White blood cell counts and differential in synovial fluid of aseptically failed total knee arthroplasty

doi:10.1016/S0883-5403(00)90578-3

The Journal of Arthroplasty

Volume 15, Issue 3, April 2000, Pages 301-304

https://doi.org/10.1016/S0883-5403(00)90578-3 Get rights and content

Abstract

A cell count and differential was obtained on synovial fluid samples from 79 total knee arthroplasties undergoing revision for aseptic failure over a 5-year period. The mean white blood cell count (WBC) was 782/mL (range, 11–7, 200/mL). The mean percentage of monocyte cells was 87%, and the mean polymorphonuclear leukocyte (PML) cell count was 13%. Eight patients (10.4%) had leukocyte cell counts >2, 000. Five knees in 4 patients with rheumatoid arthritis had PML counts >50%. There was a single postoperative infection. Inpatients with osteoarthritis as a primary diagnosis, a synovial WBC of <2, 000 and a differential with <50% PMLs had a 98% negative predictive value for the absence of infection.

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Cited by (45)

High Failure at a Minimum 5-Year Follow-Up in Primary Total Hip Arthroplasty Using a Modular Femoral Trunnion
2019, Journal of Arthroplasty
Citation Excerpt :
Failure was subcategorized as revision for mechanical failure related to the prosthesis (trunnion dissociation or femoral neck/stem fractures) and nonmechanical failures, unrelated to the prosthesis (instability/chronic dislocation or septic loosening). Criteria to define septic THA included serum erythrocyte sedimentation rate >30 mm/h, serum C-reactive protein >10 mg/L, synovial fluid white blood cell count >50,000, synovial fluid percentage of polymorphonuclear cells >75%, and positive synovial fluid cultures [15,16]. All statistical analyses were performed using SAS, version 9.1, (SAS Institute Inc., Cary, NC).
Modular femoral trunnions enable the surgeon to independently adjust offset, leg length, and anteversion in total hip arthroplasty (THA). However, modularity may result in an increased risk of fretting and corrosion along with a higher risk of implant dissociation or fracture. The purpose of this study is to evaluate mid-term survivorship of THAs using a cementless modular system.
A consecutive series of 221 patients who underwent a primary THA using the ALFA II modular stem by a single surgeon between 2002 and 2004 were reviewed. Survivorship of the ALFA II modular hip system was evaluated at a minimum of 5 years postoperatively.
Of the 221 patients, 28 (12.7%) died from causes unrelated to the surgery before adequate follow-up, and 64 (29.0%) patients were lost to follow-up. The remaining 129 patients had a mean 6.5-year (range: 5-8 years) follow-up. All-cause survivorship of the modular stem system was 81% (95% confidence interval = 69-90) at a mean 6.5-year follow-up. Of the 25 (19.4%) cases requiring revision surgery, 52.0% was for dissociation of the modular components, 32.0% was for fracture of the prosthesis, 12.0% was for instability/multiple dislocations, and 4.0% was for chronic septic THA. Body mass index (odds ratio = 1.080) and offset (odds ratio = 1.254) were independent risk factors for mechanical failures of the modular stem system.
The modular stem hip system of interest in this study demonstrates a high failure rate at mid-term follow-up, and we caution against the use of similar designs in primary THAs.
Diagnosing Periprosthetic Joint Infection in Inflammatory Arthritis: Assumption Is the Enemy of True Understanding
2018, Journal of Arthroplasty
Despite concern over the interpretation of serum and synovial fluid tests to screen and diagnose periprosthetic joint infection (PJI) in patients with inflammatory arthritis, only a single study has investigated this area. We aimed to assess accuracy of clinical and laboratory markers for PJI diagnosis in the context of underlying inflammatory arthritis.
This multicenter study was conducted on total joint arthroplasty patients at 3 different centers between 2001 and 2016. PJI was defined based on Musculoskeletal Infection Society criteria. Acute PJI cases were excluded. Patients operated for a diagnosis other than infection, who did not subsequently fail at 1-year follow-up, were considered aseptic revisions. Serum C-reactive protein and erythrocyte sedimentation rate, synovial white blood cell and differential, as well as alpha-defensin and results of frozen section were documented.
