The aim of this study was to develop a single-layer hybrid organic-inorganic sol-gel coating that is capable of a controlled antibiotic release for cementless hydroxyapatite (HA)-coated titanium orthopaedic prostheses. Coatings containing gentamicin at a concentration of 1.25% weight/volume (wt/vol), similar to that found in commercially available antibiotic-loaded bone cement, were prepared and tested in the laboratory for: kinetics of antibiotic release; activity against planktonic and biofilm bacterial cultures; biocompatibility with cultured mammalian cells; and physical bonding to the material (n = 3 in all tests). The sol-gel coatings and controls were then tested in vivo in a small animal healing model (four materials tested; n = 6 per material), and applied to the surface of commercially pure HA-coated titanium rods.Aims
Methods
Prosthetic joint infection (PJI) is the leading cause of failure of primary and revision hip and knee arthroplasty. It is challenging condition which represents a growing burden on hospital resources. In-patient hospital stay for antibiotic therapy post-operatively is costly and access to out-patient IV therapy (OPAT) varies between regions. In a tertiary referral centre for revision and infection, the suitability and cost-effectiveness of Dalbavancin was reviewed as a “single-shot” therapy following DAIR or revision lower limb arthroplasty for PJI. A prospective service evaluation was carried out for consecutive patients treated for PJI of the hip or knee who received Dalbavancin. Treatment was indicated by Consultant Microbiologist advice within an MDT setting where clinical or patient factors made alternative therapies eg. OPAT inappropriate. Service-level data was collected to allow calculation of bed-day savings compared to a traditional 14-day course of IV treatment. Readmission rates to the trust within 30 days were reviewed as a marker of clinical efficacy and safety.Introduction
Methods & Materials
Literature debates whether fluid aspirates for suspected PJI should undergo prolonged incubation for cultures. We looked at sensitivity and specificity of 14-day cultures, compared to 7-days, for aspirates from prosthetic hips and knees. Conducted at a quaternary referral centre for PJIs from Jan 2017 to July 2019. Suspected PJIs who underwent aspiration, incubated 14 days and later surgical intervention with minimum three tissue samples were included. 176 aspirates were included. This is an increased number compared to our historic figures (average 88 Vs 48 pts/yr). 47 patients had fluid and tissue positive (true positive), 20 fluid +ive but tissue -ive (false positive), 98 fluid and tissue -ive (true negative) and 15 fluid negative but tissue +ive (False negative). Thus, sensitivity 76%, specificity 83%, positive predictive value70% and negative predictive value 87%. Of 88 positive aspirates, only 75% were within 7-day cultures. Low virulence organisms as Propionibacterium acnes and coagulase negative staph were grown later. Of 48 with only one tissue sample positive, 38 were culture-negative on aspiration and 6 grew different organisms on aspirate and tissues. Also, as many were cultured later, it suggests contamination.Design and methods
Results
No single test is 100% sensitive and specific for the diagnosis of prosthetic joint infection. Joint aspiration is currently the only preoperative investigation that can establish the identity of the infecting organism and its antibiotic susceptibilities. Frequently when attempting to aspirate a joint a ‘dry tap occurs as fluid cannot be aspirated. In this situation, normal saline may be injected into the joint and then reaspirated to provide fluid for culture. The aim of this study was to ascertain the diagnostic accuracy of culture of joint aspiratie with or without saline reaspiration in the event of a dry tap. A retrospective analysis of 580 hip and knee aspirations in patients deemed to have moderate-high risk of infection and ultimately proceeded to revision arthroplasty over 12 years at a large quaternary referral centre where pre operative aspiration is routine. Fluid was aspirated in 313 (54%) cases and dry taps in which saline injection reaspiration was performed occurred in 267 (46%) cases. Overall sensitivity and specificity of diagnostic aspiration were 84% (78–89%) and 85% (81–88%) respectively. Sensitivity and specificity of saline injection-reaspiration after dry tap were 87% (79–82%) and 79% (72–84%) compared to 81% (71–88%) and 90% (85–93%) for direct aspiration. Pre operative joint aspiration and culture is a sensitive and specific test for the confirmation of diagnosis in patients at a moderate to high risk of prosthetic joint infection. Culture of saline injection-reaspiration also provides accurate diagnostic information in the event of a dry tap. Both methods allow susceptibility testing of relevant organisms and are therefore able to guide peri-operative and cement instilled antibiotic therapy. Culture of pre operative joint aspirates provides sensitive and specific diagnostic information including antimicrobial susceptibility results. Saline injection-reaspiration is a useful additional technique in those patients in whom fluid cannot be aspirated.
