PURPOSE: Retrograde intrameullary nail is one of the treatment of periprosthetic supracondylar femoral fracture after total knee replacement (TKR), but all TKRs will not permit to insert a supracondylar nail. Therefore, we have investigated the compatibility of the TKRs with supracondylar nail. MATERIALS AND METHODS: Using trial femoral component of the 5 used TKRs in Korea and saw bone model, we checked their compatibility and measured the dimensions of the intercondylar notches in both cruciate retaining (CR) and posterior stabilized (PS) type. RESULTS: Although most CR prostheses had an intercondylar notch large enough to accept a supracondylar nail, in some case, this was not possible due to the notch being situated too far posteriorly. The position of the intercondylar notch is also important factor in the PS prostheses. CONCLUSION: The notch position, rather than the notch size, was the most important factor in determining nail compatibility with femoral stem.