[Research progress of Hoffa fracture].

Hoffa fracture is a rare type of fracture confined to the coronal plane of the femoral condyle. High-energy is a common reason of Hoffa fracture, and low-energy trauma and iatrogenic injury can also cause Hoffa fracture in some cases. The commonly used classifications include Letenneur classification, CT classification, AO classification and modified AO classification. X-ray is the first choice to diagnose Hoffa fractures, fracture lines can be found. If the X-ray is negative, CT scan and MRI should be performed. Nondisplaced fractures can be managed conservatively with cast immobilization, however, there is high risk of redisplacement. Open reduction and internal fixation is preferred. For the young patient with good compliance, a simple medial or lateral condylar fractures can be treated via medial or lateral parapatellar approach. When the fracture is exposed, the headless compression screws can be inserted vertical to the fracture line from backward to forward. For a bicondylar fracture, median parapatellar incision can be selected. While for a complex fracture with osteoporosis or high body mass index, cannulated screws with anti-sliding plate fixation technique should be used.