Sex-Based Differences in the Clinical Presentation of Patients With Symptomatic Hip Labral Tears.

BACKGROUND: An increasing body of literature describes the clinical presentation and demographics of patients with hip labral tears. The differences in pelvic structure and joint laxity between sexes have been described; however, no study has evaluated differences in the clinical presentation of patients with symptomatic labral tears between sexes. PURPOSE: To describe the differences between sexes in demographics, clinical history, physical examination, and intraoperative findings in patients with symptomatic labral tears. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data were prospectively collected between February 2008 and February 2013 on 1401 patients who had symptomatic labral tears and underwent arthroscopic surgery. Hips with previous pathologic disorders were excluded. Data on demographics and clinical history were gathered, and a physical examination was performed. Preoperative pain was estimated on the visual analog scale (VAS), and 4 hip-specific patient-reported outcomes (PROs) were administered to evaluate functional status. Intraoperative findings were recorded. RESULTS: A total of 654 patients met our inclusion/exclusion criteria, with 320 males and 334 females. The median age for males was 38.3 years (range, 15.0-69.6 years) and for females 40.4 years (range, 13.1-66.8 years). Male patients had a higher incidence of acute injury than females (39.6% vs 27.6%, respectively; P < .05) and a higher incidence of workers' compensation status (14.1% vs 4.5%, respectively; P < .05). Females had increased range of motion compared with males, which was statistically significant for all range of motion measurements (P < .05). The anterior impingement test was positive in 94.4% of females and 92.9% of males, the flexion/abduction/external rotation test was positive in 59.5% of females and 61.5% of males, and the lateral impingement test was positive in 55.0% of females and 59.2% of males, but there was no statistically significant difference between sexes in any of the tests. Pain with palpation over the greater trochanter was positive in 22.0% of males and 36.9% of females (P < .0001). Females had lower PROs; however, VAS scores were similar. CONCLUSION: Male and female patients differ in their hip structure, biomechanics, and operative findings of symptomatic labral tears. However, they do not differ substantially in clinical presentation, except that males are more likely to report an acute injury and females are more likely to be evaluated with increased range of motion.

Comparison of robotic-assisted and conventional acetabular cup placement in THA: a matched-pair controlled study.

BACKGROUND: Improper acetabular component orientation in THA has been associated with increased dislocation rates, component impingement, bearing surface wear, and a greater likelihood of revision. Therefore, any reasonable steps to improve acetabular component orientation should be considered and explored. QUESTIONS/PURPOSES: We therefore sought to compare THA with a robotic-assisted posterior approach with manual alignment techniques through a posterior approach, using a matched-pair controlled study design, to assess whether the use of the robot made it more likely for the acetabular cup to be positioned in the safe zones described by Lewinnek et al. and Callanan et al. METHODS: Between September 2008 and September 2012, 160 THAs were performed by the senior surgeon. Sixty-two patients (38.8%) underwent THA using a conventional posterior approach, 69 (43.1%) underwent robotic-assisted THA using the posterior approach, and 29 (18.1%) underwent radiographic-guided anterior-approach THAs. From September 2008 to June 2011, all patients were offered anterior or posterior approaches regardless of BMI and anatomy. Since introduction of the robot in June 2011, all THAs were performed using the robotic technique through the posterior approach, unless a patient specifically requested otherwise. The radiographic cup positioning of the robotic-assisted THAs was compared with a matched-pair control group of conventional THAs performed by the same surgeon through the same posterior approach. The safe zone (inclination, 30°-50°; anteversion, 5°-25°) described by Lewinnek et al. and the modified safe zone (inclination, 30°-45°; anteversion, 5°-25°) of Callanan et al. were used for cup placement assessment. Matching criteria were gender, age ± 5 years, and (BMI) ± 7 units. After exclusions, a total of 50 THAs were included in each group. Strong interobserver and intraobserver correlations were found for all radiographic measurements (r > 0.82; p < 0.001). RESULTS: One hundred percent (50/50) of the robotic-assisted THAs were within the safe zone described by Lewinnek et al. compared with 80% (40/50) of the conventional THAs (p = 0.001). Ninety-two percent (46/50) of robotic-assisted THAs were within the modified safe zone described by Callanan et al. compared with 62% (31/50) of conventional THAs p (p = 0.001). The odds ratios for an implanted cup out of the safe zones of Lewinnek et al. and Callanan et al. were zero and 0.142, respectively (95% CI, 0.044, 0.457). CONCLUSIONS: Use of the robot allowed for improvement in placement of the cup in both safe zones, an important parameter that plays a significant role in long-term success of THA. However, whether the radiographic improvements we observed will translate into clinical benefits for patients-such as reductions in component impingement, acetabular wear, and prosthetic dislocations, or in terms of improved longevity-remains unproven.

Twin-arginine translocation system (tat) mutants of Salmonella are attenuated due to envelope defects, not respiratory defects.

The twin-arginine translocation system (Tat) transports folded proteins across the cytoplasmic membrane and is critical to virulence in Salmonella and other pathogens. Experimental and bioinformatic data indicate that 30 proteins are exported via Tat in Salmonella Typhimurium. However, there are no data linking specific Tat substrates with virulence. We inactivated every Tat-exported protein and determined the virulence phenotype of mutant strains. Although a tat mutant is highly attenuated, no single Tat-exported substrate accounts for this virulence phenotype. Rather, the attenuation is due primarily to envelope defects caused by failure to translocate three Tat substrates, the N-acetylmuramoyl-l-alanine amidases, AmiA and AmiC, and the cell division protein, SufI. Strikingly, neither the amiA amiC nor the sufI mutations alone conferred any virulence defect. Although AmiC and SufI have previously been localized to the divisome, the synthetic phenotypes observed are the first to suggest functional overlap. Many Tat substrates are involved in anaerobic respiration, but we show that a mutant completely deficient in anaerobic respiration retains full virulence in both the oral and systemic phases of infection. Similarly, an obligately aerobic mutant is fully virulent. These results suggest that in the classic mouse model of infection, S. Typhimurium is replicating only in aerobic environments.

Integrating global regulatory input into the Salmonella pathogenicity island 1 type III secretion system.

Salmonella enterica serovar Typhimurium uses the Salmonella pathogenicity island 1 (SPI1) type III secretion system to induce inflammatory diarrhea and bacterial uptake into intestinal epithelial cells. The expression of hilA, encoding the transcriptional activator of the SPI1 structural genes, is directly controlled by three AraC-like regulators, HilD, HilC, and RtsA, each of which can activate the hilD, hilC, rtsA, and hilA genes, forming a complex feed-forward regulatory loop. A large number of factors and environmental signals have been implicated in SPI1 regulation. We have developed a series of genetic tests that allows us to determine where these factors feed into the SPI1 regulatory circuit. Using this approach, we have grouped 21 of the known SPI1 regulators and environmental signals into distinct classes on the basis of observed regulatory patterns, anchored by those few systems where the mechanism of regulation is best understood. Many of these factors are shown to work post-transcriptionally at the level of HilD, while others act at the hilA promoter or affect all SPI1 promoters. Analysis of the published transcriptomic data reveals apparent coregulation of the SPI1 and flagellar genes in various conditions. However, we show that in most cases, the factors that affect both systems control SPI1 independently of the flagellar protein FliZ, despite its role as an important SPI1 regulator and coordinator of the two systems. These results provide a comprehensive model for SPI1 regulation that serves as a framework for future molecular analyses of this complex regulatory network.