**3. Management of extraarticular fractures of the distal femur**

Extraarticular fractures involving the metaphysis, and without comminution (type A1 and A2 fractures, according to AO/OTA), can be addressed efficiently with

**Figure 5.** *Type A3 high-energy fracture, managed with RIMN and three distal locking screws.*

#### *Management of Distal Femoral Fractures DOI: http://dx.doi.org/10.5772/intechopen.110692*

either LP or RIMN (**Figure 5**) [33–37]. The presence of metaphyseal comminution and/or osteopenic bone involves a high risk of varus collapse and hardware failure [38] (type A3 fractures). For these fractures numerous biomechanical studies have been published, as mentioned before, in bone models with finite element analysis and in cadaver studies, in search for stronger fixation methods [38–41]. DeKeyser et al. reported a literature review on what has been investigated in terms of mechanical fixation of distal femoral fractures with a metaphyseal defect. As a summary, medial and lateral plate fixation (dual plating of the distal femur) and the combination of IMN and LP, showed greater strength and resistance to axial, torsional and bending forces, than conventional LP or INM fixation alone. Lodde et al. published a literature review on the clinical results of double plating, that included femoral shaft fractures in polytrauma patients, femoral nonunions, proximal femoral pathological fractures, periprosthetic fractures, and distal femoral fractures. They concluded that double plating is a valid alternative for management of the latter, with high union rates (88%), but also with a 33% complication rate. Steinberg et al. reported on clinical results in double plating for acute distal femoral fractures (intra and extraarticular), nonunions and periprosthetic fractures. Only one of 32 patients developed nonunion that required bone grafting, and one had a femoral shaft fracture proximal to the hardware, requiring lateral plate exchange. Bologna et al. published on a comparative cohort of patients treated either with single or double plating with C2 and C3 (AO-OTA) distal femoral and periprosthetic fractures. A statistically significant difference was found between the two groups in terms of nonunion and time to healing, in favor of dual plating. It is clear that increasing the strength and rigidity of the construct by adding a parallel medial plate has a correlation with better clinical results and fewer mechanical failures. However, there is still lack of definitive clinical evidence whether this augmentation -which leads to increased stiffness- ultimately allows proper bone healing. In cases of poor bone quality, a stronger construct may well withstand forces irrespective of fracture consolidation. It can be difficult to interpret and clearly define the presence of bone bridging in the fracture zone on plain X-rays. To our knowledge, no large scale study has been presented assessing bone healing with a more sensitive exam, such as multiplanar CT.

A few cases reporting on the advantages of the combination of LP- RIMN in fractures in osteopenic bone have been published, as well as femoral nonunions [29, 30, 42, 43]. It seems that this method allows for earlier weight bearing and functional recovery in older patients, due to the increased strength of the construct. Engaging both the plate and the nail with screws that interlock both implants may increase even further the resistance of the system.

In our experience, the combination of IMN and LP ("augmented RIMN") in the management of fractures with metaphyseal comminution results in a construct which combines the benefits of both implants (**Figure 6**). It has been argued that it results in a more even distribution of forces, which allow for earlier weight bearing, while minimizing the risk of hardware failure [29, 44]. From the mechanical standpoint, a long lateral locking plate with far-proximal cortical screws tangential to the nail, provides a longer working length and higher resistance to cantilever forces towards varus at the proximal end of the plate (which is acting as a true tension band), in an attempt to minimize proximal screw loosening and pull-out (**Figure 7**). In our initial experience with shorter plates, however, toggling and loosening of these screws was not followed by progressive deformity in varus. We believe that the presence of a long, locked intramedullary device helps in maintaining alignment.

#### **Figure 6.**

*High-energy floating knee injury (Fraser type IIC), with open segmental tibial fracture. After damage-control orthopaedic management, definitive fixation was performed with a nail and plate combination for the femur and tibia. Reduction of the articular femoral fracture was done with 3.5 mm. cortical screws, and additional 3.5 mm. one-third tubular plate. No other procedures were needed until healing.*

*Management of Distal Femoral Fractures DOI: http://dx.doi.org/10.5772/intechopen.110692*

#### **Figure 7.**

*(a) AP X-ray showing fixation of a A3 distal femoral fracture with nail and plate combination. A short lateral locking plate and proximal monocortical locked screws were used. (b) After 5 months, loosening of most proximal locked screw is seen, due to toggling. To prevent this, extended length of the plate proximally, and proximal bicortical screws, would have been appropriate.*

Recent advances in design have brought into market extraosseous devices that engage to a RIMN through screws, adding significant stability to conventional nail interlocking screws [45]. This locked "washer" gets "unitized" to the intramedullary nail, which in mechanical testing -together with still limited clinical experiencehas shown significant improvement in endurance and strength. The combination of RIMN plus a lateral locking plate acts using the same principle. This "washer",

**Figure 8.**

*AP and lateral view of the "locking washer" in place, which engages two locking holes of a retrograde nail with screws that are locked to the external device, providing significant increase in stability over interlocking screws alone.*

moreover, could have the additional advantage of avoiding submuscular dissection for placing a long lateral plate (**Figure 8**).
