Abstract: Objective　To perform classification the distal pole fractures of patella based on three-dimensional CT.　Methods　 From May 2018 to November 2019, a retrospective analysis of 67 cases of the distal pole fractures of patella were classified by three-dimensional CT. The Kappa coefficients (K) was utilized to assess inter-observer and intra-observer reliabilities.　Results　The distal pole fractures of patella was divided into two types: a non-displaced fracture (type I) and a displaced fracture (typeⅡ).The displaced fracture was further divided into the following three subtypes: Type Ⅱa ( massive fractures, including one isolated fracture or two larger fractures), Type Ⅱb (comminuted fractures, multiple smaller fractures, including coronal plane and sagittal plane fractures), Type Ⅱc (cuff-like avulsion fractures, avulsion fractures along the entire arc of distal pole of patella, most of the fractures were comminuted and very thin). There were 8 cases of type I, 11 cases of type Ⅱa, 42 cases of type Ⅱb, and 6 cases of type Ⅱc under this study. The average K value of the inter-observer reliability was 0.782 (range 0.682~0.896), which was substantial agreement, and the average K value of the intra-observer reliability was 0.837 (range 0.786~0.884), which was perfect agreement.  Conclusions　The CT classification for the distal pole fractures of patella has high reliability and repeatability. It is simple and easy to remember, and has certain clinical implication.

Key words: Classification,  ,  , Patellar fracture,  ,  , Distal pole fractures of patella