A non-invasive acoustical system was developed for the measurement of transmission properties of acoustic waves in the hip joints. The instrumentation consisted of three sub-systems. An excitation system employed a vibratory force at the sacrum of the test subjects. A transduction system included a pair of identical microphones installed in the tubes of two stethoscopes, which were placed at the greater trochanters on both sides for picking up the acoustical signals transmitted across the hip joints. The data acquisition and analysis system was a portable signal analyzer with a program of dual channel digital filter for measuring the power of acoustical signal in 1/3-octave frequency bands. 27 normal adults, 20 normal pre-school children and 40 normal neonates were randomly selected for testing. Coherence function (CF) and discrepancy (D) was measured during the testing. Results from the three groups showed that there was a high coherence of the signals (CF > 0.9) and a small discrepancy (D < 3 dB) between bilateral hips in the frequency range of 200-315 Hz. For normal neonates, there was a wider frequency range of 160-315 Hz in which the acoustical signals maintained a high coherence (CF > 0.93) and a smaller discrepancy (D < 2 dB) was observed. This study showed that the development of the acoustical technique provided a practical method with objective parameters. The results obtained in this study can offer a baseline for further investigation of hip disorders particularly those related to structural abnormalities of the hip.
Acoustic Stimulation/*instrumentation ; Age Factors ; Hip Joint/*anatomy & histology ; Sacrum/anatomy & histology ; Signal Processing, Computer-Assisted/*instrumentation ; Sound/*diagnostic use

This study aimed to develop a non-invasive diagnostic technique for the measurement of acoustic transmission in hip joints to reflect the dynamic response of the observed structure. This instrument consists of three sub-systems. An stimulation system applied a vibratory force at the sacrum of the test subject. A transduction system included a pair of identical microphones was installed in the tubes of two stethoscopes, which were placed at the greater trochanters on both sides for picking up the acoustic signals transmitting across the hip joints. The data acquisition and analysis system was a portable frequency analyser with a program of dual channel digital filter for measuring the power of acoustic signals in 1/3-octoscn frequency bands. Twenty-seven normal adults, 20 normal pre-school children and 40 normal neonates were recruited for the testing. Coherence function (CF) of the signal and the discrepancy (D) of bilateral hips were measured during the testing. The results from the three groups showed that there was a high coherence of the signals (CF > 0.9) and a small discrepancy (D < 3 dB) between bilateral hips in the frequency range of 200-315 Hz. For normal neonates, the frequency range (160-315 Hz) was wider in which the acoustic signals maintained a high coherence (CF > 0.94) and a smaller discrepancy (D < 2 dB) were observed between bilateral hips. This study has shown that the development of the acoustical diagnostic technique could provide a practical method with objective parameters. The results obtained in this study can offer a base for further investigation of hip disorders, particularly those related to structural abnormalities of hip joints.
Acoustic Stimulation ; instrumentation ; Adult ; Child, Preschool ; Female ; Hip Joint ; anatomy & histology ; Humans ; Infant, Newborn ; Male ; Signal Processing, Computer-Assisted ; instrumentation ; Sound

A non-invasive acoustical system was developed for the measurement of transmission properties of acoustic waves in the hip joints. The instrumentation consisted of three sub-systems. An excitation system employed a vibratory force at the sacrum of the test subjects. A transduction system included a pair of identical microphones installed in the tubes of two stethoscopes, which were placed at the greater trochanters on both sides for picking up the acoustical signals transmitted across the hip joints. The data acquisition and analysis system was a portable signal analyzer with a program of dual channel digital filter for measuring the power of acoustical signal in 1/3-octave frequency bands. 27 normal adults, 20 normal pre-school children and 40 normal neonates were randomly selected for testing. Coherence function (CF) and discrepancy (D) was measured during the testing. Results from the three groups showed that there was a high coherence of the signals (CF > 0.9) and a small discrepancy (D < 3 dB) between bilateral hips in the frequency range of 200-315 Hz. For normal neonates, there was a wider frequency range of 160-315 Hz in which the acoustical signals maintained a high coherence (CF > 0.93) and a smaller discrepancy (D < 2 dB) was observed. This study showed that the development of the acoustical technique provided a practical method with objective parameters. The results obtained in this study can offer a baseline for further investigation of hip disorders particularly those related to structural abnormalities of the hip.
Acoustic Stimulation ; instrumentation ; Adult ; Age Factors ; Child ; Child, Preschool ; Female ; Hip Joint ; anatomy & histology ; Humans ; Infant ; Infant, Newborn ; Male ; Sacrum ; anatomy & histology ; Signal Processing, Computer-Assisted ; instrumentation ; Sound

