We aim to describe the microbiological spectrum and relevant antibiotic susceptibility profile of PJI in our institution over a five-year period(2009–2013) and determine its evolution considering the preceding six years(2003–2008) thus evaluating the adequacy of our empirical antibiotic regimen. We retrospectively reviewed the records of 96 consecutive PJI (51 hips:45 knees) treated from May 2009-December 2013. Demographics, microbial species and antibiotic susceptibility were recorded. These results were then compared to those previously obtained by studying the 2003–2008 time period. Infections were polymicrobial in 27 cases(28.1%) and only two cases(2.1%) were culture-negative accounting for a total of 132 different culture results. S.aureus grew in 37 samples(28.0%) being the most frequently isolated microorganism. Coagulase-negative staphylococci grew in 32 samples(24.2%) and gram negative bacteria in 35 samples(26.5%). Other Gram positive species (most commonly enterococci and streptococci) were isolated in 26 samples(19.7%). Comparing 2009–2013 to 2003–2008, there was a significant increase of polymicrobial infections – 28% vs. 8%(OR=4.6, 95%CI [1.9–11.3]) and a significant decrease of culture-negative cases – 2% vs. 18%(OR=0.1, 95%CI [0.02–0.4]). It is also noteworthy that the prevalence of gram negative isolates was significantly increased – 26.5% vs. 13.3%(OR=1.3, 95%CI [1.1–1.6]). Antibiotic susceptibilities study showed a 41.4% methicillin resistance among S.aureus and even higher among coagulase-negative staphylococci isolates(57.7%). This is a not quite significant decrease compared to the earlier period(p=0.10). We also found a high rate antibiotic resistance among gram negative: ampiciline(81.8%), amoxicilin/clavulanate(59.1%), ciprofloxacin(19.2%), aminoglycosides(17%), third generation cephalosporins(14.6%) and even carbapenems(13.6%). These results show that our sampling protocol has improved considerably as the proportion of culture-negative cases has dramatically decreased. On the other hand this may also help explain the increase in polymicrobial infections. We have no clear explanation for the increase in gram negative bacteria. Despite the downward trend we still face a very significant proportion of methicillin-resistant staphylococci infections. The antibiotic resistance profile among gram negative bacteria is also worrying. As such we believe a regimen consisting of vancomycin and gram-negative coverage such as aminoglycosides or a third generation cephalosporin is still warranted in our institution.
The goals of the present study are to describe the prevalence of both methicillin sensitive and resistant S.aureus carriage among elective total hip and knee arthroplasty candidates and to evaluate the real impact of preoperatively treating carriers in preventing prosthetic joint infection. Patients undergoing elective primary THA or TKA at a single institution were enrolled in a prospective randomized trial. S.aureus nasal carriage screening was performed in the outpatient setting and selected carriers underwent a 5-day preoperative treatment of nasal mupirocin and chlorhexidine bathing. All patients were followed regularly in the outpatient clinic. No patients were lost to follow-up at a minimum of one year after surgery. The main outcome of the study was the diagnosis of prosthetic joint infection occurring in the first year after surgery including all pathogens and a secondary outcome was defined as infections involving S.aureus bacteria only. From January 2010 to December 2012, 1305 total joint arthroplasties were performed and 1028 of those were screened. We observed a 22.2% (228/1028) S.aureus colonization rate and only eight patients colonized with MRSA (0.8%). Twenty five cases of prosthetic joint infections were identified with an overall infection rate of 2.4%. S.aureus was involved in 14 cases. PJI rate in S.aureus carriers was 3.9% (9/228), which was not significantly higher than the 2.0% (16/800) found among non carriers. Treated and untreated carriers infection rate also showed no significant differences – 3.4% (3/89) vs. 4.3% (6/139). Multivariable analysis substantiates ASA≥ 3 (OR=3.42, 95% CI=1.51 – 7.74) and duration of surgery above the 75th percentile (OR=2.74, 95% CI=1.22 – 6.16) as independent predictors of PJI but not S.aureus carrier state. We obtained similar results when considering infection involving S.aureus bacteria only. Of the 14 cases where S.aureus was present in PJI, only five were carriers preoperatively. Of those five cases, one was an untreated MSSA carrier that ultimately got an MRSA infection. Our results show no clear benefit in screening and decolonizing S.aureus nasal carriers before total joint arthroplasty. There seems to be a lack of causal relation between nasal S.aureus and PJI pathogen as most of S.aureus PJI seems to have an exogenous source.
