Functional Articulating Antibiotic Spacers for Chronic Native Septic Knee Arthritis.

Background: Semipermanent functional spacers are now utilized for prosthetic joint infection in an attempt to avoid another surgery with 2-stage treatment. This study evaluates the results of metal-on-polyethylene articulating spacers for the treatment of chronic native septic knee arthritis. Methods: This is a retrospective review of 18 patients treated with metal-on-polyethylene articulating antibiotic spacers constructed with all-polyethylene tibial components or with polyethylene inserts (PIs) with Steinmann pins or screws for chronic native knee infection. Demographic information, spacer construct type, prior knee surgery, complications, infecting organisms, infection eradication, and functional results were analyzed. Results: Of 18, 8 (44%) spacers were all-polyethylene tibial components and 10 (56%) were PI. Of 18 patients, 5 (28%) experienced spacer complications. Of 18 patients, 12 (67%) underwent a second reimplantation surgery (mean 106 days), while 6 (33%) retained their spacer (average duration 425 days). The PI group performed better in Knee Injury and Osteoarthritis Outcome score for Joint Replacement according to minimum clinically important difference and patient acceptable symptom state (PASS) criteria. The overall reimplantation group achieved Knee Injury and Osteoarthritis Outcome score for Joint Replacement PASS criteria and minimum clinically important difference criteria, while the maintained articulating spacer group did not achieve PASS criteria; however, they did reach minimum clinically important difference. Conclusions: Functional articulating spacers are a viable treatment for chronic, native knee septic arthritis. The PI patient group had a greater improvement in Knee Injury and Osteoarthritis Outcome score for Joint Replacement scores and had no significant difference in reimplantation rate as the all-polyethylene tibial components patient group. Both planned 2-stage reimplantation and longer-term spacer retention show promising results for this difficult clinical problem.

Is there sufficient evidence to support the use of antibiotic holiday just before the second stage of an infected total hip or knee arthroplasty revision surgery?

The practice of implementing an antibiotic holiday before the second stage of hip or knee arthroplasty is currently controversial due to limited evidence for this approach, as per the International Consensus Meeting 2018 on Musculoskeletal Infection. A greater understanding of this issue could augment the quality of Alrayes and Sukeik's mini-review (2023) on diagnosing, managing, and treating periprosthetic knee infections. However, a significant lack of literature exists concerning the optimal duration for the antibiotic holiday, calling for more research before establishing any clinical guidelines.

Brucellosis an Unusual presentation as isolated septic mono-arthritis of the knee joint: A case report.

Brucellosis is a zoonotic infection that is widely spread across the world. It is becoming more common in Middle Eastern countries such as Qatar, Saudi Arabia, and the Mediterranean region. Despite this, we need to remain vigilant as it is still prevalent in many parts of the world. The most common presentation is musculoskeletal, but it can also present as septic arthritis in the sacroiliac, hip, or knee joints. Brucella melitensis was only found in one extended culture of synovial fluid. Treatment involved a combination of antimicrobial therapy using gentamycin, doxycycline, and rifampin. A high level of suspicion for brucellosis is necessary for any patient coming from an endemic region with non-specific and chronic arthritis to ensure early diagnosis and treatment. In this case, we present a 28-year-old male who was diagnosed with Brucellosis after developing acute septic arthritis.

A retrospective review of the rate of septic knee arthritis after retrograde femoral nailing for traumatic femoral fractures at a single academic institution.

Background: Retrograde intramedullary nailing of the femur is a popular treatment option for femoral shaft fractures. However, this requires accessing the intramedullary canal through the knee, posing a risk of intra-articular infection. The purpose of this study was to examine the rate of intra-articular infection of the knee after retrograde nailing of femoral shaft fractures. Methods: All patients who underwent retrograde intramedullary nailing for femoral shaft fractures between June 2004 and December 2017 at a level 1 trauma center were reviewed. Six months of follow-up or documented fracture union was required. Records were reviewed for documentation of septic arthritis of the ipsilateral knee during the follow-up period. Results: A total of 294 fractures, including 217 closed and 77 open injuries, were included. Eighteen had an associated ipsilateral traumatic arthrotomy; 188 cases had an associated ipsilateral lower extremity fracture. No cases of septic arthritis were identified. Conclusion: There were no cases of septic arthritis in 294 fractures treated with retrograde intramedullary nailing. Retrograde nailing appears safe for risk of postoperative septic arthritis of the knee even in the face of open fractures and traumatic wounds.

