T1rho Magnetic Resonance Imaging at 3T Detects Knee Cartilage Changes After Viscosupplementation.

T1rho Magnetic Resonance Imaging at 3T Detects Knee Cartilage Changes After Viscosupplementation Roshan P. shah, MD; JeffRey B. staMBough, MD; Matthew fenty, MBa; RoBeRt L. Mauck, PhD; John D. keLLy, MD; RavinDeR ReDDy, PhD; fotios P. tJouMakaRis, MD Viscosupplementation may affect cartilage. Changes in T1rho magnetic resonance imaging (MRI) relaxation times correlate with proteoglycan changes in cartilage. The authors hypothesized that T1rho MRI will show an improvement in proteoglycan content at 6 weeks and 3 months after viscosupplementation and that this improvement will correlate with functional outcome scores. Ten patients (mean age, 56 years; Kellgren-Lawrence grade 1 or 2) underwent T1rho MRI at baseline, 6 weeks, and 3 months after viscosupplementation. Volumetric T1rho means were calculated by depth and region. Visual analog scale (VAS), International Knee Documentation Committee (IKDC), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were obtained. Mean T1rho values decreased in the superficial patella at 6 weeks (10.3%, P=.002) and 3 months (7.9%, P=.018) and in the middle patella at 6 weeks (7.0%, P=.014) compared with baseline values. Deep patella T1rho values increased at 3 months compared with 6 weeks (9.9%, P=.033), returning to values similar to baseline. Mean T1rho values increased in the deep tibia at 6 weeks (4.7%, P=.048) and in the middle tibia (5.2%, P=.004) and deep tibia (11.2%, P=.002) at 3 months compared with baseline. At 6 weeks, improvement was seen in VAS (5.9 to 3.9, P<.01), IKDC-9 (55.3 to 63.7, P=.03), and WOMAC (43.9 to 32.8, P=.03) scores. Functional VAS (4.0, P=.02), IKDC-9 (67.8, P=.04), and WOMAC (30.0, P=.04) scores remained better at 3 months. T1rho MRI is a feasible noninvasive method of studying molecular changes in cartilage. Some segments improved after viscosupplementation, and others worsened, possibly reflecting natural history or symptom relief and subsequent increase in activity-related wear. [Orthopedics. 2015; 38(7):e604-e610.] The authors are from the Department of Orthopaedic Surgery (RPS, JBS, RLM, JDK), McKay Orthopaedic Research Laboratory, and the Center for Magnetic Resonance and Optical Imaging and Department of Radiology (MF, RR), University of Pennsylvania, Philadelphia, Pennsylvania; and The Rothman Institute (FPT), Egg Harbor Township, New Jersey. The authors have no relevant financial relationships to disclose. Correspondence should be addressed to: Fotios P. Tjoumakaris, MD, The Rothman Institute, 2500 English Creek Ave, Egg Harbor Township, NJ 08234 (fotios.tjoumakaris@rothmaninstitute.com). Received: April 24, 2014; Accepted: September 2, 2014. doi: 10.3928/01477447-20150701-59