Lateral Approach to the Distal Femur for Anterior Cruciate Ligament Surgery

Lateral Approach to the Distal Femur for Anterior Cruciate Ligament Surgery‌

 

 

The lateral approach to the distal femur, known as the “over-the-top” approach, is used in conjunction with the medial parapatellar approach for repair or reconstruction of the anterior cruciate ligament (see the section regarding the medial parapatellar approach). Therefore, it is not used as an isolated incision. The approach exposes the posterior aspect of the

intercondylar notch by passing over the top of the posterior aspect of the lateral femoral condyle.

The lateral approach to the distal femur also provides access to the lateral aspect of the lateral femoral condyle so that drill holes can be made in the condyle (if they are needed) for reattachment of the femoral end of the anterior cruciate ligament or attachment of the femoral end of an anterior cruciate substitute.

 

Position of the Patient

 

Place the patient supine on the table with a bolster under the thigh so that the knee rests in 30 degrees of flexion. Place a tourniquet high on the patient’s thigh and exsanguinate the leg using a compression bandage or prolonged elevation before the tourniquet is inflated (Fig. 10-63).

 

Landmarks and Incision

Landmarks

Palpate the posterior lateral margin of the lateral femoral condyle as it flares out from the shaft of the femur.

Note the intersection between the iliotibial band and the biceps femoris

muscle.

Incision

Make a 10-cm incision parallel to and over the indentation between the biceps femoris muscle and the iliotibial band. Distally, the incision ends at the flare of the femoral condyle (Fig. 10-64).

 

 

 

Figure 10-63 Position for the lateral approach to the distal femur.

 

Internervous Plane

 

The dissection exploits the internervous plane between the vastus lateralis

muscle (which is supplied by the femoral nerve) and the biceps femoris muscle (which is supplied by the sciatic nerve; see Fig. 10-51).

 

Superficial Surgical Dissection

 

Incise the iliotibial band just anterior to the lateral intermuscular septum, in line with the skin incision. The incision is slightly anterior to the skin incision itself (Fig. 10-65).

 

Deep Surgical Dissection

 

Identify the vastus lateralis muscle anterior to the intermuscular septum, and retract it anteriorly and medially. Below the muscle lies the lateral superior genicular artery; it must be ligated (Figs. 10-66 and 10-67). Using cautery, incise the periosteum at the junction of the shaft and flare of the femur. Pass a small clamp or a small Cobb elevator behind the posterolateral flare of the lateral femoral condyle, staying in a subperiosteal plane. Carefully carry the dissection distally and medially over the top of the lateral femoral condyle until the instrument can be felt to enter the intercondylar notch (Fig. 10-68). Sticking to bone, pass the tip of the instrument anteriorly until it is visible in the knee, as viewed from the anteromedial incision (medial parapatellar) (Fig. 10-69).

 

 

Figure 10-64 Make an incision 10 cm long parallel to and over the indentation between the biceps femoris and the iliotibial band.

 

 

Figure 10-65 Incise the iliotibial band just anterior to the lateral intermuscular septum, in line with the skin incision.

 

 

Dang

 

 

Nerves and Vessels

The peroneal nerve may be injured if the dissection strays to the posterior side of the biceps femoris muscle.

The lateral superior genicular artery must be ligated. Otherwise, it can cause a large postoperative hematoma.

The popliteal artery may be injured if the surgical plane does not remain subperiosteal. As the intercondylar notch is felt, bend the knee to 90 degrees to allow the popliteal artery to fall posteriorly with the joint capsule.

 

How to Enlarge the Approach

Local Measures

Retract the vastus lateralis muscle vigorously toward the midline of the knee with a right-angled retractor.

Extensile Measures

This incision is very extensile. It can be extended as far proximally and distally as it has to be (see Lateral Approach in Chapter 9, see Fig. 9-14). In addition, the incision can be used in its more proximal extensions for an iliotibial-fascial graft.

 

 

 

Figure 10-66 The vastus lateralis anterior to the intermuscular septum is retracted anteriorly and medially. Identify the lateral superior genicular artery.

 

 

Figure 10-67 Retract the muscles further, ligate the lateral superior genicular artery, and incise the periosteum at the junction of the shaft and the flare of the femur.

 

 

Figure 10-68 A: Pass a small instrument behind the posterolateral flare of the lateral femoral condyle deep to the periosteum. B: Continue passing the instrument distally and medially over the top of the lateral femoral condyle until it can be felt entering the intercondylar notch.

 

 

Figure 10-69 Advance the tip of the instrument anteriorly until it is visible in the knee as viewed from the anteromedial incision.