Acute Knee Effusion Research Articles

Paediatric Knee Injuries: A Narrative Review.

The prevalence of paediatric knee injuries is increasing due to higher participation in competitive sports, larger build and more use of imaging in diagnosis. A thorough history of injury (including mechanism and symptoms of pain and instability), together with a comprehensive examination (presence of an effusion, tender areas, range of movement and joint laxity) will dictate the need for radiological investigations. Magnetic Resonance Imaging (MRI) is indicated in most paediatric patients with a history of injury and an acute knee effusion, which indicates damage to an intra-articular structure. Red flags requiring onward referral to a specialist include diagnosed fractures, traumatic knee effusion, instability, or persistent unexplained nocturnal pain or lump. Correct identification and management of injuries will help reduce long-term morbidity. The aim of this review is to provide the reader with an understanding of the management of paediatric knee injuries at primary presentation in the community setting or emergency department.

Poster 217: Local and Systemic Comparison of Senescent Profiles in Acute Knee Injury

Poster 217: Local and Systemic Comparison of Senescent Profiles in Acute Knee Injury

Lyme Arthritis in the Pediatric Knee: Clinical and Magnetic Resonance Imaging Differentiators.

The medical records and MRI scans of children who presented between 2009 and 2019 with an acute knee effusion ultimately diagnosed as LA or SA were retrospectively reviewed. Data collection included clinical information on the modified Kocher criteria (weight-bearing, fever, blood serology including white blood-cell [WBC] count, C-reactive protein [CRP], and erythrocyte sedimentation rate [ESR]), MRI findings, and serology confirmation of LA or bacterial SA. A total of 87 cases of confirmed LA and 9 cases of SA were identified. The 2 cohorts had substantial clinical overlap with regard to the ability to bear weight, fever, and joint aspirate WBC count. Differences between the 2 groups in several MRI characteristics, specifically vastus lateralis myositis, subcutaneous edema, and lymphadenopathy, were significant. A multivariate analysis demonstrated that weight-bearing, CRP of <3 mg/L, absence of subcutaneous edema, myositis of multiple muscles including the vastus lateralis, and lymphadenopathy were predictive of LA. LA should be strongly suspected in endemic areas of the United States when children present with a knee effusion. The addition of MRI criteria to clinical and laboratory findings significantly improved the predictive value for identifying LA. Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Right Knee Pain - Runner

HISTORY: A 60 year old male runner with a history of right common peroneal nerve entrapment status post-surgical decompression presented for evaluation of right lateral knee pain that had been present for 1 year. He described dull, lateral, aching knee pain, worsened by impact activity (e.g., running). He denied mechanical symptoms or effusion. Knee MRI demonstrated popliteus tendinopathy with partial-thickness intrasubstance tearing and a 10x5mm peritendinous cyst. Ultrasound (US)-guidance was used to drain and fenestrate the cyst, and fenestrate and inject the popliteus tendon with leukocyte rich platelet rich plasma (PRP). The procedure was performed without complication. The patient used crutches for 5 days post-procedure, but on day 6 he walked 6 blocks without crutches. That evening, he developed pain and swelling with erythema in the suprapatellar region. No fever, chills, or knee drainage was present. Due to the symptoms, he returned to clinic for evaluation. PHYSICAL EXAMINATION: Healthy appearing male in no acute distress. Mildly antalgic gait pattern. Grade 2 right knee effusion with erythema around the superolateral aspect of the knee. Well-healed injection site without erythema. Mild tenderness to palpation over the popliteus tendon insertion. Normal ligamentous and meniscal tests. DIFFERENTIAL DIAGNOSIS: 1. Acute knee effusion secondary to overuse after recent PRP injection 2. Septic arthritis 3. Post-injection flare TEST AND RESULTS: Right knee limited ultrasound - moderate effusion within suprapatellar recess Right knee aspiration - Appearance: straw colored - Cell count: 1283 - Neutrophils: 60 - Gram stain: negative - Culture: no growth - Crystals: intracellular CPPD crystals FINAL WORKING DIAGNOSIS: Acute right knee pseudogout flair in a patient with no history of pseudogout, status post popliteus tendon PRP injection with peritendinous cyst aspiration and fenestration. TREATMENT AND OUTCOMES: The patient was successfully treated with crutches, ice, compression, elevation, and NSAIDs.

