Background: A lack of high-quality research and data has restricted the comprehensive understanding of the conversion procedure of convertible inferior vena cava filters. The aim of this study was to present an unusual situation with a high risk of causing complication, during conversion of VenaTech convertible inferior vena cava filter and our management procedure. Methods: Lower extremity deep venous thrombi were detected in a 62-year-old woman before major orthopedic surgery. A VenaTech convertible inferior vena cava filter was placed to prevent possible pulmonary embolism and 106 days later, the filter was converted without any complications. Results: At the 6-month follow-up, no adverse events were reported. Conclusions: The long-term indwelling of a filter might increase the complexity and uncertainty of the conversion procedure. This report presented a rare but hazardous situation during conversion and our management procedure.