Abstract / Summary
Knee osteoarthritis (OA) is a common musculoskeletal disease and a major public health issue with increasing prevalence worldwide. Our objective is to evaluate the potential of acoustic emissions (AE) and kinetic instability (KI) of the osteoarthritic knee joint as diagnostic biomarkers when using magnetic resonance imaging (MRI) as the reference. Sixty-six females (age 44–67 years) and 40 males (age 45–64 years) were recruited for this single-center prospective cohort study. Knee MRI was performed and full MOAKS grading (MRI Osteoarthritis Knee Score) was applied to define the OA status of the subjects. A custom-made prototype was used to record AE and KI of the knee joint during simple physical tasks. The device included two non-contact air microphones located just below the patella and inertial measurement unit modules fixed on the thigh and shank. Statistical analysis based on logistic regression was performed. We found statistically significant associations between a set of 35 acoustic variables and 6 relevant MOAKS parameters from the MRI. A few of them showed some discriminative value in terms of detecting OA findings. We would highlight the lateral sit-to-stand high frequency and clicks acoustic emissions ratio to predict bone marrow lesions in lateral femur and the lateral sit-to-stand skewness high and low frequency acoustic emissions to predict both lateral meniscal position and morphology and effusions with AUC values ranging between 0.65 and 0.70. When stratifying the analysis by sex, we found significant results only for females, for the bone marrow lesions in lateral femur and effusion MOAKS parameters. Accordingly, the males reinforced the association when combined with females, but were not significant on their own. AE and KI showed exploratory associations with specific MRI-detected osteoarthritic changes, which may point to some diagnostic potential. Pending confirmation in larger studies, these signals might be explored as a complementary modality for characterizing knee OA. Trial registration number: This study was registered at clinicaltrials.gov with study identifier NCT02937064 date 2016-10-18.