1. OARSI Clinical Trials Recommendations: Knee imaging in clinical trials in osteoarthritis 
D.J. Hunter, R.D. Altman, F. Cicuttini, M.D. Crema, J. Duryea, F. Eckstein, A. Guermazi, R. Kijowski, T.M. Link, J. Martel-Pelletier, C.G. Miller, T.J. Mosher, R.E. Ochoa-Albíztegui, J.-P. Pelletier, C. Peterfy, J.-P. Raynauld, F.W. Roemer, S.M. Totterman, G.E. Gold 
Osteoarthritis and Cartilage 
Volume 23, Issue 5, Pages (May 2015)
DOI: /j.joca
Copyright © 2015 Osteoarthritis Research Society International Terms and Conditions

2. Fig. 1
(a). Positioning of the conventional extended knee AP or PA radiograph with horizontal beam. (b). Skewed radio-anatomic alignment of the medial tibial plateau apparent in the displacement of anterior and posterior margins (arrows) and difficulty identifying the cortex of the floor of the plateau.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
Copyright © 2015 Osteoarthritis Research Society International Terms and Conditions

3. Fig. 2
Radiographs at baseline and 2-year follow-up of a 61-year-old woman with OA. At two time points, radiographs were taken with 5°, 10°, and 15° angulation of the knee. (a) AP radiograph taken at 5° angulation shows medial JSN (OARSI grade 2 and KLG 3). (b) However, AP radiograph taken at 10° angulation shows OARSI grade 3 JSN (KLG 4). (c) Similarly, at follow-up, AP radiograph taken at 5° angulation shows OARSI grade 2 JSN (KLG 3) whereas that taken at 15° angulation (d) shows OARSI grade 3 JSN (KLG 4). If images (b) and (c) are compared longitudinally, one observes a paradoxical ‘joint space widening’.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
Copyright © 2015 Osteoarthritis Research Society International Terms and Conditions

4. Fig. 3
In this example using fixed flexion PA protocol, the joint space will appear wider when a beam that is parallel to the tibial plateau is used (thick dotted line) compared to when a beam is slightly angulated with respect to the tibial plateau (thin dotted line). Therefore, tube angulation needs to be kept constant between time points, as well as the angle of flexion of the knee. For the mLS technique with varying angles at baseline, the technologist at acquisition has to reference the baseline radiograph and tube angle used.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
Copyright © 2015 Osteoarthritis Research Society International Terms and Conditions

5. Fig. 4
QC, retrieved from accessed 05 February 2014.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
Copyright © 2015 Osteoarthritis Research Society International Terms and Conditions