Septic arthritis following joint injections: a 17 years retrospective study in an Academic General Hospital

BACKGROUND

Septic arthritis following intra-articular infiltrations is an uncommon devastating complication correlated  to high costs for the health service and often to poor outcomes. The purpose of this study is to assess a 17-years experience in a single academic multispecialist hospital managing this uncommon complication in Orthopaedic practice.

METHODS

Patients with diagnosis of septic arthritis following joint injections treated in our hospital from January 2002 to December 2019 were included in the study. Clinical and demographic data, pathogens, injected agent, conservative/surgical treatments were reviewed. Patient were classified according to the ore operative Charlson Comorbidity Index (CCI) and the Cierny-Mader Classification(CMC). Furthermore follow-up outcome and time occurred to infection eradication were registered.

RESULTS

We included in the study 11 patients with a median age of 74 years old (IQR= 61.5 - 79). The median CCI was 3  (IQR= 2 - 5) and the majority of patients belong to CMC = B class. Septic arthritis occurred mainly following corticosteroids injections and more frequently involving knees. The pathogen more often isolated was Staphylococcus aureus. Five (45%) patients referred an history of multiple intrarticular injections. 7 patients (64%) had a complete resolution following an arthroscopic debridement, 4 (36%) patients underwent to a 2-stage replacement and one of them hesitated in an arthrodesis because of a recurrent periprothesic joint infection and extensor apparatus insufficiency.

CONCLUSION

The authors observed a potential increased risk of septic arthritis following joint injection in patients with history of multiple injections and poor health/immunological conditions. They recommend an early arthroscopic debridement as the treatment of choice especially in septic knees  performed in a multispecialist dedicated center.

A Novel Three-Dimensional-Printed Ultrasound-Guided Hip Arthrocentesis Model

When evaluating patients with hip pain, clinicians may be trained to both evaluate for a hip effusion and perform ultrasound-guided arthrocentesis to evaluate the etiology of the effusion. We present a novel 3-dimensional-printed hip arthrocentesis model, which can be used to train clinicians to perform both tasks under ultrasound guidance. Our model uses a combination of a 3-dimensional-printed hip joint, as well as readily available materials such as an infant Ambu (Ballerup, Denmark) bag, syringe, intravenous line kit, and silicone. We present our experience so that others may use and adapt our model for their training purposes.

Limited improvement and high rate of complication in patients undergoing reverse total shoulder arthroplasty for previous native shoulder infection

BACKGROUND

The outcomes of reverse total shoulder arthroplasty (RTSA) surgery for the sequelae of former septic native joint shoulder arthritis are unknown but might be inferior to patients without prior bacterial arthritis.

METHODS

We performed a single-center case-control study embedded in our prospective RTSA cohort. We matched all patients with prior infections in a 1:1 ratio with patients who underwent RTSA for other indications. The matching variables were indication for surgery, age, sex, dominant/nondominant shoulder, and body mass index. We evaluated outcomes by Constant score and active function.

RESULTS

Among 1249 patients in the RTSA cohort, 14 were operated for sequelae of previous native shoulder joint infections. Although both groups significantly improved from preoperative to postoperative values, the outcome of postinfectious patients was clearly inferior in comparison with the control group (absolute [38 ± 17 vs. 75 ± 8, P < .01], relative Constant score [47 ± 19 vs. 88 ± 9, P < .01], Constant pain score [11.0 ± 3.1 vs. 14.3 ± 1.3, P < .01], subjective shoulder value [43 ± 26 vs. 85 ± 10, P < .01], abduction [70 ± 43 vs. 148 ± 29°, P = .001], and elevation [82 ± 49° to 131 ± 16°, P = .02]). Moreover, in the postinfectious group, overall surgical complications occurred in 36%, with the need for revision in 21%. There was, however, no recurrence of infection in any of the patients' shoulders.

CONCLUSION

RTSA for end-stage postinfectious joint disease is associated with a high number of complications and reoperations. Clinical outcomes are inferior to those without past infection.

Suppurative arthritis of hip in a walking child: Effect of patient's age, delay in surgical drainage, and organism virulence

INTRODUCTION

We undertook a retrospective study to stratify the effect of patient's age, delay in surgical drainage, and Staphylococcus aureus (SA) virulence on expected clinicoradiological outcomes following suppurative arthritis of hip joint in a walking child.

MATERIALS AND METHODS

The study was conducted in 18 children over 2 years of age who suffered from joint fluid culture-positive SA arthritis of hip joint and treated with open arthrotomy. Outcomes were defined on the following criteria: age of child (≥5 years or <5 years), duration of symptoms elapsed before surgical intervention (≥5 days or <5 days), and virulence of SA (methicillin-resistant Staphylococcus aureus (MRSA)/methicillin-sensitive Staphylococcus aureus)). The final clinical results were graded according to Moon's clinical criteria and radiologically by types described by Choi et al.

RESULTS

The mean patient age was 6.22 years at the time of index procedure. The average delay in surgery was 17.06 days. Follow-up averaged 15.28 months. Five patients had associated with osteomyelitis femur in preoperative radiographs. MRSA culture was grown in 8 hips (44.4%) of 18 hips. Unsatisfactory clinical results according to Moon's criteria were obtained in 55.6% patients with 38.9% being MRSA infected. Unsatisfactory Choi's radiological results were present in 33.3% patients, 27.8% under MRSA category. Our study did not find age to be a significant factor either in clinical or radiological outcome. The clinical results were unsatisfactory in 81.8% patients with surgical delays when compared to early surgery (p < 0.05).

CONCLUSIONS

The clinicoradiological outcome in suppurative hip arthritis of walking children was unsatisfactory when there was delay in treatment beyond 5 days, and the causative organism was virulent (MRSA). The presence of preoperative joint incongruency or osteomyelitis of proximal femur was another risk factor.

Factors associated with survival and racing performance of 114 Thoroughbred foals with septic arthritis compared with maternal siblings (2009-2015)

BACKGROUND

There is little consensus on factors associated with survival in foals with septic arthritis and limited data on long-term racing performance of Thoroughbred foals treated for septic arthritis. A more thorough understanding of short- and long-term outcome is necessary to help inform owners, and subsequently guide treatment.

OBJECTIVES

To investigate factors associated with survival, and to analyse racing performance of foals with septic arthritis compared with their maternal siblings.

STUDY DESIGN

Retrospective cohort and a case-control study.

METHODS

Veterinary clinical records of Thoroughbred foals ≤180 days old that underwent arthroscopic, cannulae or through-and-through needle lavage for the treatment of septic arthritis between 2009 and 2015 were reviewed. Data included signalment, and clinicopathological information. The dam's foaling records were reviewed and the lifetime racing records were obtained for affected foals and two of their maternal siblings. Logistic regression analysis was used to determine factors associated with survival to discharge or racing. Comparisons between treated foals and their maternal siblings were made.

RESULTS

Ninety (78%) of 115 foals diagnosed with septic arthritis were discharged alive. Foals <26 days old at the time of admission were five times less likely (P = .003) and foals with concurrent multisystemic disease were six times less likely (P = .02) to be discharged alive. Sixty (67%) foals discharged alive started in ≥1 race, and there was no difference in the proportion of foals that started in a race or racing performance between foals treated for septic arthritis and their maternal siblings.

MAIN LIMITATIONS

Retrospective study design, limited number of foals with multiple joint involvement and failure to accurately record duration of clinical signs.

CONCLUSIONS

Foals treated for septic arthritis at the Scone Equine Hospital, New South Wales, Australia had a good prognosis for survival, and for this cohort, foals that survived to discharge had a similar ability to race as their maternal siblings.

Frequency of Multifocal Disease and Pyogenic Arthritis of the Hip in Infants with Osteoarticular Infection in Three Neonatal Intensive Care Units

OBJECTIVE

To describe the clinical features of osteoarticular infection in infants cared for in neonatal intensive care units (NICUs) and to assess the presence of multifocal infection.

