Background: Aim of this study was to evaluate and compare clinical and radiological outcome of distal femur fracture stabilization using retrograde nailing or LISS plating.

Materials and Methods: In a retrospective study from 2003–2008 we analyzed 115 patients with distal femur fractures who had been treated by retrograde i.m. nailing (60 patients) or LISS plating (55 patients). Mean age was 55 years in the two cohort groups. Mechanism of injury was high energy impact in 57 % (SCN 53 %; LISS 76 %) and low energy injury in 43 % of all evaluated patients (SCN 47 %; LISS 33 %). Fractures were classified according to AO classification: There were 52 type A fractures (SCN 31; LISS 21) and 63 type C fractures (SCN 28; LISS 35). Interestingly severe articular fractures (type C2 and C3) were found much more often in LISS group (15 patients; 27 %) compared to 5 patients (8 %) in the SCN group.

Results: Fracture healing within 3 months was observed in type A fractures in over 90 % of the cases (SCN 29 patients, 89 %; LISS 20 patients, 95 %). A distinct diffrence was found in type C fractures. Whereas still nearly 90 % consolidation was evaluated in the SCN group (25 patients; 89 %), LISS plate group showed only 41 % (14 patients). Nonunion was found in type A fractures in only one patient per group (SCN and LISS 3 %) and in 2 patients in type C fractures treated with SCN (7 %). As expected 35 % (11 patients) nonunions were found in type C fractures treated with LISS. Both, the nail and the LISS group required additional bone grafting for successful healing (SCN 2; LISS 8). Functional outcome using the KOOS score demonstrated in type A fractures a score of 263 in the nail and 260 in the LISS plate group, and in type C fractures 257 in the nail and 218 in the LISS group. Loosening of screws without disturbing fracture healing (SCN 12 %; LISS 2 %). Deep infection (SCN 2 %; LISS 7 %), axis deviation of more than 10 degrees in the coronal or sagittal plane in 5 % in the nail and 12 % in the plate group were treated.

Conclusion: Both, retrograde i.m. nailing and LISS plating are adequate treatment options for distal femur fractures. No differences in outcome between implants regarding fracture healing, nonunion, and infection were found in type A fractures. A distinct difference occurred in type C fractures. According to high rate of severe articular and open fractures a high rate of nonunions and infections was found in the LISS group. Locked plating can be utilized for all distal femur fractures including complex type C fractures, periprosthetic fractures and osteoporotic fractures. I.m. nailing provides favorable intramedullary stability and can be successfully implanted in bilateral or multisegmental fractures of the distal femur as well as in extraarticular and type C1 to C2 fractures.