Concomitant septic and gouty arthritis--an analysis of 30 cases

Identifying septic arthritis superimposed on crystalline arthropathy: Is synovial cell count the answer?

Background

Septic arthritis (SA) is an orthopedic urgency with significant morbidity and potential mortality. Differentiating SA and crystalline arthritis (CA) is difficult as concurrent disease may exist. This study sought to identify the prevalence of and define diagnostic laboratory markers for SA in the setting of CA.

Methods

A retrospective review was conducted of adult patients presenting to a single medical center between January 2012 and March 2023 with monosodium urate (MU) or calcium pyrophosphate (CPP) in synovial knee joint fluid of a native knee. Categorical variables were assessed using chi-square and Fisher exact tests. Receiver operating characteristic curves were computed, and diagnostic accuracy was determined from associated area under the ROC curve (AUC). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated and optimal diagnostic thresholds determined by Youden index.

Results

225 knee aspirations were analyzed, 56.4 % CPP and 43.6 % MSU. There were 12 cases of superimposed SA (5.3 %), 11 culture confirmed and 1 suspected. Immunosuppression was associated with a higher incidence of SA (41.7 % versus 14.6 %, p = 0.0271). SA had a significantly higher mean synovial WBC (135,796 vs 22,510; p = 0.0007). There was no difference in percentage of PMNs between the septic and aseptic groups (90.6 % vs 69.7 %; p = 3.327). Of the 12 cases of concomitant SA, 10 (83.3 %) had a synovial WBC ≥50,000/mm3, compared to 21 (9.9 %) of the aseptic aspirations (p < 0.0001). Nine (75 %) aspirations in the septic group had ≥90 % PMNs, compared to 78 (36.6 %) in the aseptic group (p = 0.0123). The optimal diagnostic threshold for synovial WBC was 50,000/mm3 (91.7 % sensitivity, 90.1 % specificity, AUC = 0.960). The optimal synovial percentage of PMNs was 64 % (100 % sensitivity, 6.7 % specificity, AUC = 0.731).

Conclusion

In the setting of CA, synovial WBC may provide a useful diagnostic marker for SA with an optimal threshold of 50,000 cells/mm3.

Ten years of experience with elbow native joint arthritis: a multicenter retrospective cohort study

Background: Elbow native joint septic arthritis (NJSA) is a rare condition, constituting 6 %-9 % of all native septic arthritis cases. It is associated with elevated mortality and morbidity. This study aims to clarify the characteristics, management, and outcomes of elbow NJSA. Methods: We retrospectively analyzed adults diagnosed with elbow NJSA who underwent surgical intervention at Mayo Clinic facilities from January 2012 to December 2021. Diagnosis relied on clinical presentation, synovial fluid white blood cell (WBC) count, and aspiration or operative cultures. Results: Among 557 patients with NJSA during the study time frame, 19 (3.4 %) were found to have elbow NJSA. The median age of these patients was 64 years. Joint aspirations were conducted in 16 cases (84.2 %). The median synovial fluid WBC count was 43 139 cells mm-3. Crystals were observed in three patients (15.8 %). Synovial fluid and operative tissue samples revealed 12.5 % and 20 % positive Gram stains, mostly indicating Gram-positive cocci clusters. Open arthrotomy (72.2 %) was the predominant surgical approach, and three patients (16.7 %) required reoperation within 90 d. The median antimicrobial therapy duration was 30 d (interquartile range: 22-44 d). Non-tuberculosis mycobacterium (NTM) was detected in two patients, with a treatment duration of 274 and 374 d, respectively. Complications included joint contracture and joint resection. Conclusions: Elbow NJSA is an infrequent condition associated with significant complications, such as the necessity for reoperation. Although the synovial fluid WBC count, crystals, and Gram stain positivity were less helpful for diagnosis in this study, positive Gram stain and culture results from operative tissue specimens demonstrated greater effectiveness in diagnosing elbow NJSA.

Abdominal Abscess as a Rare Manifestation of Gout

Gout is a common inflammatory arthritis in adults. Elevated levels of uric acid lead to the formation of monosodium urate crystals and their deposition in joints, and rarely, other parts of the body. The tissues most frequently involved are synovium, bone, cartilage, skin, tendon, ligament, and kidney. Here, we report an unusual presentation of gout manifesting as an abdominal abscess. A 60-year-old man with a history of opioid abuse, hypertension, and knee gouty arthritis presented to the emergency department with severe right knee pain. During hospitalization, he complained of pain in the left lower abdominal quadrant and developed coffee-ground emesis. Computed tomography showed pneumoperitoneum. The patient underwent laparotomy and was found to have gastric perforation and a large abdominal abscess. Drainage of the abscess revealed necrotic and hemorrhagic fragments of omentum. Microscopic examination showed adipose tissue with fat necrosis, acute inflammation, and fungal hyphae. Eosinophilic, amorphous deposits of polarizable needle-shaped crystals were observed in all sections, indicating the presence of monosodium urate crystals. The combined characteristics suggested intra-abdominal gout with concurrent fungal infection resulting from gastric perforation. This presentation is very rare. Only one occurrence of intra-abdominal gout mimicking a pelvic abscess has been reported in the literature.

Increased Incidence and Clinical Features of Septic Arthritis in Patients Aged 80 Years and above: A Comparative Analysis with Younger Cohorts

BACKGROUND

This study aimed to determine the incidence of septic arthritis across adult age groups in Västra Götaland Region (VGR) of Sweden, while also comparing disease characteristics among different age groups with hematogenous septic arthritis.

METHODS

Using ICD-10 codes for septic arthritis from 2016 to 2019, we identified 955 patients in VGR. We reviewed the medical records of 216 adult patients with hematogenous septic arthritis and compared data across age groups.

RESULTS

The overall incidence of septic arthritis in adults was 4 per 100,000 persons annually, rising to 14 per 100,000 in those ≥80 years. The median age of the 216 patients was 71. The comparison across age groups (18-64, 65-79, and ≥80) showed significantly longer hospital stays and higher mortality rate in the older groups. CRP levels were higher in the middle age group, SF-WBC counts were lower in the youngest age group, and synovial fluid crystals were more common in the oldest. No differences were found in joint involvement or the organisms isolated.

CONCLUSION

The incidence of septic arthritis is 6.5 times higher in patients aged ≥ 80 compared to those under 65, highlighting the need to consider age-related differences in disease management.