Age and C-reactive protein as modifiers of Kocher criteria in pediatric septic knee monoarthritis.

INTRODUCTION: Although Kocher criteria can distinguish a septic hip from an aseptic cause, they may not apply to a septic knee. We aimed to identify predictors to discriminate septic and aseptic causes of acute knee monoarthritis in children who underwent arthrocentesis. METHODS: We conducted a retrospective cohort study among children who underwent arthrocentesis for suspected septic arthritis of the knee. Collected data included demographic, clinical and laboratory characteristics. We performed univariate and multivariable analyses to identify predictors of the septic knee. We further investigated accuracy of different predictive models. RESULTS: A total of 60 patients who underwent arthrocentesis for suspected knee septic arthritis were included in this study. Septic arthritis of the knee was confirmed in 32 (53%) patients. Age ≤ 5 years (OR 4.237, [95% CI 1.270-14.127], p = 0.019), WBC > 12,000 cells/mm3 (OR 5.059, [95% CI 1.424-17.970], p = 0.012), and CRP > 2 mg/dL (OR 3.180, [0.895-11.298], p = 0.074) were the most important predictors of a septic knee. Three-tier model comprising these three factors (AUC 0.766) and 4-tier model with addition of fever >38.5°C (AUC 0.776) performed better than Kocher criteria (AUC 0.677), modified Kocher criteria (AUC 0.699) and Full Model (adding age ≤ 5 years and CRP >2 mg/dL to Kocher criteria) (AUC 0.746). Full Model successfully ruled out septic arthritis if all 6 criteria were negative. CONCLUSION: Based on these findings, we propose an algorithm to identify low, intermediate and high-risk patients for knee septic arthritis. Our proposed two-step algorithm incorporating major (age, WBC, CRP) and minor (fever, ESR, non-weight bearing) criteria can serve as a simple decision-support tool to justify arthrocentesis in children with suspected knee septic arthritis.

Early diagnosis and treatment of acute brucellosis knee arthritis complicated by acute osteomyelitis: two cases report.

BACKGROUND: Brucellosis is an endemic systemic infectious disease, the most common complication is bone and joint involvement. Sacroiliac joint and spinal joint are the most frequently involved sites in adults, but knee joint infection is rare, and acute infectious knee arthritis complicated by acute osteomyelitis is even extremely uncommon in adults. Here, we report two cases of acute septic knee arthritis complicated by acute osteomyelitis caused by Brucella melitensis (B. melitensis). CASE PRESENTATION: Both patients had a history of traveling in animal husbandry areas within three months. On clinical examination, their right knee joint was tender, swollen, had limited movement and an effusion was present. Imaging examination showed effusion and synovial thickening of the right knee joint, as well as subchondral bone edema of the distal femur and proximal tibia. Laboratory examination showed that the serum agglutination test (SAT) in both patients were positive (1: 640 and 1: 320) without leukocytosis, although the proportion of lymphocytes, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) significantly increased. Both patients underwent knee joint aspiration. Real-time polymerase chain reaction (Real-time PCR) analysis of synovial fluid showed that there was B. melitensis, and blood bacterial culture was negative. We determined that two patients had acute brucellosis knee arthritis complicated by acute osteomyelitis. Antibiotic treatment was given during hospitalization consisting of doxycycline (0.1 g po bid) and rifampicin (0.6 g po qd) for six weeks, and the changes of inflammatory indexes were closely monitored. At discharge, the symptoms had completely resolved, imaging abnormalities disappeared, and inflammatory indexes returned to normal. There was no recurrence of the disease at 1-year follow-up. CONCLUSION: Acute brucellosis knee arthritis complicated by acute osteomyelitis is a rare but serious complication of brucellosis in adults. There is no obvious specificity of clinical manifestation and imaging examination. Early diagnosis and treatment can prevent the occurrence of knee joint deformity and even pathological fracture. Clinicians should fully consider the possibility of brucellosis where the travel or occupational history is suggestive.

Outcome and Predictors of Septic Failure Following Total Joint Arthroplasty for Prior Septic Arthritis of Hip and Knee Joint.

