Five-years Control after a Delayed Diagnosis of a Traumatic Posterior Hip Dislocation in a 5 years Old Boy- A Case Report

INTRODUCTION: Evaluation of pain in children after trauma can sometimes be difficult; in particular, a knee pain in a child could originate from the hip, until evidence of the contrary. Often is the low-energy trauma that leads to a joint dislocation in children. Furthermore, the present guidelines state that a hip dislocation in a child should be replaced within 6 (maximum 12) hours, to reduce the risk of avascular necrosis (AVN) of the femoral head. CASE PRESENTATION: After falling during sports activity at the kindergarten, a 5-years-old boy was taken to the emergency room of a small hospital with severe pain in his right knee. After the visit and the instrumental diagnosis, he was afterward discharged with the diagnosis of contusion of the thigh. After a week of pain and inability to load despite the analgesic therapy, he was accompanied to our hospital, from which the diagnosis of hip dislocation emerged and then reduced in short sedation. The next day he underwent to a magnetic resonance imaging (MRI) examination and pelvic-podalic cast immobilization. At the following check-ups, he had no more pain and the active ROM was complete. A long-term control after 5 years showed a complete and painless active ROM and the MRI showed a normal growth of the bone, without any sign of AVN of the femoral head. CONCLUSION: Despite the long waiting period and going against the guidelines, the child recovered his full daily and physical activity, without necrosis of the femoral head, growth disorder, or dysmetria in the lower limbs.