Geographical variation in patient outcomes of primary knee replacement across clinical commissioning groups: study from “The National Joint Registry of England, Wales, Northern Ireland and the Isle of Man” - Garriga, C; Leal, J; Price, A; Prieto-Alhambra, D; Carr, A; Rangan, A; Cooper, C; Fitzpatrick, R; Barker, K; Peat, G; Arden, N; Judge, A (European Congress of Rheumatology 2019, 2019)