Novel approach of plate assisted buttressing in Hoffa fracture.

PURPOSE: Hoffa fracture is a femoral condyle fracture in the coronal plane. The lateral condyle is more commonly involved. The diagnosis is often difficult to detect with routine radiographs. Conservative management in this type of fracture resulted in nonunion, malunion, and other complications, such as stiff knee. Therefore, surgical management is mandatory in displaced fractures. Previous studies suggest only application of cancellous screw fixation, but these are not enough to counter vertical shear stress. Therefore, this study will evaluate the clinical outcomes of open reduction and internal fixation of Letenneur type I Hoffa fracture using cancellous screws with posterior buttressing plate. METHOD: This was a prospective cohort study conducted from March 2017 to July 2022 in orthopaedics department of tertiary care center after approval of institutional ethical committee. The study included 36 patients with Letenneur type I fractures treated by open reduction and internal fixation using posterior buttress plate and cancellous screws. Radiographs and clinical outcomes, range of movement (ROM), bone union, and knee society score (KSS) of patients were assessed at the end of 4 and 12 months in the follow-ups. All statistical analysis was done using Epi info version 7.2.1.0. RESULTS: In the 36 patients with Letenneur type I fracture, the majority belong to younger age group between 25 and 54 years with 22 males and 14 females. The modes of injury were road traffic accidents in 25 patients and fall from height in 11 patients. The right knee was involved in 21 cases and left was involved in 15 cases. Lateral condyle involvement was seen in 27 cases and medial condyle in 9 cases. All 36 patients with Letenneur type I Hoffa fracture were evaluated 4 months after surgical intervention. The notable improvements were observed in terms of ROM 120.4° ± 5.0° and KSS 85.0 ± 4.2. At the 12-month follow-up, considerably better outcomes were maintained regarding ROM 128.1° ± 5.2° and KSS 89.3 ± 4.8 with p < 0.05 which was statistically significant. At the final follow-up, all patients had routine fracture healing with a union time of (3.2 ± 3.4) months. CONCLUSIONS: Fixation of Letenneur type I Hoffa fracture with cancellous screws and posterior buttress plate is effective, reliable and capable of providing adequate stability. Buttress plate assisted fixation is a valuable enhancement of the conventional technique of lag screw fixation of Hoffa fractures.

Plate fixation for Letenneur type I Hoffa fracture: a biomechanical study.

BACKGROUND: A coronal fracture of the posterior femoral condyle, also known as a Hoffa fracture, is an unusual injury, and there are only a handful of case reports or series exploring it. The optimal fixation method of these intraarticular fractures remains controversial; improper or unstable fixation usually lead to an unsatisfactory prognosis. The use of posterior-anterior or reversed lag screw fixation is still a popular method. Additional buttress plating is also recommended for fixation of these difficult fractures. The purpose of this study was to compare the mechanical strength of four different fixation patterns for this uncommon fracture. MATERIAL AND METHODS: Sixteen sawbone simulated models of Letenneur type I Hoffa fractures were created with one of four fixation patterns: two screws implanted in the anterior-posterior (AP) direction or posterior-anterior (PA) direction; one screw in the PA direction with a plate implanted in the posterior position of the distal femoral condyle or with a plate in the lateral position. Biomechanical testing was performed to determine the post-fixation axial stiffness, the maximum load to failure and the fragment vertical displacement for each of the four constructs. RESULTS: The plate fixation patterns whether implanted in the posterior or lateral position were shown to provide higher overall axial stiffness and load to failure, and less vertical displacement than the other two patterns of pure screw fixation. Among these constructs, the lateral plate fixation was found to provide the highest stiffness and load to failure and the least displacement for the posterior condylar fragments, followed by the posterior plate fixation. The lowest overall stiffness and load to failure and the largest vertical displacement were found in the construct with the AP direction placed screws. CONCLUSION: It was concluded that the lateral position implanted plate is biomechanically the strongest fixation method for Letenneur type I Hoffa fractures. However, this plate fixation is not recommended for all cases. The choice of internal fixation pattern depends on the surgeons.