Management of septic arthritis

Rapid in situ chondrocyte death induced by Staphylococcus aureus toxins in a bovine cartilage explant model of septic arthritis

OBJECTIVE

To assess in situ chondrocyte viability following exposure to a laboratory strain and clinical isolates of Staphylococcus aureus.

METHODS

Bovine cartilage explants were cultured in the presence of S. aureus 8325-4 (laboratory strain), clinical S. aureus isolates or non-infected culture medium of pH values 7.4, 6.4 and 5.4. All clinical isolates were isolated from the joint aspirates of patients presenting with S. aureus-induced septic arthritis (SA). At designated time points, in situ chondrocyte viability was assessed within defined regions-of-interest in the axial and coronal plane following live- and dead-cell image acquisition using the fluorescent probes 5-chloromethylfluorescein diacetate (CMFDA) and propidium iodide (PI), respectively, and confocal laser-scanning microscopy (CLSM). Cartilage water content, following S. aureus 8325-4 exposure, was obtained by measuring cartilage wet and dry weights.

RESULTS

S. aureus 8325-4 and clinical S. aureus isolates rapidly reduced in situ chondrocyte viability (>45% chondrocyte death at 40 h). The increased acidity, observed during bacterial culture, had a minimal effect on chondrocyte viability. Chondrocyte death commenced within the superficial zone (SZ) and rapidly progressed to the deep zone (DZ). Simultaneous exposure of SZ and DZ chondrocytes to S. aureus 8325-4 toxins found SZ chondrocytes to be more susceptible to the toxins than DZ chondrocytes. Cartilage water content was not significantly altered compared to non-infected controls.

CONCLUSIONS

Toxins released by S. aureus have a rapid and fatal action on in situ chondrocytes in this experimental model of SA. These data advocate the prompt and thorough removal of bacteria and their toxins during the treatment of SA.

Arthroscopic management of the septic ankle joint: case report of a stage-guided treatment

Ankle joint sepsis is a serious pathologic entity that, if not effectively treated, can lead to significant dysfunction and morbidity. Minimal published data are available to guide the frequency and extent of surgical irrigation and debridement in patients with ankle joint sepsis. We report on a surgical treatment protocol used at our institution based on intraoperative joint staging. We present the case of a 68-year-old female with well-controlled diabetes who presents with ankle joint sepsis. She represents a typical patient treated by our standard approach. At approximately 1 year postoperatively, the patient reported minimal residual pain and had returned to near previous activity levels, despite an advanced stage of joint sepsis at the initial presentation. The treatment protocol provides supplemental guidance to assist regular clinical judgment in managing the septic ankle joint.

Prospective evaluation of a shortened regimen of treatment for acute osteomyelitis and septic arthritis in children

BACKGROUND

We present the findings of a prospective, bi-center study to establish the appropriate duration of antibiotic therapy for acute, uncomplicated bone and joint infections in children. Historically, patients have been treated with prolonged courses of intravenous and oral therapy. Our hypothesis was that children could be safely treated with 3 days of high-dose intravenous therapy followed by 3 weeks of oral therapy.

METHODS

We prospectively collected data from children presenting to Birmingham Children's Hospital and The Royal Children's Hospital, Melbourne who fitted our diagnostic criteria for septic arthritis and osteomyelitis over a 52-month period. Inclusion criteria for entry into the database were children <or=16 years of age who had no underlying disease or medical therapy predisposing to infection, and who had symptoms for less than 14 days before presentation. They were all started on intravenous antibiotics and a predetermined treatment algorithm was followed. All patients with septic arthritis also underwent joint washout. The patients were converted to oral antibiotics once they improved clinically and hematologically. Regular outpatient follow-up continued for 1 year with blood tests and x-rays.

RESULTS

Our database included 70 consecutive, eligible children aged 2 weeks to 14 years. Staphylococci were the only organisms isolated in cases of osteomyelitis, whereas Streptococcal infection was more prevalent in patients with septic arthritis. Using our treatment protocol, we found that 59% of children could be converted to oral therapy after 3 days of intravenous therapy and 86% after 5 days. The median duration of inpatient stay was 5 days. We established that 3 weeks of oral therapy was appropriate for those patients who received 5 days or less intravenous treatment. We have identified temperature and C-reactive protein as the best quantitative means of monitoring response to therapy. All patients were clinically, hematologically, and radiologically normal before discharge 1 year post-presentation.

CONCLUSIONS

We have found that a shortened course of intravenous and oral antibiotic therapy is effective in the management of acute uncomplicated bone and joint sepsis in children.

[Evaluation of a clinical pathway for septic arthritis]

INTRODUCTION

Clinical pathways are tools that coordinate clinical work, reducing interclinican variability and improving patient care and management. The use of clinical pathways in septic arthritis is appropriate, as this disease has a predictable course and there is considerable variation in its management. The aim of this study was to evaluate a septic arthritis clinical pathway 2 years after its introduction and to describe the characteristics of the patients included.

MATERIAL AND METHODS

Clinical pathway documents: pathway matrix sheet, variance form, parent information sheet, satisfaction survey and evaluation indicators sheet.

RESULTS

Thirty-five patients were included, seven with a definitive diagnosis of septic arthritis and 28 with probable septic arthritis. No differences were found between the two groups, with good outcomes in both. Laboratory analyses were performed at admission in all patients, at discharge in 51 %, and at the end of treatment in 97 %. The indicators that best met the standard were clinical pathway coverage, performance of arthrocentesis/arthrotomy, and satisfaction with dealings with staff and the information received. The indicators furthest from the standard were admission shorter than 7 days (77 % vs > 95 %) and obtaining articular fluid prior to antibiotic therapy (76 % vs > 90 %).

CONCLUSIONS

The clinical pathway is useful for standardizing the process of septic arthritis diagnosis and treatment. With adequate clinical support, application of this pathway allows decisions to be made on hospital discharge following the clinical criteria of improvement without worsening prognosis. Our immediate challenges are to reduce inpatient stay and to obtain synovial fluid before starting antibiotic therapy.