STUDY DESIGN

Retrospective medical record review with structured data abstraction of infants with osteomyelitis or pyogenic arthritis or both in NICUs at 3 children's hospitals over a 29-year period.

RESULTS

Of the 45 cases identified, 87% occurred in prematurely born infants, with a median gestational age of 27.4 weeks (IQR, 26, 31 weeks). Median postnatal age at diagnosis of infection was 33 days (IQR, 20, 50 days). Osteomyelitis was present without joint involvement in 53% and with joint involvement in 44% of cases. Methicillin-susceptible Staphylococcus aureus (71%) was the predominant pathogen, despite prevalent methicillin-resistant S aureus in community-associated infections. More than 1 bone was infected in 34% of cases. The femur (in 50% of patients) was the most frequently involved bone and the hip (in 20% of patients) was the most frequently involved joint. Bacteremia persisted for 4 or more days in 54% of patients with a positive blood culture despite active antimicrobial therapy.

CONCLUSIONS

Among infants with osteoarticular infection in NICUs, multifocal disease is common and frequently is unsuspected. Search for additional sites of infection including the hip is warranted following the diagnosis of osteoarticular infection at a single site. Involvement of contiguous joints should be suspected in cases of osteomyelitis; conversely the presence of pyogenic arthritis usually indicates extant osteomyelitis in a contiguous bone.

Mycobacterium fortuitum and Mycobacterium abscessus infections in the foot and ankle in two immunocompetent patients

Nontuberculous mycobacteria (NTM) infections of the musculoskeletal system are commonly missed due to its rarity and the absence of systemic symptoms. A high clinical index of suspicion is required to recognize such infections as they may occur in immunocompetent hosts. We present two cases of foot and ankle NTM infections involving Mycobacterium fortuitum and Mycobacterium abscessus in two such patients. The first case involves an 83-year old lady who presented with a two-month history of multiple foot abscesses initially treated at a rural hospital. She underwent drainage and debridement of her foot, with eventual cultures growing Pseudomonas aeruginosa and Mycobacterium abscessus. She was initially treated with clarithromycin and doxycycline. At one year follow-up review, her wound healed completely. The second case involves a 55-year old man who presented with infection following midfoot fusion and anterolateral thigh flap for an open complex fracture dislocation of his right foot. Cultures eventually grew Mycobacterium fortuitum and he was treated with cefoxitin, clarithromycin and doxycycline. 10 months after his initial injury, the infection has cleared and his flap was clean. Through these 2 cases, we hope to highlight the unusual presentations of such infections and illustrate that with a high initial index of suspicion and appropriate treatment, these infections can be treated successfully.

A case of enteropathic arthritis complicated by superimposed bilateral septic arthritis of the hips

Polyarticular septic arthritis is an underappreciated clinical entity. Pre-existing joint diseases, such as osteoarthritis and rheumatoid arthritis have been shown to be risk factors for septic arthritis. However, there is a paucity of data in the literature regarding the risk of septic arthritis in those patients with enteropathic arthritis. Here, we describe the case of a 47-year-old female with a background history of ulcerative colitis who presented with difficulty mobilising and pain in the hips associated with lethargy, fever and a significant inflammatory response. After an investigative process, she was newly diagnosed with enteropathic arthritis, complicated at presentation, by bilateral septic arthritis of the hips, based on progressive radiological destruction and a joint aspirate that grew Staphylococcus aureus. After treatment with antibiotics and steroids, her pain and mobility significantly improved, and she was discharged with a plan for an elective hip replacement and to commence disease-modifying therapy with sulfasalazine. This case reminds us that we must have a high index of suspicion to diagnose septic arthritis in those who present feverish and unwell with joint pain, even in those who present with multiple joint involvement. Furthermore, it describes a rare occurrence of bilateral septic arthritis of the hips occurring in a patient with enteropathic arthritis, which unlike osteoarthritis and rheumatoid arthritis, is not well described in the literature as a risk factor for septic arthritis.

Endovascular Infection with Kingella kingae Complicated by Septic Arthritis in Immunocompromised Adult Patient

We report a case of Kingella kingae endovascular infection in an immunocompromised elderly patient in Israel who had culture-negative septic arthritis. This case highlights potential sources of metastatic infection other than infective endocarditis, and emphasizes the need for molecular diagnostic methods in detection of pathogens in culture-negative septic arthritis in immunocompromised patients.

The Expression of von Willebrand Factor-Binding Protein Determines Joint-Invading Capacity of Staphylococcus aureus, a Core Mechanism of Septic Arthritis

Septic arthritis, one of the most dangerous joint diseases, is predominantly caused by Staphylococcus aureus In contrast, coagulase-negative staphylococci are rarely found in septic arthritis. We hypothesize that coagulases released by S. aureus, including coagulase (Coa) and von Willebrand factor-binding protein (vWbp), play potent roles in the induction of septic arthritis. Four isogenic S. aureus strains differing in expression of coagulases (wild-type [WT] Newman, Δcoa, Δvwb, and Δcoa Δvwb) were used to induce septic arthritis in both wild-type and von Willebrand factor (vWF)-deficient mice. Septic arthritis severity was greatly reduced when wild-type mice were infected with the Δcoa Δvwb and Δvwb variants compared to WT or Δcoa strains, suggesting that vWbp rather than Coa is a major virulence factor in S. aureus septic arthritis. vWF-deficient mice were more susceptible to bone damage in septic arthritis, especially when the Δvwb strain was used. Importantly, no difference in arthritis severity between the Δvwb and WT strains was observed in vWF-deficient mice. Collectively, we conclude that vWbp production by S. aureus enhances staphylococcal septic arthritis.IMPORTANCE Septic arthritis remains one of the most dangerous joint diseases with a rapidly progressive disease character. Despite advances in the use of antibiotics, permanent reductions in joint function due to joint deformation and deleterious contractures occur in up to 50% of patients with septic arthritis. So far, it is still largely unknown how S. aureus initiates and establishes joint infection. Here, we demonstrate that von Willebrand factor-binding protein expressed by S. aureus facilitates the initiation of septic arthritis. Such effect might be mediated through its interaction with a host factor (von Willebrand factor). Our finding contributes significantly to the full understanding of septic arthritis etiology and will pave the way for new therapeutic modalities for this devastating disease.

Management of Native Joint Septic Arthritis, Serial Aspiration vs. Arthroscopic Washout During the COVID-19 Pandemic

Septic arthritis remains an orthopaedic emergency that requires prompt diagnosis and management. During the 2020 COVID-19 pandemic, British Orthopaedic Association (BOAST) guidelines dictated that medical treatment (closed-needle aspiration + antibiotic therapy) should be offered to patients as first-line management, and operative treatment (arthroscopic joint washout +/- synovectomy) be reserved for patients exhibiting signs of sepsis. Literature has previously shown that for native joint septic arthritis, operative treatment is not superior to medical treatment. During the COVID-19 'lock-down' period (March 2020 to June 2020), we prospectively followed the presentation, diagnosis, management and outcome of a total of six patients who presented with confirmed native joint septic arthritis. All six patients underwent initial medical management of their septic arthritis following their diagnostic aspiration, which involved serial closed-needle aspirations and antibiotic therapy as advised by our microbiology team. Four patients went on to have an arthroscopic washout at an average of eight days following admission (mean 2.5), prior to a consultant-led decision to proceed to arthroscopic washout. The decision for operative management was the patient's clinical deterioration based on physiological (fever, tachycardia) and biochemical (C-reactive protein (CRP), white blood cell (WBC)) parameters. All of the four patients that proceeded to operative treatment failed to provide culture yield at the time of arthroscopic washout. The mean time to discharge was 15.6 days, whilst the mean time to discharge following operative intervention was 12 days. One patient passed away during admission and one patient required a second arthroscopic washout. Medical management of septic arthritis may play a role in symptom control in the palliative setting or in patients where a general anaesthetic is undesirable. We found operative management to be therapeutic clinically, haemodynamically and biochemically as well as facilitative of a faster recovery and shorter inpatient stay.

