Die juvenile Knochenzyste

Background

A unicameral bone cyst (UBC) may be caused by an intraosseous venous obstruction with the accumulation of interstitial fluid. Therefore, continuous decompression of the fluid using cannulated screws would represent a causal therapeutic approach.

Materials and methods

The clinical and radiographic follow-up of 17 patients with UBCs treated by curettage and mechanical decompression using cannulated screws was evaluated retrospectively.

Results

Radiographic examination revealed the following results: complete healing of the lesion (n=2), persistent defect after healing (n=6), persistent lesion (n=6), and recurrent cyst after temporary remodeling (n=3). No pathologic fracture was subsequently observed in the group of lesions that had a persistent defect after healing. A persistent lesion occurred in the proximal femur in 75% of the cases and in the proximal humerus in 50% of the cases.

Conclusion

Continuous decompression using cannulated screws can be applied in UBCs of the proximal humerus in patients with recurrent fractures and subjective complaints. However, treatment failures are common and comparable to other therapeutic approaches. Therefore, conservative treatment must be discussed critically. Healing with residual defect must be regarded as a good treatment result, and additional operative procedures with the objective of radiographic cosmetics should not be done. Because of poor results and long-term disability related to weight bearing, treatment of UBCs with cannulated screws cannot be recommended in lesions located in the proximal femur. In these cases, immediate surgical stabilization is the appropriate procedure.