In total, 1220 patients undergoing revision total joint arthroplasty (567 PJI, 653 aseptic) were included. Fifty-five septic patients and 61 in the aseptic group had inflammatory arthritis. Although mean levels of serum C-reactive protein and synovial white blood cell in inflammatory arthritis patients were significantly higher compared to patients without inflammatory arthritis, there were no significant differences in PJI patients. The thresholds associated with increased risk for PJI in patients with and without inflammatory arthritis were similar and closely resembled traditional cut-points.
We demonstrate higher baseline immune upregulation in aseptic revision cases with inflammatory arthritis, but no significant differences are seen for PJI. Conventional PJI thresholds for serum and synovial diagnostic markers should be adhered to. Assumptions about inflammatory arthritis patients needing differential diagnostic protocols should be avoided.
Synovial IL-6 AS inflammatory marker in periprosthetic joint infections
2014, Journal of Arthroplasty
Citation Excerpt :
Further, it is possible that participants in our trial with arthralgia after TJA may have suffered from acute aseptic inflammatory arthritis in the prosthetic joint. It has been reported that the SFWBC is also elevated in prosthetic joints during some types of aseptic inflammatory arthritis, such as rheumatoid arthritis and gout [33,47,48]. These differences may have led to the different AUCs of the SFWBC in both studies.
We analyzed serum and synovial biomarkers of 69 patients. 31 of them suffered from a periprosthetic joint infection (PJI) and 38 from aseptic arthralgia after total joint arthroplasty. We used Receiver-Operating-Characteristic-curves to calculate the Area-under-the-curve (AUC), cutoff-values, positive (+ LR), negative (− LR) and interval-Likelihood-Ratios (iLR) for predicting a PJI. The most significant parameter was synovial interleukin-6 (IL-6) (cutoff-value ≥ 30,750 pg/ml, AUC = 0.959, SE = 90.0%, SP = 94.7%, + LR = 17.27), followed by synovial lactate (cutoff-value ≥ 8.3 mmol/l, AUC = 0.844, SE = 71.4%, SP = 88.0%, + LR = 5.95), and synovial glucose (cutoff-value ≤ 44 mg/dl, AUC = 0.829, SE = 79.2%, SP = 78.6%, + LR = 3.69). IL-6 ≥ 30,750 pg/ml and lactate ≥ 10 mmol/l make a PJI very likely, IL-6 < 10,000 pg/ml or lactate < 4.3 mmol/l makes a PJI very unlikely. If none of these thresholds are met, physicians should use the iLR of IL-6, glucose and lactate to estimate the likelihood of PJI.
Prevention of Late PJI
2014, Journal of Arthroplasty
Citation Excerpt :
The threshold for the leukocyte cell count and neutrophil differential from synovial fluid has varied with time. A study conducted by Kersey et al determined thresholds to rule out infection and demonstrated that a leukocyte cell count of less than 2,000 cells/μL and less than 50% polymorphonuclear leukocytes had a 98% negative predictive value [27]. Mason et al conducted one of the first studies to determine a cut-off value suggestive of PJI in TKA patients.
Synovial fluid differential cell count in wear debris synovitis after total knee replacement
2014, Knee
Determining the cause of synovitis following total knee arthroplasty (TKA) can be challenging. The differential diagnoses include infection, hemarthrosis, instability, crystalline disease, wear debris or idiopathic causes. Wear particle synovitis can mimic periprosthetic infection with symptoms of pain and effusion. Radiographs and physical exam are often inconclusive in differentiating the two. Synovial fluid analysis is routinely used in evaluating periprosthetic infections.
We examined the association between synovial white blood cell count and differentials, and polyethylene wear and osteolysis, to see if fluid analysis can aid in establishing the diagnosis of wear particle synovitis.
