Ajay Abraham

Reliability and validity of ultrasound imaging of features of knee osteoarthritis in the community

BackgroundRadiographs are the main outcome measure in epidemiological studies of osteoarthritis (OA). Ultrasound imaging has unique advantages in that it involves no ionising radiation, is easy to use and visualises soft tissue structures. Our objective was to measure the inter-rater reliability and validity of ultrasound imaging in the detection of features of knee OA.MethodsEighteen participants from a community cohort, had both knees scanned by two trained musculoskeletal sonographers, up to six weeks apart. Inter-rater reliability for osteophytes, effusion size and cartilage thickness was calculated by estimating Kappa (κ) and Intraclass correlation coefficients (ICC), as appropriate. A measure of construct validity was determined by estimating κ between the two imaging modalities in the detection of osteophytes.ResultsReliability: κ for osteophyte presence was 0.77(right femur), 0.65(left femur) and 0.88 for both tibia. ICCs for effusion size were 0.70(right) and 0.85(left). Moderate to substantial agreement was found in cartilage thickness measurements. Validity: For osteophytes, κ was moderate to excellent at 0.52(right) and 0.75(left).ConclusionSubstantial to excellent agreement was found between ultrasound observers for the presence of osteophytes and measurement of effusion size; it was moderate to substantial for femoral cartilage thickness. Moderate to substantial agreement was observed between ultrasound and radiographs for osteophyte presence.

Population prevalence of ultrasound features of osteoarthritis in the hand, knee and hip at age 63 years: the Newcastle thousand families birth cohort.

BackgroundMusculoskeletal ultrasound has been found to be more sensitive than radiographs in detecting osteophytes. Our objective was to measure the prevalence of features of osteoarthritis (OA), in the dominant hand, knees and hips using ultrasound, within the Newcastle Thousand Families birth cohort.MethodsParticipants were aged 61–63 (mean 63) years. Knee images were scored for presence of osteophytes and effusion. Hip images were scored for the presence of osteophytes and femoral head abnormality. The first carpometacarpal joint, metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints of the index finger (dominant hand) were imaged for osteophytes.ResultsAmong 311 participants, prevalence of osteophytes at the distal interphalangeal joint was 70% while it was 23%, 10% and 41% for index proximal interphalangeal and metacarpophalangeal and thumb base carpometacarpal joints respectively. Prevalence of knee osteophytes was 30%, hip OA was 41%. Prevalence of knee effusions was 24% (right) and 20% (left). Ultrasound evidence of generalised OA (48%) and isolated hand OA (31%) was common, compared to isolated hip or knee OA (5%) and both hip and knee OA (3%).ConclusionThis is the first study to assess prevalence of ultrasound features of OA in a population-based sample. The higher prevalence of hand/hip OA, when compared to previous radiographic studies, supports the hypothesis that ultrasound is more sensitive than radiography in detecting OA, particularly for osteophytes.

FRI0409 Breast is best. Lifecourse influences on the development of knee osteophytes: The newcastle thousand families study

