Anterior Approach to the Hip

Operations on the hip joint are among the most common surgical procedures performed in orthopedics. Total joint replacement for degenerative joint disease has revolutionized the lives of millions of patients. Open approaches to the hip joint are also required for hemiarthroplasties, tumor surgery, and for the treatment of infection around the hip joint.

The anterior approach was less commonly used for joint replacements than the anterolateral and posterior approaches but a variation of the approach-the minimally invasive anterior approach is increasingly used for such surgery.23

The full anterior approach allows good access to the pelvis as well as to the hip joint. The anterolateral approach, still the most common approach for total hip replacement, has many variations because of the different requirements of the several prosthetic designs that can be inserted. The standard anterolateral approach is described; readers are advised to consult the original papers of the designers of the arthroplasty before performing a particular joint replacement. The posterior approach is used extensively for hemiarthroplasty as well as for total hip joint replacement. It is both safe and easy to perform with only one assistant. The medial approach is rarely used, and then mainly for local procedures on the lesser trochanter and surrounding bone.

Minimally invasive surgical approaches to the hip have increased in popularity. Most of these techniques utilize the classical approaches described in this book. The length of the skin incision and the underlying dissection is reduced. Minimally invasive surgery can create less soft tissue damage, but the visualization of the structures is necessarily less. The techniques, therefore, are potentially more hazardous especially in obese patients and an understanding of the underlying anatomy is even more important than in larger surgical approaches. In addition, imaging may be indicated to ensure correct implant position.

Figure 8-1 The intermuscular intervals used in the anterior, anterolateral, and posterior approaches to the hip.

These four basic approaches to the hip take advantage of the muscular intervals that surround the joint. The anterior approach uses the interval between the sartorius and the tensor fasciae latae; the anterolateral approach uses the interval between the tensor fasciae latae and the gluteus medius; the posterior approach gains access either through the interval between the gluteus medius and the gluteus maximus or by splitting the gluteus maximus; and the medial approach exploits the interval between the adductor longus and the gracilis (Fig. 8-1).

Three anatomical sections augment the description of the approaches. Because the anterior and anterolateral approaches share so much anatomy, they are grouped together. The anatomy for the posterior and medial approaches follows the appropriate approach.

Anterior Approach to the Hip

The anterior approach, also known as the Smith-Petersen1,2 approach, gives safe access to the hip joint and ilium. It exploits the internervous plane between the sartorius (femoral nerve) and the tensor fasciae latae (superior gluteal nerve) to penetrate the outer layer of the joint musculature. Its uses include the following:

1.   Open reduction of congenital dislocations of the hip when the dislocatedfemoral head lies anterosuperior to the true acetabulum3

2.   Synovial biopsies

3.   Intra-articular fusions

4.   Total hip replacement

5.   Hemiarthroplasty

6.   Excision of tumors, especially of the pelvis

The upper part of the approach may also be used for pelvic osteotomies. Note however that the approach does not expose the acetabulum as completely as other incisions unless muscles are extensively stripped off the pelvis.

Position of the Patient

Place the patient supine on the operating table. If the approach is to be used for pelvic osteotomy, place a small sandbag under the affected buttock to push the affected hemipelvis forward (Fig. 8-2).

Figure 8-2 Position of the patient on the operating table for the anterior approach to the hip.

Landmarks and Incision

Landmarks

The anterior superior iliac spine is subcutaneous and is easily palpable in thin patients. In obese patients, it is covered by adipose tissue and is more difficult to find. You can locate it most easily if you bring your thumbs up from beneath the bony protuberance.

The iliac crest is subcutaneous and serves as a point of origin and insertion for various muscles. However, as none of these muscles cross the bony crest, it remains available for palpation (Fig. 8-3).

Incision

Make an 8- to 10-cm incision following the anterior half of the iliac crest to the anterior superior iliac spine. From there, curve the incision down so that it runs vertically for some 8 to 10 cm, heading toward the lateral side of the patella (see Fig. 8-3).

Figure 8-3 Make a longitudinal incision along the anterior half of the iliac crest to the anterior superior iliac spine. From there, curve the incision down so that it runs vertically for some 8 to 10 cm.

Internervous Plane

One internervous plane is used between those muscles supplied by the femoral nerve and those supplied by the superior gluteal nerve. Superficially the plane lies between the sartorius (femoral nerve) and the tensor fasciae latae (superior gluteal nerve); deeply the plane lies between the rectus femoris (femoral nerve) and the gluteus medius (superior gluteal nerve) (Fig. 8-4A,B).

Superficial Surgical Dissection

Externally rotate the leg to stretch the sartorius muscle, making it more prominent. Identify the gap between the tensor fasciae latae and the sartorius by palpation (Fig. 8-6). The best place to find it is some 4 to 5 cm below the anterior superior iliac spine, since the fascia that covers both muscles just below the spine makes the interval difficult to define at its highest point. With scissors, carefully dissect down through the subcutaneous fat along the intermuscular interval. Avoid cutting the lateral femoral cutaneous nerve (lateral cutaneous nerve of the thigh), which pierces the deep fascia of the thigh close to the intermuscular interval (Fig. 8-5).

Figure 8-4 A: The internervous plane lies between the sartorius (femoral nerve) and the tensor fasciae latae (superior gluteal nerve). B: The deeper internervous plane lies between the rectus femoris (femoral nerve) and the gluteus medius (superior gluteal nerve).

Figure 8-5 The lateral femoral cutaneous nerve (lateral cutaneous nerve of the thigh) pierces the deep fascia close to the intermuscular interval between the tensor fasciae latae and the sartorius.

