We assessed the validity of the hip-knee-ankle angle measured statically during three-dimensional (3-D) gait analysis and
the tibial angle using an inclinometer compared with the mechanical axis on radiographs. Eleven individuals (20 knees) with
radiographic knee osteoarthritis (OA) participated in this study. We determined the following: the lower-limb mechanical axis
using weightbearing long-leg radiographs; hip-knee-ankle angle using the techniques of 3-D gait analysis in a static standing
position; and tibial alignment using an inclinometer. The mean mechanical axis (± standard deviation) for this cohort was
0.7° ± 7.2° (range, −13°−16°). The tibial alignment and hip-knee-ankle angle correlated with the mechanical axis but the correlation
between the mechanical axis and the hip-knee-ankle angle was stronger. Our data suggest the inclinometer and 3-D gait analysis
are valid ways to estimate mechanical alignment of the knee.
Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest,
patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.
Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations
were conducted in conformity with ethical principles of research, and that informed consent for participation in the study
was obtained.