Diagnosis of chronic prosthetic joint infection (PJI) is often challenging. Painful prosthesis is frequently due to an infection but to diagnose it is somethimes difficult. All recent guidelines stress the central role of joint punction in diagnosis of PJI if the infection is not demonstrated. However which test on synovial fluid must be carried out is not so clearly defined. Total white blood cell count and differential leukocite count are usually considered useful in diagnosis but cut offs reported by different studies are quite different. Moreover this test needs a relatively large amount of fluid and blood contamination of it largely affects the result. What's more the synovial fluid WBC count may be unreliable in the setting of a metal-on-metal bearing or corrosion reaction.

Routine cultures should be maintained between 5 and 14 days, their sensitivity appears low in chronic infection even if witholding antimicrobial therapy before the collection of the fluid can increase the likelihood of recovery an organism.

Synovial leukocyte esterase can be performed as a rapid office or intraoperative point of care test using urinalysis strips. It is cheap and easy to perform, but the presence of blood in the sample can affect the result and it needs centrifugation.

Recently a new test has been proposed to detect alfa-defensine in synovial fluid. It shows a high sensitivity and an exellent specificity.

We performed 25 joint punctions on 25 patients with suspected PJI (enrollment is going on). Synovial fluid collected was tested for: leukocite esterase, WBC count and differential, colture in blood colture bottle for anerobe and aerobes (BacT/ALERT Biomerieux, inc) and detection of alfa-defensine level (Synovasure – Zimmer)

In patients who underwent surgery at least 5 samples of periprotesic tissue were collected for microbiologic analysis and the removed implant was sonicated according with the methodic. Furthermore samples for frozen section were sent and a histologic examination was made according to the Moriewitz – Kerr classification. The MSIS criteria was utilized to classify the case as infected or not.

Prosthetic joint infections (PJI) occur in 0.8–1.9 % of arthroplasties, but the absolute number is increasing because of the frequency of procedures. Two stage exchange is the most effective strategy, but failures are often described. Culture of perioperative tissues during removal of arthroplasty is a standard procedure but culture during second step is equally important to define a success or a failure.

We retrospectively reviewed PJI treated with two stage-exchange from January 2011 and December 2012 at “Ospedale S. Maria Misericordia”, Albenga-Italy. The procedure calls for bacterial culture not only during first step but also during reimplantation. Antibiotic treatment is prolonged after reimplantation until the cultures availability. A failure was defined by persistence of infection for positive culture or reocurrence of infection during a follow up of at least 2 years in patients with negative cultures. Three positive cultures yielding phenotypically identical organisms, or a single specimen of a virulent microorganism (e.g. Staphylococcus aureus) were required to rule out false positive for contaminants. Patients with persistence of infection were treated for 3 months with antibiotics.

86 patients underwent the two stage treatment: 45 hip and 41 knee prosthesis. The average ESR before arthroplasty removal was 59 mm/ 1st h (range 5–120), the average CRP was 3.9 mg/dl (range 0.3 – 34). Coagulase-negative staphylococci were isolated in 31 cases, Staphylococcus aureus in 19, Streptococcus spp in 8 and enterococci in 4. Gram-negatives were isolated in 4 patients and polymicrobial infection in 6 patients. In 14 patients (16%) no pathogen was identified.

A positive culture during reimplantation was documented in 11 (13%) cases: 8 coagulase-negative staphylococci, 2 Staphylococcus aureus, 1 Candida sp. All patients received 3 months of therapy after surgery and 6 of them were free of infection at 2 years of follow up after the end of treatment. Among the 75 patients with negative cultures, a relapse was documented in 2 (3%), after 5 and 24 months, respectively. These cases were treated with arthrodesis and 6 weeks antibiotic treatment, with resolution of infection but poor functional results. Overall the success rate of our strategy was 92% (79/86).

