Search

Abiotic conditions are important considerations in the species sorting process, which ultimately determines the distribution and abundance of species. Freshwater ecosystems will be impacted by ongoing temperature rise and other anthropogenically induced changes, such as nutrient enrichment and eutrophication. Changing characteristics of freshwater habitats will likely impact organisms in numerous ways, including through effects on colonization dynamics. Species are expected to colonize habitat patches where fitness will be the highest for themselves and their offspring, and how habitat selection interacts with changing environments remains an important question. We conducted a warming experiment to test the habitat selection preferences of aquatic beetles and hemipterans between habitat patches (mesocosms) of varying temperatures (via heaters), nutrient addition, and their interaction. Overall, insect abundance and richness were higher in unheated patches, with taxon-specific variation in response to heating. Although nutrients had limited effects on environmental conditions in mesocosms, their addition had no significant effects on insects. Insect assemblages had unique structures across heating treatments, with lower beta diversity and higher effective numbers of species in the warmest mesocosms. Our data support the importance of spatial variation in abiotic factors during the habitat selection process, and in determining species distributions and abundances as shallow lentic ecosystems are impacted by rising global temperatures., (© 2020 Ecological Society of America.)

Purpose: To determine the prevalence of chronic trochanteric bursitis (TB) in patient being treated for femoroacetabular impingement (FAI) and determine the effectiveness of arthroscopic bursectomy and iliotibial band lengthening (AB-ITB-L) at the time of hip arthroscopy for FAI., Methods: Patients diagnosed with primary FAI and chronic TB were included in the study. Patients were included if they underwent hip arthroscopy with labral repair, femoral and/or acetabular osteoplasty, and AB-ITB-L. Patients were matched by age and gender to patients without chronic TB., Results: The prevalence of chronic TB with FAI was 7% (90/1,278). Females were 5.3 times more likely to have TB compared with males (95% confidence interval: 3.2-8.7). Patients more than 30 years of age were 2.5 times more likely to have TB (95% confidence interval: 1.48-4.4). Of the 90 patients diagnosed with TB, 72 (54 female, 18 male) with an average age of 36.7 years underwent AB-ITB-L at the time of their index hip arthroscopy for FAI. All 72 patients had associated intra-articular pathology consisting of a combined cam and pincer pathology. The TB (average follow-up = 42 ± 9.9 months) and non-TB group (average follow-up = 42 ± 9.1 months) both had significant improvement from preoperative to postoperative scores for Hip Outcome Score Activities Daily Living, Hip Outcome Score Sport, Modified Harris Hip Score, Western Ontario and McMaster Universities Arthritis Index, Short Form (SF)-12 Physical Component score, and SF-12 Mental Component Score. There was no significant difference between the 2 groups in postoperative patient reported outcome scores., Conclusions: The occurrence of chronic TB in the FAI population, which did not adequately respond to nonoperative management, for a single surgeon high volume hip arthroscopy practice was 7%, and was more commonly seen in women older than 30 years. Patients who undergo concomitant AB-ITB-L for chronic TB report excellent pain relief, and have equivalent results and outcome scores that are not inferior when compared with patients with primary FAI without chronic TB., Level of Evidence: Level III, retrospective matched case control study., (Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: Previous studies have shown hip arthroscopy to be a highly effective treatment for symptomatic femoroacetabular impingement (FAI) in a wide range of athletes; however, the rate of return to play and length of career after hip arthroscopy in professional football players are unknown., Purpose: To determine how many athletes returned to professional football and the number of seasons they played after surgery., Study Design: Case series; Level of evidence, 4., Methods: Fifty-one professional football players (60 hips) underwent hip arthroscopy for FAI between 2000 and 2014 by a single surgeon. Return to play was defined as competing in a preseason or regular season professional football game after surgery. Data were retrospectively obtained for each player from NFL.com , ESPN.com , individual team websites, and/or CFL.ca ., Results: We found that 87% (52/60) of the arthroscopic procedures allowed professional football players to return to play in a preseason or regular season game. Athletes who returned played an average of 38 games during 3.2 seasons after arthroscopy, with an average total career length of 7.4 seasons. Ninety-two percent (48/52) of players who returned had a minimum total career length of 3 years. When participants were analyzed by position, linemen were less likely to return after hip arthroscopy compared with other players (odds ratio 5.6; 95% CI, 1.1-35; P = .04). All quarterbacks and tight ends returned to play after surgery. No significant difference in return to play rate was found between athletes who underwent microfracture and those who did not (25% vs 38%, P = .698)., Conclusion: Hip arthroscopy for treatment of FAI and associated pathologic abnormalities in professional football players resulted in a high rate of return to play. The study's findings demonstrate that 87% of the arthroscopic procedures allowed professional football players to return to play, linemen were less likely to return compared with other positions, and the presence of microfracture did not significantly affect the return to play rate. These findings support hip arthroscopy as an effective procedure to treat FAI and related pathologic abnormalities in the professional football player, and this information is important for proper counseling of athletes with FAI.