The aim of this study was to establish the diagnostic accuracy
of culture of joint aspirate with and without saline injection-reaspiration. This is a retrospective analysis of 580 hip and knee aspirations
in patients who were deemed to have a moderate to high risk of infection,
and who subsequently proceeded to revision arthroplasty over a period
of 12 years. It was carried out at a large quaternary referral centre
where preoperative aspiration is routine.Aims
Patients and Methods
Listeria monocytogenes is usually thought of as a bacterial pathogen that causes invasive disease including meningitis and bacteraemia in susceptible hosts. It remains a rare cause of bone and joint infection; there is therefore potential for clinical and laboratory delay in diagnosis and for uncertainty over optimal management. We describe our experience of two such cases of L. monocytogenes prosthetic joint infection to highlight key features in clinical presentation and management. Two case reports of L. monocytogenes prosthetic joint infection are described with reference to previous published cases. A 57 year old woman presented with a 10 day history of severe pain and swelling around a left knee prosthesis which had been implanted as bilateral total knee replacements three years previously. She had a background of rheumatoid arthritis, controlled with prednisolone, methotrexate and ritixumab. Cultures from the left knee isolated L. monocytogenes. The patient was commenced on IV amoxicillin and after 4 weeks underwent 1st stage revision including radical debridement and removal of prosthesis. During the procedure an antibiotic-impregnated spacer (gentamycin/clindamycin with additional vancomycin added in house) was inserted. Antibiotic therapy with intravenous amoxicillin was continued for 2 weeks post-procedure and on discharge the patient was converted to oral amoxicillin for a further 8 weeks. The patient went on to have a 2nd stage revision, making a good recovery. An 85 year old woman presented with an 18 month history of discomfort and recurrent abscesses along the wound line of a left hip prosthesis, implanted over 20 years ago. She had a background of osteoarthritis and bullous phemphigoid, previously on steroid treatment. Fluid from the abscess was aspirated and isolated L. monocytogenes. Due to patient preference and frailty, radical revision was not thought a viable management option. Chronic suppressive therapy with oral amoxicillin was therefore instigated; one year on the infection remains well controlled and discomfort in the left hip has improved. L. monocytogenes has previously been infrequently implicated as a pathogen in prosthetic joint infection; however, there are reports of increasing numbers of cases particularly amongst immunosuppressed individuals. With an expanding at-risk population(1), its importance as a cause of prosthetic joint infection is set to rise in the future. Optimal management has not been well studied; it is likely that the best option combines antimicrobial therapy and prosthetic removal if possible.
The purpose of the study was to retrospectively assess the patients treated to date with the vac ulta system using a technique of antibiotic instillation. The vac ulta system is licensed for use with anti-septic instillation fluid but we have now treated a number of patients with antibiotic instillation under the guidance of the microbiology department. All patients being treated with the vac ulta system were included in the study. There were no exclusions. Pathology treated, infecting organism, antibiotic used and length of treatment were all recorded. Any antibiotic related complications were noted. Treatment was judged successful with resolution of presenting symptoms, normalization of inflammatory markers and three negative foam cultures. There were 21 patients included in the study. There were 13 male and 8 female patients. Length of treatment ranged from 1 week to 10 weeks with a mean of 4.2 weeks. Follow up ranged from 1 month to 42 months with a mean follow up of 17.9 months The most common pathogen was Staph. Aureus(11 cases). Enterobacter, ESBL, Strep. Milleri, MRSA and Citrobacter were also treated. Antibiotics instilled included flucloxacillin, meropenem, gentamicin, vancomycin, meropenem and teicoplanin. There were no antibiotic reactions/allergies. Pathologies treated included osteomyelitis, two stage amputations for infection, infected non-union and infected metalwork. Infection recurred in 2 of 21 patients (10%), with one recurring at 18 months and one at 2 years. The 90% treatment success rate is highly encouraging in this notoriously difficult group of patients to treat. In this series vac instill was an effective treatment of infection and allows antibiotic treatment to be targeted to the infected tissues. There were no adverse reactions seen. Larger series with longer follow up are no needed but we believe this technique is safe, successful and easily administered can be cautiously adopted on a wider basis.
Spinal infections constitute a spectrum of disease comprising pyogenic, tuberculous, nonpyogenic-nontuberculous and postoperative spinal infections. The aim of this study was to review the epidemiology, diagnostic yield of first and second biopsy procedures and microbiology trends from Sheffield Spinal Infection Database along with analysing prognostic predictors in spinal infections. Sheffield Spinal Infection Database collects data prospectively from regularly held Spinal infection MDTs. We accrued 125 spinal infections between September 2008 and October 2010. The medical records, blood results, radiology and bacteriology results of all patients identified were reviewed. In patients with negative first biopsy, second biopsy is contemplated and parenteral broad spectrum antibiotic treatment initiated.Introduction
Materials and Methods
