Quantitative assessment of fracture healing. The value of computerised sonometry in a correlative animal experiment in sheep.

Usually follow-up of the healing process of bone fractures is by subjective assessment of standard X-rays, based on the clinician's personal experience. It is therefore impossible to completely avoid misjudgements in the evaluation of the mechanical stability. Other authors have reported that the mechanical response of bony structures to a knock impulse allows a definitive statement about the stiffness of a fracture. The practicability of computerised sonometry in computer-aided evaluation of the mechanical vibration reaction and the acoustic transmission of sound through osseous structures for assessing stability has been proved in experimental and clinical studies. We designed an animal study that would allow a systematic correlation between the diagnostic investigations in general use. As a main goal, this study tries to correlate sonography with other quantitative techniques, even if they are not used under everyday clinical conditions. Our results show that methods based on direct assessment of the mechanical stability between fracture fragments allow a more exact evaluation of fracture healing. This study helps to classify the results of computerised sonometry together with other diagnostic procedures used for the evaluation of fracture healing, and furthermore provides a basis for clinical interpretation of the findings of a new, non-invasive technique for precise quantitative assessment of fracture healing.