Pathophysiology and Evolving Treatment Options of Septic Arthritis: A Narrative Review

Pyogenic (septic) arthritis is a severe joint infection characterized by the invasion of microorganisms into the synovium, causing inflammation and joint destruction. This review article provides a comprehensive overview of pyogenic arthritis, focusing on etiology, pathogenesis, clinical manifestations, diagnosis, and management strategies. This review explores routes of microbial entry into joints, emphasizing the importance of prompt identification and treatment to prevent irreversible joint damage. Clinical manifestations, such as joint pain, swelling, and limited range of motion, are discussed, along with the challenges in differentiating pyogenic arthritis from other joint disorders. Diagnostic approaches, including joint aspiration and imaging modalities, are critically examined for accuracy in confirming diagnosis. This review also addresses the significance of early intervention through antimicrobial therapy and joint drainage, highlighting the role of multidisciplinary collaboration in optimizing patient outcomes. In summary, the present investigation underscores the complexities of pyogenic arthritis and the need for a comprehensive understanding of pathophysiology for timely and effective management to improve patient prognosis and quality of life.

Evaluation of predictive factors of septic wrist to avoid overdiagnosis

BACKGROUND

The existing diagnostic criteria for septic wrist are nonspecific, exposing patients with noninfectious etiologies to surgical morbidity. This study aimed to identify predictors differentiating septic wrist from other etiologies.

METHODS

An institutional review board-approved retrospective review was conducted on patients with a presumed diagnosis of septic wrist (2003-2022). Bivariate and multiple regression analyses were performed to identify correlation between confirmed septic wrist and comorbidities (autoimmune diseases, immunosuppression, crystalline arthropathy, intravenous [IV] drug use, smoking), penetrating trauma, fever, multi-joint involvement, inflammatory markers (erythrocyte sedimentation rate [ESR]/C-reactive protein [CRP]/white blood cells [WBC]), serum uric acid level, blood cultures, imaging findings, and synovial fluid analysis. Categorical data were reported as median [interquartile range].

RESULTS

Hundred and sixty-eight (58 females and 110 males) patients were included. The median length of hospitalization and follow-up were 6[7] days and 1[3] months. Eighty-nine (53%) patients had septic wrist confirmed with Gram stain/culture, 48 (29%) patients received alternative diagnoses, and 31 (18%) patients had undetermined diagnoses. Concomitant septic wrist and crystalline arthropathy were identified in 9 patients (6.6% of total patients). Out of the 48 patients who received alternative diagnoses, 12 (25%) underwent open drainage. Elevated synovial WBC count (95,409.4 ± 85,926.2) showed a trend of association with septic wrist (p = 0.08). Negative synovial crystals (p = 0.01), positive blood culture (p = 0.04), negative history of crystalline arthropathy (p = 0.08), and multi-joint involvement (p = 0.05) were identified as predictors of septic wrist with a combined sensitivity of 87.5%, specificity of 86.2%, and area under the curve 0.93.

CONCLUSIONS

Current diagnostic criteria for septic wrist have low specificity. Negative history of crystalline arthropathy, multi-joint involvement, absence of synovial crystals, and positive blood culture are helpful indicators for predicting septic wrist in patients presenting with a painful, erythematous, and swollen wrist.

Orthopedic Articular and Periarticular Joint Infections

Acute nontraumatic joint pain has an extensive differential. Emergency physicians must be adept at identifying limb and potentially life-threatening infection. Chief among these is septic arthritis. In addition to knowing how these joint infections typically present, clinicians need to be aware of host and pathogen factors that can lead to more insidious presentations and how these factors impact the interpretation of diagnostic tests.

Diagnosis, Treatment, and Outcomes of Crystalline Arthropathy in the Setting of Total Knee Arthroplasty: A Critical Analysis Review

» Emerging evidence suggests the prevalence of crystalline arthropathy (CA) in the setting of total knee arthroplasty (TKA) is increasing, and diagnosis of CA is often intricate because of symptom overlap with other common postoperative complications such as periprosthetic joint infection (PJI). Consequently, an accurate and timely diagnosis becomes pivotal in guiding the choice of treatment.» CA includes gout and calcium pyrophosphate deposition (CPPD) disease, and accurate diagnosis in patients with prior TKA requires a multifaceted approach. The diagnosis algorithm plays a critical role in determining the appropriate treatment approach.» Management of CA typically involves a conservative strategy, encompassing the administration of nonsteroidal anti-inflammatory drugs, colchicine, and steroids, regardless of whether patients have undergone prior TKA.» There is conflicting evidence on the effect CA has on the surgical outcomes in postoperative TKA patients. While these patients may expect excellent functional outcomes and pain relief, they may be at a higher risk of complications such as infections, medical complications, and revision procedures.» Additional research is required to fully comprehend the impact of CA on postoperative TKA outcomes and to establish effective strategies for enhancing patient care and optimizing long-term joint function.

Rare Case of Gout Leading to Septic Arthritis, Osteomyelitis, and Septic Shock in an Elderly Patient

Gout is a common, chronic inflammatory arthritis that oftentimes accompanies an initial acute and painful attack characterized by intense pain and swelling. Although it may present in different sites such as the ankles, wrists, knees, elbows, and fingers, the lower extremities are the most common site of involvement. The pathophysiology of gout is complex, but typically, the deposition of monosodium urate crystals within the joint space and the subsequent acute inflammatory response play an important role. Following an acute attack, chronic gout can present with tophi or nests of monosodium urate crystals surrounded by macrophages and multinucleated giant cells that trigger granulomatous inflammation. Progressively, chronic gout can lead to several other complications including joint destruction, gout nephropathy, spinal compression, and secondary infections. In this case report, we present an elderly female patient with chronic gout and multiple tophi formations in all digits of both of her hands. The tophi led to an ulceration and secondary septic arthritis and osteomyelitis of the right second digit. By the time the patient presented and was admitted to the hospital, she was in septic shock. We will review the pathogenesis of gout and other cases of concomitant septic arthritis and gout, as well as medical management and necessary surgical intervention as a means of treatment.

Gouty tenosynovitis with compartment syndrome in the hand: A case report

BACKGROUND

Gout is a common type of inflammatory arthritis caused by the deposition of monosodium urate crystals in the joints and surrounding tissues. It typically appears with abrupt and intense pain, redness, and swelling in the affected joint. It frequently targets the lower extremities, such as the big toe. However, rarely, gout can manifest in atypical locations, including the hands, leading to an uncommon presentation known as gouty tenosynovitis. However, it can result in significant morbidity owing to the potential for severe complications, such as myonecrosis and compartment syndrome.

