Liu SS, Buvanendran A, Rathmell JP, Sawhney M, Bae JJ, Moric M, Perros S, Pope AJ, Poultsides L, Della Valle CJ, Shin NS, McCartney CJ, Ma Y, Shah M, Wood MJ, Manion SC, Sculco TP. Predictors for moderate to severe acute postoperative pain after total hip and knee replacement. Int Orthop. 2012 Nov; 36(11):2261-7.