Kuvista oivalluksiin olkapäävaivojen hoidossa : Olkapään kuvantamislöydösten esiintyvyys ja yhteys oireisiin yleisväestössä

Background: Structural abnormalities of the rotator cuff and glenohumeral joint are frequently detected on shoulder imaging, yet their true population prevalence and relationship with shoulder symptoms remains uncertain. Clinical practice often assumes a causal link between imaging findings and symptoms, despite limited evidence. Aims: This thesis aimed to (1) synthesise existing evidence on the prevalence of rotator cuff abnormalities and glenohumeral osteoarthritis in asymptomatic individuals (Studies I–II); (2) generate robust population-level prevalence estimates and examine their association with symptoms using a large population-based imaging study (Studies III–V); and (3) translate these findings into clinical guidance for primary care (Study VI). Methods: Two systematic reviews were conducted to evaluate the existing literature. To address the substantial evidence gaps identified, the FIMAGE study was designed as a population-based imaging cohort of 602 adults aged 41–76 years randomly sampled from the Finnish Health 2000 cohort. Participants underwent clinical examination, bilateral shoulder Magnetic Resonance Imaging (MRI), and shoulder radiography. Prevalence estimates were calculated, and associations with shoulder symptoms were evaluated using confounder-adjusted models. Results: The systematic reviews demonstrated very low certainty of evidence: nearly all included studies were at high risk of bias, and only five were population-based. Reported prevalence estimates of imaging abnormalities ranged from 0% to 100%, and differences between symptomatic and asymptomatic individuals were inconsistent. In the FIMAGE study, rotator cuff abnormalities were highly prevalent: 99% of participants had at least one imaging abnormality, with prevalence and severity increasing with age. Among 1204 shoulders, rotator cuff abnormalities were similarly common in asymptomatic (96%) and symptomatic (98%) shoulders. Although full-thickness tears were more frequent in symptomatic shoulders, the association was attenuated and no longer statistically significant after adjustment; most full-thickness tears occurred in asymptomatic individuals. Glenohumeral osteoarthritis was present in 39% of participants, increased with age, and was more common in men. The prevalence difference of osteoarthritis between asymptomatic (29%) and symptomatic (36%) shoulders was small and diminished after adjustment. Conclusions: Structural shoulder imaging abnormalities are common in the general population and show only weak associations with symptoms. These findings challenge structurally centred diagnostic models and suggest that many imaging findings may represent age-related variation rather than a direct cause of pain. Routine imaging in the absence of clear clinical indications is therefore unlikely to improve diagnostic precision or patient outcomes. Future progress will depend on improving our understanding of the mechanisms underlying shoulder symptoms and aligning diagnostic and therapeutic strategies with those mechanisms rather than with structural findings alone.