BACKGROUND: Arthroplasty patients with prior septic arthritis are at a high risk of developing periprosthetic joint infection (PJI). The aims of this study are to investigate the outcome and predictors of septic failure following total joint arthroplasty (TJA) for prior septic arthritis. In addition, the optimal timing of TJA is also discussed. METHODS: A retrospective review of 105 TJA patients with prior septic arthritis between January 2000 and December 2019 was performed. Patient-specific and surgery-related factors, organism profiles, and other relevant variables were recorded. RESULTS: At a mean follow-up of 10.3 years, the PJI rate was 16.2%. The adjusted Cox proportional hazards model showed that male gender (HR, 9.95; P < .01), end-stage renal disease (HR, 37.34; P < .01), debridement surgery ≥3 times (HR,4.75; P = .04) and polymicrobial infection in primary septic arthritis (HR, 10.02; P = .02) were independent risk factors for PJI. Neither the types of initial debridement, nor one-stage vs two-stage arthroplasty was related to the risk of PJI. While delaying the timing of TJA did not correlate with a reduction of PJI rate, there was a higher risk of PJI re-infection by the same microorganisms isolated in prior septic arthritis if TJA was performed within 6 months after septic arthritis. CONCLUSIONS: Our study demonstrated that male gender, end-stage renal disease (ESRD), multiple debridement surgeries and polymicrobial septic arthritis predisposed septic failure of TJA following prior septic arthritis. Surgeons should counsel patients with the potential complications, and be cognizant about the risk factors pertaining to septic failure when considering TJA.

Knee Septic Arthritis Caused by Pantoea agglomerans.

Introduction: Septic arthritis usually affects native joints and represents an invasion of the joint space by a wide variety of microorganisms, most commonly bacteria, such as Staphylococci, Streptococci, and Gram-negative rods. An extremely rare case of septic knee arthritis caused by Pantoea agglomerans in a 67-year-old male is presented. Case Report: The patient was initially treated with arthroscopic debridement, but due to persistent symptomatology open surgical debridement 3 days after initial surgery was also performed. Cultures yielded P. agglomerans and Streptococcus agalactiae. He was commenced on causative antimicrobial treatment including intravenous linezolid, ciprofloxacin, and clindamycin. He was discharged 10 days later, on oral linezolid and ciprofloxacin for 3 months. Conclusion: Delayed diagnosis in septic arthritis cases and inadequate control of the infection may lead to insufficient treatment and devastating consequences for the patient. The treatment includes surgical debridement and proper antimicrobial agents. Cultures dictate the proper treatment; hence, microbiological examination is of utmost importance, since it may reveal unusual organisms for which empirical treatment may prove insufficient.

MRI Findings of Early Osteoarthritis in Patients Who Sustained Septic Arthritis of the Knee After ACL Reconstruction.

BACKGROUND: Although a rare complication, septic arthritis (SA) after anterior cruciate ligament (ACL) reconstruction has potentially devastating consequences for the knee joint. PURPOSE: To prospectively analyze, at a mean 4-year follow-up, subjective, clinical, radiographic, and magnetic resonance imaging (MRI) findings between patients with SA and those with no septic complication after ACL reconstruction. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Of 2006 ACL reconstructions performed between 2004 and 2014, a total of 20 patients experienced SA. All patients were treated with arthroscopic irrigation and graft-retaining debridement immediately after diagnosis and at least 6 weeks of antibiotic treatment. After the exclusion process, 18 patients were included in the SA group and 20 in the control group. At final follow-up at a mean 48 months, a physical examination, KT-1000 arthrometer laxity test, Lysholm knee score, Tegner activity score, and International Knee Documentation Committee radiographic score were completed and then compared with preoperative data. The Boston-Leeds Osteoarthritis Knee Score was used for MRI evaluation at final follow-up to note chondral changes. RESULTS: No significant differences between the SA and control groups were observed in pre- and perioperative variables that could indicate a higher incidence of early osteoarthritis (OA). Although range of motion and knee stability were not significantly different between the groups at final follow-up, the Lysholm score (mean ± SD, 79.8 ± 13.1 vs 90.9 ± 8.6; P < .01) and Tegner score (6.0 ± 1.1 vs 7.0 ± 1.4; P = .03) were significantly lower in the SA group as compared with the control group. MRI evaluation at final follow-up demonstrated a significantly higher degree of early knee OA in the SA group versus the control group. However, no differences in the degree of OA were seen on plain radiographs at final follow-up between the groups. CONCLUSION: MRI evaluation provided signs of worsened chondral state in the SA group, which could be associated with reduced functional outcome and return to sports. In contrast to radiograph analyses, MRI was excellent at distinguishing damage to the cartilage and can be useful in early follow-up evaluation of patients with SA after ACL reconstruction.

