Arthroscopic surgical procedures versus sham surgery for patients with femoroacetabular impingement and/or labral tears: study protocol for a randomized controlled trial (HIPARTI)... por Risberg, M, Ageberg, E, Nilstad, A, Lund, B, Nordsletten, L, Løken, S, Ludvigsen, T, Kierkegaard, S, Carsen, S, Kostogiannis, I, Crossley, K, Glyn-Jones, S, Kemp, J