Tricuspid Valve Endocarditis: A Disguise In Multifocal Septic Arthritis

Infective endocarditis (IE) is a rare cause of multifocal septic arthritis. We report a patient who presented with oligo-articular septic arthritis as a complication of tricuspid valve endocarditis, a rare condition. A 69-year-old female presented to the emergency department with complaints of fever, myalgia, right shoulder, and right knee pain. Initial investigation elaborated on elevated C-reactive protein, erythrocyte sedimentation rate (ESR), and white blood cell. Imaging studies, including X-ray, were unrevealing. Blood cultures came out positive for Methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia. Magnetic resonance imaging (MRI) of the right shoulder and right knee showed joint effusion with soft tissue swelling. Diagnostic arthroscopic washout of right shoulder and right knee showed neutrophilic pleocytosis, and the cultures were positive for MSSA. Despite adequate antibiotic coverage for MSSA bacteremia with oligo-articular/multifocal septic arthritis, the patient's fever did not resolve. Initial transthoracic echocardiography (TTE) was negative for any vegetation. Transesophageal echocardiography (TEE) showed vegetations on the tricuspid valve with tricuspid regurgitation and was diagnosed with acute bacterial IE. A multi-disciplinary approach was adopted. She underwent tricuspid valve repair with annuloplasty and was treated with nafcillin for six weeks. She successfully recovered from MSSA bacteremia, and follow-up TEE was negative for any vegetations.

Inflammatory Joint Disease Is a Risk Factor for Streptococcal Sepsis and Septic Arthritis in Mice

Septic arthritis is a medical emergency associated with high morbidity and mortality, yet hardly any novel advances exist for its clinical management. Despite septic arthritis being a global health burden, experimental data uncovering its etiopathogenesis remain scarce. In particular, any interplay between septic arthritis and preceding joint diseases are unknown as is the contribution of the synovial membrane to the onset of inflammation. Using C57BL/6 mice as a model to study sepsis, we discovered that Group A Streptococcus (GAS) – an important pathogen causing septic arthritis - was able to invade the articular microenvironment. Bacterial invasion resulted in the infiltration of immune cells and detrimental inflammation. In vitro infected fibroblast-like synoviocytes induced the expression of chemokines (Ccl2, Cxcl2), inflammatory cytokines (Tnf, Il6), and integrin ligands (ICAM-1, VCAM-1). Apart from orchestrating immune cell attraction and retention, synoviocytes also upregulated mediators impacting on bone remodeling (Rankl) and cartilage integrity (Mmp13). Using collagen-induced arthritis in DBA/1 × B10.Q F1 mice, we could show that an inflammatory joint disease exacerbated subsequent septic arthritis which was associated with an excessive release of cytokines and eicosanoids. Importantly, the severity of joint inflammation controlled the extent of bone erosions during septic arthritis. In order to ameliorate septic arthritis, our results suggest that targeting synoviocytes might be a promising approach when treating patients with inflammatory joint disease for sepsis.

Optimizing the Composition of Irrigation Fluid to Reduce the Potency of Staphylococcus aureus α-Toxin: Potential Role in the Treatment of Septic Arthritis

OBJECTIVE

Septic arthritis is commonly caused by Staphylococcus aureus and is a medical emergency requiring antibiotics and joint irrigation. The bacteria produce α-toxin causing rapid cartilage cell (chondrocyte) death. Saline (0.9%NaCl) lavage is normally used to remove bacteria and toxins, however, its composition might be suboptimal to suppress the lethal effects of α-toxin. We utilized rabbit erythrocyte hemolysis as a sensitive, biologically relevant assay of α-toxin levels to determine if changes to osmolarity, temperature, pH, and divalent cation (Mg²⁺, Ca²⁺) concentration were protective.

DESIGN

Erythrocytes were incubated in the various conditions and then exposed to α-toxin ("chronic" challenge) or incubated with α-toxin and then exposed to experimental conditions ("acute" challenge).

RESULTS

Raising osmolarity from 300 mOsm (0.9%NaCl) to 400, 600, or 900 mOsm (sucrose addition) when applied chronically, significantly reduced hemolysis linearly. As an acute challenge, osmotic protection was significant and similar over 400 to 900 mOsm. Reducing temperature chronically from 37°C to 25°C and 4°C significantly reduced hemolysis, however, when applied as an acute challenge although significant, was less marked. Divalent cations (Mg²⁺, Ca²⁺ at 5mM) reduced hemolysis. Varying pH (6.5, 7.2, 8.0) applied chronically marginally reduced hemolysis. The optimized saline (0.9% NaCl; 900 mOsm with sucrose, 5 mM MgCl₂ (37°C)) rapidly and significantly reduced hemolysis compared with saline and Hank's buffered saline solution applied either chronically or acutely.

CONCLUSIONS

These results on the effect of S. aureus α-toxin on erythrocytes showed that optimizing saline could markedly reduce the potency of S. aureus α-toxin. Such modifications to saline could be of benefit during joint irrigation for septic arthritis.

Case Report on Pediatric Septic Arthritis of the Hip

Septic arthritis is a condition from the presence of microbial agents in a joint space. A 9 year old boy presented with pain in right hip joint which was tender on palpation, associated with fever (38.3°C). Blood tests showed elevated levels of C reactive protein and erythrocyte sedimentation rate. No pathological findings were found in X-ray of the hip and ultrasound of right hip joint showed mild increase in joint space. Pus culture and sensitivity yielded plenty pus cells in pairs of chains and Methicillin sensitive Staphylococcus aureus was isolated. Treatment with antibiotics was started and right hip arthrotomy and debridement was done followed with skin traction. Follow up was done and the boy had regained his full range of motion with no sign of complications.

Iclaprim reduces the incidence and severity of Staphylococcus aureus-induced septic arthritis in a murine model

Staphylococcus aureus is the most common non-gonococcal aetiology of septic arthritis. The efficacy of iclaprim against S. aureus LS-1, a clinical strain identified from a patient with septic arthritis, was studied in MF1 mice to evaluate the activity of iclaprim, which is in clinical development, in preventing joint infections. Iclaprim (2.5–80 mg kg⁻¹) administered as a single dose via the tail vein reduced the incidence of S. aureus septic arthritis and mortality in an experimental murine model of septic arthritis.

Infectious arthritis and the temporomandibular joint. A review

OBJECTIVE

Microorganisms can cause acute infectious arthritis, chronic infectious arthritis, or reactive inflammatory arthritis. The aim of this study is to perform a narrative review of the pathophysiology, etiology, and diagnostic features of infectious arthritis and TMJ infectious arthritis.

METHODS

A search of the literature was performed using Medline, Scielo, Embase, and Google Scholar databases. The terms employed for the search were "Temporomandibular Joint Disorders" and "Infectious Arthritis"; or "Septic Arthritis"; or "Bacterial, Fungal, or Viral Arthritis." Over three hundred articles were screened for eligibility.

RESULTS

The selected articles were utilized to perform a narrative review of the general aspects of infectious arthritis and infectious arthritis affecting the TMJ.

CONCLUSION

Infectious arthritis is a rare, yet very morbid, form of arthritis. Understanding general aspects of joint infections and specific features of TMJ infectious arthritis is imperative for an adequate diagnosis.