CASE SUMMARY

An 82-year-old male patient with a history of hypertension, cerebral infarction, Parkinson's disease, and recurrent gout attacks sought medical attention because of progressive pain and swelling in the right hand. Imaging findings revealed forearm swelling, raising concerns of possible tenosynovitis, bursitis, septic arthritis, and compartment syndrome. A fasciotomy was performed to decompress the patient's hands and forearms. The procedure revealed diffuse tenosynovitis, tophi with a pus-like discharge surrounding the carpal tunnel, and involvement of the flexor and extensor tendon sheaths. However, microbiological investigations, including Gram staining, acid-fast bacilli, tuberculosis, and non-tuberculous mycobacteria, yielded negative results. The patient was ultimately diagnosed with a severe gouty attack with compartment syndrome and myonecrosis. Septic arthritis and infectious flexor tenosynovitis were ruled out. Serial debridement and inflammation control were initiated, followed by staged closure with a skin graft.

CONCLUSION

Septic-like complications can occur in the absence of infection in severe gout attacks with pus-like discharges due to compartment syndrome and myonecrosis. Cultures can be used to differentiate between gouty attacks, septic arthritis, and infectious tenosynovitis. Involvement of the flexor and extensor muscles, as in this case, is rare. This study contributes to the literature by reporting a rare case of successful fasciotomy and serial debridement in an elderly patient with multiple comorbidities.

Arthroscopic Treatment of the Septic Ankle

Ankle joint sepsis is a relatively rare but potentially devastating pathologic process of the lower extremity that requires expeditious identification and management. Establishing the diagnosis of ankle joint sepsis is often challenging as it may present with concomitant pathologies and often lacks consistency in regard to classic clinical characteristics. Once a diagnosis has been established, prompt management is imperative to minimize the potential for long-term sequelae. The purpose of this chapter is to address the diagnosis and management of the septic ankle with a focus on arthroscopic treatment.

Does concomitant gout in septic arthritis affect surgical outcomes?

BACKGROUND

We aim to review and describe the proportion of patients with co-existing gout amongst patients with surgical treated septic arthritis, characterize their clinical presentation, outcomes and complications compared to patients with native joint septic arthritis.

METHODS

Sixty-one patients with surgically treated primary joint septic arthritis were identified from the period of January 2011 to December 2016. There were 13 (21.3%) patients with co-existing septic arthritis and crystal proven gout. Pertinent details such as demographics, comorbidities, clinical features on presentation, infection markers, number of surgeries, length of stay (LOS) in general and individual LOS in supportive care units, limb amputations, readmissions and mortality were reviewed. Multiple linear and logistic regression models were used to control for confounders during analysis.

RESULTS

The average age of patients was 60.8 years (range: 23-87 years). The patients with gout are associated with comorbidities such as being hypertensive, hyperlipidemia and renal impaired. They tend to present with ankle joint involvement (46.2% vs 8.3%; p = 0.004) while septic arthritis patients without gout tend to present with knee joint involvement (75% vs 46.2%; p = 0.046). In terms of complications, up to two thirds of them require supportive care in the High Dependency Unit and/or Intensive Care Unit during treatment (61.5% vs 29.2%; p = 0.031) and having gout with septic arthritis independently predicted a significant increase in LOS by an additional 12.6 days on average (95% CI: 2.11 - 23.03; p = 0.019). They are also more likely to end up with limb amputation (23.1% vs 0%; p = 0.008) on univariate analysis.

CONCLUSION

Gout accompanying septic arthritis in the same joint is potentially associated with major systemic and joint related sequela, complications in terms of prolonged hospital stay, need for complex care and risk for limb amputation. Our findings further indicate the value and need for well-designed prospective controlled cohort studies to explore the relationship between gout and septic arthritis.

Acute gout attacks during the perioperative period and risk factors of recurrence after orthopedic surgery among untreated gout patients

BACKGROUND

This study aimed to explore the clinical characteristics of perioperative acute gout attacks in patients with varying uric acid levels undergoing orthopedic surgery, identify the risk factors for gout recurrence within the first postoperative year, and provide a disease prevention and diagnostic reference.

METHODS

This hospital-based retrospective study was conducted between January 2018 and December 2020. According to the blood uric acid levels at admission, the patients were grouped into either the normal uric acid level group or the hyperuricemia group. Patient comorbidities, serum uric acid levels, inflammatory indicators, follow-up recurrence rates, and other indicators were compared.

RESULT

The uric acid decline ratio and the inflammatory indexes (white blood cell count and C-reactive protein level) at the time of the attack were significantly higher in the normal uric acid level group than in the hyperuricemia group (P < 0.05). Patients in the hyperuricemia group with diabetes and tophi and those administered diuretics were more prone to acute gout attacks than those in the normal uric acid level group (P < 0.05). In the normal uric acid level group, 22 patients (84.6%) exhibited single joint involvement, whereas only 18 patients (47.4%) in the hyperuricemia group demonstrated single joint involvement (P < 0.05). After 1 year of follow-up, the gout recurrence rate in the hyperuricemia group was 44.7%, which was significantly higher that the recurrence rate in the normoglycemic group (11.5%; P < 0.05). Presenting tophi in perioperative orthopedic surgery patients was found to be an independent risk factor for gout recurrence within 1 year (RR = 4.80; P = 0.029).

CONCLUSION

The recurrence rate of gout in patients with hyperuricemia during perioperative period increased 1 year after operation. Therefore, it is crucial to monitor the uric acid level to prevent acute gout attacks during the perioperative period and recurrence during the 1-year follow-up period. Moreover, the risk of an acute gout recurrence 1 year after operation increased in patients who presented tophi; therefore, it is necessary to maintain appropriate blood uric acid level during perioperative period among patients undergoing orthopedic surgery.

Orthopaedic Management of Gout

Gout is characterized by the deposition of monosodium urate crystals in patients with chronically elevated blood levels of uric acid. It is the most common form of inflammatory arthritis in the United States and is often comorbid with hypertension, obesity, and chronic kidney disease. Initial presentation is usually an acutely warm, swollen joint, most commonly the first metatarsophalangeal joint, but a variety of locations may be affected. The main treatment for gout is medical management of acute inflammation and chronic uric acid levels, but surgical treatment may be indicated in cases of damage to the surrounding soft tissue, concomitant septic arthritis, symptomatic cartilage loss, or neurologic deficits. Based on the literature to date, gout does not seem to independently affect outcomes after total hip, knee, and ankle arthroplasty, but associated comorbidities affecting outcomes in these patients should be considered.

