Electroarthrography Provides a Non-invasive Streaming Potential-Based Method for Detecting Cartilage Degeneration in an Equine Model Transactions

Degenerative joint diseases, like osteoarthritis, are characterized by progressive cartilage degeneration, which can lead to pain and loss of mobility. Low-grade cartilage deterioration occurs early in disease progression and may be treatable. However, current clinical assessment methodologies, including physical exam, synovial fluid analysis and imaging, may not be sensitive enough to detect early degenerative changes. Electroarthrography (EAG) is a new technology capable of measuring streaming potentials produced by cartilage during compression through electrodes applied to skin surrounding an articular joint. Streaming potentials arise from interactions among constituents of the cartilage extracellular matrix during load bearing and provide a sensitive measure of cartilage degeneration. Consequently, EAG may provide a sensitive, non-invasive method for detecting low-grade cartilage degeneration. Its response to trypsin degradation of cartilage was explored here in an equine model. EAG coefficients were significantly reduced (p<0.05) following trypsin degradation of cartilage duringstanding (1630±81 N) & walking (3082±134 N) loads. More dramatic reductions were observed during walking, 48%±6%, compared to standing, 27%±4%, at palmar sites (CH 1, CH 2, CH 7, CH 8) (Fig. 5). Higher QP, indicating lower cartilage stiffness, were measured in degraded cartilage on both the cannon (p<10-4, n=40) & phalanx (p<10-5, n=35) (Fig. 6), which corroborates reductions in EAG. Both indirect and direct measurements of cartilage streaming potentials, by EAG and the Arthro-BST, respectively, detected cartilage damage that was not visible to the unaided eye. These data demonstrate the potential for EAG to provide a sensitive, non-invasive diagnostic of cartilage health that could contribute to the early detection and treatment of osteoarthritis and other degenerative joint diseases.