Role of joint aspiration before re-implantation in patients with a cement spacer in place

BACKGROUND The usefulness of a mandatory joint aspiration before re-implantation in patients with a cement spacer already in place is unclear.AIM To evaluate the role of culturing synovial fluid obtained by joint aspiration before re-implantation in patients who underwent a two-stage septic revision.METHODS A retrospective observational study was conducted,including patients that underwent a two-stage septic revision(hip or knee)from 2010 to 2017.After the first stage revision and according to intraoperative culture results,all patients were treated with an antibiotic protocol for 6-8 wk.Following 2 wk without antibiotics,a culture of synovial fluid was obtained.The results of these cultures were recorded and compared with cultures obtained during re-implantation surgery.RESULTS Forty-one patients(20 hip and 21 knee spacers)were included in the final analysis.In 39 cases,the culture of synovial fluid was negative,while in the remaining 2 cases(knee spacers)no analysis was possible due to dry tap.In 5 of the patients,two or more intraoperative cultures taken during the re-implantation surgery were positive.CONCLUSION We found no evidence to support mandatory joint aspiration before re-implantation in patients with a cement spacer in place.

Reducing bacterial adhesion to titanium surfaces using low intensity alternating electrical pulses

BACKGROUND Orthopedic implant-related infection remains one of the most serious complications after orthopedic surgery.In recent years,there has been an increased scientific interest to improve prevention and treatment strategies.However,many of these strategies have focused on chemical measures.AIM To analyze the effect of alternating current electrical fields on bacterial adherence to titanium surfaces.METHODS Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli)were exposed to 6.5 V electrical currents at different frequencies:0.5 Hz,0.1 Hz,and 0.05 Hz.After exposure,a bacterial count was then performed and compared to the control model.Other variables registered included the presence of electrocoagulation of the medium,electrode oxidation and/or corrosion,and changes in pH of the medium.RESULTS The most effective electrical model for reducing S.aureus adhesion was 6.5 V alternating current at 0.05 Hz achieving a 90%adhesion reduction rate.For E.coli,the 0.05 Hz frequency model also showed the most effective results with a 53%adhesion reduction rate,although these were significantly lower than S.aureus.Notable adhesion reduction rates were observed for S.aureus and E.coli in the studied conditions.However,the presence of electrode oxidation makes us presume these conditions are not optimal for in vivo use.CONCLUSION Although our findings suggest electrical currents may be useful in preventing bacterial adhesion to metal surfaces,further research using other electrical conditions must be examined to consider their use for in vivo trials.