Brucellosis unusually presented as septic knee arthritis: A case report

Brucellosis is one of the world's most prevalent zoonotic illnesses. The most often afflicted joints are the sacroiliac joints, although spondylitis and peripheral arthritis are becoming increasingly prevalent. We described a case of a 40-year-old male patient with Brucellosis presented as septic knee arthritis.

Comparison of MR Findings between Patients with Septic Arthritis and Acute Gouty Arthritis of the Knee

Purpose

To compare the MR findings of septic and acute gouty arthritis of the knee joint.

Materials and Methods

This retrospective study included patients who underwent knee MRI for septic or gouty arthritis at our hospital between October 2012 and October 2018. The MR findings were analyzed for the presence of bone marrow edema, soft tissue edema, abscess, pattern of synovial thickening (frondlike, lamellated, diffuse linear), maximum thickness of the synovium, and joint effusion volume. The gouty (n = 5) and septic arthritis (n = 10) groups were compared using the Wilcoxon rank-sum test and Fisher's exact test.

Results

No statistically significant differences were observed for each item. One patient in the gouty arthritis group and seven in the septic arthritis group had bone marrow edema. Soft tissue abscess formation was only observed in the septic group. The incidence of each synovial thickening pattern was as follows: 100% (diffuse linear) in the gouty arthritis group and 20% (frondlike), 50% (lamellated), and 30% (diffuse linear) in the septic arthritis group.

Conclusion

Differentiation of gouty arthritis and septic arthritis based on imaging findings is difficult. However, lamellated synovial thickening patterns, bone marrow edema, and soft tissue abscess formation are more commonly observed in patients with septic arthritis than in those with gouty arthritis.

Sepsis complicated with secondary hemophagocytic syndrome induced by giant gouty tophi rupture: A case report

BACKGROUND

Gouty tophi are a chronic granulomatous caused by a deposition of monosodium urate crystal deposition in the body. Once broken, it may easily induce severe infection. Sepsis complicated with secondary hemophagocytic syndrome induced by gouty tophi rupture is extremely rare in the clinical setting, and no such serious complications have been reported in literature.

CASE SUMMARY

This is a 52-year-old Chinese male patient with a 20-year history of gouty arthritis. At admission, the gout stone in the patient’s right ankle was broken and it secreted a white mucoid substance. During the course of treatment, the patient suffered from systemic inflammatory response syndrome multiple times. His condition gradually deteriorated, further complicated by hemophagocytic syndrome. After thorough removal of gout lesions and active anti-infection treatment and control of blood uric acid level, combined with multidisciplinary cooperation, the patient was finally cured.

CONCLUSION

Sepsis complicated with secondary hemophagocytic syndrome induced by gouty tophi rupture is extremely rare in the clinical setting. Timely and accurate diagnosis is very important to save patients' lives.

Gonococcal arthritis: case series of 58 hospital cases

OBJECTIVES

Extra-genital manifestations of gonococcal infection are rare (0.5-3%). Among them, gonococcal arthritis (GA) is the most frequent, accounting for 30-90% of disseminated infections. Our study aimed to describe all hospital cases of GA in Reunion Island, a French overseas territory.

METHODS

We conducted a retrospective, multicentric, observational study of all cases of certain, probable or possible GA from 2008 to 2020.

RESULTS

We identified 58 cases of GA, mostly certain cases (n = 48). Sex ratio was balanced, but men were older than women (51 vs 27 years, p < 0.001). A total of 41% had travelled abroad during the previous 3 months, mostly in Madagascar or South-East Asia. The most frequently infected joint was the knee, followed by ankle, wrist and fingers or carpal joints. Only 16% of cases had genital symptoms, but 50% had another extra-genital manifestation, mainly skin lesions (40%). Positivity rate of joint puncture was 91%, with a purulent liquid. Only 58% had a positive culture, and 33% had only a positive PCR. There was no 3GC-resistant strain. In comparison with gonococcal infection without arthritis, patients were older and had fewer genital but more extra-genital symptoms. On discharge 60% had persistent articular symptoms. GA represented 18% of all hospitalised septic arthritis cases with microbial identification in 2019.

CONCLUSIONS

GA is rare but it is important to make an early diagnosis and treat promptly, as joint destruction may be important, leading to persistent symptoms after discharge. PCR use in joint puncture is useful in cases with negative culture.

Septic Arthritis With Superimposed Acute Gouty Arthritis in a Rheumatoid Arthritis Patient

Septic arthritis is a rare but serious complication of both rheumatoid and gouty arthritis and can lead to significant morbidity and even mortality. Here, we report a case of septic arthritis with bacteremia, monosodium urate crystals, and hyperuricemia in a 75-year-old male with long-standing rheumatoid arthritis. Arthrocentesis revealed gram-positive cocci representing group B streptococcus (Streptococcus agalactiae) infection and monosodium urate crystals. A diagnosis of septic arthritis with superimposed acute gouty arthritis was made and the patient was treated accordingly. Management included surgical irrigation and debridement, antibiotic therapy, and systemic glucocorticoids which resulted in a significant improvement in the patient’s clinical status.

The Use of Ultrasound to Differentiate Between Gout and Infection in the Wrist

Background:

Gout is a common condition and its prevalence is increasing. In the wrist, acute gouty arthritis is difficult to distinguish from infection and may occur concomitantly. Though aspiration is helpful, it is not always technically feasible or definitive. Imaging may assist in the differential diagnosis.

Case Presentation:

Two cases are described in which the use of ultrasound evaluation assisted in the diagnosis and ultimate treatment.

Conclusion:

Ultrasound can be a helpful adjunct in the diagnosis of arthritis of the wrist, helping to tailor treatment in complex cases.

Comparison of Rates of Lower Extremity Amputation in Patients With and Without Gout in the US Department of Veterans Affairs Health System

Importance

Cardiometabolic and other risk factors could render patients with gout more likely to undergo lower extremity amputation (LEA).

Objective

To examine the rate of and factors associated with LEA in patients with gout.

Design, Setting, and Participants

In this matched cohort study using national administrative data, multivariable Cox proportional hazards regression models were used to examine the associations of gout with LEA. In analyses limited to patients with gout, attributes of serum urate control and treatment with urate-lowering therapy were examined as factors associated with LEA. This study included patients who used US Department of Veterans Affairs services from January 1, 2000, to July 31, 2015. Patients with gout were identified using diagnostic codes and matched with up to 10 controls by age, sex, and year of benefit enrollment. Data analysis was performed from January 26, 2021, to September 3, 2021.

Exposures

Gout classification served as the primary independent variable of interest. In analyses limited to patients with gout, factors associated with serum urate control and urate-lowering therapy were examined.

