Design of novel drill guide device for cement removal in revision hip arthroplasty.

Total hip arthroplasty (THA) is one of the most commonly performed surgical procedures. The requirement for revision hip arthroplasty (RHA) is increasing due to the increased use of THA in the elderly population and in younger patients with high physical demands. The revision rate for THA is approximately 10% at ten years. Removal of the distal cement plug in revision hip arthroplasty is a technically challenging procedure. Its location makes it difficult to visualise and this can lead to perforation or fracture of the surrounding bone during removal of the plug. The primary aim of this work was to design a drill guide device that would guide a drill bit along a pre-determined path through the centre of the cement plug. This would then ensure its safe removal and thus decrease the risk of perforation or fracture of the surrounding bone. The design chosen was a pre-drilled femoral prosthesis. This prosthesis was then tested on a series of synthetic bones and cadaveric specimens. The two most common implants used in primary THA, Chamley and Exeter, were tested. There were two other components to the study. Firstly, a radiographic assessment of all RHAs performed at Cappagh hospital over a one-year period was undertaken. Secondly, an experiment to assess the cutting forces experienced as the drill bit passes through the cement was designed. This was in an attempt to determine the most favourable drill bit characteristics for cement drilling