Background: Studies have demonstrated hip arthroscopy to be an effective treatment for femoroacetabular impingement (FAI) with associated labral tears. The purposes of this study were to report 10-year outcomes and hip survival following hip arthroscopy for FAI and to compare labral debridement with labral repair., Methods: Prospectively collected data on patients followed for a minimum of 10 years after hip arthroscopy for FAI with either labral debridement or labral repair performed by a single surgeon were retrospectively analyzed. The primary patient-reported outcome measure was the Hip Outcome Score (HOS) Activities of Daily Living (ADL) subscale. Mann-Whitney U tests were used to compare outcomes between groups, and Wilcoxon signed-rank tests were used to compare preoperative with postoperative scores. Survival analysis was performed using a multivariate Cox proportional hazards model., Results: Seventy-nine patients who underwent labral repair and 75 who underwent debridement were included in the study, and 94% (145) were followed for ≥10 years. Fifty patients (34%) underwent total hip arthroplasty (THA) within 10 years following the arthroscopy. Older patients, hips with >2 mm of joint space preoperatively, and patients requiring acetabular microfracture had significantly higher prevalences of THA. The multivariate Cox proportional hazards model showed that increased age (hazard ratio [HR] for 31 years to 51 years = 3.06, 95% confidence interval [CI] = 1.69 to 5.56, p < 0.001), a joint space of ≤2 mm (HR = 4.26, 95% CI = 1.98 to 9.21, p < 0.001), and acetabular microfracture (HR = 2.86, 95% CI = 1.07 to 7.62, p = 0.036) were independently associated with an increased hazard rate for THA. When the analysis was adjusted for these factors, there was no significant difference in the HR between treatment groups (HR = 1.10, 95% CI = 0.59 to 2.05, p = 0.762). There was also no significant difference in postoperative outcome scores between groups. The debridement group demonstrated a significant increase, between the preoperative and postoperative evaluations, in the HOS-ADL score (from 71 to 96; p < 0.001), HOS-Sport score (from 42 to 89; p < 0.001), modified Harris hip score (mHHS) (from 62 to 90; p < 0.001), and Short Form-12 physical component summary (SF-12 PCS) score (from 43 to 56; p < 0.001). The repair group also demonstrated a significant increase in the HOS-ADL score (from 71 to 96; p < 0.001), HOS-Sport score (from 47 to 87; p < 0.001), mHHS score (from 65 to 85; p < 0.001), and SF-12 PCS score (from 41 to 56; p < 0.001). The median patient satisfaction score was 10 (very satisfied) in both groups., Conclusions: Hip arthroscopy for FAI with labral debridement or repair resulted in significant improvements in the patient-reported outcomes and satisfaction of patients who did not eventually require THA. Higher rates of conversion to THA were seen in older patients, patients treated with acetabular microfracture, and hips with ≤2 mm of joint space preoperatively, regardless of labral treatment., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background: The incidence of hip arthroscopic surgery is increasing in the young athlete. This has also led to increased numbers of revision hip arthroscopic surgery., Hypothesis/purpose: The purpose of this study was to describe the outcomes after revision hip arthroscopic surgery in patients ≤18 years of age in comparison to a matched cohort of patients undergoing primary hip arthroscopic surgery. Our hypothesis was that patients undergoing revision hip arthroscopic surgery would demonstrate similar outcomes to those patients undergoing primary hip arthroscopic surgery., Study Design: Cohort study; Level of evidence, 3., Methods: Patients were included in the study if they underwent revision hip arthroscopic surgery by a single surgeon and did not undergo prior open hip surgery. Each patient in the revision hip arthroscopic surgery cohort was matched with 2 patients undergoing primary hip arthroscopic surgery from the same institution. Cohorts were matched by age, sex, and year of surgery. Preoperatively and at a minimum follow-up of 2 years, outcome scores were collected. The primary outcome measure was the Hip Outcome Score for activities of daily living scale (HOS-ADL), a self-reported validated outcome instrument, in addition to the HOS for sports scale (HOS-Sport), modified Harris Hip Score (mHHS), and 12-Item Short Form Health Survey Physical Component Summary (SF-12 PCS)., Results: Forty-two patients were included in the revision group and were matched with 84 patients in the primary group. The mean age in both groups was 16 years (range, 14-18 years). All female patients in the study were ≥14 years of age, and all male patients were ≥16 years of age. In patients undergoing revision, 13 underwent 1 prior surgical procedure, 22 underwent 2 prior surgical procedures, and 7 underwent ≥3 prior surgical procedures. The mean time from last surgery to revision was 18.7 months (range, 4.7-74 months). Eleven patients (26%) had prior femoroacetabular impingement treated, which required osteoplasty or rim trimming at revision. Subsequent hip arthroscopic surgery was reported in 3 of 84 (4%) patients in the primary group and 6 of 42 (14%) patients in the revision group (P = .162). The mean follow-up in the revision group was 43 ± 17 months, and scores significantly improved (HOS-ADL: 59.6 to 77.6; HOS-Sport: 37.6 to 64.8; mHHS: 55.3 to 74.3; SF-12 PCS: 41.0 to 50.4; P < .05). The mean follow-up in the primary group was 45 ± 18 months, and all scores significantly improved (HOS-ADL: 65.8 to 87.4; HOS-Sport: 46.3 to 79.9; mHHS: 57.5 to 84.2; SF-12 PCS: 39.0 to 51.8; P < .05). At follow-up, there were no significant differences between the primary and revision groups for the HOS-ADL values (P = .051) and SF-12 PCS values (P = .846). Patients in the primary group had significantly higher HOS-Sport values (P = .008), mHHS values (P = .008), and patient satisfaction (P = .008). Patients who underwent 1 prior hip arthroscopic procedure had a higher mean postoperative mHHS value (79.5 vs 72, respectively), HOS-ADL value (91.2 vs 73.4, respectively), and HOS-Sport value (76 vs 60, respectively) (P < .05) compared with those who underwent more than 1 prior procedure. Median patient satisfaction was 9.0 (range, 2-10) in the primary group and 8.0 (range, 2-10) in the revision group., Conclusion: In conclusion, young patients who required revision hip arthroscopic surgery showed significant improvement in patient-reported outcome scores; however, final outcome scores in the revision group for sport activity, general health, and satisfaction were lower than those in the primary group. Patients who underwent 1 revision surgical procedure had higher outcome scores than patients who underwent more than 1 revision surgical procedure., (© 2016 The Author(s).)