Main Outcomes and Measures

Overall LEA, as well as toe, transmetatarsal, below-the-knee, and above-the-knee amputation.

Results

This cohort study included 5 924 918 patients, 556 521 with gout (mean [SD] age, 67 [12] years; 550 963 (99.0%) male; 88 853 [16.0%] Black non-Hispanic; 16 981 [4.3%] Hispanic/Latinx; 345 818 [62.1%] White non-Hispanic; 80 929 [14.5%] with race and ethnicity data missing; and 23 940 [4.3%] classified as other) and 5 368 397 without gout (mean [SD] age, 67 [12] years; 5 314 344 [99.0%] male; 558 464 [10.4%] Black non-Hispanic; 204 291 [3.0%] Hispanic/Latinx; 3 188 504 [59.4%] White non-Hispanic; 1 257 739 [23.4%)] with race and ethnicity data missing; and 159 399 [3.0%] classified as other). Compared with patients without gout, patients with gout were more likely to undergo amputation, an increased rate that remained after adjustment (adjusted hazard ratio, 1.20; 95% CI, 1.16-1.24) and was highest for below-the-knee amputation (adjusted hazard ratio, 1.59; 95% CI, 1.39-1.81). In those with gout, poor serum urate control (mean >7 mg/dL during the preceding year) was associated with a 25% to 37% increase in the rate of amputation. In contrast, treatment with urate-lowering therapy was not associated with the LEA rate.

Conclusions and Relevance

In this matched cohort study, patients with gout were more likely to undergo LEA. This increase was independent of other comorbidities that have been associated with amputation, including diabetes and peripheral vascular disease. Serum urate control was independently associated with the LEA rate, suggesting the possibility that lower extremity amputation may be preventable in some patients.

A narrative review of the last decade's literature on the diagnostic accuracy of septic arthritis of the native joint

While septic arthritis can be a straightforward diagnosis, there are many cases when the diagnosis is difficult to make. The aim of this study was to review the last decade’s literature on the diagnosis of septic arthritis of the native joint in adults and summarize that data in an easy to follow algorithm to clarify how the last decade’s data may be applied to the diagnosis of septic arthritis. A search of PubMed and CINAHL databases was performed to identify studies that compared results diagnostic tests for septic arthritis. We cross referenced this search with searches of additional databases (including Cochrane Library and Scopus) to confirm similar search results. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool was used by two independent reviewers to determine study quality and risk of bias. After applying inclusion and exclusion criteria to the initial search, 15 papers total were included for analysis. All 15 papers were of high quality methodology as determined by the QUADAS tool. There were 26 different diagnostics tests used across the 15 papers included for review. Three of those diagnostic tests had specificity and sensitivity greater than 80%. Eight tests had a positive likelihood ratio of ≥10. Three tests had a negative likelihood ratio < 0.1, indicating that they may help to rule out septic arthritis. A flowchart was created to summarize the findings of our review, so that physicians may reference this visual in making the appropriate diagnosis when the commonly held standards of cell count, gram stain, and culture aren’t enough to make the diagnosis.

Gout in primary total knee arthroplasty: Prevalent but not independently associated with complications

BACKGROUND

Gout is a common synovial pathology, but its prevalence in patients undergoing total knee arthroplasty (TKA) and potential association with complications such as periprosthetic infection (PJI) and revision are unknown.

METHODS

Medicare data from 2009 to 2013 was retrospectively reviewed using PearlDiver. All patients 65 years of age or older and undergoing primary TKA with at least 3 years of pre-TKA records were included. The prevalence of gout was based on ICD-9 codes. Univariable associations of gout with PJI and revision at 1 year were assessed using odds ratios with 95% confidence intrervals (C.I.). To control for potential confounding, patients with a history of gout were matched on age, gender, smoking history, and Elixhauser Comorbidity Index (ECI) to patients without gout and associations reassessed.

RESULTS

The prevalence of gout in Medicare patients undergoing primary TKA was 5.7%. On univariable analysis, patients with a history of gout were more likely to develop PJI (O.R., 1.58; 95% C.I., 1.45-1.72) and undergo revision (O.R., 1.33; 95% C.I., 1.25-1.41) at 1 year. After matching for confounders, a history of gout was no longer associated with developing PJI (O.R., 0.98; 95% C.I., 0.90-1.06) or undergoing revision (O.R., 0.94; 95% C.I., 0.89-1.00) at 1 year.

CONCLUSIONS

Gout is a relatively common pathology in patients undergoing TKA. While gout is associated with increased complications, this appears to be driven by confounding through its association with other medical comorbidities. Gout does not appear to be an independent risk factor for complications following TKA.

External validation of Gout-calculator performance on a cohort of acute arthritis (SYNOLACTATE) sparing distal joints such as hallux and midfoot. A cross-sectional study of 170 patients

OBJECTIVE

To evaluate the performance of the Gout-calculator in a cohort of consecutive acute arthritis affecting large and intermediate joints (without an attack on hallux or midfoot joints).

METHODS

A retrospective study. Gout-calculator data were collected in medical records of patients included in the prospective consecutive cohort of acute arthritis called SYNOLACTATE. The diagnosis of gout was defined by the presence of sodium urate crystals in synovial fluid. The diagnostic performance of the Gout-calculator was studied by performing an ROC curve with the calculation of its AUC (95% CI) as well as the calculation of Sensitivity (Se), Specificity (Sp), and positive likelihood ratio (LR+).

RESULTS

170 patients with acute arthritis were included. Variables associated with the diagnosis of gout were as follows: serum uric acid > 350 μmol/L (OR 5.52 (2.52-12.1), p < 0.001), joint redness (OR 5.08 (1.85-14.0), p = 0.001), previous patient-reported arthritis attack (OR 4.04 (1.92-8.49), p < 0.001), male (OR 3.00 (1.17-7.69), p = 0.02), hypertension or cardiovascular disease (OR 2.33 (1.07-5.06), p = 0.03). The median (IQR) of Gout-calculator was significantly higher in gouty arthritis (7.0 [5.5-8.1]) than in associated-CPP acute arthritis (4.0 [2.0-5.8]), septic arthritis (3.0 [2.0-5.1]), or others arthritis (3.5 [2.0-5.5]). The AUC was 0.833 (0.768-0.897) with for the threshold ≥ 8, a Se at 27.5% (0.161-0.428), Sp 97.7% (0.934-0.992), and LR+ 11.9 (3.5-40).

