Identification of Asymptomatic Prosthetic Joint Infection: Microbiologic and Operative Treatment Outcomes.

BACKGROUND: This prospective study investigated the role of mechanical and biological factors in aseptic implant loosening or presumed silent prosthetic joint infection (PJI). METHODS: Thirty-seven patients were investigated. Microbiologic and molecular methods were used to detect bacteria on the surface of the failed implants removed during revision arthroplasty. Histopathologic analysis was performed. The influence of body mass index (BMI) and various co-morbidities on implant failure also was determined. RESULTS: The results of sonicated fluid cultures were positive for bacteria in 29.7% and the results of intra-operative tissue and joint liquid cultures in 18.9% and 16.2%, respectively. Molecular detection with 16S rRNA sequencing revealed a large variety of bacteria. The most frequent organism was coagulase-negative Staphylococcus (CNS). The outcomes of histopathologic tests of peri-prosthetic tissue showed evidence of the infection type in all culture-positive joints and in 41.4% of the cases with negative culture results. Overweight status or obesity was present in 82.8% of the culture-negative patients. CONCLUSIONS: The results of this study proved the presence of micro-organisms on the surface of implants in both aseptic and presumed PJI cases. Inclusion of the sonication procedure in the diagnostic algorithm increased the ability to identify the pathogen. The results of our study suggest the co-existing roles of BMI and the time to implant loosening as well as biological agents in causing prosthesis loosening.

Identification of silent prosthetic joint infection: preliminary report of a prospective controlled study.

PURPOSE: We will test the hypothesis that ultrasound supported by polymerase chain reaction (PCR) could improve bacterial identification in non-infected prosthetic joint loosening. The aim was to detect bacterial species in non-infected prosthetic joint loosening using ultrasound and 16S rRNA gene sequencing. METHODS: A total of 16 patients (11 women and five men) aged 46-80 years (mean age 65.7) with diagnosed knee or hip implant loosening (mean implant survival of 102.1 months) were investigated. Bacterial culture and DNA sequencing were used to detect bacteria on the surface of failed implants removed during revision arthroplasty. The results of pre- and intraoperative culture and DNA sequencing were compared. Histopathological analysis was also performed. RESULTS: The number of positive cultures rises with a higher level of C-reactive protein (CRP). The results of the cultures from synovial fluid obtained through joint aspiration were consistent with sonicates from components of prostheses in 12 cases (75%). Bacterial DNA was found in 90% of patients with negative synovial fluid culture. PCR revealed two or more bacterial species, often of the same genus: Ralstonia pickettii, Pseudomonas spp., Brevibacterium spp., Lactobacillus spp., Propionibacterium spp. and Staphylococcus spp.These are micro-organisms present in the environment or on the human body and often associated with compromised immunity. CONCLUSIONS: The ultrasound procedure followed by PCR and sequencing improve bacterial identification in silent prosthetic joint infection. The lack of clinical signs of infection and negative preoperative and intraoperative cultures do not exclude the presence of micro-organisms on the implants.

Neglected, developmental hip dislocation treated with external iliofemoral distraction, open reduction, and pelvic osteotomy.

Between 1995 and 2003, we operated upon 18 children with 20 hips involved, aged 5-11 years (average: 7.5 years) suffering from an inveterate high developmental dislocation of the hip joint. An average follow-up period of our middle-term study was 51 months (range: 34-96 months). A two-staged management was applied. First, femoral head was lowered back to the level of acetabulum with an external fixator or a distractor device. The second stage involved open reduction combined with pelvic osteotomy and, in four cases with femoral derotation osteotomy. We noted two cases of avascular necrosis. Equal limb length was achieved in 15 cases. There were two cases of 0.5-cm length discrepancy, two cases of 1-cm length inequalities, and one case of 5-cm limb shortening. We endorse this method in neglected cases of previously untreated unilateral high developmental hip dislocations in children aged 8-10 years. It results in a usable hip joint without the need of femoral shaft shortening and facilitates future joint replacement.

CXCL8 and CCL5 expression in synovial fluid and blood serum in patients with osteoarthritis of the knee.

Chemokines proved able to induce release of enzymes relevant in cartilage damage. The present study addressed the levels of CXCL8 and CCL5 and the potential role of these chemokines in predicting the morphological changes in the course of osteoarthritis (OA). Synovial fluid (SF) and blood serum were obtained from 20 patients undergoing knee replacement surgery because of OA. For comparison, samples were also obtained from another 20 patients during diagnostic or therapeutic arthroscopy performed because of knee injury. The samples were analyzed for CXCL8 and CCL5 using enzyme-linked immunosorbent assay. SF from the group with OA showed significantly (p = 0.024) increased levels of CXCL8 when compared with the group after knee injury. We have not demonstrated any significant correlation between chemokine expression and clinical or radiological signs of OA. Mediators of inflammation are the potential predicting factors of OA, however, with respect to examined chemokines development of a diagnostic test can be limited by the low serum concentration and lack of correlation with clinical and radiological signs of the disease.

Ultrasound measurement of rotator cuff thickness and acromio-humeral distance in the diagnosis of subacromial impingement syndrome of the shoulder.

The usefulness of ultrasound measurements in the diagnosis of the subacromial impingement syndrome of the shoulder was evaluated. Fifty-seven patients with unilateral symptoms of the impingement syndrome underwent ultrasound examination of both shoulder joints, which included assessment of rotator cuff integrity, measurement of rotator cuff thickness and the distance between the infero-lateral edge of acromion and the apex of the greater tuberosity of humerus (AGT distance) in the standard ultrasonographic positions. As a control group, 36 volunteers (72 shoulders) with no history of shoulder pain were examined sonographically. Ultrasonographic assessment of humeral head elevation, measured as the AGT distance, proved to be useful in establishing the diagnosis of the subacromial impingement syndrome of the shoulder. A difference in rotator cuff thickness of more than 1.1 mm and a difference in the AGT distance of more than 2.1 mm between both shoulder joints may reflect dysfunction of rotator cuff muscles.