These fractures are seen either in young patients after higher energy trauma, or in elderly patients with osteoporosis after low energy falls.
Careful inspection of radiographs should be undertaken to ensure that intraarticular extensions are not missed. Traction radiographs, oblique radiographs, or a CT scan may help to elucidate occult articular extensions. Surgeons should always be aware that it may not be until during surgery that an occult intraarticular extension is discovered and that they may need to deal with such a fracture by reducing the articular surface using a lag screw technique.
Some fractures may be open and some may be combined with a patellar fracture. There may be significant osteochrondral joint surface injury in these fractures.
X-ray taken from Orozco R et al, (1998) Atlas of Internal Fixation. Used with kind permission.