Roseomonas species infections in humans: a systematic review

Roseomonas species have been recognized to cause infections in immunocompromised individuals. The purpose of this study was to systemically review all published cases of Roseomonas infections in humans and describe the epidemiology, microbiology, antimicrobial susceptibility, treatment and outcomes of these infections in humans. We performed a systematic review of PubMed (through 20th Octrober 2019) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of Roseomonas species infections. A total of 37 studies, containing data of 99 patients, were included in the analysis. The most common Roseomonas infections were those of the bloodstream in 74.7% (74 patients), musculoskeletal infections in 8.1% (8 patients), skin and soft tissue infections (SSTIs) and peritoneal dialysis-associated peritonitis in 6.1% (6 patients) each. Epidemiology of these infections differed, with bacteremias being more prevalent in patients with malignancy and central venous lines, musculoskeletal infections being more prevalent after orthopedic surgery, and SSTIs occurring without any reported underlying cause. Resistance to beta-lactams was very high with penicillin, piperacillin/tazobactam resistance and cephalosporin resistance at 96.6%, 90.7% and 77.8% respectively, while quinolone resistance was 9.1%. Quinolones, carbapenems and cephalosporins are the most common agents used for treatment, irrespectively of the infection site. Overall mortality was 3% (3 patients), with the mortality attributed to Roseomonas being at 1% (1 patient).

Standing Arthroscopic Treatment of Temporomandibular Joint Sepsis in a Horse

A 15-year-old Thoroughbred gelding was presented for investigation of fever, right temporomandibular region swelling, and progressive pain when opening the mouth. Right temporomandibular joint (TMJ) sepsis was diagnosed based on synovial fluid analysis, sonographic imaging, and standing robotic cone-beam computed tomography. Concurrent otitis media and temporohyoid osteoarthropathy (THO) were also noted. The horse was treated with arthroscopic debridement and lavage during standing sedation followed by local and systemic antimicrobial therapy. There were no complications associated with the surgical procedure and the gelding's clinical signs resolved. Arthroscopy of the TMJ can be accomplished in the standing horse and should be considered when arthroscopic exploration or debridement of this joint is indicated. This is also the first case report of concurrent otitis media, TMJ sepsis, and THO; due to their close anatomic relationship, it is possible that septic otitis media could lead to pathology in the TMJ and temporohyoid joint, as described in humans.

Pigmented Villonodular Synovitis Mimicking an Acute Septic Hip in an Eight-Year-Old Male

Pigmented villonodular synovitis (PVNS) is a less common but known cause of joint pain in the adult population. PVNS in pediatric patients is even more rare, with only case reports of occurrence in persons under the age of 18 years. Presentation is typically that of more insidious pain and limited range of motion, and is primarily seen in the knee joint. Diagnosis can be suspected with imaging, but ultimately surgical intervention is needed for tissue confirmation. We present a case of PVNS in a pediatric patient with acute symptoms concerning for a septic joint. The patient’s workup revealed a large effusion on hip ultrasound, with operative intervention pursued and further imaging deferred given the patient's symptom burden. A 4 × 1 × 1.5 cm intra-articular pigmented mass excised from the synovium in the operating room. The patient’s symptoms improved after the procedure, with pathology showing sheets of plump mononuclear cells in a collagenized stroma with hemosiderin deposits, confirming the diagnosis. This case highlights the importance of keeping non-infectious etiologies in the differential diagnosis of acute onset joint pain.

Post-procedural Bacillus cereus septic arthritis in a patient with systemic lupus erythematosus

INTRODUCTION

Bacillus species are often considered as contaminants when cultured from clinical samples. Bacillus cereus may be a pathogen in certain circumstances and is known to cause musculoskeletal infections. This report aims to educate clinicians and clinical microbiology laboratories on B. cereus musculoskeletal infections and to heighten awareness that Bacillus species should not always be dismissed as contaminants.

CASE PRESENTATION

We report the case of a patient who presented to a tertiary hospital in Pretoria, South Africa, in November 2018 with B. cereus septic arthritis and underlying systemic lupus erythematosus (SLE). The isolate would otherwise have been dismissed as a contaminant had it not been for the crucial interaction between the laboratory and the treating clinicians. To our knowledge, this is the first case report of septic arthritis caused by B. cereus in an SLE patient where the organism was cultured from the joint specimen. Identification of the organism was performed using matrix-assisted laser desorption/ionisation mass spectrometry.

MANAGEMENT AND OUTCOME

Definitive treatment was with intravenous vancomycin, continued for four weeks, in addition to arthroscopy and management of the underlying SLE. The patient had a good clinical outcome and regained full mobility.

CONCLUSION

Musculoskeletal infections, specifically septic arthritis caused by B. cereus, are exceedingly rare infections. Immune suppression, trauma, prosthetic implants and invasive procedures are important risk factors for B. cereus musculoskeletal infections. Close collaboration with a multi-disciplinary team approach will effect the best outcome for complicated patients with B. cereus infections.

Diagnostic Accuracy of Synovial Lactate, Polymerase Chain Reaction, or Clinical Examination for Suspected Adult Septic Arthritis

BACKGROUND

Adult septic arthritis can be challenging to differentiate from other causes of acute joint pain. The diagnostic accuracy of synovial lactate and polymerase chain reaction (PCR) remains uncertain.

OBJECTIVE

Our aim was to quantify the diagnostic accuracy of synovial lactate, PCR, and clinical evaluation for adults with possible septic arthritis in the emergency department (ED).

METHODS

We report a prospective sampling of ED patients aged ≥ 18 years with knee symptoms concerning for septic arthritis. Clinicians and research assistants independently performed history and physical examination. Serum and synovial laboratory testing was ordered at the discretion of the clinician. We analyzed frozen synovial fluid specimens for l- and d-lactate and PCR. The criterion standard for septic arthritis was bacterial growth on synovial culture and treated by consultants with operative drainage, prolonged antibiotics, or both. Diagnostic accuracy measures included sensitivity, specificity, likelihood ratios, interval likelihood ratios, and receiver operating characteristic area under the curve.

RESULTS

Seventy-one patients were included with septic arthritis prevalence of 7%. No finding on history or physical examination accurately ruled in or ruled out septic arthritis. Synovial l- and d-lactate and PCR were inaccurate for the diagnosis of septic arthritis. Synovial white blood cell count and synovial Gram stain most accurately rule in and rule out septic arthritis.

CONCLUSIONS

Septic arthritis prevalence in ED adults is lower than reported previously. History and physical examination, synovial lactate, and PCR are inadequate for the diagnosis of septic arthritis. Synovial white blood cell count and Gram stain are the most accurate tests available for septic arthritis.

Septic Arthritis: An Evidence-Based Review of Diagnosis and Image-Guided Aspiration

OBJECTIVE. The purpose of this evidence-based review is to equip radiologists to discuss and interpret findings obtained with various imaging modalities, guide patient selection for percutaneous aspiration, and safely perform arthrocentesis to assess for infection in both native and prosthetic joints. CONCLUSION. Septic arthritis is an emergency that can lead to rapidly progressive, irreversible joint damage. Despite the urgency associated with this diagnosis, there remains a lack of consensus regarding many aspects of the management of native and periprosthetic joint infections.

