A rare traumatic triad: Open bicondylar non-conjoint Hoffa fracture with partial tibial tubercle and medial epicondyle avulsions - A case report and biomechanical analysis.

Coronal shear fractures of the distal femoral condyles are rare intra-articular injuries, and the simultaneous occurrence of a non-conjoint bicondylar Hoffa fracture with a partial anterior tibial tubercle avulsion and a medial epicondyle avulsion constitutes an exceptionally complex traumatic triad. We report the case of a 35-year-old male motorcyclist who sustained this "floating" articular block injury (AO/OTA 33-B3.3) following a high-velocity accident. Diagnostic assessment utilizing Computed Tomography with 3D reconstruction revealed a vertical Letenneur Type II fracture of the medial condyle and a comminuted Letenneur Type I fracture of the lateral condyle, complicated by significant rotational instability. Surgical management prioritized the posterior femoral instability through a double posterior approach, which allowed for direct visualization and anatomical reduction. Fixation was achieved using posterior-to-anterior headless compression screws, augmented by a posterior buttress plate on the lateral column to neutralize shear forces, while the medial epicondyle was anatomically reduced and fixed; the stable partial tibial tubercle avulsion was treated conservatively. At the two-year follow-up, the patient demonstrated excellent functional recovery with 120 degrees of flexion, a Lysholm score of 91, and a successful return to recreational sports. This case highlights the importance of the double posterior approach and "targeted rigidity" in managing multidirectional instability, permitting early mobilization even in the presence of complex extensor mechanism involvement. Introduction: Coronal shear fractures of the distal femoral condyles (Hoffa fractures) are rare intra-articular injuries, with bicondylar patterns being exceptionally uncommon. A non-conjoint bicondylar Hoffa fracture combined with a partial anterior tibial tubercle (ATT) avulsion and a medial epicondyle avulsion represents a complex, "floating" articular block that challenges standard treatment algorithms. This case report analyzes the biomechanics and management of this rare traumatic triad. Case presentation: A 35-year-old male motorcyclist presented with a Gustilo-Anderson Type I open knee injury following a high-velocity crash involving hyper-flexion and valgus stress. CT imaging confirmed a non-conjoint bicondylar Hoffa fracture (AO/OTA 33-B3.3, Bagaria Type 3). The lateral condyle presented as a Letenneur Type I fracture with extensive comminution, while the medial condyle was a Letenneur Type II vertical fracture. Associated injuries included an Ogden Type I partial ATT avulsion and a Watson-Jones Type I medial epicondyle avulsion.Surgical management utilized a double posterior approach to visualize and reduce the posterior fragments. Fixation involved headless cannulated compression screws for both condyles, augmented by a posterior buttress plate on the lateral column to resist shear forces. The medial epicondyle was refixed with a screw and washer, while the stable ATT avulsion was managed conservatively. At the two-year follow-up, the patient achieved excellent functional outcomes, including 120° of flexion, a Lysholm score of 91, and a Tegner Activity Scale score of 7. Conclusion: Managing this complex triad requires a thorough understanding of the injury mechanism, which involves coronal shear, valgus stress, and eccentric extensor loading. 3D CT reconstruction is mandatory for planning, and a double posterior approach provides superior visualization for anatomical reduction and posterior-to-anterior fixation. Rigid fixation, particularly using anti-glide plating for the lateral column, permits early mobilization and the conservative management of stable associated injuries, leading to high patient satisfaction.