Background: Malnutrition is a common and modifiable risk factor for postoperative complications and adverse outcomes in orthopedics. The purpose of this study was to identify biomarkers of malnutrition in patients undergoing elective total knee arthroplasty (TKA) that are predictive of adverse in-hospital postoperative complications, to facilitate the identification of at-risk patients for nutritional optimization before surgery. Methods: A total of 624 patients who underwent elective TKA between 2013 and 2017 were evaluated; potential biomarkers of preoperative malnutrition, including hypoalbuminemia (serum albumin < 3.5 g/dL), total lymphocyte count (TLC < 1500 cells/mm3), and body mass index (BMI), were assessed for any association with in-hospital postoperative complications. Results: The prevalence of hypoalbuminemia, low TLC, overweight, obesity class I, and obesity class II were, respectively 2.72%, 33.4%, 14.8%, 44.5%, and 26.9%. There was a significant association between hypoalbuminemia and obesity class II (BMI ≥ 30.0 kg/m2) with rates of peri-prosthetic joint infection, and no significant association between such complications and low TLC, overweight, or obesity class I. Logistic regression analysis showed that patients with hypoalbuminemia or being in obesity class II with gouty arthritis were more likely to suffer from peri-prosthetic joint infection. Conclusions Hypoalbuminemia and obesity class II together is a reliable biomarker of preoperative malnutrition for predicting peri-prosthetic joint infection after elective TKA, whereas low TLC, overweight, and obesity class I were not significantly associated with an increased risk of such complications.

Background: Total knee arthroplasty (TKA) is associated with significant perioperative blood loss and postoperative allogenic blood transfusion. Tranexamic acid (TXA) reversibly blocks lysine binding sites on plasminogen molecules and inhibits plasmin formation. Comparisons of the efficacy and safety of intra-articular and intravenous TXA in primary TKA have not previously been reported. Methods: A prospective randomized trial was conducted in 150 patients who underwent TKA, and these patients were randomized into three groups. Patients in Group A were injected by intra-articular TXA according to body weight (20 mg/kg). Patients in Group B received a standard dose of intra-articular TXA (2000 mg), and those in Group C were infused with TXA according to body weight (20 mg/kg) before tourniquet deflation and again 3 h later. Baseline characteristics and data collected at blood transfusion were compared. Differences among four time points (baseline, day 0, day 2, and day 5) were carried out using ANOVA. Results: The hemoglobin levels at postoperative day 5 were 10.6 g/dL for Group A, 10.6 g/dL for Group B, and 10.7 g/dL for Group C. The drain output was 399 ml for Group A, 314 ml for Group B, and 305 ml for Group C (p = 0.03). Group C had significantly less drain output than Group A after post hoc comparisons (p = 0.05), whereas no significant difference was observed between Group A and B (p = 0.09) or between Group B and C. Conclusion The weight-adjusted dose of TXA administered intravenously significantly reduced the drain output but not the total blood loss when compared with the weight-adjusted dose of TXA administered intra-articularly. No significant difference was observed in the other parameters among the three groups.Trial registrationThe Joint CUHK-NTEC CREC, CRE-2013.644-T. Registered 1 March 2014.

Background: Total knee arthroplasty (TKA) is associated with significant perioperative blood loss and postoperative allogenic blood transfusion. Tranexamic acid (TXA) reversibly blocks lysine binding sites on plasminogen molecules and inhibits plasmin formation. Comparisons of the efficacy and safety of intra-articular and intravenous TXA in primary TKA have not previously been reported. Methods: A prospective randomized trial was conducted in 150 patients who underwent TKA, and these patients were randomized into three groups. Patients in Group A were injected by intra-articular TXA according to body weight (20 mg/kg). Patients in Group B received a standard dose of intra-articular TXA (2000 mg), and those in Group C were infused with TXA according to body weight (20 mg/kg) before tourniquet deflation and again 3 h later. Baseline characteristics and data collected at blood transfusion were compared. Differences among four time points (baseline, day 0, day 2, and day 5) were carried out using ANOVA. Results: The hemoglobin levels at postoperative day 5 were 10.6 g/dL for Group A, 10.6 g/dL for Group B, and 10.7 g/dL for Group C. The drain output was 399 ml for Group A, 314 ml for Group B, and 305 ml for Group C (p = 0.03). Group C had significantly less drain output than Group A after post hoc comparisons (p = 0.05), whereas no significant difference was observed between Group A and B (p = 0.09) or between Group B and C. Conclusion The weight-adjusted dose of TXA administered intravenously significantly reduced the drain output but not the total blood loss when compared with the weight-adjusted dose of TXA administered intra-articularly. No significant difference was observed in the other parameters among the three groups.Trial registrationThe Joint CUHK-NTEC CREC, CRE-2013.644-T. Registered 1 March 2014.