24: Supracondylar Femur Fractures

PROCEDURE 24 Supracondylar Femur Fractures



Don W. Weber



image


Open Reduction and Internal Fixation




PITFALLS



• Medically unstable patients

• Nonambulatory patients

• Nondisplaced or stable (impacted) fracture patterns

• Severe osteopenia (device/technique sensitive)

• Severe comminution

• Lack of surgical expertise



Indications



image Displaced/irreducible fracture

image Unstable/comminuted fracture

image Intra-articular fractures (partial or complete)

image Open fractures (staged?)

image Pathologic fractures

image Bilateral femur fractures

image Ipsilateral tibial fractures

image Vascular compromise (may be staged)

image Associated knee ligament injuries


Examination/Imaging




Controversies



• This is a technically demanding fracture, and thorough knowledge of deforming forces, complications, implant limitations, and surgical technique is required.


image Diagnosis is usually obvious clinically.

image The minimal imaging required is good-quality anteroposterior (AP) and lateral radiographs.

image A traction or splinted view can greatly aid in preoperative planning.

image Imaging of the uninjured femur/knee can also be helpful prior to surgery.

image Computed tomography scans are rarely necessary unless there is extensive intra-articular involvement.


Surgical Anatomy




Treatment Options



• Alternatives to open reduction and internal fixation include retrograde intramedullary nailing, cast or brace treatment, and (rarely) revision total knee arthroplasty.

• Open reduction and internal fixation can be completed with numerous devices depending on the fracture type, bone quality, and surgical experience.
image Condylar blade plate

image Dynamic condylar screw

image Distal femoral locking plate

image LISS plate

image Condylar buttress plate



PEARLS



• Prep the limb as high as possible and use a sterile tourniquet during the entire case. If necessary, do the articular reduction under tourniquet control and deflate for the reduction of the condyles to the shaft.

• Preparation and exposure of the ipsilateral iliac crest may be useful if bone grafting is anticipated.

• Examine the opposite limb prior to preparation to determine rotational alignment.

• Use of a femoral distractor or external fixator can greatly aid in reduction of the fracture (especially intra-articular components).

• Place the distractor out of the area for plating. One pin should be placed at the level of the lesser trochanter laterally and the second in the lateral proximal tibia. Distract with the knee in approximately 20° of flexion.



PITFALLS



• Avoid use of a traction table as it will tension the muscle and make exposure and reduction more difficult.


image The most important structure at risk is the superficial femoral artery, which enters the popliteal fossa around 10 cm proximal to the knee joint as it passes through the adductor magnus. (Be especially cautious with the medial approach.)

image Soft tissues
• The quadriceps muscle anteriorly (rectus femoris, vastus medialis, vastus intermedius, and vastus lateralis) is separated from the posterior compartment (hamstring muscles) by the medial and lateral intermuscular septa. These large muscles shorten the fracture, and their force must be overcome in reduction techniques.

• The gastrocnemius muscles attach to the posterior femoral condyles and create an extension force to the condyles. This produces the typical deformity of supracondylar femur fractures which is extension and shortening (Fig. 1).

image Bone
• The distal femur has many unique features that are critical to understand for reduction and fixation techniques.

• The metaphysis widens at the end of the femoral diaphysis and supports the femoral condyles. Anteriorly, a shallow articular concavity between the condyles provides a contact surface for the patella. Posteriorly, the intercondylar fossa separates the condyles and is the attachment area for the cruciate ligaments.

• In the lateral projection, the femoral shaft aligns with the anterior half of the lateral condyle (Fig. 2).

• The lateral femoral condyle is larger anterior to posterior than the medial condyle and has a flat lateral surface. The medial condyle is wider posteriorly, and this creates the trapezoidal shape to the distal femur when viewed end on (Fig. 3). This is extremely important in placing fixation devices to avoid errant hardware placement and to avoid malreductions such as medial translation.

• The alignment of the knee joint is parallel to the ground, with the anatomic axis of the femur averaging 9° of valgus (range, 7–11°).

image

FIGURE 1


image

FIGURE 2


image

FIGURE 3



Positioning




Equipment



• Use of a radiolucent support such as a triangle, adjustable support, or rolled-up sheeting will reduce the effect of the gastrocnemius muscles and aid reduction attempts.



Controversies



• Some surgeons prefer a lateral position; however, this makes AP imaging slightly more difficult.


image The most widely accepted position for fixation of supracondylar femur fractures is with the patient supine on a radiolucent table. This allows for C-arm fluoroscopy intraoperatively.

image The operative hip can be elevated on a sandbag, rolled flannel, or intravenous solution bag to rotate the femur and knee into a true AP projection.

image The knee is usually draped free with a sterile tourniquet and partially flexed over a radiolucent support (Fig. 4).

image

FIGURE 4



Portals/Exposures




PEARLS



• Preoperative planning will give a better understanding of the fracture, the exposure required, and the equipment necessary for reduction and fixation. This is especially true if a tibial tubercle osteotomy is anticipated.

• Start with articular exposure to reduce blood loss and unnecessary dissection.

• A combined lateral and small medial approach may have less morbidity than an extensile exposure and osteotomy.



PITFALLS



• Although rarely needed, when performing a tubercle osteotomy, take care to elevate a large enough portion of the tubercle to allow stable fixation and early mobilization.


image Most supracondylar fractures can be reduced and stabilized through a single lateral approach. The exceptions to this would be medial condyle fractures and extensively comminuted intra-articular fractures.

image Surgical technique should include careful soft tissue handling, indirect reduction where possible, anatomic articular reconstruction, and restoration of limb length, rotation, and alignment.

image Bone grafts should be used where necessary, and stable fixation should be achieved to allow for early active rehabilitation.

image For the single lateral approach, a straight lateral incision is made over the distal femur extending to the midpoint of the lateral condyle (Fig. 5A). The incision should stay anterior to the lateral collateral ligament.
• Proximally the incision can be extended as high as necessary depending on the length of the fracture, reduction technique, and implant chosen (Fig. 5B). The proximal incision is completed after the articular reduction has been achieved if possible.

• Distally, the incision can be extended across the knee joint and then curved anteriorly to the lateral border of the tibial tubercle.

• The fascia lata is incised in line with the skin incision, and the anterior fibers of the iliotibial band are divided distally. The approach continues through the joint capsule and synovium, taking care to ligate the superior lateral geniculate artery and not damage the lateral meniscus.

• Next the vastus lateralis is elevated from the intermuscular septum and any perforating vessels are ligated (Fig. 6A and 6B). Only as much soft tissue is elevated as necessary for the reduction and fixation.

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Jun 7, 2016 | Posted by in ORTHOPEDIC | Comments Off on 24: Supracondylar Femur Fractures

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