Surgical Tips and Tricks for Distal Femur Plating

Christopher Lee, MD; Dane Brodke, MD; Ajay Gurbani, MD

Disclosures

J Am Acad Orthop Surg. 2021;29(18):770-779. 

In This Article

Adjunctive Fixation

For fractures with severe medial metaphyseal comminution and/or missing metaphyseal bone, adjunctive fixation may be warranted (Figure 8). One option is medial plating, which can be done through minimally invasive methods in a "safe zone" on the anteromedial aspect of the distal femur.[21–23] This "safe zone" was characterized by Kim et al[23] in a study of the CT angiography of 30 patients as the anteromedial aspect of the femur from the adductor tubercle up to a point halfway from the adductor tubercle to the lesser trochanter (15 cm below the lesser trochanter). In this distal aspect of the femur, the deep femoral artery has already given off its final perforator (8 cm distal to the lesser trochanter) and the superficial femoral artery has moved posteromedially, posterior to a coronal plane–bisecting line through the femur.[23]

Figure 8.

Radiograph showing the adjunctive fixation options. The postoperative AP and lateral radiographs on the left show the use of a construct combining a lateral plate and an intramedullary nail. The postoperative AP radiographs on the right show the use of both medial and lateral plates with the medial plate greater than 15 cm distal to the lesser trochanter and therefore in the "safe zone" on the anteromedial distal femur.

A multitude of plate options exist for medial plate application, with the proximal tibia variable angle locking plate found to contour well with the medial supracondylar femur anatomy.[24] A 12-hole 3.5-mm recon plate (168 mm in length) is the authors' preferred option. This can be contoured to allow for fixation in the medial femoral condyle and has adequate length to obtain proximal fixation above most metaphyseal comminution. This plate length allows for fixation within the "safe zone" of percutaneous medial plating because less than 15 cm of the plate will project above the adductor tubercle. Typically, a 5-cm incision is made just anterior and distal to the adductor tubercle. Dissection is carried down to the level of the vastus medialis, with the vastus medialis retracted anteriorly and the sartorius fascia retracted posteriorly. The contoured plate is then slid submuscularly along the anteromedial aspect of the femur, with fluoroscopy used to guide placement. Once confirmed proximally, a distal cortical screw is placed. Next, a 2- to 3-cm incision is made along the cranial aspect of the plate, with dissection carried down superficially between the sartorius and rectus femoris. The vastus medialis is then isolated and retracted anteriorly, and a variable angle drill guide is placed in the cortical slot of the plate. A long 2.5-mm drill bit is then used, followed by removal of the inner sleeve. It is important to first unseat the inner sleeve with the drill bit engaged in the bone so as to facilitate abutment of the outer sleeve against the screw slot and to carefully remove the drill bit and inner sleeve simultaneously with immediate screw placement because the outer sleeve does not engage within the cortical screw slot (the inner sleeve does engage in this slot).

Another option for adjunctive fixation is the addition of an intramedullary nail to a lateral plate. Fixation constructs combining plates and intramedullary nails initially emerged for the treatment of long bone nonunions.[25] More recently, this construct has been advocated for the acute treatment of distal femur fractures, both native and periprosthetic.[26–28] The authors' preferred approach involves fracture reduction with initial plate application and subsequent nail placement (Figure 8). A midline approach is made with a lateral parapatellar arthrotomy. The fracture is reduced as described above, and a 16- to 18-hole plate is placed with an apex medial bend over the cranial aspect of the plate in addition to an external rotation twist to allow for screw placement into the femoral neck. For native distal femur fractures, the most distal posterior screw is placed followed by a cortical screw cranial to the fracture. One to two unicortical locking screws (typically 12 to 14 mm) in the distal shaft cranial to the fracture and one cortical screw through the femoral neck are placed, followed by removal of the cortical screw in the shaft. The retrograde nail is then placed, and distal interlocks can be placed from medial to lateral or placed through the plate, thus unitizing the construct. Proximal interlocks are placed using a perfect circles' technique with an anterior-to-posterior trajectory. Distal locking screws are then placed through the plate. Finally, screws are placed in the shaft, bicortically where possible, with unicortical locking screws in areas blocked by the nail. In periprosthetic fractures where retrograde nail insertion typically begins more posteriorly, the most distal anterior locking screw through the plate can be placed first in lieu of the distal posterior screw to avoid interference with eventual nail placement.

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