Diagnostic Criteria for the Painful Swollen Pediatric Knee: Distinguishing Septic Arthritis From Aseptic Effusion in a Non-Lyme Endemic Area.

Purpose: The child with a painful swollen knee must be worked-up for possible septic arthritis; the classic clinical prediction algorithms for septic arthritis of the hip may not be the best models to apply to the knee. Materials and methods: This was a retrospective case-control study of 17 years of children presenting to one hospital with a chief complaint of a painful swollen knee, to evaluate the appropriateness of applying a previously described clinical practice algorithm for the hip in differentiating between the septic and aseptic causes of the painful knee effusions. The diagnoses of true septic arthritis, presumed septic arthritis, and aseptic effusion were established, based upon the cultures of synovial fluid, blood cultures, synovial cell counts, and clinical course. Using a logistic regression model, the disease status was regressed on both the demographic and clinical variables. Results: In the study, 122 patients were included: 51 with true septic arthritis, 37 with presumed septic arthritis, and 34 with aseptic knee effusion. After applying a backward elimination, age <5 years and C-reactive protein (CRP) >2.0 mg/dl remained in the model, and predicted probabilities of having septic knee arthritis ranged from 15% for the lowest risk to 95% for the highest risk. Adding a knee aspiration including percent polymorphonucleocytes (%PMN) substantially improved the overall model performance, lowering the lowest risk to 11% while raising the highest risk to 96%. Conclusions: This predictive model suggests that the likelihood of pediatric septic arthritis of the knee is >90% when both "age <5 years" and "CRP > 2.0 mg/dl" are present in a child with a painful swollen knee, though, in the absence of these factors, the risk of septic arthritis remains over 15%. Aspiration of the knee for those patients would be the best next step.

Current surgical practice for septic arthritis of the knee in the United States.

For septic arthritis of the knee, we attempted to determine: the preferred surgical technique in the United-States (US), the believed "gold-standard" treatment among others. This was performed by an electronic-survey distributed to all academic orthopaedic faculty throughout the US. The preferred method was arthroscopy (69.8%). Arthroscopy is believed to be the gold-standard in 27.0%, arthrotomy in 29.4%, while 43.5% believe no gold-standard exists. In conclusion the majority of surgeons prefer arthroscopy when managing a native, septic knee in an adult patient. However, there is no national consensus on a gold-standard treatment or the role of synovectomy.

Successful two-stage primary total knee arthroplasty for infective arthritis of the knee - our experience.

BACKGROUND: The incidence of septic arthritis is 2-10/100,000. Morbidity is higher with persistent joint dysfunction in up to 30%. Osteoarthritic knee with infection presents a rare challenge, with no established approach for treatment exists. We present our experience of managing infected degenerative joint disease (DJD) with two-stage primary arthroplasty similar to the management of periprosthetic joint infection. PATIENTS AND METHODS: Four patients presented to us between 2016 and 2018 with advanced DJD associated with coexistent joint sepsis with or without adjacent osteomyelitis. The diagnosis of joint sepsis with periarticular osteomyelitis was made based on clinical presentation, radiographic findings, inflammatory serological markers, and culture of knee joint aspirate. All were operated with primary arthroplasty in two stages of debridement with a static spacer followed by antibiotics and implantation. DISCUSSION: With no established method of treating DJD superadded with infection, our experience adds valuable information in treating the same. Our 2-staged primary arthroplasty had a short antibiotic duration between stages, a mean of 63.5 days, and stopped within 3 days of 2ndstage reducing hospital stay, morbidity, and cost.Our approach is a very viable method of treating infected DJD with a minimum drug holiday time of two weeks before implantation with a better outcome, reducing the recurrence rate of infection.Though a small number with a minimum follow-up of 24 months, we believe we provide valuable additional information. CONCLUSION: All patients had painless return to early activities with no signs of recurrent infection. Our approach is a very viable and could serve as a cost-effective method treatment for an infected arthritic knee.