CONCLUSION

Despite diagnostic performances close to those published, the use of the Gout-calculator is not sufficient for the diagnosis of gout or to exclude the differential diagnosis of septic arthritis in the SYNOLACTATE cohort.

KEY POINTS

• For a Gout-calculator threshold of ≤ 4, Sensitivity is 92.5%, Specificity 50.8% and LR- 0.15 to the gout diagnosis. • For a Gout-calculator threshold of > = 8, Sensitivity is 27.5%, Specificity 97.7% and LR+ 11.9 to the gout diagnosis. • In a population of acute arthritis affecting large joints, Gout-calculator is not sufficient to discriminate between gouty arthritis and septic arthritis.

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.

Pilot study of a novel serum mRNA gene panel for diagnosis of acute septic arthritis

BACKGROUND

Septic arthritis is an orthopedic emergency requiring immediate surgical intervention. Current diagnostic standard of care is an invasive joint aspiration. Aspirations provide information about the inflammatory cells in the sample within a few hours, but there is often ambiguity about whether the source is infectious (e.g. bacterial) or non-infectious (e.g. gout). Cultures can take days to result, so decisions about surgery are often made with incomplete data. Novel diagnostics are thus needed. The “Sepsis MetaScore” (SMS) is an 11-mRNA host immune blood signature that can distinguish between infectious and non-infectious acute inflammation. It has been validated in multiple cohorts across heterogeneous clinical settings.

AIM

To study whether the SMS holds diagnostic validity in determining the etiology of acute arthritis.

METHODS

We conducted a blinded, prospective, non-interventional clinical study of the SMS. All patients undergoing work-up for a septic primary joint were enrolled. Patients proceeded through the normal standard-of-care pathway, including joint aspiration and inflammatory labs [white blood cell (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)]. Venous blood was also drawn into PAX gene RNA-stabilizing tubes and mRNAs were measured using Nano String nCounter™. SMS was calculated blinded to clinical results.

RESULTS

A total of 20 samples were included, of which 11 were infected based on aspiration or intra-operative cultures. The SMS had an area under the ROC curve (AUROC) of 0.87 for separating infectious from non-infectious conditions. For comparison, the AUROCs for ESR = 0.58, CRP = 0.6, and WBC = 0.59. At 100% sensitivity for infection, the specificity of the SMS was 40%, meaning nearly half of non-septic patients could have been ruled out for further intervention.

CONCLUSION

In this pilot study, SMS showed a high level of diagnostic accuracy in predicting septic joints compared to other diagnostic biomarkers. This quick blood test could be an important tool for early, accurate identification of acute septic joints and need for emergent surgery, improving clinical care and healthcare spending.

Evaluation and Management of Septic Arthritis and its Mimics in the Emergency Department

Septic arthritis is a dangerous medical condition associated with significant morbidity and mortality. However, the differential diagnosis can be broad with conditions that mimic this disease and require different evaluation and treatment. This narrative review presents the emergency medicine evaluation and management, as well as important medical conditions that may mimic this disease. Septic arthritis commonly presents with monoarticular joint pain with erythema, warmth, swelling, and pain on palpation and movement. Fever is present in many patients, though most are low grade. Blood testing and imaging may assist with the diagnosis, but the gold standard is joint aspiration. Management includes intravenous antibiotics and orthopedic surgery consult for operative management vs. serial aspirations. Clinicians should consider mimics, such as abscess, avascular necrosis, cellulitis, crystal-induced arthropathies, Lyme disease, malignancy, osteomyelitis, reactive arthritis, rheumatoid arthritis, and transient synovitis. While monoarticular arthritis can be due to septic arthritis, other medical and surgical conditions present similarly and require different management. It is essential for the emergency clinician to be aware how to diagnose and treat these mimics.

Infection of a tophaceous nodule of the wirst and hand

Tophaceous gout occurs years after recurrent attacks of acute inflammatory arthritis. The urate deposits are incriminated in the inflammatory process; however, their infection is exceptional. We report the observation of an infected gouty tophus of the pinky and the wrist of a 40-year-old man, presented as an excruciating inflammatory pain with buff-yellow swelling of the fifth right finger and wrist in a febrile context. As a matter of fact, the evolution was favourable after surgical excision and antibiotic therapy. The infection of a tophus is an exceptional complication of the gout. In daily practice, this diagnosis is really a difficult challenge for the clinician. The systematic bacteriological examination of the tophi with cutaneous fistulation is necessary to introduce prematurely an adapted treatment.

Aspiration and Injection Techniques of the Lower Extremity

Orthopaedic surgeons frequently use aspirations and injections to both diagnose and treat disorders of the lower extremity. Comprehensive knowledge of regional anatomy, procedural indications, and appropriate techniques are essential. Clinicians must be well versed in a range of musculoskeletal aspiration and injection techniques, including patient positioning, equipment needs, injectable solutions, aspirate analysis, and potential complications. Safe and effective aspiration and injection techniques for the lower extremity, including the hip, knee, foot, and ankle, are reviewed. Image guidance modalities include fluoroscopy, ultrasonography, CT, and MRI.

Upper Extremity Compartment Syndrome in a Patient with Acute Gout Attack but without Trauma or Other Typical Causes

We report the case of a 30-year-old Polynesian male with a severe gout flare of multiple joints and simultaneous acute compartment syndrome (ACS) of his right forearm and hand without trauma or other typical causes. He had a long history of gout flares, but none were known to be associated with compartment syndrome. He also had concurrent infections in his right elbow joint and olecranon bursa. A few days prior to this episode of ACS, high pain and swelling occurred in his right upper extremity after a minimal workout with light weights. A similar episode occurred seven months prior and was attributed to a gout flare. Unlike past flares that resolved with colchicine and/or anti-inflammatory medications, his current upper extremity pain/swelling worsened and became severe. Hand and forearm fasciotomies were performed. Workup included general medicine, rheumatology and infectious disease consultations, myriad blood tests, and imaging studies including Doppler ultrasound and CT angiography. Additional clinical history suggested that he had previously unrecognized recurrent exertional compartment syndrome that led to the episode of ACS reported here. Chronic exertional compartment syndrome (CECS) presents a difficult diagnosis when presented with multiple symptoms concurrently. This case provides an example of one such diagnosis.

