Vogel M, Frenzel L, Riediger C, et al. - Researchers aimed at assessing the influence of borderline personality organization (BPO) on the outcomes of TKA 1 year postoperatively. They evaluated knee pain and function in 144 patients scheduled for primary TKA before and after the operation using the IPO-16 and the WOMAC. Observations revealed non-parametric correlations between primitive defenses and knee-pain, not function. As per linear regression, the preoperative WOMAC scores could predict knee pain and knee function, whereas there was an additional prediction of knee-pain by gender and primitive defenses. The results propose a psychodynamic mechanism of maladaptation following TKA possibly describing the bodily manifestations of fundamental psychic defenses.