Physical Activity and Investigation With Magnetic Resonance Imaging Partly Explain Variability in the Prevalence of Patellar Tendon Abnormalities: A Systematic Review With Meta-analysis of Imaging Studies in Asymptomatic Individuals

Objective To estimate the pooled prevalence of, and factors associated with, the presence of patellar tendon abnormalities observed on imaging in people without symptoms. Design Systematic review with stratified meta-analysis and meta-regression. Literature Search We searched Embase, Scopus, MEDLINE, CINAHL, SPORTDiscus, and Web of Science from 1980 to August 2020. Study Selection Criteria We included studies that reported the prevalence of asymptomatic patellar tendon abnormalities on imaging. We excluded studies of participants with current tendon pain, a history of tendon pain, or other systemic conditions. Data Synthesis Stratification and meta-regression of studies based on study-level descriptive statistics (mean age, body mass index, proportion of female participants, physical activity participation, imaging modality) were performed using a random-effects model to account for between-study heterogeneity. Risk of bias was assessed using the modified Newcastle-Ottawa scale. Results Meta-analysis of 64 studies (7125 limbs from 4616 participants) found significant between-study heterogeneity (I 2 ≥90%, P<.01), which precluded a summary prevalence estimate. Heterogeneity was partially explained by studies that included participants who were physically active and studies that assessed tendon abnormalities using magnetic resonance imaging compared to ultrasound (P<.05). Mean age, body mass index, proportion of female participants, and sample size did not explain the remaining heterogeneity. Conclusion There was substantial variability in the reported prevalence of asymptomatic patellar tendon abnormalities. A clear and valid method is needed to assess and report the presence of patellar tendon abnormalities to increase research capacity and establish the clinical value of imaging the patellar tendon. J Orthop Sports Phys Ther 2021;51(5):216–231. Epub 28 Mar 2021. doi:10.2519/jospt.2021.10054