Recent developments in treatment for simple bone cysts.

PURPOSE OF REVIEW: The purpose of this paper is to review treatment strategies for simple bone cysts (SBCs). RECENT FINDINGS: Recent studies have focused on disrupting the wall of the cyst in combination with injectable bone substitutes. Bone substitutes are minimally invasive, provide an osteoconductive scaffold, and are relatively easy to use. Many of these studies, however, have methodological issues (uncontrolled, not randomized, unblinded outcome assessment, or short-term follow-up) and inconsistent radiographic outcomes making it difficult to determine the benefits of these newer treatment strategies. SUMMARY: Based on a single randomized clinical trial, steroids are the only evidence-based treatment for SBCs. Further basic science is needed to understand the pathoetiology and to develop future biologic solutions. Multimodal treatment strategies with opening of the medullary canal and disruption of the cyst wall, filling defect with a bone substitute, and possible biologic treatment of the cyst membrane may be the best strategy. When considering cysts of the lower extremity, structural support may be required in addition to treatment of the cyst.