Retrograde intramedullary nailing of the femur: identifying the true anatomic axis for the ideal start point

Matthew W Kavolus; David C Landy; Kendall M Horan; Jeffrey A Foster; Jarod T Griffin; Eben A Carroll; Arun Aneja

doi:10.1007/s00590-023-03654-3

Retrograde intramedullary nailing of the femur: identifying the true anatomic axis for the ideal start point

Eur J Orthop Surg Traumatol. 2024 Jan;34(1):347-352. doi: 10.1007/s00590-023-03654-3. Epub 2023 Jul 31.

Authors

Matthew W Kavolus¹, David C Landy², Kendall M Horan², Jeffrey A Foster², Jarod T Griffin³, Eben A Carroll⁴, Arun Aneja²

Affiliations

¹ Department of Orthopaedic Surgery, Wellstar Kennestone Hospital, Atlanta, GA, USA.
² Department of Orthopaedic Surgery and Sports Medicine, University of Kentucky, 740 S Limestone, Lexington, KY, USA.
³ Department of Orthopaedic Surgery and Sports Medicine, University of Kentucky, 740 S Limestone, Lexington, KY, USA. jarod.griffin@uky.edu.
⁴ Wake Forest School of Medicine, Department of Orthopaedics, Winston Salem, Wake Forest, NC, USA.

PMID: 37523032
DOI: 10.1007/s00590-023-03654-3

Abstract

Purpose: Retrograde femoral intramedullary nailing (IMN) is commonly used to treat distal femur fractures. There is variability in the literature regarding the ideal starting point for retrograde femoral IMN in the coronal plane. The objective of this study was to identify the ideal starting point, based on radiographs, relative to the intercondylar notch in the placement of a retrograde femoral IMN.

Methods: A consecutive series of 48 patients with anteroposterior long-leg radiographs prior to elective knee arthroplasty from 2017 to 2021 were used to determine the femoral anatomic axis. The anatomic center of the isthmus was identified and marked. Another point 3 cm distal from the isthmus was marked in the center of the femoral canal. A line was drawn connecting the points and extended longitudinally through the distal femur. The distance from the center of the intercondylar notch to the point where the anatomic axis of the femur intersected the distal femur was measured.

Results: On radiographic review, the distance from the intercondylar notch to where the femoral anatomic axis intersects the distal femur was normally distributed with an average distance of 4.1 mm (SD, 1.7 mm) medial to the intercondylar notch.

Conclusion: The ideal start point, based on radiographs, for retrograde femoral intramedullary nailing is approximately 4.1 mm medial to the intercondylar notch. Medialization of the starting point for retrograde intramedullary nailing in the coronal plane aligns with the anatomic axis. These results support the integration of templating into preoperative planning prior to retrograde IMN of the femur, with the knowledge that, on average, the ideal start point will be slightly medial. Further investigation via anatomic studies is required to determine whether a medial start point is safe and efficacious in patients with distal femur fractures treated with retrograde IMNs.

Keywords: Anatomic axis; Femur; Intramedullary nail; Retrograde.

MeSH terms

Arthroplasty, Replacement, Knee* / methods
Bone Nails
Femoral Fractures* / diagnostic imaging
Femoral Fractures* / surgery
Femoral Fractures, Distal*
Femur / diagnostic imaging
Femur / surgery
Fracture Fixation, Intramedullary* / methods
Humans