Patella sleeve avulsion fracture

Introduction: the patella sleeve fracture is a rare injury that can affect the patella during the infant growth stage. Its early diagnosis is important to obtain a good clinical and functional result and to avoid sequelae derived from the injury. Differential diagnosis is made with Sinding-Larsen-Johansson syndrome and the fracture of the lower pole of the patella.

Clinical Case: we present the case of a 12-year-old male, with no history of interest, who came to the emergency room reporting right knee pain after making a bad movement while running. The patient is discharged oriented as patellar tendonitis. Two weeks later, he returned with pain and complete functional impotence to extend his right knee after falling again doing sport. In the conventional X-ray image, a displaced osteochondral avulsion of the lower pole of the patella, 'sleeve' type, is observed. Because of the functional limitation, surgical intervention was decided doing reinsertion of the lower patellar pole using Krakow suture and transosseous stitches.

Conclusions: patella sleeve type fracture is rare and may go unnoticed. The lesion mechanism (indirect by traction), the history of previous pain and conventional radiology images should provide a high level of suspicion and reduce underdiagnosis of this entity and thus avoid derived sequelae such as patella alta, anterior knee pain or loss of quadriceps strength.