Clinical characteristics of infectious ulceration over tophi in patients with gout

Objective The aim of this study was to investigate the clinical characteristics of infectious ulceration over tophi in patients with gout. Methods Participants were recruited from the First Affiliated Hospital of Wenzhou Medical University. The clinical characteristics of the patients and wound characteristics were recorded. Results Of the 38 enrolled patients, 18 were found to have infectious ulceration over tophi. Staphylococcus aureus was the most common pathogen and was identified in nine patients. Patients with infection were significantly older (69.6 vs. 60.1 years) and had a worse quality of life than those without infection. Patients with infection also had a significantly longer ulcer duration (125.6 vs. 54.2 days), larger ulcer size (2.47 vs. 1.99 cm²), a higher rate of tissue necrosis in the ulcer bed (55.6% vs. 20.0%), a lower rate of callus at the edge (27.8% vs. 70.0%), and a higher moisture level than did patients without infection. Additionally, patients with infection had significantly delayed wound healing (35.3 vs. 20.3 days) compared with patients without infection. Conclusions Older patients with a long ulcer duration and larger ulcer size are more susceptible to infection. Infection can lower patients' quality of life and delay wound healing.

Septic Arthritis of the Wrist

Septic arthritis of the wrist is an uncommon condition, but one that can result in substantial morbidity. Timely identification and treatment is critical to patient care. No serum laboratory values have been shown to consistently confirm wrist joint infection. Thus, diagnosis is made based mainly on a thorough patient history, physical examination, and joint aspiration. When infection is suspected, aspiration of the wrist should be performed to confirm the diagnosis. Broad-spectrum antibiotics and joint aspiration or surgery are required to manage the infection and prevent sequelae.

An Algorithmic Approach to the Suspected Septic Wrist

An acutely painful, erythematous wrist can be due to a variety of pathologic processes, including crystalline arthropathy, infection, trauma, osteoarthritis, and systemic disease. The broad differential diagnosis of the inflamed wrist and nonspecific clinical findings make accurate diagnosis challenging. There is no published clinical or laboratory criterion that reliably differentiates septic wrist arthritis from a sterile inflammatory arthropathy. For septic joint patients, long-term results are notably poorer in patients with a delay in treatment, therefore establishing evidenced-based guidelines deserves attention.After a comprehensive literature review, we present evidenced-based guidelines and an algorithm for the management of the patient with an acutely inflamed wrist concerning for septic arthritis.For determining a diagnosis, systemic blood laboratory results are extremely variable and unreliable. Despite the attention given to the diagnostic potential of synovial fluid tests, the literature consistently demonstrates that diagnostic certainty cannot always be ascertained at the time of presentation based on aspiration fluid samples. Additionally, the investigative work does not necessarily end at the discovery of crystals since concomitant infection is a rare but well reported entity.Relative to larger joints, the wrist is far less likely to be infected and is easier to drain of debris, and therefore the empiric management of an inflamed wrist joint should reflect these differences. For treatment of the suspected or confirmed septic wrist, prompt initiation with appropriate antibiotics and drainage of joint purulence is critical to rapid recovery. However, the best strategy to clear the joint space of infectious material is controversial. Although the traditional standard of care is open drainage of a septic joint, a growing body of literature supports that for a septic wrist joint, a less invasive approach with serial aspiration can be equally efficacious with reduced morbidity and quicker recovery. If the wrist fails to improve with daily aspirations, then arthroscopy or open washout is needed.For patients with suspected wrist joint infection or crystalline arthropathy with probable concomitant infection, a reasonable approach is admission for systemic antibiotics and daily arthrocentesis. If the wrist fails to improve or worsens, then surgical treatment may be pursued. This treatment strategy could potentially avoid the morbidity of surgery while ensuring that no septic wrist goes untreated.

Management of gout and hyperuricemia: Multidisciplinary consensus in Taiwan

Gout is an inflammatory disease manifested by the deposition of monosodium urate (MSU) crystals in joints, cartilage, synovial bursa, tendons or soft tissues. Gout is not a new disease, which was first documented nearly 5,000 years ago. The prevalence of gout has increased globally in recent years, imposing great disease burden worldwide. Moreover, gout or hyperuricemia is clearly associated with a variety of comorbidities, including cardiovascular diseases, chronic kidney disease, urolithiasis, metabolic syndrome, diabetes mellitus, thyroid dysfunction, and psoriasis. To prevent acute arthritis attacks and complications, earlier use of pharmacotherapeutic treatment should be considered, and patients with hyperuricemia and previous episodes of acute gouty arthritis should receive long-term urate-lowering treatment. Urate-lowering drugs should be used during the inter-critical and chronic stages to prevent recurrent gout attacks, which may elicit gradual resolution of tophi. The goal of urate-lowering therapy should aim to maintain serum uric acid (sUA) level <6.0 mg/dL. For patients with tophi, the initial goal can be set at lowering sUA to <5.0 mg/dL to promote tophi dissolution. The goal of this consensus paper was to improve gout and hyperuricemia management at a more comprehensive level. The content of this consensus paper was developed based on local epidemiology and current clinical practice, as well as consensuses from two multidisciplinary meetings and recommendations from Taiwan Guideline for the Management of Gout and Hyperuricemia.

Bilateral First-Ray Amputation of the Foot Due to Severe Tophaceous Gout Complicated by Infection and Discharged Sinus A Case Report

BACKGROUND

Gout is a purine metabolism disease. Tophaceous gout may cause joint destruction and other systemic problems and sometimes may be complicated by infection. Infection and sinus with discharge associated with tophaceous gout are serious complications, and treatment is difficult. We present a patient with tophaceous gout complicated by infection and discharging sinus treated by bilateral amputation at the level of the first metatarsus.

METHODS

A 43-year-old man previously diagnosed as having gout, and noncompliant with treatment, presented with tophaceous gout associated with discharging sinus and infection on his left first metatarsophalangeal joint. Because of the discharging sinus associated with the tophaceous deposits, the soft-tissue and bony defects, and the noncompliance of the patient, amputation of the first ray was undertaken, and a local plantar fasciocutaneous flap was used to close the defect. After 8 months, the patient was admitted to the emergency department with similar symptoms in his right foot, and the same surgical procedure was performed.

RESULTS

One year after the second surgery, the patient had no symptoms, there was no local inflammatory reaction over the surgical areas, and laboratory test results were normal.

CONCLUSIONS

Gout disease with small tophi often can be managed conservatively. However, in patients with extensive lesions, risk of superinfection justifies surgical treatment. Results of complicated cases are not without morbidity; therefore, early surgical treatment may prevent extremity loss and further complications. In severe cases, especially with compliance issues, amputation provides acceptable results.

