Commercially available shoe inserts as transducers for limb load monitoring

Limb load monitoring presents a continuing challenge in rehabilitation engineering. Patients who undergo lower extremity surgery like joint replacement and reconstruction, or fracture healing are required to exert minimal or gradually increasing amount of force on their lower limbs during recovery. However, it is generally observed that these patients exert forces much larger than those prescribed. Exerting large loads can lead to problems like pain, and blistering. On the other hand not exerting a minimal force can lead to muscular atrophy in the limbs. To prevent this atrophy, a minimal exertion force is prescribed. Several investigators implanted pressure transducers on the inserts to measure the pressure distribution in the foot. However, these transducers are expensive, and require the presence of a qualified engineer to place, monitor, and calibrate them. Currently, there is no simple, low-cost technique to assist the patient and the clinician in determining the amount of load exerted by the limb as the patient is walking. The purpose of this investigation is to study the use of commercially available shoe inserts and their transducing properties for the monitoring of extremity loads during gait.