Staphylococcus aureus is the most frequently isolated organism in periprosthetic joint infections. The mechanism by which synovial fluid (SF) kills bacteria has not yet been elucidated, and a better understanding of its antibacterial characteristics is needed. We sought to analyze the antimicrobial properties of exogenous copper in human SF against S. aureus. SF samples were collected from patients undergoing total elective knee or hip arthroplasty. Different S. aureus strains previously found to be sensitive and resistant, UAMS-1 and USA300 WT, respectively, were used. We performed in-vitro growth and viability assays to determine the capability of S. aureus to survive in SF with the addition of 10µM of copper. We determined the minimum bactericidal concentration of copper (MBC-Cu) and evaluated the sensitivity to killing, comparing WT and CopAZB-deficient USA300 strains. UAMS-1 evidenced a greater sensitivity to SF when compared to USA300 WT, at 12 (p=0.001) and 24 hours (p=0.027). UAMS-1 significantly died at 24 hours (p=0.017), and USA300 WT survived at 24 hours. UAMS-1 was more susceptible to the addition of copper at 4 (p=0.001), 12 (p=0.005) and 24-hours (p=0.006). We confirmed a high sensitivity to killing with the addition of exogenous copper on both strains at 4 (p=0.011), 12 (p=0.011), and 24 hours (p=0.011). Both WT and CopAZB-deficient USA300 strains significantly died in SF, evidencing a MBC-Cu of 50µM against USA300 WT (p=0.011). SF has antimicrobial properties against S. aureus, and UAMS-1 was more sensitive than USA300 WT. The addition of 10µM of copper was highly toxic for both strains, confirming its bactericidal effect. We evidenced CopAZB-proteins involvement in copper effluxion by demonstrating the high sensitivity of the mutant strain to lower copper concentrations. Thus, we propose CopAZB-proteins as potential targets and the use of exogenous copper as possible treatment alternatives against S. aureus.
The purpose of this study was to compare pre-operative acetabular cup parameters using this novel dynamic imaging sequence to the Lewinnek safe zone We retrospectively reviewed 350 consecutive primary THAs that underwent dynamic pre-operative acetabular cup planning utilizing a pre-operative CT scan to capture the individual's hip anatomy, followed by standing (posterior pelvic tilt), sitting (anterior pelvic tilt), and supine X-rays. Using these inputs, we modeled an optimal cup position for each patient. Radiographic parameters including inclination, anteversion, pelvic tilt, pelvic incidence, and lumbar flexion were analyzed.Introduction
Methods
Intervention is rare following minimally displaced radial head fractures or positive elbow ‘fat pad’ signs. A pilot study (n=20) found no patient required active treatment after discharge following their first fracture clinic visit. We therefore initiated routine discharge from A&E with an advice sheet, and an ‘open-door policy’ if patients failed to progress. 51 patients were managed by A&E according to this protocol over a six-month period. A standardised assessment of symptoms, satisfaction and functional limitation was completed for 24 patients by phone; average time to follow-up 4.2 months (range 2–9 months). Fourteen (58.4%) reported no pain. The 10 patients (41.6%) with on-going pain reported a median visual analogue score (VAS 0–10) of 0.7 (0–4) at rest, 0.25 (0–4) at night, 3.0 (0–10) carrying heavy objects and 2.75 (0–10) during repetitive movement. 4 of 24 (16.7%) reported minor functional impairment. 3 of 24 (12.5%) patients requested orthopaedic review, but all were satisfied with outcome, seeking reassurance and discharged without any intervention. 3 of 24 (12.5%) were unhappy with their progress, but all had suffered from chronic pain or psychological conditions predating their injury. When offered further review, none of these patients accepted. 22 (91%) were satisfied with their treatment and 23 (95.8%) returned to work and hobbies. This data suggests routine discharge from A&E with advice does not compromise care, as no intervention is usually required beyond advice. These findings have obvious positive clinical and financial implications in streamlining clinical workload.
Despite tendencies for Claims against medical practitioners around Australia to fall, litigation continues to be a burden on individual practitioners and the system. Unlike Claims frequency, Claims costs are not falling and indemnity insurance remains a significant practice cost. Data is presented to illustrate some trends in litigation and illustrative cases are also presented to outline some of the difficulties in defending Claims. Particular emphasis on the degree of difficulty is made in respect of Epidural Abscess.
