Innovative design and evaluation of a reusable drill guide for distal cement plug removal in total hip arthroplasty revision

Abstract

Distal cement plug removal in total hip arthroplasty revision is a time-consuming and technically challenging procedure. There is a risk of perforating the femur while drilling in the cement plug. This risk increases when the orientation of the prosthesis tip is excentric. The aim of this study was to design a reusable drill guide that facilitates centric drilling in the cement plug and to evaluate this design. The extremity of the drill guide contains two centralizers. Activation of the centralizers results in the centralization of the drill guide in the femur. A set of requirements was defined for the drill guide. To check if the drill guide meets these requirements, different tests were performed. The centralizers were tested in a fatigue test and a radial force test. The usability and functionality of the drill guide were tested in a simulation of the cement plug removal procedure performed by an orthopaedic surgeon. In this simulation was a cement plug in a bone sample drilled in three different conditions. The first condition was without the drill guide. The second condition was with the drill guide by which the handle was kept pressed during the drilling. The third condition was with the drill guide but the handle was released after activation. Furthermore, the disassembly and assembly of the drill guide were tested by five inexperienced test subjects, and the cleaning and sterilization of the drill guide were discussed with experts. This study's results show that the drill guide prototype meets the requirements. The centralizers could be activated ten times without breaking and will not apply a force on the bone that exceeds the yield stress of cortical bone. The absolute deviation of the position of the drilled hole from the centre of the cement plug was significantly lower in the tests with the drill guide compared to the tests without the drill guide. The same test showed that the generated temperature by the drill guide will not cause bone necrosis. Furthermore, the (dis)assembly of the drill guide was performed in less than 110 s. However, the drill guide would benefit from some design adjustments and further testing, such as testing the durability after multiple sterilization cycles. When this is included in the design, the drill guide could be a valuable addition to the standard tools in THA revision.