O3021 ARTHROFIBROSIS IN TKA IS ASSICIATED WITH FEMORAL COMPONENT MAL-ROTATION

Abstract

Aims: The purpose of this study was to determine whether internal malrotation of the femoral component is associated with arthroþbrosis in TKA. We hypothesized arthroþbrosis may be triggered by a combination of nonphysiological kinematics (femoral component internal rotation) and a tight medial compartment. Methods: From a consecutive cohort of 3058 mobile bearing TKA forty-four (1.4%) cases were diagnosed as having arthroþbrosis, of which thirty-eight (86%) cases could be recruited. Thirty-eight patients with a well functioning TKA served as matched controls. Evaluation included CT investigation to determine femoral component rotation with reference to the transepicondylar axis (TEA). Results: Femoral components in the AF group were signiþcantly (p< 0.00001) internally mal-rotated by a mean of 4.7 degrees ranging from ten degrees internal rotation (IR) to one degree external rotation (ER). Mean femoral rotational in the control group was parallel (0.3 degrees IR) to the TEA (six degrees IR to four degrees ER). Arthroþbrosis was not associated with age, gender, body-mass-index, or preoperative diagnosis. Conclusions: There is a highly signiþcant association between arthroþbrosis in TKA and internal mal-rotation of the femoral component. On the base of these results it was hypothesized that non-physiological kinematics in TKA with mal-aligned femoral components inßuence and/or trigger arthroþbrosis in TKA. In TKA with arthroþbrosis, we now consider femoral CT evaluation with the view to surgically rebalancing the ßexion gap and realigning the femoral component, when internal mal-rotation is conþrmed.