Two-stage Total Knee Arthroplasty for Treatment of Surgical Failure of Septic Arthritis in Degenerative Knee Joints.

BACKGROUND: The ultimate goal of the treatment of infectious knee arthritis is to protect the articular cartilage from adverse effects of infection. Treatment, however, is not always hundred percent successful and has a 12% failure rate. Persistent infection is more likely to happen in elderly patients and those with underlying joint diseases, particularly osteoarthritis. Eradication of infection and restoration of function in the involved joint usually are not possible by conventional treatment strategies. There are few case series reporting two-stage primary knee arthroplasty as the salvage treatment of the septic degenerative knee joint; however, the treatment protocol remains to be elucidated. METHODS: Based on a proposed approach, patients with failure of common interventions for treatment of septic knee arthritis and underlying joint degeneration were treated by two-stage TKA and intervening antibiotic loaded static cement spacer. Suppressive antibiotic therapy was not prescribed after the second stage. RESULTS: Complete infection eradication was achieved with mean follow up of 26 months. All cases were balanced with primary total knee prosthesis. The knee scores and final range of motions were comparable to other studies. CONCLUSION: The two-stage total knee replacement technique is a good option for management of failure of previous surgical treatment in patients with septic arthritis and concomitant joint degeneration. Our proposed approach enabled us to use primary prosthesis in all of our patients with no need for suppressive antibiotic therapy.

Arthroscopy versus arthrotomy for the treatment of septic knee arthritis.

PURPOSE: To compare complications following arthroscopy and arthrotomy for treatment of septic knee arthritis. METHODS: Patients undergoing arthroscopy and arthrotomy for a diagnosis of septic knee arthritis were identified in National Surgical Quality Improvement Program and placed in a multivariate analysis to determine if type of surgery contributed to postoperative complications. RESULTS: Knee arthrotomy was associated with an increased risk for increased operative time [Parameter estimate 4.555 (95% CI:3.023-6.085); p < 0.0001], minor morbid events [OR 2.064 (95% CI: 1.447-2.943); p < 0.0001], and any morbidity [OR 2.285 (95% CI:1.527-3.419); p < 0.0001]. CONCLUSIONS: Knee arthrotomy was associated with a higher risk of complications.

A rare case of right-sided infective endocarditis caused by group B Streptococcus complicated with septic knee arthritis and subcutaneous abscess in the lower extremity.

BACKGROUND: Several reports have assessed group B Streptococcus (GBS) infections in non-pregnant cohorts, especially in immunocompromised hosts and patients with severe disease, including diabetes mellitus. CASE PRESENTATION: We report a rare case of large GBS -associated tricuspid valve infective endocarditis (IE) complicated with septic knee arthritis and s.c. abscess formation in the lower extremity of a non-i.v. drug user. After confirming the absence of vegetation on transthoracic echocardiography (TTE) at admission, the lower extremity was irrigated, and antibiotic therapy was initiated. One week later, the causes of persistent fever were reinvestigated. The TTE detected a large mass around the tricuspid valve. The cultured GBS was penicillin sensitive. The vegetation completely disappeared without surgery within 4 weeks. CONCLUSION: When patients with untreated diabetes mellitus have persistent fever and s.c. abscess or septic arthritis, IE is a possible differential diagnosis. Repetitive evaluation by TTE is warranted to avoid this fatal complication.

The Use of Tantalum Metaphyseal Cones for the Management of Severe Bone Defects in Septic Knee Revision.

