Unifragmentary and Isolated Tibial Bony Avulsion Fracture of the Posterior Cruciate Ligament: A Case Report

A unifragmentary and isolated tibial bony avulsion fracture of the posterior cruciate ligament is an infrequent entity caused by high-energy trauma.Recognition of the injury mechanism and evaluation of the degree of displacement and size of the bone fragment are decisive for guiding therapeutic management.We present the case of a 29-year-old male patient who sustained a motorcycle accident with direct pretibial impact to the right knee.Physical examination revealed pain, edema, and a positive grade III posterior drawer test.Plain radiographs showed a posterior bony detachment, which was confirmed by 3D tomography, with a displaced bone fragment measuring 1.81 cm × 1.20 cm at the tibial insertion of the posterior cruciate ligament.Given the severe instability and the large size of the fragment, conservative management was ruled out, and open reduction and internal fixation (ORIF) was performed three days after the injury using an inverted-J posteromedial approach with a 4.0-mm cannulated screw.The patient showed restoration of joint stability, a negative posterior drawer test, and adequate functional recovery during follow-up.This case demonstrates how clinical suspicion based on the trauma mechanism and the quantitative precision of 3D tomography are essential for guiding timely treatment.Open reduction and internal fixation via a posteromedial approach offers effective, rigid, and anatomical fixation for large fragments, potentially preventing chronic sequelae such as nonunion or residual joint instability.