Spinal Reflex Excitability does not Associate with Persistent Muscle Inhibition after Anterior Cruciate Ligament Reconstruction

Persistent deficits in quadriceps voluntary activation affect muscle function following anterior cruciate ligament reconstruction (ACLR). Previous research has attributed voluntary activation deficits to lower quadriceps spinal reflex excitability following acute knee effusion or injury. There is little evidence to indicate that spinal reflex excitability exists or influences persistent voluntary activation deficits in individuals with an ACLR. PURPOSE: To determine if quadriceps spinal reflex excitability in individuals with a unilateral ACLR differs between limb or compared to a control group. Additionally, we evaluated the ability of quadriceps spinal reflex excitability to predict full voluntary activation following ACLR. METHODS: One hundred and forty-seven individuals (74 ACLR and 73 controls) participated in this cross-sectional, case-control study. Quadriceps spinal reflex excitability was quantified using the Hoffmann reflex normalized to the maximal muscle response (H:M ratio). Quadriceps voluntary activation was evaluated with the burst superimposition technique and calculated via the central activation ratio (CAR). Separate 2x2 ANOVAs were used to compare differences between-limbs and between-groups for H:M ratio and CAR. From a receiver operating characteristic curve analysis, the area under the curve (AUC) was used to determine the accuracy of H:M ratio to predict full voluntary activation (CAR>0.95) in ACLR individuals. We determined the odds ratio (OR) of demonstrating full voluntary activation from spinal reflex excitability cutoff scores that maximized the sensitivity and specificity for predicting full activation. RESULTS: ACLR quadriceps H:M ratios were not different between limbs or compared to the control group (P>0.05). Quadriceps CAR was bilaterally lower in individuals with an ACLR compared to the control group (P<0.01), yet CAR did not differ between limbs. H:M ratio had poor accuracy for predicting ACLR participants exhibiting full voluntary activation (AUC=0.53, 95% CI=0.39,0.67; OR = 2.37, 95% CI=0.91,6.2). CONCLUSIONS: Spinal reflex excitability did not differ between limbs in individuals with ACLR or compared to controls. Quadriceps spinal reflex excitability has poor accuracy for predicting which ACLR individuals will demonstrate a CAR>0.95.

Effectiveness of aspiration in knee joint effusion management: a prospective randomized controlled study

Knee effusion is a common symptom in various knee disorders of both traumatic and non-traumatic aetiology. Although intra-articular aspiration is a widespread treatment approach, its beneficial effect has not been confirmed by a randomized controlled study. The purpose was to evaluate the effectiveness and safety of joint aspiration in acute knee effusion, in relation to traumatic or non-traumatic aetiology. One hundred and sixty-seven consecutive patients with acute knee joint effusion were allocated in a randomized controlled fashion into two groups. In the first group, joint aspiration was performed, while in the second group, no aspiration was performed. Range of motion, pain relief, use of analgesics and oedema were evaluated post management. The Knee Society Score and the International Knee Documentation Committee Subjective Evaluation Form were also obtained. In addition, a subgroup analysis of our results in relation to the presence of trauma or not was performed. Aspiration exhibited a temporary improvement in all clinical parameters evaluated, especially in the post-traumatic effusion. However, this improvement lasted only for the first week, due to the early re-accumulation of the effusion. There was no difference between the different groups regarding the clinical outcome in neither trauma or non-trauma patients at the end of the follow-up period. Aspiration aided in earlier establishment of the diagnosis in the non-trauma cases of effusion. Aspiration resulted in only temporary improvement of the outcome in the treatment of traumatic or not traumatic knee effusion. Aspiration is suggested in effusions of unknown origin in order to establish the diagnosis and for immediate clinical relief. However, aspiration should be performed with consideration in the presence of trauma.