A cell count and differential was obtained from synovial fluid samples from 54 TKAs undergoing revision for aseptic failure. Explanted polyethylene inserts were analyzed for linear and volumetric wear, oxidation (ketone peak height), and damage features. Analysis was performed to assess the relationship between cell counts and polyethylene wear indicators as well as severity of intra-operative and radiographic osteolysis.
Total and percent mononuclear (monocyte and lymphocyte) cell counts were found to be elevated in the presence of documented wear debris synovitis and an association was suggested between their levels and maximum ketone levels.
The present study implies that the differential cell count of knee fluid can help distinguish wear debris from infection as a source of synovitis following TKA and identifies the value of the mononuclear cell count as a possible tool to assess abnormal wear rates of the polyethylene insert. Further research into identifying the exact role of monocytes in the wear debris synovitis and osteolytic pathways is warranted.
Level II, diagnostic study.
Correlation of aspiration results with aseptic loosening in total hip arthroplasty
2013, Journal of Arthroplasty
Citation Excerpt :
The following data were collected regarding the pre-operative or intra-operative aspirate: WBC count, red blood cell (RBC) count, percent of segmented WBCs, percent of lymphocytic WBCs, percent of monocytic WBCs, percent of eosinophilic WBCs, percent of basophilic WBCs, percent of bands, percent of nucleated RBCs, and final culture results. Because the majority of previous studies did not perform any adjustment to WBC or differential counts using the RBC counts, no adjustment was performed here [4–7,29,30]. The pre-operative consultation notes, operative reports and radiographs for each patient were reviewed.
In the evaluation of patients with a persistently painful total hip arthroplasty establishing an accurate diagnosis is paramount in the selection of a successful treatment regimen. It is unknown whether synovial analysis might differentiate aseptic loosening from other causes of failure. A physiological basis exists to suggest that aseptic loosening might be a process of non-segmented leukocytes. The objective of this study was to determine if the synovial fluid differential cell count might aid in the diagnosis of aseptic loosening. A retrospective chart review of all patients who had undergone revision hip arthroplasty with pre-operative or intra-operative aspiration results was performed. Aseptic loosening was defined as gross intraoperative movement in the absence of infection. From these results Relative-Operating Characteristic (ROC) curves were created, and sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. A diagnosis of aseptic loosening was established in 76 of the 253 hips. The ROC curves indicated that lymphocyte count does have utility in the diagnosis of aseptic loosening. If an aspirate has a combination of fewer than 2500 WBCs (sensitivity 93%, specificity 42%, NPV 94%, accuracy 57%) or more than 10% lymphocytes (sensitivity 86%, specificity 42%, NPV 87%, accuracy 55%) then the sensitivity for aseptic loosening is 96%, the specificity is 33%, the NPV is 95% and the accuracy is 52%. In patients with painful total hip arthroplasties in whom infection has been excluded, aspiration data can be a useful adjunct in the diagnosis of aseptic loosening. In aspirates with neither a WBC cell count of less than 2500 nor a lymphocyte cell count of greater than 10% aseptic loosening can be effectively “ruled out” as fewer than 5% of these patients will have aseptic loosening. While non-specific, aspirate differential can be useful to “rule-out” aseptic loosening with a sensitivity and negative predictive value well exceeding that of standard radiographs.

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White blood cell counts and differential in synovial fluid of aseptically failed total knee arthroplasty

Abstract

Orthop Clin North Am

Am J Med

Aspiration of the knee joint before revision arthroplasty

Clin Orthop

Infected total knee replacements

J Am Acad Orthop Surg

Primer on the rheumatic diseases

Synovial fluid leukocytosis in bacterial arthritis versus reactive arthritis and rheumatoid arthritis in the adult knee

Scan J Rheumatol

The value of preoperative aspiration prior to total knee revision

Clin Orthop