Partial articular, sagittal, fractures of the lateral patella may be due to direct impact to the front of the knee (eg, dashboard injury).
These are classified by AO/OTA as 34B1 fractures.
The surgeon must not confuse a well-corticated superolateral bipartite patella (see patient examination ) with an acute fracture.
1. Partial articular, lateral sagittal simple fracture (AO/OTA 34B1.1)
When the fracture pattern is simple, it is classified by AO/OTA as a 34B1.1 fracture.
2. Partial articular, lateral sagittal fragmentary fracture (AO/OTA 34B1.2)
When the fracture pattern is fragmentary, it is classified by AO/OTA as a 34B1.2 fracture.