In patients treated with two-stage exchange, the combination of cultures at reimplantation and antibiotic suppressive treatment for 3 months in presence of positive cultures, are associated with a high rate of success. Only a prolonged follow up can rule out a relapse and agree with a true resolution of infection.

Background. Total hip replacement (THR) has become the ideal treatment for any disorder causing joint destruction. Surgery-related infections are reported only in 1–2 % of THR, but antibiotic prophylaxis is necessary because infections are associated with significant morbidity and occasionally death. 1st and 2nd –generation cephalosporin or, in hospital with methicillin-R Staphylococcus spp (MRSA, MRSE) high prevalence, vancomycin, are the most frequently drug emplojed. The most frequent side effects of antibiotic prophylaxis are allergic reaction and pseudomembranous enterocolitis.

The objective of the present study was to assess the efficacy and tolerability of antibiotic prophylaxis for THR at S. Corona Hospital Pietra Ligure SV (Italy).

In our hospital the majority of prostethic device infections are due to MRSA, but recently we have described increment of infection due to Pseudomonas spp and other gram-. For this reason we used association of vancomycin plus pefloxacin in primary prophylaxis.

Methods. Retrospective analysis of 1118 THR performed in the period 2003–2004, receiving surgical prophylaxis with a single dose of the association vancomycin 1000 mg plus pefloxacin 400 mg. Data collection regarded patients’ age at surgery and reasons for THR. The presence of a surgery-related infection was investigated by means of a phone interview about the function of the hip device (presence of pain, deambulation impairment, fever). Patients with pain or other problems were submitted to physical exam, laboratory tests, plain radiograph and if necessary to exclude of infection, radioisotopic scans.

Results. We report the preliminary data on 218 THR in 211 patients (81 M, 122 F, median age 67.49 aa, range 29–91). THR was performed for: osteoarthrites in 168 cases, trauma in 26, osteonecrosis in 9, displasia in 4 cases, previous osteotomy in 4. 167/211 patients were submitted to a phone interview and 44 to a clinical examination.

Conclusions. In our center, the association of vancomycin-pefloxacin resulted effective and well tolerated as single dose prophylaxis for THR.

Background: In recent years there has been an increase in the insertion of prosthetic devices in orthopaedics. In spite of improvements in surgical techniques and antibiotic prophylaxis, the absolute number of infectious complications is high. Infections have a negative impact in patient’s quality of life and have high costs of management.

Patients and Methods: Retrospective analysis of diagnosis, aetiology, and therapy of prosthetic devices infections observed from 1985 to 1999 in the operative unit for diagnosis and treatment of Infections in orthopaedics of Ospedale S. Corona- Pietra Ligure (SV).

Results: During the study period, 251 patients with infected hip prosthesis and 133 with infected knee prosthesis had been treated. Diagnosis of infection was made by means of clinical features supported by x-ray, MRI, CT scan, ultrasonography and radio-nuclide scan. Aetiology was established by microbiological culture and histology. The majority of cases were single agent infections due to Gram-positives, especially S. aureus and S epidermidis, isolated in 41% of hip and 53% of knee prosthesis infection, while P. aeruginosa represented the most frequently isolated Gram-negative (3% in hip prosthesis and 10.6 % in kne prosthesis).

Polymicrobial infections (with constant presence of S. aureus and/or S. epidermidis) accounted for 8% of hip and 7% of knee prosthesis infections. Treatment was represented by prolonged antibiotic administration (at least 8 weeks) associated with surgical debridment inacute infections, and two-stage exchange in chronic infections. In 23 hip infections in patients in poor clinical conditions or in suspected persistence of latent infection a new prosthesis was not replaced and Girdlestone’s hip arthroplasty was performed.

Conclusions: Gram-positives are the main cause of orthopaedic infections but Gram-negatives, especially P aeruginosa, are often isolated. The treatment must necessarily be combined: antibiotic therapy and surgical treatment. Only in presence of optimal conditions a new prosthesis can be replaced.