The use of the walker in rehabilitation has increased in the past few years. Therapists evaluate patient's rehabilitation by observation and subjective tests. Thus, it is necessary the use of an assistive tool which can measure and quantify the patient's walker-assisted movement and stability, providing an objective clinical assessment. The aim of this study is to detect differences in assisted gait when using the assistive devices (ADs) - crutches, standard walker and rollator (4-wheeled walker) with forearm supports (RFS) - in patients with knee osteoarthritis (KOA) that suffered the surgery - Total Knee Arthroplasty (TKA). Additionally, it is to verify the link between gait parameters and acceleration signals. The evaluation is reached by the use of two 3 axis-accelerometers. The signals extracted from the sensors, at the ankle and trunk, are related to gait events and evaluation of fall risk, respectively. Results show that despite the differences between the signals obtained with the three ADs and with the subjects in this study, it is possible to identify effectively the gait parameters and prove the stability that the RFS provides.