Background: As the number of hip arthroscopic surgeries being performed increases, so too does the prevalence of revision hip arthroscopic surgery., Hypothesis/purpose: The purpose of this study was to compare outcomes in patients requiring revision hip arthroscopic surgery to patients undergoing primary hip arthroscopic surgery. The hypothesis was that patients undergoing revisions would demonstrate similar outcomes to those undergoing primary hip arthroscopic surgery., Study Design: Cohort study; Level of evidence, 2., Methods: Included in the study were patients undergoing revision hip arthroscopic surgery who did not have a history of prior open hip surgery. Each patient in the revision cohort was matched with 2 patients undergoing primary hip arthroscopic surgery. Preoperatively and at a minimum follow-up of 2 years, outcome scores were collected, including the Hip Outcome Score-Activities of Daily Living subscale (HOS-ADL), which was the primary outcome variable; modified Harris hip score (mHHS); Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC); Hip Outcome Score-Sports subscale (HOS-Sports); and the 12-Item Short Form Health Survey (SF12). At follow-up, scores from the Tegner activity scale and patient self-reported satisfaction with surgical outcome were also collected., Results: A total of 246 patients in the revision cohort were matched with 492 patients in the primary cohort. In the revision cohort, 183 patients had 1 prior surgery, 45 had 2 surgeries, and 18 had ≥3 prior surgeries. Subsequent hip arthroscopic surgery was reported in 39 of 492 (8%) patients in the primary cohort and 5 of 246 (2%) patients in the revision cohort (P = .001). Subsequent surgery was reported in 50 of 492 (10%) patients in the primary cohort and 15 of 246 (6%) patients in the revision cohort (P = .07). Both groups saw significant improvement in outcome scores from preoperation to follow-up. The HOS-ADL was lower in the revision cohort preoperatively (65 vs 70) and postoperatively (79 vs 87) (P = .001). This was also seen in the HOS-Sports, WOMAC, and SF12 physical component scores. Patients who had 1 prior hip arthroscopic procedure had higher postoperative mHHS (81 vs 75) compared with patients with >1 hip arthroscopic procedure; however, there was no difference in postoperative mHHS between the single-revision cohort and the primary cohort. In the revision group, patients whose HOS-ADL improved ≥10 points had greater joint space. Patients with greater improvement were more likely to have had a previous labral tear that was not repaired and to require capsular plication at revision., Conclusion: Patients who underwent revision hip arthroscopic surgery had significant improvement in outcome scores but did have lower scores compared with patients with primary hip arthroscopies. Patients with ≥2 revisions had lower outcomes. Improvement in the revision cohort was seen in patients with increased joint space, no prior labral repair, and capsular plication at revision., (© 2016 The Author(s).)

