What is a waddling gait?

PURPOSE: A patient's gait can provide important diagnostic and functional information. Though 'waddling gait' is a long-established concept, we question whether this description is precise or clinically useful. METHODS: We searched 'waddling gait' in all main medical specialties core textbooks, in animal locomotion books and in Medline, Healthstar and Embase. Further we obtained expert advice on the gait of ducks. RESULTS: Many names are used for 'waddling gait', and its description is imprecise and inconsistent. Trendelenburg described it as a pelvic drop on the side of the swinging leg and compensatory lateral trunk bending towards the side of the standing leg. Many conditions have been described as producing a waddling gait. We accepted the gait pattern of ducks as being true waddling. This often-used comparison does not accurately reflect the gait pattern seen in humans with a range of medical disorders; nor is it the same as a Trendelenburg gait. CONCLUSIONS: As we have found no condition in which patients have a truly duck-like gait, we propose that the phrase 'waddling gait' should be abandoned. We suggest that for clarity and good communication, clinicians should describe the observed elements of the gait rather than using imprecise and unhelpful terms such as 'waddling gait'.