Pathological Fracture of the Proximal Tibia from an Intraosseous Gouty Tophus: A Rare Presentation of Gout

Intraosseous gouty tophus as the cause of pathological fracture is a seldom encountered condition. Not only does the tophus lesion affect the bone, but recent literature has also demonstrated a correlation between bone health in relation to gout as a disease entity, and showed the importance of medical treatment to improve the bone quality in patients with gout. We present a rare case of a pathological fracture due to an intraosseous gouty tophus as the presentation of gout, which imposed a diagnostic challenge, and illustrates the importance of multidisciplinary management in such conditions.

Septic Arthritis of the Wrist: Incidence, Risk Factors, and Predictors of Infection

Septic arthritis of the wrist can result in permanent damage to the joint, making timely diagnosis crucial to initiate empiric antibiotics and surgical intervention. Although septic arthritis is routinely included in the differential diagnosis of atraumatic wrist pain, the incidence is unknown. Unlike large joints, there is no consensus on cell count values considered pathognomonic for wrist septic arthritis. The goal of this retrospective study was to determine the incidence of wrist septic arthritis and to identify the clinical, serum, and joint fluid values that predict infection. The records of patients who presented to a single urban hospital with a swollen, painful wrist without trauma during a 10-year period were reviewed. For patients who had a joint fluid analysis, the records were examined for history as well as demographic and laboratory data. Joint fluid analysis consisted of cell count, Gram stain, and cultures. Of 892 patients who met the inclusion criteria, 1.5% had wrist septic arthritis. Variables associated with septic arthritis included serum white blood cell count above 11,000/µL, core temperature above 100.4°F within 24 hours of aspiration, history of intravenous drug abuse, and smoking. No joint cell count analysis predicted septic arthritis, although patients with septic wrists had an elevated joint white blood cell count above 97,000/µL. Wrist septic arthritis is uncommon; however, objective factors can help identify patients at risk. Because joint cell count analysis cannot reliably predict a septic wrist, priority for joint aspirations with limited fluid should be given instead to Gram stain, culture, and crystal analysis. [Orthopedics. 2017; 40(3):e526-e531.].

Septic Arthritis of Native Joints

Septic arthritis is a rheumatologic emergency that may lead to disability or death. Prompt evacuation of the joint, either by arthrocentesis at the bedside, open or arthroscopic drainage in the operating room, or imaging-guided drainage in the radiology suite, is mandatory. Methicillin-resistant Staphylococcus aureus (MRSA) has become a major cause of septic arthritis in the United States. MRSA joint infection seems to be associated with worse outcomes. Antibiotic courses of 3 to 4 weeks in duration are usually adequate for uncomplicated bacterial arthritis. Treatment duration should be extended to 6 weeks if there is imaging evidence of accompanying osteomyelitis.

Predictors of Septic Arthritis in the Adult Population

Septic arthritis is a devastating condition; well-established criteria for diagnosis exist in the pediatric population, but not for adults. This study evaluated patient factors and laboratory parameters that may be associated with the diagnosis of septic arthritis in adults. A total of 458 knee aspirates for suspected septic arthritis were evaluated with serum and synovial leukocyte counts and differentials as well as Kocher criteria for pediatric septic arthritis. Twenty-two patients (4.8%) had septic arthritis confirmed by a positive synovial fluid culture. Erythrocyte sedimentation rate (ESR) and serum white blood cell (WBC) counts were not statistically different between the 2 groups, with 64% of septic arthritis patients having a normal serum WBC count and 77% being afebrile. Mean synovial fluid WBC count was 26,758 cells/µL and 70,581 cells/µL in the nonseptic and septic groups, respectively. The likelihood ratio for a synovial fluid WBC count greater than 65,000 cells/µL was 2.8 (95% confidence interval, 1.2-6.7). Evaluation receiver operating characteristic curves using synovial WBC counts resulted in a significant area under the curve of 0.66 (P=.02). To achieve 90% specificity, a WBC cutoff of 64,000 cells/µL was required with a corresponding sensitivity of 40%. There was no significant difference in the synovial cell differential of 80% vs 90% in diagnosing infection. Synovial fluid WBC count greater than 64,000 cells/µL yielded the optimal combination of sensitivity and specificity. Polymorphonuclear leukocytes, ESR, serum WBC count, fever, and weight-bearing status were not significant predictors of septic arthritis. This study demonstrates the limited utility of Kocher criteria in the adult population and the importance of synovial leukocyte counts. [Orthopedics. 2016; 39(4):e657-e663.].

Brucella Septic Arthritis: Case Reports and Review of the Literature

Brucellosis is one of the commonest zoonotic infections worldwide. The disease is endemic in Saudi Arabia, the Middle East, and the Mediterranean area. Osteoarticular involvement is a frequent manifestation of brucellosis. It tends to involve the sacroiliac joints more commonly; however, spondylitis and peripheral arthritis are increasingly reported. Brucellosis can be overlooked especially in the presence of companion bacteria. Hence, it should be suspected in all patients with septic arthritis in endemic areas or in patients visiting such areas.

Native Joint Septic Arthritis: Epidemiology, Clinical Features, and Microbiological Causes in a New Zealand Population

Objective.

To determine the epidemiology, clinical features, and microbiology of adult native joint septic arthritis in Canterbury, New Zealand, over a 5-year period in individuals with and without an underlying rheumatic disorder.

Methods.

Patients with native joint septic arthritis were identified retrospectively and classified by Newman’s criteria. The clinical characteristics were described and comparisons made between those with and without underlying rheumatic disease.

Results.

Two hundred forty-eight cases of native joint septic arthritis (mean age 60, range 16–97 yrs) were identified with an overall incidence rate of 12.0/100,000/year (95% CI 10.6–13.6). Yearly incidence increased with age to a maximum of 73.4/100,000 in those > 90 years of age. Septic arthritis was iatrogenic in 16.9% of cases while 27% had an underlying inflammatory arthritis including gout (14.9%), calcium pyrophosphate disease (8.5%), and rheumatoid arthritis (4%). Few patients were taking immunosuppressant therapy, with just 1 taking a biological agent. Staphylococcus aureus was the most commonly identified organism. Those with underlying inflammatory arthritis were significantly older (73.6 yrs vs 55.6 yrs; p < 0.001), more likely to be female (55.2% vs 26.0%; p < 0.001), and to have septic polyarthritis (16.4% vs 4.4%; p = 0.002). The 30-day mortality was 2%, increasing to 6% at 90 days.

Conclusion.

The incidence of septic arthritis in Canterbury, New Zealand, is higher than in previous studies. Crystal arthropathy commonly coexisted with infection although autoimmune arthritis and immunosuppression was less of a factor than anticipated.