The knee x-rays show lateral tibial plateau fracture.
This is an easily overlooked fracture especially in elderly women. The cancellous bone in the tibial plateau buckles along with the articular surface which can be very subtle finding. Presence of knee effusion or lipohaemarthrosis should raise high index of suspicion.
Tibial plateau fractures can be seen as a result of high velocity trauma in younger population.
Further details on tibial plateau fractures including Schatzker classification can be found herehttps://www.orthobullets.com/trauma/1044/tibial-plateau-fractures?msclkid=5b81a83bab2611ecaef711a008898a06