Utilising advanced imaging to understand joint pain and function limitations in older adults

Joint pain and physical function limitation are highly prevalent in older adults and are key symptoms of osteoarthritis. Imaging joints using modern advanced imaging techniques allow assessment of joint abnormalities in soft tissue, which may allow prediction of pain and prevention of deformities and functional loss, should adequate treatment targets be identified. Therefore, this thesis aims to study joint structural abnormalities of the knee and hand using advanced imaging technologies and investigate associations with pain, physical function limitation and other symptoms in TASOAC, the Tasmanian older adult cohort study, a population-based sample of 1099 community-dwelling adults aged of 50-80 years examined at baseline and after 2.7 and 10.7 years. This thesis encompasses four studies using TASOAC data. In the first study, cross-sectional and longitudinal associations between knee abnormalities at the patellar tendon enthesis (PTE) and knee symptoms and other important knee structural abnormalities were assessed. The prevalence of PTE abnormalities (bone signal and/or erosion) was 20%. PTE abnormalities were associated with greater pain intensity while going up and down stairs, greater risk of femoral BMLs, worse tibial cartilage defect scores, and smaller infrapatellar fat pad area. The presence of baseline PTE abnormalities was associated with a deleterious increase in tibial BML size over 10.7 years but not symptoms, other structural changes, or total knee replacement. In the second study, associations between knee bone marrow lesions (BMLs) present on two different MRI sequences with clinical outcomes, cartilage changes over 2.7 years, and total knee replacement surgery over 13.3 years were investigated. BMLs seen on T1-weighted GRE and T2-weighted FSE MRI sequences were equivalently associated with clinical outcomes, including symptoms, worsening cartilage defects, cartilage volume loss, and total knee replacement surgery. The third study describes cross-sectional associations between abnormal joint features observed on ultrasound or clinical joint examination and hand symptoms. Joint abnormalities measured using clinical assessment and ultrasonography had moderate reliability, which may have widened the confidence interval compared to a measure with high or very high reliability. The presence of hand joint nodules and osteophytes detected using clinical assessments and ultrasound was ubiquitous in older adults and was not associated with any symptoms. While most joint abnormalities were asymptomatic, we found several joint abnormalities that correlated with symptoms. A greater number of tender joints were associated with greater pain (target hand pain on VAS and AUSCAN pain), poorer physical function limitation, and poorer grip strength. Power Doppler imaging synovitis was associated with greater pain but not function. The greater number of joints with deformity was associated with poorer physical function limitation and grip strength but not pain. Grey scale synovitis was associated only with poorer grip strength. Despite the moderate reliability of clinical examinations, our study found significant associations, demonstrating that the examinations performed were clinically useful. In the fourth study, cross-sectional associations between hand abnormalities on MRI or radiographs and pain and function limitation were determined. Absent collateral ligaments and joint space narrowing were associated with painful joints and weak grip strength, independent of pain and other imaging features. Joint space narrowing was also associated with tender joints and absent collateral ligaments with stiff joints. Unexpectedly, effusions were associated with reduced odds of pain. In conclusion, this series of studies indicated that PTE abnormalities may not play a major role in symptom development or knee structural changes, except tibial BMLs, and that BMLs assessed on both T2 and T1 MRI sequences have equal clinical predictive value. Absent CLs and JSN were associated with painful joints and weak grip strength independent of pain and other imaging features. JSN was also associated with tender joints and absent CLs with stiff joints. Unexpectedly, effusions were associated with reduced odds of pain. Overall, most abnormalities seen on hand MRIs were not associated with pain and physical function limitation. Tender joints on palpation and ultrasound-detected PDI synovitis are potential treatment targets for hand pain; adequate treatment of tender joints and prevention of hand deformity are needed to improve hand function in older adults. This thesis contributes to the discovery of new knowledge about the relationship between several knee and hand joint abnormalities and joint symptoms. The results described in this thesis will help researchers and clinicians to make important decisions about treatment targets for clinical trials. This thesis also showed that using advanced imaging is practical in routine clinical practice, especially hand joint ultrasonography and MRI.