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.

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.

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.