Irreducible, incarcerated vertical dislocation of the patella into a Hoffa fracture

Sir,

I read with interest the article by Soraganvi et al.¹ titled as “Irreducible, incarcerated vertical dislocation of the patella into a Hoffa fracture.” I congratulate the authors for their good results in this rare case. I would like to discuss few issues with this article.

1. I would like to draw attention to the fact as it is a lateral condylar fracture rather than a Hoffa fracture. Hoffa fracture is a fracture of femoral condyle in a coronal plane.² This injury is the result of violent force and generally occurs in young adults. There is usually a combination of forces: Direct trauma along with an element of abduction, the ground reaction is transmitted through the tibial plateau and the axial compression on a flexed knee concentrates the force in the posterior half of the femoral condyles. In flexion, lateral condyle is the leading part of the knee to receive the impact, and hence the fracture.³ X-rays and computed tomography scan images shown in the manuscript show a lateral femoral condyle fracture in the sagittal plane. That is why, it has been adequately fixed from lateral to the medial side with the help of two cancellous screws as shown in postoperative radiograph. On the contrary, Hoffa fracture would require an anterior to posterior, preferably headless compression screws for fixation.

2. Closed reduction of dislocation of the patella is difficult in vertical dislocations due to increased tension in quadriceps mechanism and can cause small avulsion fractures of the patella. A small avulsion fracture can be seen in the 2 years followup radiograph of manuscript. I would like to know if the authors did any attempt at closed reduction.