Introduction: The objective of the study was to track the impact of endoprosthesis-plasty of the genicular joint upon the pelvic gait pattern in three dimensions at a natural velocity. Material and methods: 27 persons ranging from 60 to 74 years of age who had underwent arthroplasty of the genicular joint a s a result of degenerative lesion were incorporated into the study. The first study session occurred prior to the surgery and the second took pace 6 months afterwards, when the patient regained unaided mobility. Results: The outcome of locomotion analysis were presented against a comparative group of 30 healthy persons within the age range of 50 - 70 years. The subject of the evaluation featured angular variations with regard to pelvis position in the three motor planes. Conclusions: The analysis of results indicates that the largest deviation from norm was present in the sagittal plane.