MRI Findings in Adolescent Patients With Acute Traumatic Knee Hemarthrosis

Physical examination may be inconclusive in adolescents presenting with an acute traumatic knee effusion because of pain and guarding. The purpose of this study was to describe the magnetic resonance imaging (MRI) findings in adolescents with traumatic knee effusions and to compare injuries based on age, sex, and physeal maturity. All MRIs using a knee trauma protocol performed at our institution over a 2-year period were evaluated. One hundred thirty-one patients between the ages of 10 to 18 years of age with a clinical history of acute knee trauma and an effusion confirmed on MRI met our study inclusion criteria. They were divided into 2 age groups: 10 to 14 and 15 to 18 years old. Pathology was confirmed using clinical history, MRI, and any available surgical reports. Of the 131 patients with an acute knee effusion, there were 59 patients in the younger group (10 to 14 y old) and 72 patients in the older group (15 to 18 y old). In the younger group, patellar dislocations (36%), anterior cruciate ligament (ACL) tears (22%), and isolated meniscus tears (15%) were the most common injuries. In the older group, ACL tears (40%), patellar dislocations (28%), and isolated meniscus tears (13%) were the most common injuries. ACL injuries represented 28% of injuries in males and 38% of injuries in females, whereas patellar dislocations represented 28% of injuries in males and 37% of injuries in females. There was a trend toward adolescents with active growth plates sustaining more patellar dislocations and adolescents with closed growth plates sustaining more ACL injuries. Forty-one percent of patients in this study underwent surgery. Patellar dislocation is a common injury in children who present with a traumatic knee effusion, especially in young adolescents and females. Adolescents presenting with a traumatic knee effusion should undergo MRI because of the high rate of positive findings missed by physical examination and plain radiographs that may warrant surgical repair or reconstruction. Level III.

Poster 440 Pseudogout as a Cause of Acute Knee Effusion in a Patient With Spinal Cord Injury: A Case Report

Poster 440 Pseudogout as a Cause of Acute Knee Effusion in a Patient With Spinal Cord Injury: A Case Report

Results of Laboratory Evaluation of Acute Knee Effusion after Anterior Cruciate Ligament Reconstruction

Background Infection after anterior cruciate ligament reconstruction is a rare and potentially devastating complication. No normative data have been reported for knee aspiration after anterior cruciate ligament reconstruction in the early postoperative period. Hypothesis Determining normative laboratory data from a retrospective review of noninfected early postoperative anterior cruciate ligament reconstruction knee effusions will allow for the calculation of an aspirate white blood cell (WBC) threshold value indicative of infection. Study Design Case series (diagnosis); Level of evidence, 4. Methods A 2-year retrospective chart review of 151 anterior cruciate ligament reconstruction patients was performed. Thirty-one noninfected patients meeting the inclusion and exclusion criteria and 1 infected patient had laboratory data collected, including peripheral blood and knee effusion aspirate analyses. Laboratory data from pertinent published studies of infected knees after anterior cruciate ligament reconstruction were combined with the data of our 1 infected patient, establishing a historical control group. Data were analyzed and results were then compared. Infected aspirate WBC threshold value statistics were then calculated. Results Analysis of noninfected knee effusion aspirates revealed a mean WBC count of 9600/uL (standard deviation [SD], 15 200), and a mean of 66% polymorphonuclear (PMN) cells (SD, 34). Aspirate WBC 98% confidence interval (CI) was 2800/uL to 16 200/uL, and the 98% CI for PMN cells was 58% to 84%. Aspirate WBC count >16 200/uL is 86% sensitive, 92% specific, and has a positive likelihood ratio of 10.4 as an indicator of infection. Conclusion Benign effusion after anterior cruciate ligament reconstruction is common and is associated with elevated inflammatory markers. When concerned, knee aspiration after anterior cruciate ligament surgery gives the highest yield to differentiate between a painful effusion and a septic knee in the early postoperative period while awaiting definitive culture results. The authors report confidence intervals defining the range of cell count variables for noninfected patients requiring aspiration, specifically WBC and PMN, and suggest a WBC threshold value of >16 200/uL be used as an indicator of infection. On the basis of comparison with historical control data, the authors believe these data are significant and will be reliable for clinical use.

