Novel "Screw First" Technique to Get Past Nail-Jig Mismatch in Proximal Femoral Nailing

Proximal femoral nailing is the gold standard of surgical treatment for unstable intertrochanteric hip fractures. One of the intraoperative complications encountered in this procedure is the nail–jig mismatch due to causes such as manufacturing errors and fatigue deformation of sleeves or jig.

Nail–jig mismatch leads to eccentric placement of guidewire within the screw slots of PFN and subsequent difficulty in reaming and screw insertion. The potential complications of this include guide wire deformation, breakage, nail damage and screw malposition.

Atmananda S. Hegde et al propose a simple and effective technique to tackle this complication, called as "Screw first" technique. The principle of this technique is to utilize screws as guide wire sleeves to effectively centralize the guidewire position within nail slots. On identifying a mismatch by the eccentric position of guidewire, a long screw is first inserted partially till its shaft engages into the screw slot allowing subsequent insertion of a guidewire which assumes a centralized position, thus bypassing the mismatch of jig. Following this, the usual steps of reaming and final screw insertion are undertaken. This method is effective, simple, quick and requires no special instrumentation.

Step 1: Look for eccentric position of guidewire through the screw slot in PFN using image intensifer to anticipate nail–jig mismatch.

Step 2: Retaining the guidewire in the proximal slot to act as derotation device, first tackle the compression screw. This step involves reaming of only the lateral cortex of proximal femur over the eccentric guidewire.

Step 3: The longest available screw is selected (usually 120 mm) and partially introduced over the eccentric guidewire without a sleeve. Because of the tapered nature of the screw tip, it will find its way inside the slot even in case of eccentric position, and it should be advanced till the threaded portion of the screw just crosses the nail. Thus, the smooth shaft of the screw snugly fits into the nail slot. Some deformation of the guide wire is expected at this stage, and care should be taken not to break the guidewire.

Step 4: Then, the eccentric bent guide is removed carefully.

Step 5: A fresh, straight guidewire is inserted through the cannulation of the partially inserted long screw without the sleeves. Here, the partially inserted long screw acts as a guidewire sleeve and centralizes the guidewire within the slot. The guidewire is inserted deep enough to achieve a strong subchondral purchase.

Step 6: Now, the partially inserted long screw is carefully removed.

Step 7: Sizing and reaming are done over the guidewire.

Step 8: Appropriate screw is chosen and inserted. Note the guidewire does not undergo any deformation as the screw is inserted.

Step 9: Same steps are followed for the derotation screw.

The authors commented - "In most Indian setups, where nail–jig mismatch is not an unusual occurrence, this technique can be a valuable method to bail out the surgeon intraoperatively and prevent complications." 

Key Words: Proximal femoral nail, Nail–jig mismatch, Screw first technique, Indian Journal of Orthopaedics.

Further reading:

"Screw First" Technique to Get Past Nail–Jig Mismatch in Proximal Femoral Nailing.

Atmananda S. Hegde, Prajwal P. Mane, Chethan B. Shetty, Samarth A. Thakkar

Indian Journal of Orthopaedics (2022) 56:699–704

https://doi.org/10.1007/s43465-021-00552-w