Sleeve Fracture of the Superior Pole of the Patella with an Intra-Articular Dislocation

Abstract

Patellar fractures in children are uncommon and represent 1% of all pediatric fractures1-3. Of all patellar fractures, less than 2% occur in the skeletally immature patient2. Intra-articular dislocation of the patella is also a rare occurrence. Sleeve fractures represent the most common type of patellar fracture in children2, with most reported cases involving sleeve fractures of the inferior patellar pole. To our knowledge, only two cases of sleeve fractures of the superior pole have been reported in the English-language literature4,5 and the association of a sleeve fracture of the superior patellar pole with an intra-articular dislocation of the patella has not been previously reported. Our patient and his family were informed that data concerning the case would be submitted for publication, and they consented. A fourteen-year-old boy presented to our institution after sustaining a direct blow to the suprapatellar area of the right knee. The injury occurred as a result of the knee striking a concrete block while the patient was swinging on a rope. Following the injury, the boy was unable to walk and could not move the right knee. Examination revealed bruising of the anterior aspect of the knee and an unusual shape of the patella. The patient could neither perform a straight leg raise nor flex the knee. Radiographs of the knee revealed an intra-articular dislocation of the patella (Figs. 1-A and 1-B). In the lateral projection (Fig. 1-B), the patella was seen to be lying in a transverse position, with the articular surface facing in a distal direction. Fig. 1-A Fig. 1-B Preoperative anteroposterior (Fig. 1-A) and lateral (Fig. 1-B) radiographs of the knee, showing the transverse orientation of the patella with the articular surface facing in a distal direction. With the patient under intravenous morphine sedation, the patella …