Background: Ravitch repair is a common surgical procedure to correct chest wall deformities. In this procedure, a subperichondreal cartilage resection of the deformed parasternal cartilage, and if necessary a repositioning of the sternum, is performed. Insufficient regeneration of the resected cartilage may result in sternocostal instability or even floating sternum. This rare complication presents with symptoms of pain and exercise intolerance. Methods: We describe sternocostal instability in 3 adolescent patients after the Ravitch procedure for pectus carinatum and reviewed the literature on this topic. Results: Our patients suffered different degrees of instability. In all cases, we eventually achieved a satisfactory outcome. There is little literature on sternocostal instability. It is a rare complication, mainly occurring after reoperation by damaging the perichondrium. Conclusions: Malunion of costal cartilage is a rare complication of open pectus repair. To achieve the best regeneration and stability of the sternum, less extended resection of cartilage should be performed and the number of cartilages resected should be limited. The perichondrium must be kept intact. Autologous grafts, growthenhancing materials, and metal or bioabsorbable struts may contribute to stabilization and regeneration of the cartilage.