Update on Acute Bone and Joint Infections in Paediatrics: A Narrative Review on the Most Recent Evidence-Based Recommendations and Appropriate Antinfective Therapy

Acute bone and joint infections (BJIs) in children may clinically occur as osteomyelitis (OM) or septic arthritis (SA). In clinical practice, one-third of cases present a combination of both conditions. BJIs are usually caused by the haematogenous dissemination of septic emboli carried to the terminal blood vessels of bone and joints from distant infectious processes during transient bacteraemia. Early diagnosis is the cornerstone for the successful management of BJI, but it is still a challenge for paediatricians, particularly due to its nonspecific clinical presentation and to the poor specificity of the laboratory and imaging first-line tests that are available in emergency departments. Moreover, microbiological diagnosis is often difficult to achieve with common blood cultures, and further investigations require invasive procedures. The aim of this narrative review is to provide the most recent evidence-based recommendations on appropriate antinfective therapy in BJI in children. We conducted a review of recent literature by examining the MEDLINE (Medical Literature Analysis and Retrieval System Online) database using the search engines PubMed and Google Scholar. The keywords used were “osteomyelitis”, OR “bone infection”, OR “septic arthritis”, AND “p(a)ediatric” OR “children”. When BJI diagnosis is clinically suspected or radiologically confirmed, empiric antibiotic therapy should be started as soon as possible. The choice of empiric antimicrobial therapy is based on the most likely causative pathogens according to patient age, immunisation status, underlying disease, and other clinical and epidemiological considerations, including the local prevalence of virulent pathogens, antibiotic bioavailability and bone penetration. Empiric antibiotic treatment consists of a short intravenous cycle based on anti-staphylococcal penicillin or a cephalosporin in children aged over 3 months with the addition of gentamicin in infants aged under 3 months. An oral regimen may be an option depending on the bioavailability of antibiotic chosen and clinical and laboratory data. Strict clinical and laboratory follow-up should be scheduled for the following 3–5 weeks. Further studies on the optimal therapeutic approach are needed in order to understand the best first-line regimen, the utility of biomarkers for the definition of therapy duration and treatment of complications.

Point-of-care hip ultrasound leads to expedited results in emergency department patients with suspected septic arthritis

BACKGROUND

The evaluation of septic hip arthritis often incorporates the utilization of hip ultrasonography to determine the presence of a hip joint effusion, as well as to guide arthrocentesis. Point-of-care (POC) hip ultrasound has previously been demonstrated to be accurate when performed by the emergency physician. Time to diagnosis and subsequent intervention in septic arthritis (SA) is critical to favorable outcomes.

METHODS

Retrospective single-center study of all emergency department (ED) patients who had a POC or radiology hip ultrasound or arthrocentesis as part of their ED evaluation for SA in a 3-year period. We investigated the difference in time to obtain hip ultrasonography results and the time to arthrocentesis between radiology and emergency physician-performed studies in cases of suspected septic hip arthritis.

RESULTS

Seventy-four patients met inclusion criteria. The median time to hip ultrasound completion was 68 (interquartile range [IQR], 38.8-132) minutes in the emergency physician-performed ultrasound group versus 208.5 (IQR, 163.8-301.3) minutes for the radiology group (P < 0.001). A total of 17 patients had a hip arthrocentesis performed. Time to arthrocentesis was 211 (IQR 141.3-321.5) minutes in the emergency physician-performed arthrocentesis group and 602 (IQR 500-692) minutes in the radiology arthrocentesis (P < 0.001).

CONCLUSION

There was a statistically shorter time to ultrasound result and arthrocentesis when POC hip ultrasound was utilized by the emergency physician. Given that unfavorable outcomes in SA are associated with delay in treatment, further study is warranted to determine if emergency physician-performed hip ultrasound and arthrocentesis could lead to improved patient-centered clinical end points.

Septic arthritis of the acromioclavicular joint: a case series and review of the literature

OBJECTIVE

To report a case series of three patients with septic arthritis of the acromioclavicular joint and a review of the literature for this condition. Additionally, we developed an algorithm for diagnosing and treating septic arthritis of the acromioclavicular joint.

METHODS

A retrospective review of patients treated at our institution for septic arthritis of the acromioclavicular joint during the collection period was performed and three cases were identified. A review of the English literature on this rare condition was also performed with only 28 cases being identified.

RESULTS

A series of three consecutive patients were treated for septic acromioclavicular arthritis with resolution of the infection. Two patients underwent open surgical debridement and one underwent aspiration. All patients were treated with a minimum of six weeks of tailored intravenous antibiotic therapy.

CONCLUSION

Septic arthritis of the acromioclavicular joint can be difficult to diagnose and requires a high index of suspicion. Surgical debridement, open or arthroscopic, with tailored antibiotic therapy is an effective means for the management of septic arthritis of the acromioclavicular joint. In patients who are unable to have surgical debridement, aspiration and tailored antibiotics have been shown to be effective.

Differential Accumulation and Activation of Monocyte and Dendritic Cell Subsets in Inflamed Synovial Fluid Discriminates Between Juvenile Idiopathic Arthritis and Septic Arthritis

Despite their distinct etiology, several lines of evidence suggest that innate immunity plays a pivotal role in both juvenile idiopathic arthritis (JIA) and septic arthritis (SA) pathophysiology. Indeed, monocytes and dendritic cells (DC) are involved in the first line of defense against pathogens and play a critical role in initiating and orchestrating the immune response. The aim of this study was to compare the number and phenotype of monocytes and DCs in peripheral blood (PB) and synovial fluid (SF) from patients with JIA and SA to identify specific cell subsets and activation markers associated with pathophysiological mechanisms and that could be used as biomarkers to discriminate both diseases. The proportion of intermediate and non-classical monocytes in the SF and PB, respectively, were significantly higher in JIA than in SA patients. In contrast the proportion of classical monocytes and their absolute numbers were higher in the SF from SA compared with JIA patients. Higher expression of CD64 on non-classical monocyte was observed in PB from SA compared with JIA patients. In SF, higher expression of CD64 on classical and intermediate monocyte as well as higher CD163 expression on intermediate monocytes was observed in SA compared with JIA patients. Moreover, whereas the number of conventional (cDC), plasmacytoid (pDC) and inflammatory (infDC) DCs was comparable between groups in PB, the number of CD141⁺ cDCs and CD123⁺ pDCs in the SF was significantly higher in JIA than in SA patients. CD14⁺ infDCs represented the major DC subset in the SF of both groups with potent activation assessed by high expression of HLA-DR and CD86 and significant up-regulation of HLA-DR expression in SA compared with JIA patients. Finally, higher activation of SF DC subsets was monitored in SA compared with JIA with significant up-regulation of CD86 and PDL2 expression on several DC subsets. Our results show the differential accumulation and activation of innate immune cells between septic and inflammatory arthritis. They strongly indicate that the relative high numbers of CD141⁺ cDC and CD123⁺ pDCs in SF are specific for JIA while the over-activation of DC and monocyte subsets is specific for SA.

Case Studies and Literature Review of Pneumococcal Septic Arthritis in Adults

We saw an increase in this condition related to emergence of Streptococcus pneumoniae serotype 23B.

We conducted a retrospective study on all cases of pneumococcal septic arthritis (SA) in patients >18 years of age reported to the Picardie Regional Pneumococcal Network in France during 2005–2016. Among 1,062 cases of invasive pneumococcal disease, we observed 16 (1.5%) SA cases. Although SA is uncommon in adult patients, the prevalence of pneumococcal SA in the Picardie region increased from 0.69% during 2005–2010 to 2.47% during 2011–2016 after introduction of the pneumococcal 13-valent conjugate vaccine. We highlight the emergence of SA cases caused by the 23B serotype, which is not covered in the vaccine.

Use of in vitro assays to identify antibiotics that are cytotoxic to normal equine chondrocytes and synovial cells

BACKGROUND

Intra-articular (IA) antibiotic usage is prevalent in equine practice. However, recent emergence of antimicrobial resistance prompts re-evaluation of antibiotic selection, particularly when used prophylactically. Furthermore, many commonly used antibiotics exert direct cytotoxicity to equine cells, and appropriate IA doses have not been defined.

OBJECTIVES

To screen antibiotics in vitro as an initial assessment of cytotoxicity against normal equine joint cells in monolayer culture and explant tissues.

STUDY DESIGN

In vitro experimental study.

