Retrograde intramedullary nailing of comminuted intra-articular distal femur fractures results in high union rate.

Purpose: Retrograde intramedullary nailing of intra-articular distal femur fractures with metaphyseal and/or epiphyseal comminution is controversial and considered a contraindication to nailing. The purpose of this study was to report union rate, complications, and secondary procedures after open reduction and retrograde intramedullary nailing of comminuted, intra-articular, distal femur fractures.

Materials and methods: A retrospective review performed at an urban level one trauma center identified 16 patients AO/Orthopedic Trauma Association (OTA) 33-C2 and 33-C3 femur fractures treated with open reduction, lag screws, and retrograde intramedullary nail fixation. Radiographic union, complications, secondary operations were reviewed.

Results: At the 3-month follow-up 12 (86%) of the 14 patients with radiographs had healed. At last follow-up, all 16 femur fractures achieved radiographic union after the index procedure. No patient required a revision procedure for delayed union or nonunion. Complications occurred in 6 (38%) patients, including failed distal interlocking screws (n = 2), knee arthrofibrosis (n = 3), superficial wound infection (n = 1), and wound dehiscence (n = 1). Three (19%) patients required secondary procedures, which included knee manipulation under anesthesia (n = 3), distal interlocking screw removal (n = 2), and closure of a wound dehiscence (n = 1).

Conclusions: Comminuted intra-articular distal femur fractures that can be successfully treated with retrograde IMN fixation will reliably go on to union with a complication rate that is favorable to that reported for plate fixation.

Level of evidence: Level IV, retrospective case-series.