Background. Hardware examinations are the key to standardizing the assessment of the patient’s condition, they reduce the doctor’s error, make it possible to obtain digital material, which can be used to determine the functional ability of the patient. One of such studies is the GAITRite system, the purpose of which is to assess the parameters of a person’s walking. The study was aimed to determine the basic parameters of walking in patients with gonarthrosis before and after the endoprosthesis. Materials and methods. There were examined 23 patients with gonarthrosis after unilateral endoprosthesis. The studies carried out concern the analysis of temporal, geometric parameters of walking, as well as the assessment of the functional ability of patients with degenerative diseases of the hip joint before treatment and one year after arthroplasty. Results. Before treatment for knee arthrosis, patients experience a violation of walking in the form of asymmetry of steps. There is a decrease in the time of support on the foot of the impaired limb and, therefore, an increase in the time of transfer of the foot of this limb. Changes in the impaired limb are reflected in the opposite one. After surgery, the changes in the parameters of walking in patients were as follows: an increase in the time of support on the prosthetic limb, and, therefore, a decrease in the time of support on the foot of the opposite limb that manifested in an increase in the symmetry of the parameters of steps. Reduction of pain syndrome and restoration of limb support ability increase the indicator of gait functionality. Osteoarthritis is a systemic disease and develops more often in both knee joints, and other structures of the skeleton are often involved in the degenerative process. Therefore, in elderly patients, FAP after arthroplasty reaches only satisfactory values. We examined patients after endoprosthesis on one knee joint, and this does not always give the expected good result immediately. Conclusions. Instrumental methods of studying patients’ gait make it possible to determine the degree of impairment of dynamics. Knee arthroplasty eliminates pain and restores limb resistance, which improves gait. This method of assessing walking allows determining the degree of recovery of patients and to adjust the need for further methods of correcting walking or a plan for further treatment.