METHODS

Chondrocytes and synovial cells were harvested from three horses and plated on 24-well plates (100 000 cells/wells in triplicate) for 48 hours prior to addition of antibiotics. Joint cells were exposed to antibiotics (n = 15) at various doses (25-0.39 mg/mL in complete DMEM media) for 24 hours and viability was assessed by trypan blue dye exclusion. The half maximal inhibitory concentration (IC50) was determined for each antibiotic. Cartilage explants were obtained from 3 horses, minced and exposed to antibiotics (n = 5) for 72 hours. Live/dead staining was performed, and fluorescence was visualised using Olympus IX83 spinning disk confocal microscope. Percentage of live vs dead cells was quantified.

RESULTS

Antibiotics from different antimicrobial classes expressed dose-dependent but variable cytotoxicity to equine joint cells in vitro. Aminoglycosides and doxycycline had the lowest IC50 (most toxic). Ampicillin sulbactam, imipenem, tobramycin, ceftiofur sodium and amoxicillin had IC50 > 25 mg/mL for at least one cell line, representing potentially less cytotoxic alternatives.

MAIN LIMITATIONS

Further studies are necessary to extrapolate these in vitro data results to the in vivo joint environment.

CONCLUSIONS

Targeted IA antibiotic therapy would involve selection of the safest antibiotics (highest IC50) with efficacy based on bacterial culture/sensitivity. Antimicrobial selection and evidence-based dosing may minimise damage to native articular cartilage and synovial cells and development of antimicrobial resistance when IA antibiotics are used in equine practice.

Are Patients With a History of Septic Arthritis Undergoing Total Knee Arthroplasty at Higher Risk for Revision Surgery? A Single-Center Study

BACKGROUND

The decision to perform a total knee arthroplasty (TKA) on a previously infected knee is made complicated by the higher risk for both a periprosthetic joint infection (PJI) and early failure. There is currently no standard in the treatment strategy for this group of patients. We here report the outcomes of performing a primary TKA on patients with a prior septic knee arthritis. The aim of our study is to analyze the survival rates of patients with a history of septic arthritis undergoing TKA.

METHODS

From 2010 to 2018, all patients treated in our institution with a minimum follow-up of 1 year, who have previous histories of knee joint infections and underwent a primary TKA were included in the study. All patients underwent the same surgical protocol and were given systemic and local antibiotic treatment.

RESULTS

Of the 68 knees, there were 4 surgical revisions (5.9%). These included 2 septic revisions due to PJI (2.9%), 1 open arthrolysis for arthrofibrosis (1.5%), and 1 aseptic revision for implant loosening (1.5%). Sixty-four (64) knees (94%) had survived without any surgical interventions and the Kaplan-Meier analysis demonstrated an overall survivorship free from PJI of 97.1% at a mean of 5 years (range 1-9, standard deviation ±2.5 years).

CONCLUSION

TKA is a suitable option for patients with a prior septic arthritis of the knee, provided that proper surgical technique and the utilization of systemic and local antibiotics are employed.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Graft-Preserving Arthroscopic Debridement With Hardware Removal Is Effective for Septic Arthritis After Anterior Cruciate Ligament Reconstruction: A Clinical, Arthrometric, and Magnetic Resonance Imaging Evaluation

BACKGROUND

Arthroscopic debridement with graft preservation has been advocated as the treatment of choice for septic arthritis after anterior cruciate ligament (ACL) reconstruction, but no previous studies have investigated if hardware removal, while retaining the graft in situ, improves the success rate. Moreover, it is unclear whether the premature removal of fixation devices may affect graft integration and knee stability.

PURPOSE/HYPOTHESIS

The purpose was to assess the clinical and functional outcomes of patients with septic arthritis after ACL reconstruction who underwent arthroscopic debridement, while retaining the graft in situ but removing fixation devices, and to determine if premature hardware removal affects graft integrity and function. The hypothesis was that arthroscopic debridement with hardware removal would be effective in eradicating infections while not compromising graft integration and function.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

From a cohort of 2384 cases of arthroscopic ACL reconstruction, 24 patients with postoperative septic arthritis were included for the analysis; 18 patients were available for a clinical evaluation using the International Knee Documentation Committee (IKDC) form, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lysholm score, and Tegner score at a minimum 12-month follow-up. Knee laxity was assessed clinically with standardized manual laxity tests and instrumentally using an arthrometer and a triaxial accelerometer. Additionally, 3-T magnetic resonance imaging (MRI) at final follow-up was performed, focusing on the graft signal, the cartilage status, and the occurrence of arthrofibrosis.

RESULTS

Eradication of the infection was achieved in all cases, and only 1 graft removal was performed because of insufficient tension. Among the remaining 23 patients, a single arthroscopic debridement procedure with hardware removal while preserving the graft was effective in 21 cases (91%) at a mean of 30 ± 37 days from ACL reconstruction to debridement. At last follow-up, 2 patients required a further ACL revision procedure. The mean IKDC, WOMAC, Lysholm, and Tegner scores of the patients available for the clinical evaluation were 75 ± 19, 90 ± 8, 79 ± 21, and 6 ± 2, respectively. No abnormal laxity was reported on manual testing, and arthrometric and accelerometer tests also demonstrated good knee stability (mean KT-1000 arthrometer side-to-side difference was 1.6 ± 1.2 mm at manual maximum force). On MRI, a good graft signal was found in 50% of cases, while concomitant signs of arthrofibrosis were detected in 81% of patients. Severe cartilage defects (International Cartilage Repair Society grade ≥3) were reported in 63% of cases.

CONCLUSION

Arthroscopic debridement with hardware removal was effective in the eradication of infections after ACL reconstruction with extra-articular fixation while preserving graft integrity without compromising knee stability. Patients and surgeons should be aware of complications that might affect the outcome, particularly arthrofibrosis and chondrolysis.

The Epidemiology and Outcomes of Septic Arthritis in the Maltese Islands: A Hospital-Based Retrospective Cohort Study

Objective/Aim:

Septic arthritis is an uncommon but important disease with significant morbidity and mortality, especially if inadequately managed. The aim of this epidemiological study was to identify the characteristics and outcomes of patients treated for septic arthritis at Mater Dei Hospital, Malta, over a 10-year period.

Methods:

This was a retrospective observational study. Patients diagnosed with septic arthritis between 2008 and 2018 were recruited. Cases were identified by reviewing all inhospital episodes of patients diagnosed with septic arthritis according to Newman criteria.

Results:

There were 124 cases of native joint septic arthritis and 138 of prosthetic joint infection. Cases were present amongst all age groups, with the highest incidence amongst those aged 61–70 years for both native and prosthetic infections. Fever was present in around 40% of cases. Raised white cell count was prevalent in 66.9% of native joint infections and 52.9% of prosthetic joints. Elevated C-reactive protein was overwhelmingly seen in most cases, present in 93.5% (median=159.5 mg/L; IQR=85.8–291) of native joints and 92.0% of prosthetic joint infections (median=68.7 mg/L; IQR=20.5–186). Over 55% of patients had one or more risk factors for joint sepsis, diabetes mellitus being the most prevalent clinical comorbidity (22.6% and 24.6% for native and prosthetic joint infections respectively). Synovial cultures were positive in 66% and 82% of native and prosthetic joint aspirates respectively. Staphylococcus aureus was the most commonly isolated organism from both native and prosthetic joint infection, followed by streptococcal infections in native joints and coagulase negative staphylococci and gram-negative infections in prosthetic joints. Fifteen deaths were directly attributed to joint sepsis.

Conclusion:

Absence of fever and elevated white cell count does not exclude the diagnosis. The mortality rate due to septic arthritis in this cohort of patients was found to be 5.7%. All deaths occurred in elderly patients with clinical comorbidities suggesting that this group is at highest risk.

Hybrid Use of Negative Pressure Therapy in the Management of Partial Wound Closure After Girdlestone Procedure

In a patient with septic arthritis and pressure ulcers requiring bilateral Girdlestone pseudoarthroplasty, hybrid open and closed incisional negative pressure therapy (ciNPT) is used to manage a closed surgical incision confluent with a large, open wound. Hybrid open and ciNPT facilitates both the healing of the primary closure as well as preparation of the wound bed for skin grafting. ciNPT can be used in partially closed wounds in combination with traditional NPT of the open portion of the wound to allow for more successful closure in wounds under tension.