Background There has been very little lifecourse research looking at the risk of osteoarthritis (OA). Several studies have demonstrated the association between adult risk factors such as obesity and higher bone mineral density with subsequent knee OA. Objectives We performed a lifecourse analysis of risk factors for knee OA (defined by osteophytes on ultrasound) acting at different stages of life, including early life factors, among members of the Newcastle Thousand Families birth cohort. Methods Potential risk factors for knee osteoarthritis (including birth weight, breast feeding data and socioeconomic status) have been collected prospectively in this birth cohort of subjects aged 63 (born in May-June 1947) and an a priori conceptual framework was developed. Subjects had both knees scanned by a trained musculoskeletal sonographer. Ultrasound protocols were derived from EULAR guidelines. The presence of knee osteophytes was assessed at the tibial and femoral sites, medially and laterally. These data were analysed in relation to a range of factors from across the lifecourse using logistic regression models. Results Among the 311 participants, the prevalence of knee osteophytes was 22%, 25% and 30% for right, left and “any” knee, respectively. While birth weight, exclusive breast feeding and social class at birth showed significant univariate associations with knee osteophytes, only exclusive breast feeding (among factors acting in early life) showed a significant association in the adjusted model (OR 0.81 per month; CI 0.68, 0.97; p=0.02). BMI (OR 1.11; CI 1.02, 1.20; p=0.01) and total hip bone mineral density at age 50 (OR 1.37 per 0.1 g/cm2; CI 1.06, 1.78; p=0.02) were the factors acting in adulthood that increased the risk of knee osteophytes at age 63. Serum fibrinogen levels at age 50 (a surrogate marker of inflammation) showed a borderline significant association in the multivariate model (OR 1.68 per g/L; CI 0.99, 2.85). The univariate effect of social class at birth on knee osteophytes was found to be mediated by its subsequent effect on breast feeding and total hip bone mineral density. Conclusions This is the first study to perform a lifecourse analysis of knee OA risk using prospectively collected data. While exclusive breast feeding is known to decrease risk of adult obesity and therefore of knee OA, this study suggests that exclusive breast feeding is an independent predictor of knee OA. The mechanism might be reduced burden of infection and inflammation through the lifecourse, a testable hypothesis. Systemic inflammation itself (as measured by serum fibrinogen at age 50) might be an independent predictor of knee osteophytes. Disclosure of Interest None Declared

OP0032 Ultrasound features of osteophytes and cartilage thickness at the knee are associated with pain and functional impairment: The newcastle thousand families study

Background The association of structural changes of osteoarthritis (OA) on imaging and clinical symptoms has seen contradictory results in previous studies. Objectives We performed a comparison of ultrasound features of knee OA with clinical symptoms among members of the Newcastle Thousand Families birth cohort. Methods Participants from the cohort aged 63 (born in May-June 1947), had both knees scanned by a trained musculoskeletal sonographer. Ultrasound protocols were derived from EULAR guidelines. Knee osteophytes (yes/no), minimum femoral cartilage thickness in right knee (cm) and effusion >4 mm (yes/no) were the pathologies identified. These data were analysed in relation to pain, stiffness and dysfunction in the lower limbs as reported by participants using the WOMAC questionnaire. Each of the three WOMAC subscales was subdivided in to four categories of severity. Logistic and linear regression was used to calculate the association of features of knee OA with clinical symptoms. Adjustment for potential confounders such as BMI, sex and presence of knee effusion were also performed. Results 311 participants were scanned; 55% women, mean BMI was 27.9. Prevalence of knee osteophytes was 30%, mean right knee minimum cartilage thickness was 1.47 cm; prevalence of knee effusions was 22%. Those in the highest category of pain had an OR of 4.42 for osteophytes (95% CI 2.17, 8.98) when compared to those without knee pain. Similarly, those with severe stiffness had an OR of 4.21 (95% CI 2.01, 8.83) and those with physical dysfunction had an OR of 4.15 (95% CI 1.96, 8.80) for knee osteophytes when compared to those with no symptoms. These estimates were reduced in magnitude but remained statistically significant after adjustment for BMI and sex. Minimum cartilage thickness was associated with pain (adjusted co-efficient -0.11; 95% CI -0.20, -0.01) and physical dysfunction (adjusted co-efficient -0.13; 95% CI -0.24, -0.02) but not stiffness; when comparing those in the most severe symptom category with those without symptoms. Knee effusion had no association with any of the three subscales of the WOMAC questionnaire. Conclusions This is the first study to compare ultrasound features of OA with clinical symptoms in a population based cohort. The presence of knee osteophytes had a positive association with pain, stiffness and physical dysfunction in the lower limbs. Femoral cartilage thickness in the knee had an inverse association with pain and physical dysfunction. However, there was no association of knee effusion with pain, stiffness or dysfunction. The associations of ultrasound detected osteophytes and cartilage thickness with clinical symptoms improve our understanding of the relationship between symptoms and structural changes in knee OA. This also demonstrates the potential utility of ultrasound in prospective population based epidemiological studies of OA as well as in clinical practice. Disclosure of Interest None Declared