Approach to Pathologic Fractures in Children

Amy K. Williams; Alexandre Arkader


Curr Orthop Pract. 2013;24(3):260-266. 

In This Article

Unicameral Bone Cysts

Unicameral bone cysts (UBCs) or simple bone cysts are latent or active benign bone lesions of unknown etiology. Among the different theories is an obstruction to the drainage of interstitial fluid forming a cavity under pressure.[1,2,3] These lesions usually are metaphyseal or metadiaphyseal. In order of decreasing frequency, UBCs most commonly occur in the proximal humerus, proximal femur, proximal tibia, distal tibia, distal femur, calcaneus, distal humerus, radius, fibula, ilium, ulna, and rib, with 40–80% occurring in the proximal humerus and proximal femur.[1–5] A pathologic fracture is the presenting symptom in up to 80% of the patients (Figure 1). Specifically, large lesions involving 50–80% of the bone diameter and with cortical thinning have a high risk of fracture.[1,6]

Figure 1.

A 6-year-old boy with a pathologic fracture of the proximal humerus caused by a unicameral bone cyst. (Printed with permission from Children's Orthopaedic Center, CHLA, Los Angeles, CA).

Pathologic fractures associated with UBCs are best initially treated conservatively. The healing process is not affected by the presence of the cyst and in approximately 10% of patients, the traumatic decompression of the cyst leads to the spontaneous healing of the lesion (Figure 2).[7–10] Furthermore, our favored minimally invasive surgical approach is easier when there is no fracture instability. This minimally invasive technique has been described by Dormans et al.[10] Briefly, the lesion is aspirated with a Jamshidi trocar, and a cystogram is performed under fluoroscopic guidance. Then, the contents of the lesion are removed percutaneously, and the cyst is decompressed. Finally, the cavity is tightly packed with medical-grade calcium sulfate pellets (Figure 3).

Figure 2.

The patient in Figure 1 is noted to have healed the pathologic fracture without surgical management, but the cyst persists. (Printed with permission from Children's Orthopaedic Center, CHLA, Los Angeles, CA).

Figure 3.

The same patient after the described minimally invasive procedure for unicameral bone cyst. (Printed with permission from Children's Orthopaedic Center, CHLA, Los Angeles, CA).

One exception to the conservative treatment algorithm is a lesion in the proximal femur. Since a malunion in that area can have serious long-term effects, these lesions often need to be treated acutely with curettage of the cyst followed by bone grafting and internal fixation when indicated. Minimally displaced fractures in young children can be treated conservatively with a spica cast and treated at a second stage as needed.