Infections of Deep Hand and Wrist Compartments

The human hand is the most exposed part of the body to highest risk for injuries, loss of the skin integrity, and to the inoculation of bacteria, most commonly Staphylococcus aureus, Streptococcus β-haemolytic, and gram-negative. In case of an infection, the mobile anatomical structures and the synovial membranes in close proximity to each other may spread the pus towards deep spaces and compartments. Mild early infections without an abscess formation may respond to antibiotics, but at more advanced stage, erythema, swelling, stiffness, and severe pain may ensue. Abscess formation will cause debilitating pain, fever, systemic symptoms, and even sepsis. Necrotizing infections may threaten not only the limb, but also patient’s life. Therefore, an initially “trivial” hand injury should never be neglected, as it might turn into a deep space infection, which must be treated immediately with drainage, wound debridement, and i.v. antibiotics. Delay in diagnosis and inadequate initial management might rapidly lead to abscess formation, destruction of the gliding surfaces and the normal anatomy, and irreparable functional deterioration.

Cutibacterium (Propionibacterium) acnes Infection of the Native Wrist Joint

Cutibacterium (Propionibacterium) acnes (C. acnes, previously known as P. acnes) is an anaerobic organism that commonly colonizes the human skin. After Staphylococcus spp. and Streptococcus spp., it is a common organism associated with deep prosthetic shoulder joint infections. We describe the case of rapidly progressive arthropathy of the native wrist secondary to infection with C. acnes. Diagnosis was made on prolonged enrichment cultures. The patient went on to complete a long-term course of oral sulfamethoxazole-trimethoprim with clinical improvement. To the best of our knowledge, this is the first report in the literature that C. acnes has been the main causative organism implicated in infection of the native wrist joint. It is imperative to request and wait for results of prolonged enrichment cultures to aid microbiological diagnosis in such cases.

Functional Outcome for Arthroscopic Treatment of Septic Arthritis of the Wrist

Background  Septic arthritis is a potentially joint-destructing condition if not treated properly. Septic wrist accounts for ∼5% of all septic arthritis. Arthroscopic lavage is a well-documented treatment for septic arthritis of the knee, hip, or shoulder only. Previous studies on septic wrist were limited to case reports or retrospective studies focusing on open treatment, and functional outcome was seldom documented. Our study aims to evaluate the effectiveness of arthroscopic treatment and to investigate the functional outcome. Materials and Methods  Patients were retrospectively reviewed over a period of 10 years. Parameters including age, gender, history of prior injury, duration of symptoms, joint aspirates and intraoperative tissue culture, radiological and arthroscopic findings, antibiotics used, number of operations, and hospital stay were reviewed. Functional outcomes were evaluated with QuickDASH (disabilities of the arm, shoulder, and hand) score. Results  From 2007 to 2016, 14 patients (15 septic wrists) underwent arthroscopic surgery. One patient had bilateral involvement. The average age was 63.9 years and the average duration of symptoms was 6.08 days. Average follow-up time was 10 months. All except two patients (85.7%) responded to single arthroscopic treatment. Two required subsequent operations for concomitant tenosynovitis. There were no major complications. The most common isolated organism was Staphylococcus aureus . Only one case had severe joint erosion during follow-up. The average QuickDASH score was 19.7. Duration of symptoms 5 days or more before admission was associated with higher QuickDASH score ( p  = 0.04). Conclusion  Early arthroscopic treatment should be considered for all patients admitted for septic arthritis of the wrist if not contraindicated. Level of Evidence  This is a Level III, retrospective review.

Multicentric Septic Osteomyelitis and Arthritis Caused by Staphylococcus aureus in a Gyrfalcon (Falco rusticolus)

An adult female gyrfalcon (Falco rusticolus) was presented with a right-wing droop and weight loss. Radiographic images revealed osteolysis and osseous proliferation of the right shoulder and the mobile vertebra between the notarium and synsacrum. The tentative diagnosis was vertebral osteomyelitis secondary to septic arthritis. The bird did not respond to antibiotic and anti-inflammatory therapy and represented 10 days later, with feathers soiled with feces, an impacted, dilated cloaca, and an inability to stand due to spastic paralysis of the hind legs. The bird's condition did not improve with 24 hours of supportive care and its quality of life was considered poor; therefore, the patient was euthanatized and submitted for postmortem examination. Multicentric septic osteomyelitis and arthritis were confirmed in the mobile vertebra between the notarium and synsacrum and the right shoulder. Despite 10 days of antibiotic therapy, Staphylococcus aureus was isolated from within the 2 locations in which septic osteomyelitis and arthritis were identified. This report describes the clinical features, diagnosis, and pathologic findings of septic osteomyelitis and arthritis caused by S aureus in a falcon.

Sonography of musculoskeletal infection in children

Musculoskeletal infection, especially in young children, often presents with non-specific clinical signs and symptoms necessitating early imaging to identify the source of infection. While MRI is the investigation of choice to demonstrate bone infection, it is expensive and often requires a general anaesthetic in the young child. Ultrasound can be a useful tool in the initial assessment due to its easy availability and portable equipment. It does not involve ionising radiation and is used to guide aspiration and drainage procedures. This review explains sonographic features of septic arthritis, osteomyelitis, pyomyositis and soft tissue infection in children and highlights advantages and limitations of sonography when assessing the child with suspected musculoskeletal infection.

Synovial Cell Count Poorly Predicts Septic Arthritis in the Presence of Crystalline Arthropathy

Introduction: A synovial cell count greater than 50,000/mm³ is the threshold most commonly used to diagnose septic arthritis. This lab value may be nonspecific in the setting of crystalline arthropathy. The purpose of this study was to evaluate the accuracy of diagnosing septic arthritis using a synovial cell count cut-off of 50,000/mm³ in the setting of crystalline arthropathy.

Methods: This was a retrospective review of joint aspirations performed between July 1^st, 2013 and June 30^th, 2016. Synovial fluid samples were evaluated for cell count, crystals, Gram stain, and culture. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the synovial markers were calculated.

Results: During the study period, 738 joint aspirations were sent for testing, of which 358 aspirations in 348 patients met inclusion criteria. There were 49 (13.7%) cases of culture-positive septic arthritis, and 47 patients underwent surgical irrigation and debridement. Gout and pseudogout crystals were present in 163 aspirates (45.5%). Three joints (0.8% overall rate) had concomitant crystalline arthropathy and septic arthritis, each of which had a synovial WBC ≥85,000/mm³. Increasing the WBC count cutoff to 85,000/mm³ demonstrated a specificity of 100%, but a PPV of 12.0%.

Conclusions: A cut-off of 85,000/mm³ may be more appropriate to diagnose concomitant septic arthritis and crystalline arthropathy. We recommend medical management and observation in patients with crystal-positive joint aspirations unless the synovial cell count is elevated above 85,000/mm³. Prospective studies using this treatment guideline are needed to evaluate its validity and accuracy.

The difference between native septic arthritis and prosthetic joint infections: A review of literature

Current literature occasionally considers septic arthritis in native joints and prosthetic joint infections as equal pathologies. However, significant differences can be identified. The aim of this review of literature is to describe these differences in definitions, pathology, diagnostic workups, treatment strategies, and prognosis.

