Case report: unique failure of a Synthes TFNA fenestrated lag screw in a peritrochanteric nonunion

Abstract

Background: Intertrochanteric femur fractures are a common orthopaedic injury that are often treated surgically. Cephalomedullary nails (CMN) are frequently the implant of choice for intertrochanteric femur fractures, resulting in low complication rates. Implant failure is a rare but reported complication. Common locations of failure include the proximal nail aperture, distal screw holes, and implant shaft. In this case report, we describe a CMN failure pattern through fenestrated cephalic screw holes.Case: A 70-year-old female sustained an OTA 31A-2.2 peritrochanteric fracture during a motor vehicle collision. She was treated the following day with a Synthes Trochanteric Fixation Nail-Advanced CMN utilizing a fenestrated cephalic screw. There were no intraoperative complications. She was made non-weight bearing for 8 weeks after the procedure due to ipsilateral foot fractures. At 6 months follow-up she was noted to have a delayed union. 11 months postoperatively she suffered a ground level fall and the cephalic lag screw failed through its fenestrations, resulting in varus collapse of her fracture at the femoral neck. The patient then underwent nail extraction and salvage total hip arthroplasty. Conclusion:Cephalomedullary nail implant failure is presented with implant fracture propagation through a fenestrated cephalic screw. Cephalomedullary lag screw failure is rare and can be difficult to manage. It is important to monitor new implants for unique failure mechanisms.

Trust But Verify: Design Differences in The Prevention of Targeting Errors in Cephalomedullary Nails

“…One study describes how the configuration of the helical blade was modified to reduce failures that occured in that region as a result of implant design. 15 However, a continued potential for jamming as a result of accessory rotation of the prong outside of its intended path during deployment was encountered with each of the 4 variants.…”