Clinical and Radiographic results of a Retrograde Nail - Washer Combination Versus Lateral Locked Plating for Distal Femur Fractures.

Objectives: The objective of this study was to report outcomes of the Retrograde Femoral Nail-Advanced with Lateral Attachment Washer (RFNA-LAW) (Synthes; Paoli, PA) compared to laterally locked plates (LLP) when treating AO/OTA type 33 distal femoral fractures.

Methods: Design: Retrospective chart review.

Setting: Single, academic, Level-1 Trauma Center.

Patient selection criteria: All adult patients who had fixation of an AO/OTA type 33 distal femoral fracture with the RFNA-LAW combination or LLP from 2018-2023 with follow-up to union or a minimum of one year. immediately post-operatively and at final follow-up.

Outcome measures and comparisons: The main outcome measure was union. Secondary outcomes included implant failure, infection, and alignment immediately post-operatively and at final follow-up. Patients were followed for a minimum of 1-year or to skeletal healing.

Results: Forty-eight patients (19 female) with a mean age of 56 years (range 19-94 years) were in the RFNA-LAW group. Fifty-three patients (29 female) with a mean age of 66 years (24-91 years) were in the LLP group. There were no significant differences when comparing Body Mass Index, diabetes, smoking status, mechanism of injury, or fracture classification between groups (p>0.05). There was no difference in immediate, post-operative alignment (p = 0.49). When comparing aLDFA measurements at final follow-up, there was significantly more malalignment in the LLP group (p = 0.005). There were 8 implant failures (15%) in the LLP group compared to 1 in the RFNA-LAW group (2%) (p = 0.02). There were 14 reoperations (26%) in the LLP group compared to 4 (8%) in the RFNA-LAW group (p = 0.02).

Conclusions: The Retrograde Nail Advanced - Lateral Attachment Washer combination demonstrated a high union rate when treating complex fractures of the distal femur. When compared to lateral locked plating, this implant combination demonstrated significantly lower rates of nonunion and reoperation.

Level of evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.