Leg length measurement: a new method to assure the correct leg length in total hip arthroplasty

The precise measurement of leg length plays an important role in total hip arthroplasty. Leg length inequality occurs frequently after total hip arthr oplasty and may cause patient discomfort. Current clinical methods used for measuring leg length are not accurate enough to meet the demands of precis ion required for hip replacement. The aim of this study was to examine the validity of determining leg length differences using an ultrasound system, The proposed system measures the distance between three points, in millimet res, so that the difference between preoperative and postoperative measurem ents gives an indication about the leg length. The mean ultrasound variatio n observed in in vitro measurements showed a relative error of 1.7% (range: 52-133 mm) that means a leg length inequality of about 0.4 mm (range: 52-1 33 mm). The method is non-invasive (ultrasound is not limited by radiation hazards), easy, quick to use, and can be used for standard clinical screeni ng. (C) 2000 IPEM. Published by Elsevier Science Ltd. All rights reserved.