Minimally Invasive Surgery for Retrograde Intramedullary Nailing of the Femur
The minimally invasive approach for retrograde intramedullary nailing utilizes a small portion of the medial parapatellar approach to the knee. It allows excellent percutaneous access to the distal femoral intercondylar
region. Its sole use is for the insertion of retrograde intramedullary nails used to treat femoral shaft fractures.
Position of the Patient
Place the patient supine on a radiolucent table. Place a large triangular ridge underneath the knee to allow the knee to flex to 90 degrees. Finally, place a small sandbag under the ipsilateral buttock to correct the natural external rotation of the limb and ensure that the patella faces directly anteriorly. Ensure that this sandbag does not block radiographic visualization of the trochanteric region of the femur where proximal locking may be needed. This will allow you to more accurately access rotational control during fracture reduction and fixation.
Landmarks and Incision
Internervous Plane
There is no internervous plane available for this approach. The approach is merely through the medial patellar retinaculum and synovium.
Figure 9-43 Make a 3-cm longitudinal incision approximately 1 cm from the medial border of the patella, beginning about 2 cm proximal to the distal pole of the patella.
Superficial Surgical Dissection
Deep Surgical Dissection
Divide the underlying synovium of the knee. Insert two retractors to
visualize the intercondylar notch. The insertion point and direction of guidewires used for nail introduction must be confirmed using appropriate x-ray control (Figs. 9-45 and 9-46).
Dang
The infrapatellar branch of the saphenous nerve should lie distal to the distal end of the incision. It is only in danger if the incision is extended distally.
The posterior cruciate ligament inserts into the lateral aspect of the medial femoral condyle. The insertion may be damaged by the intramedullary nail or the reamers used to create the opening if the entry point is not correctly located.
How to Enlarge the Approach
Local Measures
The approach can be extended a short distance both proximally and distally, and this may be required in obese patients. The skin incision may be extended distally and an extra-articular approach to the proximal tibia may be used to insert a tibial nail in cases of floating knee. (See Minimally Invasive Approach for Tibial Nailing in Chapter 11, page 626.)
Figure 9-44 Deepen the incision through subcutaneous tissue in the line of the skin incision. Identify the capsule of the knee joint and divide it longitudinally.
Figure 9-45 Divide the underlying synovium of the knee. Insert two retractors to visualize the intercondylar notch and the insertion of the posterior cruciate ligament onto the lateral aspect of the medial femoral condyle.
Figure 9-46 Insert a guidewire into the distal femur. The entry point in the intercondylar notch varies with the implant to be used, and accurate positioning of the guidewire must be confirmed by C-arm imaging at the time of surgery.
