A spindle assembly of a surgical instrument includes a body and a cutter pin. The body has at least one wall forming first and second channels therein. The cutter pin is disposed within the second channel and operably coupled to a knife rod extending therethrough and is operatively coupled at its distal end to a knife. When the knife rod is moved between a retracted position and a deployed position, the spindle assembly is moved between a first and a second position along the shaft. The cutter pin is configured to deform and exit the body when the knife is deployed and disposed in a trapped condition and in response to an applied force, thereby decoupling the knife from the spindle assembly.