Arthroscopic estimation of the extent of chondropathy S.P. Oakley, M.B.B.S., F.R.A.C.P., Grad Dip Clin Epi, Ph.D., I. Portek, M.B.B.S., F.R.A.C.P., Z. Szomor, M.D., F.R.A.C.S. (Ortho), R.C. Appleyard, B.E. Mech (Hons), Ph.D., P. Ghosh, D.Sc., Ph.D., B.Sc. (Hons), F.R.A.C.I., F.R.S.C., B.W. Kirkham, M.B., Ch.B., M.D., F.R.C.P., F.R.A.C.P., G.A.C. Murrell, M.B.B.S., D.Phil. (Oxon), M.N. Lassere, M.B.B.S. (Hons), Grad Dip Epi, F.R.A.C.P., F.A.F.P.H.M., Ph.D.  Osteoarthritis and Cartilage  Volume 15, Issue 5, Pages 506-515 (May 2007) DOI: 10.1016/j.joca.2006.10.013 Copyright © 2006 Osteoarthritis Research Society International Terms and Conditions

Fig. 1 Receiver–Operator characteristic curve for determining the optimal cut-off of dynamic shear modulus (G∗) for discriminating normal AC from AC softened due to OA. At bottom-left a lower AC stiffness cut-off (G∗=0.50) yields high specificity (>0.95) but low sensitivity (<0.10). At top-right a higher AC stiffness cut-off (G∗=3.50) yields high sensitivity (>0.95) but low specificity (<0.30). The optimal performance is the point on the curve closest to the top-left corner (G∗=1.375, sensitivity 0.55, specificity 0.75). Osteoarthritis and Cartilage 2007 15, 506-515DOI: (10.1016/j.joca.2006.10.013) Copyright © 2006 Osteoarthritis Research Society International Terms and Conditions

Fig. 2 Hybrid non-arthroscopic grade of the severity of chondropathy. At each grid reference point macroscopic assessments were used to distinguish between fibrillated and non-fibrillated articular cartilage and chondro-osteophyte AC. Dynamic shear modulus (G∗) was then used to distinguish between normal and softened AC while superficial and deep fibrillation and exposed bone were defined by micrometer measurements of AC thickness. Osteoarthritis and Cartilage 2007 15, 506-515DOI: (10.1016/j.joca.2006.10.013) Copyright © 2006 Osteoarthritis Research Society International Terms and Conditions

Fig. 3 Content validity: the mean extent of each grade of chondropathy within areas “seen” and “not seen” arthroscopically are shown. Extensive pathological changes occurred in both areas “seen” and “not seen” arthroscopically. Osteoarthritis and Cartilage 2007 15, 506-515DOI: (10.1016/j.joca.2006.10.013) Copyright © 2006 Osteoarthritis Research Society International Terms and Conditions

Fig. 4 (a) Arthroscopic estimates (top row) and hybrid non-arthroscopic assessments (middle row) of the extent of chondropathy and the differences between them (accuracy difference scores, bottom row) at the patella, femoral trochlea and medial femoral condyle. Significance of changes over time for arthroscopic estimates (top row) is indicated as one-way ANOVA P values and Bonferroni comparisons with pre-MMx assessments [#P<0.05, ##P<0.01 and ###P<0.001 and NS not significant]. Error bars have not been included for “true extent of chondropathy” and “accuracy of arthroscopy” because numbers were too small to assess statistical significance. (b) Arthroscopic estimates (top row) and hybrid non-arthroscopic assessments (middle row) of the extent of chondropathy and the differences between them (accuracy difference scores, bottom row) at the medial tibial plateau, lateral femoral condyle and lateral tibial plateau. Significance of changes over time for arthroscopic estimates (top row) is indicated as one-way ANOVA p values and Bonferroni comparisons with pre-MMx assessments [#P<0.05, ##P<0.01 and ###P<0.001 and NS not significant]. Error bars have not been included for “true extent of chondropathy” and “accuracy of arthroscopy” because numbers were too small to assess statistical significance. Osteoarthritis and Cartilage 2007 15, 506-515DOI: (10.1016/j.joca.2006.10.013) Copyright © 2006 Osteoarthritis Research Society International Terms and Conditions

Fig. 4 (a) Arthroscopic estimates (top row) and hybrid non-arthroscopic assessments (middle row) of the extent of chondropathy and the differences between them (accuracy difference scores, bottom row) at the patella, femoral trochlea and medial femoral condyle. Significance of changes over time for arthroscopic estimates (top row) is indicated as one-way ANOVA P values and Bonferroni comparisons with pre-MMx assessments [#P<0.05, ##P<0.01 and ###P<0.001 and NS not significant]. Error bars have not been included for “true extent of chondropathy” and “accuracy of arthroscopy” because numbers were too small to assess statistical significance. (b) Arthroscopic estimates (top row) and hybrid non-arthroscopic assessments (middle row) of the extent of chondropathy and the differences between them (accuracy difference scores, bottom row) at the medial tibial plateau, lateral femoral condyle and lateral tibial plateau. Significance of changes over time for arthroscopic estimates (top row) is indicated as one-way ANOVA p values and Bonferroni comparisons with pre-MMx assessments [#P<0.05, ##P<0.01 and ###P<0.001 and NS not significant]. Error bars have not been included for “true extent of chondropathy” and “accuracy of arthroscopy” because numbers were too small to assess statistical significance. Osteoarthritis and Cartilage 2007 15, 506-515DOI: (10.1016/j.joca.2006.10.013) Copyright © 2006 Osteoarthritis Research Society International Terms and Conditions