Aim

Diagnosing prosthetic joint infections(PJI) is sometimes difficult. Being able to identify the bacteria involved in intraoperative samples is an essential diagnostic criterion.

There are however some cases in which the traditional cultures are not capable of providing a definitive diagnosis. In this regard, implant sonication has emerged as a complementary test.

The aim of this study was to analyze the results of microbiological studies obtained with and without implants sonication, in order to understand its real contribution to diagnosis.

Aim

The aim of this study is to evaluate the value of inflammatory parameters normalization and/or increased time between stages necessary in predicting healing and preventing infection recurrence.

Primary tuberculous bursitis was a relatively frequent manifestation of the disease before the antituberculosis drug era. Nowadays, it is considered a rare condition; it accounts for 1–2% of all musculoskeletal tuberculosis. The diagnosis and treatment of tuberculous bursitis may be delayed because the paucity of symptoms, its indolent clinical course and a low clinical suspicion. A 50-year-old patient with tuberculous trochanteric bursitis is reported.

A 50-year-old woman was referred to our department to investigate a persistent pain in her left hip with 6 months duration. She was afebrile. The examination revealed a diffuse swelling from the buttock through the thigh, notable over the trochanter, but no sign of acute inflammation such as heat and redness. Her past medical and family histories revealed no previous tuberculosis.

Plain films of the left hip showed a partial destruction of the margin of the greater trochanter, lytic foci in the underlying bone and a small focus of calcification in the adjacent soft tissues. A computed tomogram showed a soft tissue mass and demonstrated the relationship with the trochanter. We performed a needle biopsy which revealed granulomatous tissue. The patient underwent complete excision of the bursa and curettage of the surface of the trochanter. The postoperative course was uneventful. Mycobacterium tuberculosis was isolated and definitive diagnosis of tuberculous bursitis was made. There was no evidence of concomitant tuberculosis at other musculoskeletal sites. The patient completed a treatment with rifampicin and etambutol for 6 months.

There has been a complete resolution of the symptoms after 3 months and no recurrence after 4 years of follow-up. On plain radiograph the remodeling of the bone structure is clearly visible.

Tuberculosis in the region of the greater trochanter is extremely rare. This rarity leads orthopedic surgeons to neglect this potential diagnosis, resulting in a delay in treatment. The pathogenesis of tuberculosis of the greater trochanteric area has not been well defined. The incidence of concomitant tuberculosis at other musculoskeletal sites, as well as the lung, is approximately 50%. Both hematogenous infection and propagation from other locations are reasonable explanations. Surgical intervention is mandatory for cure and the use of several antituberculosis agents is a standard approach.

Several risk factors can and should be addressed during first stage or spacer implantation surgery in order to minimize complications. Technical aspects as well as practical tips and pearls to overcome common nuisances such as spacer instability or femoral and acetabular bone loss will be discussed and shown with pictures.

Total joint arthroplasty (TJA) is one of the most successful procedures in orthopaedics and excellent results are expected in virtually all cases. Periprosthetic joint infection (PJI) though unusual, is one of the most frequent and challenging complications after TJA. It is the third most common cause of revision in total hip replacement, responsible for up to 15% of all cases.

In the past few years several improvements have been made in the management of an infected total hip prosthesis. Nevertheless it remains a challenging problem for the orthopaedic surgeon. Although numerous studies report favourable outcomes after one-stage revision surgery, two-stage has traditionally been considered as the gold standard for management of chronic infection. Two-stage exchange consists of debridement, resection of infected implants and usually temporary placement of an antibiotic-impregnated cement spacer before reimplantation of a new prosthesis.

Spacers can be classified as static or articulating. The goals of using an articulating antibiotic loaded cement spacer are two-fold: to enhance the clearance of infection by local antibiotic therapy and dead-space management while maintaining joint function during treatment thus improving the functional outcome at reimplantation. Still, hip spacer implantation is not innocuous and there are several possible complications.

Going forward, one must consider not just eradicating infection but also the importance of restoring function. In this regard using a mobile spacer adds an element of physiologic motion that both increases patient comfort between stages and facilitates re-implantation surgery. Conversely, mechanical complications are one of the major consequences of this preference. Be that as it may there are ways to minimize these problems. It is the surgeon responsibility to optimize mechanical circumstances as much as possible.

I would like to thank Dr. Ricardo Sousa for his help with this work

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.

Evaluation of the effectiveness of biodegradable bone substitute with high doses of antibiotics in cavitary osteomyelitis and infected nonunions.

The authors evaluated 8 cases, 5 of them related to osteomyelitis with bone sequestration and other 3 regarding infected nonunions. All of them had in common the persistence of infection after antibiotic therapy.

All infections were confirmed by microbiological studies. In all cases the surgeons conducted a thorough surgical debridement and filling of bone defects with Herafill®. Later a tight clinical, analytical and imagiological control was performed.

Five of the cases were a success with simultaneous healing of the bone loss and treatment of the infection. These corresponded to the cases of cavitary osteomyelitis. In the remaining 3 cases, despite infection eradication, union was not achieved and additional surgical procedures were required for definitive treatment of nonunion.

In the treatment of bone infection, use of high doses of antibiotics at the site is a consensus as it allows eradication of the infection with lower systemic effects. With the emergence of biodegradable bone substitutes, the need for a new surgical intervention for their removal can be avoided. Properties of calcium sulfate and calcium carbonate stimulate osteogenesis at the site, allowing their absorption and replacement by bone matrix. These properties make them ideal to usage in cases of cavitary bone defects.

Our experience supports the idea that the use of high doses of antibiotics locally permits remission of the infection. However, when this is implemented through a bone substitute, it is possible to achieve osteogenesis in bony cavities. Nevertheless, when applied to infected nonunions, their role seems to be limited to the eradication of the infection.

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.