Applied Surgical Anatomy of the Anterior, Lateral, and Anterolateral Approaches to the Hip

Overview

The fascia lata covers all the thigh and hamstring muscles around the hip joint. In hip surgery, its importance lies in its relationship to three muscles: the sartorius, the tensor fasciae latae, and the gluteus maximus. The fascia lata covers the sartorius; it also splits into a deep and superficial layer to enclose the tensor fasciae latae and gluteus maximus (Fig. 8-46). If the iliac crest is viewed from the lateral side, the outer layer of the covering seems to consist of the fascia lata of the thigh and the muscles that it encloses. The sartorius lies farther anteriorly. The gluteus medius, which arises from the outer wing of the ilium, is covered by the fascia lata, not enclosed by it (Fig. 8-47).

The key to the anterolateral approach to the hip lies in the relationship between the tensor fasciae latae and the gluteus medius. The tensor fasciae latae, a superficial structure, arises from the anterior portion of the outer lip of the iliac crest. The gluteus medius arises from the outer wall of the ilium, between the anterior and posterior gluteal lines. The origins of the two muscles are, therefore, almost continuous, but the tensor fasciae latae is slightly more superficial (lateral) and anterior than the gluteus medius (Fig. 8-48).

The tensor fasciae latae inserts into the iliotibial tract, the thickening of the deep fascia of the thigh, while the gluteus medius inserts into the anterior and lateral part of the greater trochanter. Thus, as the muscles run from origins to insertions, the tensor fasciae latae rises to an even more superficial position in relation to the gluteus medius (see Figs. 8-47 and 848).

To exploit the intermuscular plane between the gluteus medius and the tensor fasciae latae, incise the fascia lata posterior to the posterior margin of the tensor fasciae latae and retract the cut fascial edge anteriorly. Because the fascia lata actually encloses the tensor fasciae latae, the muscle is retracted with the fascia (see Fig. 8-47).

Figure 8-46 Superficial musculature of the lateral aspect of the hip.

All anterolateral approaches use this one intermuscular plane to reach the femoral neck; then they follow the joint capsule medially to expose the anterior rim of the acetabulum. The techniques used in this approach differ mainly in how they detach the abductor mechanism to allow adduction of the femur for femoral reaming and retraction of the femoral neck posteriorly for adequate exposure of the acetabulum.

The anterior approach is more straightforward: Two distinct muscle layers must be incised. The outer layer consists of the tensor fasciae latae (superior gluteal nerve) and the sartorius (femoral nerve) (see Fig. 8-14). The interval between them forms a true internervous plane. Two structures, the lateral femoral cutaneous nerve and the ascending branch of the lateral femoral circumflex artery, lie between them; they must be identified and avoided during the dissection (see Figs. 8-14 and 8-15).

The deep layer of muscle consists of the rectus femoris (femoral nerve) and the gluteus medius (superior gluteal nerve). The interval between them is also an internervous plane; exploiting it is difficult, mainly because the short head of the rectus femoris originates partly from the anterior capsule of the hip joint, where the iliopsoas partly inserts (see Figs. 8-15 and 8-16).

The lateral approach splits vastus lateralis and gluteus medius to provide direct access to the hip joint capsule. The approach is limited superiorly by the superior gluteal nerve, which traverses the substance of gluteus medius.

Landmarks and Incision

Landmarks

The anterior superior iliac spine is the site of attachment of two important structures. The sartorius takes its origin from it, and the inguinal ligament uses it as a lateral attachment. The anterior superior iliac spine is rarely used as a bone graft because the lateral cutaneous nerve of the thigh lies so close to it.

The anterior third of the iliac crest serves as the origin for the following three muscles:

1.  The external oblique forms the outer layer of the muscles of the anterior abdominal wall. It inserts into the outer strip of the anterior half of the iliac crest.

2.  The internal oblique forms the middle layer of the muscles of the anterior abdominal wall. It originates from the center strip of the anterior half of the iliac crest.

3.  The tensor fasciae latae arises from the outer lip of the anterior half of the iliac crest.

Figure 8-47 Resecting the sartorius, tensor fasciae latae, and fascia lata and reflecting the anterior portion of the gluteus maximus posteriorly reveal the gluteus medius and more anterior structures of the hip region. The fascia lata splits to envelop the tensor fasciae latae, but it only covers the gluteus medius muscle.

