the ocean by this mechanism. We present a mechanistic study of bursting bubbles transporting microplastics. We demonstrate and quantify that jet drops are efficient at emitting microplastics up to 280µm in diameter and are thus expected to dominate the emitted mass of microplastic. The results are integrated to provide a global microplastic emission model which depends on bubble scavenging and bursting physics; local wind and sea state; and oceanic microplastic concentration. We test multiple possible microplastic concentration maps to find annual emissions ranging from 0.02 to 7.4-with a best guess of 0.1-mega metric tons per year and demonstrate that while we significantly reduce the uncertainty associated with the bursting physics, the limited knowledge and measurements on the mass concentration and size distribution of microplastic at the ocean surface leaves large uncertainties on the amount of microplastic ejected.

Symptom duration predicts inferior mid-term outcomes following hip arthroscopy.

INTRODUCTION: Studies have demonstrated a negative relationship between the length of time with symptoms and patient-reported outcome measures in primary hip arthroscopy. Our aim was to expand the generalizability of this finding with a multi-center cohort. METHODS: A multi-center hip arthroscopy registry was queried for patients undergoing primary hip arthroscopy from 2014 to 2017. Patients were stratified according to whether pre-operative symptom duration exceeded two years or did not exceed two years. A Wilcoxon rank sum test was performed for differences in two year post-operative outcome scores. Logistic regression models analyzed the influence of symptom duration on achieving clinically meaningful thresholds (minimum clinically important difference, patient-acceptable symptom state, substantial clinical benefit) when controlling for baseline scores, age, BMI, and sex. RESULTS: Seven hundred forty-four patients met the inclusion criteria, from which 620 had complete outcomes information. The mean ± SD 2-year iHOT-12 scores of patients with symptom duration greater than two years (69 ± 26) were significantly lower than patients with symptom duration less than two years (77 ± 23) (Dunn test, p < 0.001). Chronic duration of pain was a negative predictor of achieving iHOT-12 MCID (0.47 [0.31-0.72]), PASS (0.53 [0.37-0.76]), and SCB (0.67 [0.47-0.94]). CONCLUSION: When controlling for differences in baseline demographic factors and pre-operative iHOT-12 scores, patients with chronic pain report poorer functional outcomes at mid-term follow-up. These results suggest that chronic pain predicts inferior outcomes from primary hip arthroscopy and that surgical intervention at earlier time points may be beneficial in achieving better outcomes.

Acetabular Cartilage Lesions Predict Inferior Mid-Term Outcomes for Arthroscopic Labral Repair and Treatment of Femoroacetabular Impingement Syndrome.

PURPOSE: To analyze the effect of acetabular chondrosis at a minimum of 2 years following hip arthroscopy in patients undergoing labral repair and treatment of femoroacetabular impingement. METHODS: From 2014 to 2017, patients undergoing arthroscopic labral repair were prospectively enrolled in a multicenter hip arthroscopy registry. The registry was retrospectively queried for primary labral repair patients with complete 2-year outcomes and a Tonnis grade of less than 2. Patients were grouped according to severity of articular cartilage damage noted intraoperatively using the Beck classification system: none, low-grade (Grade 1 or 2), or high-grade (Grade 3 or 4) damage. A Kruskal-Wallis test and post hoc Dunn's test with Holm correction compared 2-year postoperative outcome scores of the iHOT-12 scale between groups. The proportion of patients in each cohort who achieved the clinically significant thresholds of the minimum clinically important difference (MCID), patient-acceptable symptom scale, and substantial clinical benefit (SCB) were analyzed. Multivariate logistic regression models identified predictors of achieving clinical thresholds while controlling for demographic variation. RESULTS: 422 patients met inclusion criteria, from which 347 completed 2-year outcomes. All groups experienced improvement in iHOT-12 scores from baseline to follow-up (P < .001). iHOT-12 scores at follow-up were inferior for Low-Grade Damage and High-Grade Damage Groups relative to the No Damage Group (P = .04; P = .03). When accounting for age, body mass index, gender, and preoperative iHOT-12 scores in logistic regression models, the presence of high-grade lesions was a negative predictor for achieving SCB (OR [95% CI], 0.54 [0.29-0.96]) and low-grade lesions a negative predictor for achieving MCID (0.50 [0.27-0.92]. Among patients with high-grade lesions, there was no significant difference in 2-year iHOT-12 scores between those undergoing chondroplasty (n = 50) and those undergoing microfracture (n = 14) (P = .14). CONCLUSIONS: Acetabular cartilage damage portends inferior patient-reported outcomes 2 years after primary labral repair and treatment of femoroacetabular impingement. The presence of cartilage lesions was a negative predictor of individual achievement of several clinical thresholds. LEVEL OF EVIDENCE: III, Retrospective comparative cohort.

Labral Degeneration Predicts Inferior Mid-Term Outcomes in Hip Labral Repair: A Multicenter Comparative Analysis.

PURPOSE: To analyze and compare the mid-term outcomes of hip arthroscopy for patients with and without labral degeneration from multiple orthopaedic centers. The purpose of this research is to develop an understanding of the impacts of labral degeneration on patient outcomes following arthroscopic treatment of labral tears. METHODS: A prospective multicenter hip arthroscopy registry was queried for primary surgeries from January 2014 to October 2017 with completed 2-year International Hip Outcome Tool-12 (iHOT-12) reports. Patients were placed into cohorts based on the presence or absence of labral degeneration noted intraoperatively during hip arthroscopy. Degeneration was defined as yellowing, ossification, or calcification present in at least 50% of the labrum. Differences in baseline variation between groups were assessed with a Wilcoxon rank-sum test or χ2 test. Two-year outcomes were assessed with iHOT-12. Multivariate logistic regression models were fitted while controlling for age, body mass index, sex, and preoperative iHOT-12 scores to identify significant predictors of achieving the clinically significant thresholds of minimal clinically important difference, substantial clinical benefit, and patient-acceptable symptom scale. RESULTS: In total, 735 patients met inclusion criteria, of whom 613 had complete outcomes information. Relative to the control group, the labral degeneration group was significantly older (mean age 44 ± 11 years vs 33 ± 12 years; P < .01). Both groups experienced statistically significant improvement in iHOT-12 scores from baseline to final follow-up (P < .001); however, patients with labral degeneration reported inferior 2-year iHOT-12 scores when compared with patients without degeneration (P < .001). In the logistic regression models, labral degeneration was a significant negative predictor of achieving iHOT-12 minimal clinically important difference (odds ratio [OR] 0.47; 95% confidence interval [95% CI] 0.28-0.79), patient acceptable symptom state (OR 0.50; 95 CI 0.32-0.77), and substantial clinical benefit (OR 0.58; 95% CI 0.37-0.89). CONCLUSIONS: The results of our study conclude that patients with nondegenerative labral tissue at the time of repair have superior patient-reported outcomes at mid-term follow-up. The presence of labral degeneration was a negative predictor of achieving clinically significant thresholds after controlling for patient age, body mass index, sex, and baseline iHOT-12 scores. LEVEL OF EVIDENCE: III, retrospective comparative prognostic trial.