Prevalence of Helicobacter pylori Infection in Bariatric Surgery Patients.

OBJECTIVE: To determine the rate of histology-proven Helicobacter pylori (HP) infection in patients undergoing bariatric surgery and to identify risk factors for HP infection. METHODS: In a retrospective analysis, patients who underwent bariatric surgery with gastric resection in a single hospital between January 2004 and January 2019 were analyzed. For each patient, a surgical specimen was submitted for anatomopathological examination and analyzed for gastritis or other anomalies. When gastritis was present, HP infection was confirmed by the identification of curvilinear bacilli in conventional histology or by specific immunohistochemical detection of HP antigen. RESULTS: A total of 6388 specimens were available for review (4365 women, 2023 men) with a mean age of 44.9 ± 11.2 years and a mean body mass index (BMI) of 49.3 ± 8.2 kg/m2. Histology-proven HP infection rate was 6.3% (n = 405). There was no significant difference in sex, BMI, and body weight between HP + and HP - patients. Logistic regressions identified age as a risk factor for HP infection in this population (OR 1.02, p < 0.0001, CI 95% 1.01-1.03 for every 1-year increase, OR 1.26, p < 0.0001, CI 95% 1.14-1.40 for every 10-year increase). CONCLUSIONS: The rate of histology-proven HP infection is low in patients with severe obesity who present for bariatric surgery and is associated with age.

Objective grading of the pivot shift phenomenon using a support vector machine approach.

The pivot shift test is the only clinical test that has been shown to correlate with subjective criteria of knee joint function following rupture of the anterior cruciate ligament. The grade of the pivot shift is important in predicting short- and long-term outcome. However, because this grade is established by a clinician in a subjective manner, the pivot shift's value as a clinical tool is reduced. The purpose of this study was to develop a system that will objectively grade the pivot shift test based on recorded knee joint kinematics. Fifty-six subjects with different degrees of knee joint stability had the pivot shift test performed by one of eight different orthopaedic surgeons while their knee joint kinematics were recorded. A support vector machine based algorithm was used to objectively classify these recordings according to a clinical grade. The grades established by the surgeons were used as the gold standard for the development of the classifier. There was substantial agreement between our classifier and the surgeons in establishing the grade (weighted kappa=0.68). Seventy-one of 107 recordings (66%) were given the same grade and 96% of the time our classifier was within one grade of that given by the surgeons. Moreover, grades 0 and 1 were distinguished from grade 2 to 3 with 86% sensitivity and 90% specificity. Our results show the feasibility of automatically grading the pivot shift in a manner similar to that of an experienced clinician, based on knee joint kinematics.

Accounting for velocity of the pivot shift test manoeuvre decreases kinematic variability.

The pivot shift test is the only clinical test which correlates with knee function following rupture of the ACL. A grade is given to the pivot shift in a subjective manner, leading to efforts to quantify the bone movements and correlate them to the grade. However, the dynamic and unconstrained nature of the manoeuvre introduces important kinematic variability. Our main objective was to develop a method to lessen the variability attributable to clinician technique, therefore increasing inter-grade differences. Three different orthopaedic surgeons each performed the pivot shift test on 12 subjects. Knee joint kinematics were recorded using electromagnetic motion capture devices. Inter-clinician variability was quantified and a method was developed to diminish it, using the angular velocity of flexion. This method was then applied to a larger population composed of 127 knees with various degrees of instability, evaluated by one of eight different orthopaedic surgeons. The clinical grades given by the clinicians were in almost perfect agreement (kappa=0.83). Normalization of kinematic parameters using the angular velocity of knee joint flexion produced by the clinicians reduced the intra-clinician variability by 20%, resulting in an intra-class correlation coefficient (ICC) of 0.52, up from 0.41 before normalization. This allowed for more significant differences between the grades of pivot shift. Simple normalisation of pivot shift kinematics using the angular velocity of flexion reduces clinician-related variability and allows for significant differences between the different grades. These results are an important step towards developing an objective measurement tool for the pivot shift phenomenon.

Feature selection using a principal component analysis of the kinematics of the pivot shift phenomenon.

The pivot shift test reproduces a complex instability of the knee joint following rupture of the anterior cruciate ligament. The grade of the pivot shift test has been shown to correlate to subjective criteria of knee joint function, return to physical activity and long-term outcome. This severity is represented by a grade that is attributed by a clinician in a subjective manner, rendering the pivot shift test poorly reliable. The purpose of this study was to unveil the kinematic parameters that are evaluated by clinicians when they establish a pivot shift grade. To do so, eight orthopaedic surgeons performed a total of 127 pivot shift examinations on 70 subjects presenting various degrees of knee joint instability. The knee joint kinematics were recorded using electromagnetic sensors and principal component analysis was used to determine which features explain most of the variability between recordings. Four principal components were found to account for most of this variability (69%), with only the first showing a correlation to the pivot shift grade (r = 0.55). Acceleration and velocity of tibial translation were found to be the features that best correlate to the first principal component, meaning they are the most useful for distinguishing different recordings. The magnitudes of the tibial translation and rotation were amongst those that accounted for the least variability. These results indicate that future efforts to quantify the pivot shift should focus more on the velocity and acceleration of tibial translation and less on the traditionally accepted parameters that are the magnitudes of posterior translation and external tibial rotation.

Soft-tissue stabilizers of the elbow.

Elbow stability is afforded by both static and dynamic structures. Static structures include the complex bony architecture and soft-tissue stabilizers. Knowledge of the anatomy and biomechanics of the stabilizers is important to understand, diagnose, and treat elbow instability. Bony anatomy, detailed elsewhere, contributes to the inherent stability of the elbow. The static soft-tissue stabilizers consist of the anterior and posterior joint capsule and both medial and lateral collateral ligament complexes. Additional stability is conferred by dynamic structures--the muscles crossing the elbow joint.