Raman needle probe for compositional and structural analysis of articular cartilage during early osteoarthritis

Osteoarthritis (OA) is a painful, debilitating disease characterized by the degeneration of articular cartilage. We have developed a novel multiplexed polarized, hypodermic-needle-compatible Raman arthroscope probe that can achieve intra-articular assessments of the compositional and structural changes to cartilage associated with early-stage OA, including depletion of glycosaminoglycans from the cartilage superficial regions and changes to superficial zone collagen alignment. Through ex vivo models on human and bovine cartilage, we demonstrate that using multivariate linear regression, this platform can accurately measure superficial zone cartilage GAG depletion. This work shows that Raman needle arthroscopy can provide a practical, minimally invasive, point-of-care clinical tool capable of diagnosing OA before irreparable cartilage degeneration is radiographically evident.