Results of the Local Steroid Injections in the Simple Bone Cyst

Objective: Steroid injections represent one of the simple treatment alternatives for simple bone cysts (SBC). The aim of this study was to evaluate the results of local steroid injections in the treatment of SBC. Methods: Seventeen patients (11 males, 6 females; mean age 12.4 years; range=2 to 39 years) with SBC were treated with injection of methylprednisolone acetate (MPA) with the use of the two-needle technique. The cysts were localized in the proximal humerus (n=6), the calcaneus (one patient had bilateral lesions) (n=2), proximal femur (n=7) and the tibia (n=2). Pathological fractures occurred in three patients before steroid injection. These three patients with pathological fractures were treated with injection of MPA after fractures healed. Each patient received a maximum of four injections at eight week intervals, each consisting of 40-160 mg of MPA. The patients were followed up with plain radiographs obtained in the first month, third month, sixth month, and at the end of a year. After the first year, patients were followed up with plain radiographs once a year. The mean follow-up duration was twenty two months (range=3 to 48 months). Cyst healing was assessed according to the modified Neer classification. Results: Treatment with MPA resulted in complete recovery in ten cysts (55%) and recovery with residual lesions in three cysts (17%). Three cysts (17%) did not respond to steroid treatment and two patients (11%) developed recurrence. The results were satisfactory (72%) in patients with complete recovery and partial recovery with residual lesions, and unsatisfactory in five patients (28%). The patients with recurrence were treated with curettage and grafting or cementation. No procedure-related complications were encountered. Conclusion: Our findings suggest that, the treatment with local steroid injection in SBC provides satisfactory results, thus this treatment with low morbidity can be applied to these patients before aggressive treatment.