Active unicameral bone cysts: control firstly, cure secondly

PURPOSE: This retrospective study evaluated the efficacy of minimally invasive surgery to control cyst progression for active unicameral bone cysts (AUBC) by intracystic methylprednisolone injection, percutaneous curettage, and autogenous bone marrow grafting. METHODS: From May 2010 to May 2017, patients diagnosed with AUBC who underwent percutaneous double-needle intracystic methylprednisolone injection, percutaneous curettage, and autogenous bone marrow grafting were retrospectively reviewed. Recurrence was defined by modified Neer scale score. Patients were followed up regularly, and previous imaging findings were compared to evaluate treatment efficacy. RESULTS: The 26 patients (17 boys, 9 girls, mean age, 9.4 ± 3.1 years) were followed up for a mean 45.1 months (range, 24–82 months). Follow-up consisted of clinical evaluation and radiographic review. Twenty patients (77%) achieved latent disease stage after the first treatment, while six (23%) achieved it after the second treatment. Postoperative pathological fracture imaging scores were score I in 18 (70%), score II in five (19%), score III in two (8%), and score IV in one patient (4%). All 26 patients returned to their full activities and were asymptomatic at the most recent follow-up. The success rate (scores I and II) independent of the number of treatments was 89%. Treatment time was correlated with cyst size and length. Sex, age, cyst location and size, pathological fracture, and other clinical factors or radiological data did not influence the curative effect. No other complications occurred. CONCLUSIONS: For AUBC, minimally invasive treatment is feasible to control cyst progression and then cure it without sequelae. Intracystic methylprednisolone injection, percutaneous curettage, and autogenous bone marrow grafting are an excellent choice.