Open traumatic distal femoral physeal fracture in a pediatric patient with tetrasomy 18p syndrome

Background. Because they are associated with a high energy mechanism, open distal femoral physeal fractures are rare injuries. Appropriate management of these injuries is critical in the pediatric population due to the increased risk of damage to the physis and subsequent growth disturbance and deformity after injury. Pediatric fractures may also represent the sequelae of genetic syndromes (particularly connective tissue disorders), nutritional abnormalities, or conditions that predispose to abnormal bone mineral density.

Clinical case. In this case report, we present the case of a 9-year-old girl with tetrasomy 18p who presented with a grossly displaced right open distal femoral physeal fracture in the setting of isolated, lower extremity trauma. The patient underwent an irrigation and debridement, followed by an open reduction and cross-pinning through the distal femoral epiphysis. After the operation, the patient was made non-weight-bearing in a cast for 4 weeks, and at 6 weeks, the pins were removed. The patient had full range of motion at the 6-month follow-up and then resumed her preinjury level of play at school.

Discussion. Tetrasomy 18p results in inherent muscle weakness that may interfere in the normal soft tissue sleeve of muscles stabilizing long bones. This may result in greater displacement of fractures sustained during trauma, which may lead to a greater rate of vascular injury, physeal injury, and poor overall prognosis. It is imperative for clinicians to be familiar with tetrasomy 18p and its associated orthopedic manifestations.

Conclusion. There is scarce literature on the management of physeal fractures in patients with tetrasomy 18p. In the case described here, we report a good outcome with the standard of care using preoperative and postoperative antibiotics, irrigation and debridement, open fracture fixation, and immobilization in a cast postoperatively. The duration of non-weight-bearing was also increased by 1 week and the pins were removed 1 week later than we would have for patients without any bone or connective tissue disorders.