Gluteus Medius. Origin. Outer aspect of ilium between anterior and posterior gluteal lines and its overlying fascia. Insertion. Lateral surface of greater trochanter. Action. Abductor and medial rotator of hip. Nerve supply. Superior gluteal nerve.

The insertion of the external oblique and origin of internal oblique are not detached during the anterior approach; the tensor fasciae latae is.

The greater trochanter is the traction apophysis of the proximal femur and the site of the insertion of the gluteus medius and minimus muscles.

The vastus lateralis ridge results partly from the pull of the aponeurosis of the vastus lateralis during growth and partly from the fusion of the trochanter apophyses of the shaft of the femur (Figs. 8-49 and 8-50; see Fig. 8-47).

Incisions

The anterior, lateral, and anterolateral incisions largely ignore the lines of cleavage in the skin, but the scars are seldom broad and are nearly always hidden by clothing.

Superficial Surgical Dissection and Its Dangers

The anterior and anterolateral approaches use planes that involve the tensor fasciae latae. The anterior approach passes in front of it; the anterolateral approach passes behind it (Fig. 8-51). The lateral approach splits gluteus medius and vastus lateralis.

Anterior Approach

The tensor fasciae latae and the sartorius run side by side from an almost continuous line of origin along the anterior end of the iliac crest. The two muscles diverge a short distance below the anterior superior iliac spine so that the rectus femoris can emerge from between them (see Fig. 8-14).

Figure 8-48 The gluteus medius, gluteus minimus, and rectus femoris have been resected to reveal the muscular layers down to the hip joint capsule. Resection of the joint capsule exposes the acetabulum and the femoral head and neck.

Figure 8-49 Osteology of anterolateral aspect of the hip and pelvis.

Figure 8-50 Osteology of the lateral aspect of the hip and pelvis.

The tensor fasciae latae itself is triangular. In cross section, it is unusually slim at its origin and thick just before it inserts into the iliotibial tract. Its action is difficult to interpret, because another large muscle, the gluteus maximus, also inserts into the iliotibial tract. In cases of poliomyelitis, dividing the iliotibial tract relieves flexion and abduction contractures of the hip joint.

Evidence suggests that the tensor fasciae latae may be important in standing in a one-legged stance, waiting in a bus line, for instance, where the muscle may maintain the stability of the extended knee and hip.8 The tensor fasciae latae may also have the primary function of balancing the weight of the body and the non–weight-bearing leg during walking.26

The muscle fibers of the tensor fasciae latae are considerably finer than those of the gluteus medius, but the difference in the quality of fibers rarely makes it easier to identify the plane between the two muscles.

The sartorius is the longest muscle in the body crossing both the hip and the knee. The individual fibers within the muscle are also the longest in the body; they leave the sartorius weak but capable of extraordinary contraction.

Two structures cross the plane between the tensor fasciae latae and the sartorius. Both complicate the superficial surgical dissection of the anterior approach.

1.  The ascending branch of the lateral femoral circumflex artery is a comparatively large artery that often requires ligation. It is one of a series of vessels that run circumferentially around the thigh (see Anterior Approach to the Hip above). This is one of the rare instances in which a vessel crosses an internervous plane (see Figs. 8-15 and 8-16).

2.  The lateral femoral cutaneous nerve (lateral cutaneous nerve of the thigh) arises from the lumbar plexus or, occasionally, from the femoral nerve itself. From there, it descends through the pelvis on the surface of the iliacus muscle. It enters the thigh under the inguinal ligament anywhere between the anterior superior iliac spine and the midinguinal point. The nerve pierces the fascia lata just below and medial to the anterior superior iliac spine. The path it takes may vary considerably, as it can pass either around or through the sartorius muscle (see Fig. 8-14). It may divide into three or more branches just below the inguinal ligament.

Compression syndromes (meralgia paresthetica) of the lateral femoral cutaneous nerve have been reported, particularly from the section that runs behind the inguinal ligament and from the point where the nerve pierces the fascia lata. These syndromes consist of painful paresthesias on the lateral side of the thigh, conditions that may be relieved by decompressing the nerve. Occasionally, decompression may have to extend into the pelvis, since the nerve may be compressed on the surface of the iliacus.

Figure 8-51 The anterior and anterolateral approaches to the hip joint, showing their muscular boundaries.