Previous data from our institution show that more than half of all prosthetic joint infections are due to S. aureus. A significant proportion of these bacteria may have an endogenous source. Detecting and treating asymptomatic S. aureus nasal carriers preoperatively has been shown to reduce the risk of infection. This is an ongoing prospective study that started in March/2009 and involves primary total knee or hip arthroplasties candidates. So far preoperative nasal swab cultures were performed in 211(61%) out of 347 patients operated until April/2010. Carriers are identified and randomly chosen for preoperative treatment consisting of nasal mupirocin twice a day and daily cloro-hexidine baths in the 5 days that precede surgery. Antibiotic prophylaxis is cefazolin 24hours adding a single vancomycin dose in MRSA carriers.Background
Material and Methods
The rate of infections in primary and revision surgery (hip and knee) The success rate in treating those infections Long term survival rate of revision arthroplasties
Considering an infection free arthroplasty as the goal, the overall success rate of treatment was under 48% (30/69). The success of treating infections with debridement and retention of components was even lower (29%). Further analysis revealed a higher success of this approach (45%) when considering more appropriate candidates (short term infections). An interesting statistically significant difference was found favoring this approach in the knee. Two-stage revision strategy was successful in achieving revision arthroplasty in 43% (20/46) of the cases. Most patients were never considered candidates to the second stage procedure. Knee joint and resistant microorganisms were found to be predictors of bad prognosis. There was a 90% (18/20) survival rate of revision arthroplasties after two years average follow-up. There were only 2 cases of relapsing infection both controlled without prosthetic removal.
Primary synovial chondromatosis, defined by Jaffe (1951), is a rare, benign arthropathy, of unknown aetiology, distinguished by the chondroid metaplasia of the synovial membrane of the joint, bursa or tendon sheath, which leads to the formation of loose bodies, usually intra-articular. It is characteristically monoarticular and the knee, hip and elbow are the joints most commonly affected. The shoulder is a rare localisation and the extra-articular involvement even rarer, with only few cases presented in the literature. The diagnosis is possibilited by the clinical examination and by the confirmation of the presence of multiple intra-articular loose bodies by roentgenographic studies and magnetic resonance (MR). The treatment is always surgical. Malignant degeneration of synovial chondromatosis into chondrosarcoma is described, although rare. We report an exceptionally rare case of synovial osteochondromatosis of the shoulder with combined intra and extra-articular involvement in a 28 years old female patient, former athlete. She presented with a five-year history of shoulder pain and slight limitation of motion. Radiographic examination and magnetic resonance imaging led us to the diagnosis of synovial chondromatosis of the shoulder. The patient underwent arthroscopic removal of the intra-articular loose bodies and partial synovectomy. The subscapularis recess was then identified through an anterior deltopectoral incision and multiple loose bodies were removed from within. Primary synovial chondromatosis of the shoulder is rare (5% of the cases) and the involvement of the extra-articular shoulder site is even rarer. Bloom and colleagues reported ten cases involving the shoulder in a meta-analysis of 191 synovial chondromatosis cases. The arthroscopic removal of the loose bodies combined with the partial sinovectomy has demonstrated efficacy and low recurrence rates, allowing excellent visualization of the joint, decreased morbidity and early functional return. Nevertheless, we think that this approach may become insufficient when the extra-articular involvement is verified.
Chondrosarcoma is the second most frequent primary malignant tumour of bone, representing approximately 25% of all primary osseous neoplasms. Chondrosarcomas are a group of tumours with highly diverse features and behavior patterns, ranging from slow-growing non-metastasizing lesions to highly aggressive metastasizing sarcomas. As radio and quimio-resistant tumours, the surgery constitutes the unique chance of cure. Nowadays, besides the curative intention, the reconstructive surgery is also a priority in order to save the limb and optimize the function. This case report is about a young woman, of 24 years old, with hip-related pain and a large mass in the left pelvis. The imagiologic study showed a large mass of about 8 cm of large diameter, starting at the anterior wall of the acetabulum, involving the pubic arcs and with matrix calcification. The core needle biopsy confirmed the presence of a chondrosarcoma, staged as a IIB of Enneking. Because of its size and localization the limb salvage surgery has been a challenge. The surgery included a broad approach of the left hemipelvis, with wide excision of the tumour, reconstruction of the abdominal wall with a propylene prothesis and reconstruction of the hemipelvis with a “custom-made” prothesis with preservation of the femoral neurovascular bundle. The patient started to walk with total bearing after three months and had a normal gait and a nearly normal life during eleven months. Fifteen months after the surgery lung metastasis and local recurrence were diagnosed and she died six months after.