Diagnostic value of duplex ultrasound and liquid crystal contact thermography in preclinical detection of deep vein thrombosis after proximal femur fractures.

During a prospective clinical study the diagnostic value of the two non-invasive examinations colour-coded duplex ultrasound (Duplex) and fluid crystal contact thermography (LCCT) was investigated in relation to phlebography, the standard examination for the diagnosis of deep vein thrombosis (DVT), in 112 patients with proximal femur fractures. In 19% of the patients, DVT was diagnosed by phlebography, with the main localisation in the lower leg in 19 of 21 (90%) thromboses. With a negative prediction value of 83%, Duplex is less suitable than LCCT under such difficult examination conditions as the early postoperative period. The specificity of Duplex is 95%, but the sensitivity only 18%. The specificity of LCCT is 85% and the sensitivity 75%. Considering the frequency of postoperative DVT after surgery on the legs, especially hip surgery, a postoperative screening for DVT should become mandatory. LCCT has proved to be a suitable, cheap, non-invasive examination with a negative prediction value of 94%.