Stress-shielding mimicking recurrence in a paediatric left proximal femur unicameral bone cyst with pathological fracture – A case report

Background

Simple/unicameral bone cyst (SBC) is a common bone lesion found especially in the pediatric population often diagnosed incidentally on X-ray or due to a pathological fracture. Most of such fractures require curettage with or without fixation depending on fracture stability. Those that require fixation may pose an issue to post-operative surveillance of cyst recurrence due to the stress shielding phenomenon.

Case report

We present a case of a pathological subtrochanteric femoral fracture on the background of an SBC in a 6-year-old boy. Curettage of the lesion and surgical fixation of the femur were performed for the patient with favourable outcomes.

Conclusion

Pathological fractures of SBCs that need fixation should be have a less rigid fixation with the intent of allowing better visualization/monitoring under CT scan to better allow surveillance of cyst recurrence, and also reduce the effect of stress shielding.