Minimally Invasive Polarization Sensitive Optical Coherence Tomography (PS-OCT) for assessing Pre-OA, a pilot study on technical feasibility

OBJECTIVE: Efforts to develop chondroprotective approaches to halt osteoarthritis (OA) progression have recently increased. Current imaging techniques are critical in managing advanced OA, but greater resolution is needed to identify reversible stages (pre-OA). Optical coherence tomography (OCT) is a micron scale imaging technology widely used in ophthalmology, cardiology, and neurology. We previously demonstrated that polarization sensitive OCT (PS-OCT) can identify pre-OA in vitro, in animals, and in open surgical fields. This feasibility study examines performing intraarticular PS-OCT using a flexible endocatheter introduced through a stiff 18-gauge spinal needle. Results are critical for designing larger clinical trials examining minimally invasive PS-OCT's ability to identify pre-OA. DESIGN: Fifteen patients undergoing arthroscopic partial medial meniscectomy were selected to confirm their risk for rapid progression to OA. Magnetic resonance imaging (MRI) was obtained at time 0 and at 2.5 years to determine if significant OA developed over this short period and for correlation with time zero PS-OCT results. RESULTS: Over half of the patients developed frank OA by 2.65 ​± ​0.28 years. All cartilage surfaces were successfully imaged by PS-OCT, but endocatheter redesign is needed. Normal to severely abnormal areas by PS-OCT (all normal by MRI) were successfully identified. PS-OCT assessments were promising for predicting OA progression (p ​< ​0.008). However, the study's low power prevented definite conclusions regarding predictive value. CONCLUSIONS: This pilot study produced at least two outcomes critical for future larger trial designs: medial meniscectomy patients are well-suited for studying PS-OCT's ability to predict future OA and substantial endocatheter redesign is needed.