Prediction of leg-length discrepancy in pediatric femoral shaft fracture using bone SPECT/CT: A case report.

RATIONALE: Children's bones are in the process of growing in both length and width. Therefore, evaluating whether fractures affect the growth plate or not is very crucial. However, even in cases of lower limb fractures where the growth plate remains unaffected, overgrowth or shortening of the affected limb are encountered.

PATIENT CONCERNS: An 11-year-old boy was admitted to the emergency department after a passenger car accident.

DIAGNOSES: A comminuted fracture of the right femoral shaft was diagnosed by X-ray image.

INTERVENTIONS: Closed reduction and internal fixation were performed using intramedullary titanium elastic nails. Six months after the operation, bone union was achieved and the nails were removed.

OUTCOMES: Nine months after nail removal, the right leg was unexpectedly noticed 5 mm shorter than the left one. On the initial and follow-up bone single-photon emission computed tomography/computed tomography images with a 9-month interval, radioactivity of growth plate in the right proximal femur was much lower than that of the left femur, suggesting a further increasing of leg-length discrepancy (LLD) in the future. As we expected, LLD had progressively increased up to 20 mm. Epiphysiodesis was finally decided for the left distal femur. Twenty-two months after the length equalization operation, LLD decreased to 5 mm.

LESSONS: This case emphasizes that quantitative analysis of growth plate activity using bone single-photon emission computed tomography/computed tomography could predict LLD and help us decide when and which limb should be operated on for pediatric patients with lower limb fractures.