Predictors of Septic Wrist: A Dual-Center 10-Year Review of Risk Factors

Introduction Expeditious and accurate diagnosis of septic wrist arthritis is essential to prevent further cartilage damage, systemic infection, osteomyelitis, and loss of limb. There is limited literature on the incidence and clinical factors that are predictive of septic wrist arthritis. Objective We aimed to investigate the incidence of septic wrist arthritis and identify risk factors and laboratory values associated with septic wrist arthritis. Materials and Methods Data were collected on adult patients presenting with a painful, swollen wrist to two level 1 urban hospitals from 2004 to 2014. Demographics, comorbidities, and laboratory values of patients who had wrist aspiration were collected. Results There was an overall incidence of 0.4%. Increased synovial white blood cells (WBC), being febrile, positive blood cultures, and smoking were significantly associated with septic wrist arthritis on univariate analysis. Synovial WBC was also found to be significant on multivariate analysis. A synovial WBC of 87,750 cells/µL had an optimal sensitivity and specificity of 73% and 86%, respectively, for diagnosing septic wrist arthritis. Conclusion Synovial WBC can be a useful diagnostic tool for septic wrist arthritis. In addition, positive blood cultures, being febrile, and smoking history can help predict septic wrist arthritis in patients with presenting with painful, swollen wrists.

Burkholderia pseudomallei septic arthritis in Type-2 diabetes mellitus patients: Report of two cases

Two cases of Burkholderia pseudomallei septic arthritis are presented with a brief review of the literature. B. pseudomallei septic arthritis most commonly occurs in diabetics and other immunocompromised patients and may prove fatal despite appropriate therapy. Clinical and microbiological suspicion of B. pseudomallei infection may help in providing appropriate empirical therapy.

Transmissible arthritis in a man from Guinea

We report the case of a 32-year-old man with septic arthritis and Neisseria gonorrhoeae tenosynovitis, diagnosed after joint fluid culture treated with ceftriaxone. It is one of the most frequent causes of purulent septic arthritis in young people in undeveloped countries. Early diagnosis is important to avoid complications.

Septic Arthritis of the Pediatric Wrist: A Case Report and Review of the Literature

Septic arthritis of the wrist in pediatric patients is a rare diagnosis and is not well described in the literature. We present a case of a 4-month old patient with monoarticular septic arthritis of the wrist treated with surgical drainage and antibiotics. Although a rare diagnosis, septic arthritis of the wrist should be considered in patients with pseudoparalysis of the upper extremity and systemic signs of inflammation. Prompt diagnosis and treatment is critical to prevent permanent damage to the joint. Further data is needed to describe the epidemiology, microbiology, diagnostic findings and treatment of septic arthritis of the pediatric wrist.

Calprotectin discriminates septic arthritis from pseudogout and rheumatoid arthritis

OBJECTIVE

We aimed to determine whether calprotectin and α-defensins could discriminate septic from other inflammatory arthritides.

METHODS

Synovial fluids with a predominance of neutrophils from patients with septic arthritis, pseudogout and RA were prospectively collected. Neutrophil-related proteins calprotectin and human neutrophil α-defensins levels were assessed in synovial fluids. Demographic parameters and biomarkers with P-value ⩽0.05 for differentiating septic from non-septic arthritis were included in a multivariable model. Multivariable logistic regression with stepwise selection was performed to build the final combined model.

RESULTS

A total of 74 patients were included: septic arthritis (n = 26), pseudogout (n = 28) and RA (n = 20). Patients with septic arthritis were more likely to be male and young, and to display higher synovial neutrophil count. Calprotectin was significantly increased in patients with septic arthritis. The multivariable model included calprotectin, synovial fluid neutrophil count and gender. Calprotectin was the only biomarker that discriminated septic arthritis from non-septic inflammatory arthritides, with 76% sensitivity, 94% specificity and a positive likelihood ratio = 12.2 at the threshold for calprotectin of 150 mg/l.

CONCLUSION

Synovial fluid calprotectin is a relevant biomarker to discriminate septic arthritis from other inflammatory arthritides. This biomarker should be tested in an independent cohort.

Driveline Sepsis Presenting As Gout

In patients with a history of gout, there could be a delay in diagnosis of a septic joint, which increases morbidity and mortality. The literature reports rare instances of coexistent gout and septic arthritis. We present a 64-year-old male with non-ischemic cardiomyopathy, supported by a HeartWare ventricular assist device, who developed a methicillin-resistant Staphylococcus aureus (MRSA) driveline infection four months after device implant. He achieved suppression with minocycline 100 mg by mouth twice a day for five months before presenting to the emergency room with symptoms of gout. Joint aspirate was consistent with a diagnosis of MRSA as well as gout. The patient presented with typical symptoms of a percutaneous driveline infection: soreness at the exit site, erythema, and thick, purulent drainage. Wound culture of the driveline confirmed MRSA and guided antibiotic treatment. His presentation was unusual in that sepsis was identified only after he presented with septic arthritis, which led to the collection of blood cultures. He had no fever, chills, nausea, vomiting, or hypotension. This case illustrates that unresolving gout symptoms after one treatment, in a patient with a known driveline infection, should be further evaluated for possible sepsis and septic arthritis. The patient’s unusual presentation of sepsis caused difficulties in diagnosis and management. To our knowledge, this is the first reported case of a driveline infection seeding a joint and causing septic arthritis.

Surgical Options and Approaches for Septic Arthritis of the Native Hip and Knee Joint

Septic arthritis (SA) of the adult knee and hip is a constantly evolving and urgent surgical issue. The epidemiology has shifted over the last few decades as have the most popular antibiotics and surgical treatments. SA of all types is increasing in the United States. There remains a high variability in the conservative and surgical management options available. This review will outline the most current understanding of the etiology and epidemiology of SA and will also discuss the distribution of causative organisms and appropriate treatments for each. A summary of evidence for different debridement and reconstructive techniques will also be presented in addition to novel areas of research to decrease the morbidity of this constantly growing problem.

Septic Arthritis and the Opioid Epidemic: 1465 Cases of Culture-Positive Native Joint Septic Arthritis From 1990-2018

BACKGROUND

The clinical spectrum of septic arthritis in the era of the opioid crisis is ill-defined.

METHODS

This is a retrospective chart review of 1465 cases of culture-positive native joint septic arthritis at Boston teaching hospitals between 1990 and 2018.

RESULTS

Between 1990-2008 and 2009-2018, the proportion of septic arthritis cases involving people who inject drugs (PWID) rose from 10.3% to 20% (P < .0000005). Overall, methicillin-sensitive Staphylococcus aureus (MSSA) caused 41.5% of cases, and methicillin-resistant Staphylococcus aureus (MRSA) caused 17.9%. Gram-negative rods caused only 6.2% of cases. Predictors of MRSA septic arthritis included injection drug use (P < .001), bacteremia (P < .001), health care exposure (P < .001), and advancing age (P = .01). Infections with MSSA were more common in PWID (56.3% vs 38.8%; P < .00001), as were infections with MRSA (24% vs 16.8%; P = .01) and Serratia sp. (4% vs 0.4%; P = .002). Septic arthritis in the setting of injection drug use was significantly more likely to involve the sacroiliac, acromioclavicular, and facet joints; 36.8% of patients had initial synovial fluid cell counts of <50 000 cells/mm³.

CONCLUSIONS

Injection drug use has become the most common risk factor for septic arthritis in our patient population. Septic arthritis in PWID is more often caused by MRSA, MSSA, and Serratia sp., and is more prone to involve the sacroiliac, acromioclavicular, sternoclavicular, and facet joints. Synovial fluid cell counts of <50000 cells/mm³ are common in culture-positive septic arthritis.

Sternoclavicular joint septic arthritis presenting as cervical abscess and subcutaneous emphysema: A case report

Sternoclavicular joint septic arthritis results from hematogenous spread of a bacterial infection, usually in the immunocompromised. It commonly presents as a chest wall abscess. Cervical abscess resulting from sternoclavicular joint septic arthritis is a rare complication with only one reported case in the English literature. We describe a case of sternoclavicular joint septic arthritis in an elderly diabetic adult with cervical abscess as initial presentation.