The Knee Osteoarthritis Grading System (KOGS) for arthroplasty - Oosthuizen, CR; Takahashi, T; Rogan, DM; Hans, Snyckers C; Peter, Vermaak D; Griffith, Jones G; Porteous, A; Maposa, I; Pandit, H (The Journal of Arthroplasty, 2019)