Classification and morphology of hyperextension tibial plateau fracture

Purpose This study was aimed at analyzing the incidence and characteristics of hyperextension tibial plateau fractures (HTPFs) by using a computed tomography (CT)–based “four-column and nine-segment” classification. Methods In the coronal plane, HTPFs are divided into four types: pure hyperextension, hyperextension–varus, hyperextension–valgus, and hyperextension–bicondylar. Fractures in the sagittal plane were divided into three types: type 1, pure depression; type 2, cleavage extending to the posterior cortex with no displacement; and type 3, cleavage extending to the posterior cortex with a significant displacement. A retrospective analysis of CT images of the tibial plateau fractures from December 2007 to December 2021 was conducted. Fracture mapping was analyzed and drawn using the new classification system. Results A total of 136 (10.9%, 136/1253) fractures fulfilled the radiographic criteria for HTPF pattern in 136 knees (53.5 ± 13.3 years). There were 11 knees with pure hyperextension fracture (8.1%), 23 with hyperextension–varus fracture (16.9%), 46 with hyperextension–valgus fracture (33.8%), and 56 with hyperextension–bicondylar fracture (41.2%) in the coronal plane. Furthermore, there were 64 (47.1%), 47 (34.6%), and 25 (18.4%) cases of type 1, type 2, and type 3 fractures, respectively, in the sagittal plane. In the three-dimensional heat map, the fracture lines were mainly located at the anterior rim of the tibial plateau, while the posterior articular surface was rarely involved. Conclusions The main manifestations of HTPF are anterior compression and posterior avulsion injury. The CT-based four-column and nine-segment classification system could be used to categorize the injury characteristics of HTPF in the coronal and sagittal planes.