TKA-Revision with maintenance of well-fixed metaphyseal sleeves: Indications and surgical technique.

Due to the compromised bone situation revision implants need extended fixation options in order to achieve good long-term survival. Over decades this has been achieved with stems, either cemented or uncemented. In the last decade additional fixation options in terms of cementless metaphyseal sleeves or metaphyseal cones have been introduced and widely accepted. Revision of such implants is challenging, in particular if those porous coated parts are well integrated. Therefore, partial revision leaving the well-fixed parts in place can be an option if the indication is allowing it. This can help to preserve bone. In this study we show 2 cases with metaphyseal sleeves, in which we demonstrate when and how revision can be performed leaving sleeves in place. Meticulous pre-Op analysis of the failure mechanism is mandatory to find those few cases in which a partial revision can be recommended. In our cases, it was one patient with persistent tibia stem pain and another patient with secondary instability. In both cases implant fixation was not the problem, and therefore leaving the well-fixed sleeves in place was considered. Before final decision was made, specific information on implants sizes and constraint are needed. In our tibial revision stem thickness was less than 14 mm decision, in this situation the stem can be removed through the sleeve, leaving the sleeve in place. The technique how to do it, is shown in this study. In the second case a traumatic MCL rupture was leading to a secondary instability, needing a revision from a VVC constraint to a rotating hinge. Again, pre-Op analysis and the surgical technique of femoral component removal are described. In the great majority of cases a full revision with complete implant removal is required. In a few cases a partial revision with maintenance of implant parts can be considered but only after careful analysis of the failure mode. Even if the failure mode allows a partial revision specific implant information need to be obtained to clarify whether it is really possible. If it is possible, a specific surgical technique is recommended and described in this study.