Anterior hip pain can be difficult to diagnose due to the many pathologies and overlapping pain patterns that exist in the hip region. Clinical findings of pain at the anterior inferior iliac spine with passive hip flexion, proximal quadriceps pain and weakness, and painful impingement tests of the hip may be indicative of subspine hip impingement. This report describes the diagnosis and treatment of anterior hip pain, including subspine impingement and femoroacetabular impingement in an elite weightlifter. This case also describes how with the correct diagnosis and treatment, the athlete returned to play to her previous level of sport 11 months after a complex hip injury.

We examine numerically the yielding or failure of small granular packings subjected to an increasing deviatoric stress. As the load increases, the packing softens and the number of sliding contacts rises. When the packing fails, the kinetic energy starts to rise exponentially in time. It is always possible to identify a contact status change that triggers the collapse of the packing. Furthermore, by use of the stiffness matrix, we show that this change often causes a mechanical instability or a motion with neutral stability. In some cases, the status change provokes an oscillation and a second status change following shortly thereafter introduces an instability. Failure can also be considered from the perspective of energy flux: before failure, the energy injected by the load is stored as potential energy in the contacts. When this is no longer possible, failure occurs and the injected energy is converted to kinetic energy. However, the force disequilibrium then soon becomes the dominant energy source.

Quasirigidity means that one builds a theory for assemblies of grains under a slowly changing external load by using the deformation of those grains as a small parameter. Is quasirigidity a complete theory for these granular assemblies? Does it provide unique predictions of the assembly's behavior, or must some other process be invoked to decide between several possibilities? We provide evidence that quasirigidity is a complete theory by showing that two possible sources of indeterminacy do not exist for the case of disk-shaped grains. One possible source of indeterminacy arises from zero-frequency modes present in the packing. This problem can be solved by considering the conditions required to obtain force equilibrium. A second possible source of indeterminacy is the necessity to choose the status (sliding or nonsliding) at each contact. We show that only one choice is permitted, if contacts slide only when required by Coulomb friction.

Cystic fibrosis (CF) is one of the most common autosomal recessive disorders in North America, leading to significant morbidity and early mortality. The defect in the cystic fibrosis transmembrane conductance regulator protein (CFTR) function can be corrected in vitro by gene replacement with a wild-type gene. A Phase I, single administration, dose escalation trial was designed and executed to assess safety and delivery of tgAAVCF, an adeno-associated virus (AAV) vector encoding the human CFTR cDNA, by nebulization to the lungs of CF subjects. Four cohorts of three subjects each were administered increasing doses of the study agent, beginning with 10(10) DNase-resistant particles (DRP) and escalating in log increments up to 10(13) DRP. Sequential bronchoscopies were performed to gather analytical samples throughout the study. All 12 subjects completed the study. There were a total of 242 adverse events (AEs), six of which were defined as serious and three of which were defined as possibly being related to the study drug. A clear dose-response relationship was observed in vector gene transfer. A maximum of 0.6 and 0.1 vector copies per brushed cell were observed 14 days and 30 days, respectively, following nebulization of 10(13) DRP tgAAVCF, and this declined to nearly undetectable levels by day 90. Vector gene transfer was evenly distributed throughout the fourth airway generation following single-dose administration. RNA-specific PCR did not detect vector-derived mRNA. This Phase I trial shows that aerosolized tgAAVCF is safe and widely delivered to the proximal airways of CF subjects by nebulization.