A New Technique for Removal of Fractured Locking Screws from Intramedullary Nails

BACKGROUND

Locking screw or bolt breakage in fractures treated by intramedullary nailing can cause difficulty in exchange nailing as the fractured screw may prevent nail extraction (Fig. 1a) resulting in a bigger incision, extensive soft tissue dissection and cortical disruption for its retrieval. Methods described to push out the broken screw from the nail include using K wires,¹ another screw² and this punch.³ We describe a new technique, which utilises instruments available in a standard nailing tray.

Figure 1.

(a) Broken screw remnant preventing nail extraction. (b) Angulation of fractured screw due to nail migration. (c) Trocar tapping away fractured screw remnant.

TECHNIQUE

A radiolucent operating table is used. The broken screw head is removed with an appropriate screwdriver. Sometimes, the nail may have migrated distally with the broken screws lying at an angle to the bone and nail (Fig. 1b). Nail extractor is attached to the nail which is then moved to align the locking holes in the bone and nail with the broken screw. A trocar from the proximal/distal locking system (consisting of tissue protection sleeve, drill sleeve and trocar; Fig. 2) is passed through the skin incision and, under image-intensifier guidance, is aligned with the screw remnant to tap it out of the nail and bone into the soft tissues (Fig. 1c). In some nails, it may be necessary to enlarge the near cortex using a proximal/distal locking drill if the trocar diameter is larger.

Figure 2.

Trocar, drill sleeve, tissue protection sleeve.

DISCUSSION

The trocar is an ideal instrument for this purpose as it is of narrow bore, long enough to reach the broken screw and has a tap-ping end. All the instruments thus used are part of a standard nailing set obviating the need for any special tool.