<p>An orthopaedic device for generating one or more strain signals representative of the strain in a bone in response to a force applied to the bone. The device includes an encircling member (11) for encircling the bone of a subject and a sensor member (13) connected thereto, the sensor member including a strain sensor (14). In a preferred embodiment the strain sensor comprises one or more bridging members configured to break when subjected to a particular strain.</p>