Results of the Between Groups Principal Components Analysis (BgPCA) based on patellar measurements.

Abbreviations: bgPC, between-group principal component; PD, total proximodistal height of the patella; PDAS, proximodistal height of the articular surface; AP, anteroposterior thickness; ML, mediolateral breadth. a Each original variable was size-adjusted by the geometric mean (GM) of the four variables and log-transformed (using natural logarithms) prior incorporation into the analysis. The variables with absolute loadings of 0.5 or more are marked in bold. Only the two first bgPC axes provided meaningful discrimination and are therefore shown.