Session Information
Date: Tuesday, November 10, 2015
Title: Osteoarthritis - Clinical Aspects Poster II: Biomarkers, Biomechanics and Health Services Research
Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
Background/Purpose:
Most of our understanding of the clinical significance of a knee joint effusion is derived from trauma in young patients, with surprisingly little assessment of the meaning of an effusion in osteoarthritis (OA). It is unclear whether clinical examination of the knee for effusion is of any practical use or correlation to outcome. We sought to determine the specificity and sensitivity of clinical evaluation of knee joint effusion in OA for presence of an effusion on MRI, and the relationship of a clinical effusion to patient status and clinical outcome.
Methods:
We performed a case-control study of 80 patients with OA, with a 5 year follow-up, and validation in the Osteoarthritis Initiative dataset. This cohort study included knees from 40 subjects from the OAI dataset that had a knee corticosteroid injection within 1 year after baseline evaluation, and 40 that did not, matched by age, sex, and Kellgren-Lawrence (K-L) grade of radiographic OA.
Baseline MRI, clinical examination (patella tap and patella bulge test), Kellgren-Lawrence grading, and WOMAC scores were obtained. The MRI were evaluated for effusions by two semi-quantitative scoring systems (MOAKS and KIMRISS). The incidence of corticosteroid injection and WOMAC scores at 12 months, and of total knee replacement (TKR) within 5 years, as well as 5-year radiographic progression using K-L grade, were recorded. Pearson correlation coefficients, one-way analysis of variance (ANOVA) and multivariate logistic regression were used as appropriate to assess for significant associations.
Results:
Subjects averaged 62.3 years old (range: 45-78), 78% were women, and BMI averaged 30.3±4.6, with moderate to severe OA (K-L grade 2.8±1.0 (mean±standard deviation).
The clinical bulge test was 100% specific but only 29% sensitive for knee joint effusion as detected by MRI. The patella tap sign was only 4.8% sensitive, and not analyzed further. Bulge-positive knees were associated with higher baseline WOMAC disability (26.9 vs 18.2, p=0.02) and pain scores (5.4 vs 3.7, p=0.03) compared to bulge-negative knees. Bulge-positive knees were significantly more likely to have corticosteroid injection within 12 months (78% vs 58%, p=0.007).
An analysis of the whole OAI dataset revealed a 3-fold increase in 5 year TKR for bulge-positive patients (9% vs 3%, p<0.0001, n=9302), with bulge-positivity significantly predicting TKR using multivariate logistic regression (odds ratio 2.0 [95% CI 1.4-2.9], p<0.0001, n=4324).
Conclusion:
The patellar bulge test is a relatively insensitive but highly specific clinical marker for joint effusion in OA. A positive patellar bulge test at presentation is associated with greater pain, disability, a higher rate of corticosteroid injections and a 2- to 3-fold increase in TKR within 5 years.
To cite this abstract in AMA style:
Smith B, McDougall D, Lambert RG, Maksymowych W, Jaremko J. Implications of a Positive Patellar Bulge Sign of Knee Joint Effusion in Patients with Osteoarthritis: Association with MRI Signs of Inflammation and with Increased Rate of 5-Year Total Knee Arthroplasty. Data from the Osteoarthritis Initiative [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/implications-of-a-positive-patellar-bulge-sign-of-knee-joint-effusion-in-patients-with-osteoarthritis-association-with-mri-signs-of-inflammation-and-with-increased-rate-of-5-year-total-knee-arthropla/. Accessed .« Back to 2015 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/implications-of-a-positive-patellar-bulge-sign-of-knee-joint-effusion-in-patients-with-osteoarthritis-association-with-mri-signs-of-inflammation-and-with-increased-rate-of-5-year-total-knee-arthropla/