The Results of Laboratory Evaluation of Acute Knee Effusion After ACL Reconstruction: What is Normal? (SS-52)

The Results of Laboratory Evaluation of Acute Knee Effusion After ACL Reconstruction: What is Normal? (SS-52)

24 Acute knee effusion - diagnosis and outcome

24 Acute knee effusion - diagnosis and outcome

Pigmented Villonodular Synovitis Causing Painless Chronic Knee Swelling in an Adolescent

It is uncommon for an adolescent to present with a painless chronic knee effusion without a history of trauma. Acute knee effusions are usually caused by internal derangement, patellar dislocations, or fractures. The differential diagnosis of a chronic knee effusion must include the more uncommon diagnoses of juvenile rheumatoid arthritis, septic arthritis, reactive arthritis, synovial osteochondromatosis, synovial hemangioma, synovial sarcoma, or pigmented villonodular synovitis. Radiographic imaging, plain radiographs, and magnetic resonance imaging in addition to a biopsy specimen are most helpful in differentiating these diagnoses. Pigmented villonodular synovitis is an uncommon diagnosis that is rarely seen in an adolescent. Treatment includes synovectomy via arthroscopy or open arthrotomy.

Serum-synovial gradient data of normouricemic patients with history of gout and acute knee effusion

The etiology of arthritis episodes in normouricemic patients with gout is still unclear. We propose that the fluctuation in synovial urate level, as well as pH, ion strength, albumin, and globulin values relative to serum levels, could be involved in crystal formation. To assess serum-synovial gradient (SSG), the sera and synovial fluid (SF) of six normouricemic patients (men, age 48-79) with a history of gout (American College of Rheumatology criteria) and acute knee effusion were screened for uric acid, pH, osmolality (Osm), P/Ca, albumin, globulin, and SSG. Monosodium urate monohydrate (MSUM) crystals were determined by polarized light (PL). Infectious arthritis was ruled out via Gram staining and synovial fluid culture. Negative X-ray and PL microscopy results excluded chondrocalcinosis. Five patients (1-5) had inflammatory knee effusion (WBC >2,000/mm(3)), and one (patient 6) had noninflammatory knee effusion (600 WBC/mm(3)). MSUM crystals were found in the WBC of patient 1 only. He had tophaceous gout with normal serum uric acid levels and showed significant negative Osm and P and positive Ca SSG. Two crystal negative patients had severe negative pH SSG with alkaline synovial fluid, significant P/Ca SSG, and high positive globulin SSG, while one of them had supersaturated SF uric acid content. The other patients displayed an increased Osm and P/Ca SSG. All SSG values were five to ten times higher than the coefficient of variance for used methods. Noninflammatory SF of patient 6 does not appear to be related to active gout. The data on SSG for MSUM, pH, Osm, Alb/Glob, and P/Ca in normouricemic patients with gout history and acute knee effusion was not homogeneous. We propose that acid-base and ionic-protein gradient may lead to instability of subsaturated urate solution, thereby predisposing to MSUM deposits within synovial membrane and inducing inflammation.

Synovial-fluid D-lactic acid in bacterial and other acute joint effusions.

The use of D-lactic acid in differential diagnosis of bacterial arthritis was evaluated in a prospective study. The concentration of D-lactic acid was determined by the enzymatic UV-method in sixty-eight synovial fluids (SF) and in twenty four sera from adult patients with acute knee effusion. High concentrations of D-lactic acid (> 0.15 mmol/l) were measured most frequently in SF from bacterial arthritis, but also in individual culture-negative SF samples from patients with inflammatory culture-negative joint effusions with and without identified history of infections. Determination of SF D-lactic acid is not useful in differential diagnosis of bacterial arthritis.

Influence of Proquazone (Biarison®) On the Levels of Complement Components (C3 and C4) In Synovial Fluid and on Igm in Serum in Patients with Active Rheumatoid Arthritis: A Preliminary Report

Four patients with erosive rheumatoid arthritis and one with psoriasis arthropathy were treated with 600-900 mg/day proquazone for 4-7 weeks. All patients had acute knee effusions. The complement components C3 and C4, as well as IgG, IgA, IgM and total protein, were measured in both the synovial fluid and serum before and after treatment. In the 4 patients with rheumatoid arthritis, a marked increase in C3 and/or C4 levels in the synovial fluid was found, correlating in 3 cases with a good clinical response. However, no corresponding changes in complement levels were recorded in the serum. The patient with psoriasis arthropathy did not show any reaction. These preliminary results suggest that proquazone may influence the immunological processes in rheumatoid arthritis.