Ultrasound of the knee during voluntary quadriceps contraction: a technique for detecting otherwise occult effusions.

OBJECTIVE: To describe 1) a technique that can detect synovial effusions not seen on static ultrasound (US) examination and 2) the characteristics of patients with knee osteoarthritis (OA) for whom this technique proved useful. METHODS: From reviewed records of 76 patients with knee OA (112 knees) that we had seen for US-guided injections over a defined period, we found 45 knees with no detectable effusion on static US, of which 18 (14 patients) showed fluid when scanned during voluntary quadriceps contraction. For all patients, we had recorded effusion features (physical examination, presence and size on US), and success of joint entry was determined by getting synovial fluid and/or seeing an air echo or inflow of injected material. RESULTS: The 14 patients we studied were obese (mean +/- SEM body mass index 32.7 +/- 2.3 kg/m(2); 3 morbidly obese), with moderate to severe OA by radiography in most (Kellgren/Lawrence class 3 or 4 in 10 of 14 knees for which radiographs were available). The suprapatellar synovial space seen by US was small (mean +/- SEM depth 0.38 +/- 0.04 cm). Arthrocentesis obtained 0.5-16 ml of synovial fluid (mean +/- SEM 2.9 +/- 0.6 ml), which correlated with the depth of effusion as seen on US with the quadriceps in maximum contraction (Spearman's rho = 0.5597, P = 0.0157). In 4 knees where arthrocentesis failed to retrieve fluid, we observed at injection the inflow of material and a linear air echo. CONCLUSION: US of the knee during voluntary quadriceps contraction can find effusions not detectable on static US. Such effusions provide targets for accurate aspiration and injection that would not be appreciated with static US.

Measuring process of arthritis care: the Arthritis Foundation's quality indicator set for rheumatoid arthritis.

OBJECTIVE: To describe the scientific evidence that supports each of the explicit process measures in the Arthritis Foundation's Quality Indicator Set for Rheumatoid Arthritis. METHODS: For each of the 27 measures in the Arthritis Foundation's Quality Indicator set, a comprehensive literature review was performed for evidence that linked the process of care defined in the indicator with relevant clinical outcomes and to summarize practice guidelines relevant to the indicators. RESULTS: Over 7500 titles were identified and reviewed. For each of the indicators the scientific evidence to support or refute the quality indicator was summarized. We found direct evidence that supported a process-outcome link for 15 of the indicators, an indirect link for 7 of the indicators, and no evidence to support or refute a link for 5. The processes of care described in the indicators for which no supporting/refuting data were found have been assumed to be so essential to care that clinical trails assessing their importance have not, and probably never will be, performed. The process of care described in all but 2 of the indicators is recommended in 1 or more practice guidelines. CONCLUSION: There are sufficient scientific evidence and expert consensus to support the Arthritis Foundation's Quality Indicator Set for Rheumatoid Arthritis, which defines a minimal standard of care that can be used to assess health care quality for patients with rheumatoid arthritis.

Validation of American College of Rheumatology classification criteria for knee osteoarthritis using arthroscopically defined cartilage damage scores.

OBJECTIVE: To validate the ability of the American College of Rheumatology (ACR) clinical classification criteria and the ACR clinical plus radiographic classification criteria for osteoarthritis of the knee to predict articular cartilage damage. METHODS: Ninety subjects with knee osteoarthritis (OA) who were enrolled in a prospective study determining the therapeutic efficacy of arthroscopic irrigation were characterized as to whether they fulfilled the ACR clinical classification criteria or the ACR clinical plus radiographic classification criteria. Ten rheumatoid arthritis (RA) patients were included as controls. Cartilage damage was defined using the ACR/Knee Arthroscopy Osteoarthritis Scale (ACR/KAOS) system, which is a validated outcome instrument for knee OA based on arthroscopic visualization. Mean values of the damage scores in each group were calculated and compared by t-test to determine statistical significance between the 3 groups. RESULTS: The mean ACR/KAOS score for the 10 RA patients was 1.8 [SD 1.22; range 0 to 4]. Of the 90 OA patients who underwent arthroscopy, only 73 patients had sufficient videotape to make an accurate assessment by the blinded assessor. The mean ACR/KAOS score for the 6 OA patients who fulfilled only the ACR clinical classification was 17.4 [SD 11.3; range 5 to 34.3] and the mean ACR/KAOS score for the 67 patients who fulfilled the ACR clinical plus radiographic classification criteria was 42.0 [SD 29.1; range 5.1 to 118.4]. These differences were statistically significant (RA versus OA clinical P=0.02; RA versus OA clinical+radiographic P