BACKGROUND: Femoral and tibial massive bone defects are common findings in septic total knee revision and pose considerable challenges for the orthopedic surgeon. The aim of this study was to report the midterm clinical and radiographic outcomes with the use of tantalum cones for the management of massive bone defects after 2-stage knee revision. METHODS: We retrospectively reviewed the medical records of 60 patients (mean age, 67.9 ± 8.8 years) treated with 94 tantalum cones associated with constrained or semiconstrained knee for massive bone loss (mean follow-up, 43.5 ± 17.4 months). In all cases, the indication was a staged revision for periprosthetic knee infection. Functional scores, radiographic outcomes, and implant survivorship were analyzed. RESULTS: The mean Knee Society Score and Oxford Knee Score improved from 44.1 ± 7.4 and 19.2 ± 4.1 to 85.4 ± 5.6 and 38.4 ± 3.9 (P < .01), respectively. The mean flexion increased from 60.6° ± 15.5° to 96.8° ± 10.9° at the last evaluation (P < .01). The mean improvement in flexion contracture was 6.2 ± 8.0 (P < .01). Two failures (3.3%) due to periprosthetic knee infection recurrence were observed, but no cone-related mechanical failures were reported. The cone-related survival rate was 97.8%. CONCLUSION: Excellent clinical and radiographic midterm outcomes were achieved with a low complication rate. Tantalum cones may be considered a safe and effective option in the management of massive bone defects also in septic knee revision surgery.

Cutibacteriumacnes Septic Arthritis of the Nonoperated Knee: A Case Report.

Cutibacterium (Propionibacterium) acnes , a gram-positive bacillus with low pathogenicity, is an uncommon but known cause of prosthetic joint infections, particularly related to shoulder surgery. C. acnes , however, is an extremely rare pathogen in the nonoperated knee joint. This report details an uncommon case of C. acnes septic knee arthritis after multiple intra-articular steroid injections in a 56-year-old male patient. After an indolent presentation and late diagnosis, the patient underwent surgical debridement with IV antibiotic management. This case illustrates that intra-articular corticosteroid injections for the management of osteoarthritis are not without risk. Literature supporting their use remains limited and clinicians should use proficient clinical judgment for appropriate patient selection for these injections. Vigilance following injections or aspirations of the knee should be maintained to identify the indolent clinical presentation of C. acnes septic arthritis.

Temporary arthrodesis using fixator rods in two-stage revision of septic knee prothesis with severe bone and tissue defects.

PURPOSE: The present study describes a new temporary arthrodesis procedure, which aims for septic knee prosthesis replacement, in particular for larger bone and soft tissue defects. Our technique offers high stability and full weight-bearing capacity of the knee joint. METHODS: The study included 16 patients with major bone defects (AORI type IIb or greater) after receiving a radical debridement and a septic two-stage revision total knee arthroplasty. After removing the infected prosthesis and debridement, two AO fixator rods were positioned into the intramedullary space of the femur and tibia. Subsequently, both rods were joined tube-to-tube and adjusted in the center of the knee joint. Finally, the whole cavity of the knee joint was filled with PMMA. The number of previous surgeries, bacterial spectrum, risk factors for further infection and reinfection rates was recorded. Immediately after the temporary arthrodesis, radiographs of the knee with the enclosed spacers were taken in order to compare to previous radiographs and avoiding to miss possible spacer loosening. RESULTS: Nine of sixteen patients underwent more than two revision surgeries before receiving our new arthrodesis technique. No cases of spacer loosening were observed in all 16 patients; further, there were no peri-implant fractures, and four persistent infections were noted. CONCLUSIONS: Temporary arthrodesis using AO fixator rods offers a high stability without loosening. Its potential to replace conventional augmentation techniques should be taken into account, particularly in the case of larger bone and tissue defects. In clinical practice, the cemented spacer using AO fixator rods could be an alternative technique for temporary knee arthrodesis after septic debridement. LEVEL OF EVIDENCE: Retrospective case series, Level IV.

Corynebacterium septic arthritis of the knee presenting as a ruptured septic popliteal cyst.

A rare case of a septic knee arthritis presenting as an infected ruptured popliteal cyst is described. Infection of a popliteal cyst is an uncommon complication of septic arthritis and presentation can mimic that of an acute deep vein thrombosis, leading to delay in diagnosis and treatment. Of interest, the typical hallmarks of infection and haematological markers of inflammation were all unremarkable in the current case. This case was of additional interest in that there have been no reports in the literature of Corynebacterium spp. being isolated from an infected popliteal cyst. Invasive infections caused by Corynebacterium spp. seem to have a predilection for patients who are immunocompromised. It is especially important in this subset of patients that delays in diagnosis are avoided by including it in the differential of an immunocompromised patient presenting with unilateral lower-extremity pain and swelling.