Figure 8-6 Identify the gap between the tensor fasciae latae and the sartorius by palpation.

Figure 8-7 Incise the deep fascia on the medial side of the tensor fasciae latae. Retract the sartorius upward and medially and the tensor fascia downward and laterally.

Incise the deep fascia on the medial side of the tensor fasciae latae. Staying within the fascial sheath of this muscle will protect you from damaging the lateral femoral cutaneous nerve because the nerve runs over the fascia of the sartorius. Retract the sartorius upward and medially and the tensor fasciae latae downward and laterally (Fig. 8-7).

Detach the iliac origin of the tensor fasciae latae to develop the internervous plane. The large ascending branch of the lateral femoral circumflex artery crosses the gap between the two muscles below the anterior superior iliac spine. It must be ligated or coagulated.

Deep Surgical Dissection

Retracting the tensor fasciae latae and the sartorius brings you on to two muscles of the deep layer of the hip musculature, the rectus femoris (femoral nerve) and the gluteus medius (superior gluteal nerve) (Fig. 8-8).

The rectus femoris originates from two heads: the direct head, from the anterior inferior iliac spine, and the reflected head, from the superior lip of the acetabulum. The reflected head also takes origin from the anterior capsule of the hip joint. It is intimate with the capsule making dissection between the two structures difficult.

If you have difficulty identifying the plane between the rectus femoris and the gluteus medius, palpate the femoral artery. The femoral pulse is well medial to the intermuscular interval; if you dissect near it, you are out of plane. Detach the rectus femoris from both its origins and retract it medially. Retract the gluteus medius laterally (Fig. 8-9).

The capsule of the hip joint is now exposed. Inferomedially, you can see the iliopsoas as it approaches the lesser trochanter: retract it medially (Figs. 8-10 and 8-11). The iliopsoas is often partly attached to the inferior aspect of the hip joint capsule and must be released from it. These muscular fibers arising from the capsule and insertion just inferior to the lesser trochanter are named iliocapsularis.24 Inferolaterally, the shaft of the femur lies under cover of the vastus lateralis.

Adduct and fully externally rotate the leg to put the capsule on stretch; define the capsule with blunt dissection. Incise the hip joint capsule, with either a longitudinal or a T-shaped capsular incision (Fig. 8-12). Dislocate the hip by external rotation after the capsulotomy.

Figure 8-8 The deep layer of musculature, consisting of the rectus femoris and the gluteus medius, is now visible. The ascending branch of the lateral femoral circumflex artery must be ligated.

Dangers

Nerves

The lateral femoral cutaneous nerve (lateral cutaneous nerve of the thigh) reaches the thigh by passing over, behind, or through—usually over —the sartorius muscle, about 2½ cm below the anterior superior iliac spine. The nerve must be preserved when you incise the fascia between the sartorius and the tensor fasciae latae; cutting it may lead to the formation of a painful neuroma and may produce an area of diminished sensation on the lateral aspect of the thigh (Fig. 8-14; see Fig. 8-5). Be aware that the nerve may divide into three or more branches just below the inguinal ligament and that its anatomical course is very variable. Always be on the lookout for the nerve when dissecting superficial to the deep fascia.

The femoral nerve lies almost directly anterior to the hip joint itself, within the femoral triangle. Because the nerve is well medial to the rectus femoris, it is not really in danger unless you stray far out of plane to the wrong side of the sartorius and the rectus femoris. If you lose the correct plane during deep dissection, locate the femoral pulse by palpation. Within the femoral triangle, the artery lies medial to the nerve (Figs. 8-15 and 816).

Vessels

The ascending branch of the lateral femoral circumflex artery crosses the operative field, running proximally in the internervous plane between the tensor fasciae latae and the sartorius. Ligate or coagulate it when you separate the two muscles (see Figs. 8-8, 8-15, 8-16, 8-17).

Figure 8-9 Detach the rectus femoris from both its origins, the anterior inferior iliac spine and the superior lip of the acetabulum.

Figure 8-10 The hip joint capsule is now partly exposed. Retract the iliopsoas tendon medially.

Figure 8-11 The hip joint capsule is fully exposed. Detach the muscles of the ilium if further exposure is needed.

Figure 8-12 Incise the hip joint capsule.

Figure 8-13 Proximal extension of the wound exposes the ilium. Distal extension of the incision exposes the anterior aspect of the femur in the interval between the vastus lateralis and the rectus femoris. It may be necessary to split muscle fibers to actually expose the lateral aspect of the femur.

Figure 8-14 Superficial view of the muscles of the anterior region of the hip, including the femoral triangle and its contents.

Sartorius. Origin. Anterior superior iliac spine and upper half of iliac notch. Insertion. Upper end of subcutaneous surface of tibia. Action. Flexor of thigh and knee and external rotator of hip. Nerve supply. Femoral nerve (L2-L4).

Tensor Fasciae Latae. Origin. From outer aspect of iliac crest between the anterior superior iliac spine and the tubercle of the iliac crest. Insertion. By iliotibial tract into Gerdy’s tubercle of the tibia. Action. Maintains stability of extended knee and extended hip. Nerve supply. Superior gluteal nerve.

Figure 8-15 The tensor fasciae latae, the sartorius, and the fascia lata have been resected on the anterior aspect of the hip to reveal the gluteus medius, the rectus femoris, and the ascending branch of the lateral femoral circumflex artery. The hip joint capsule is visible between these two muscles. Medially, note the relationship between the iliopsoas and the rectus femoris.

How to Enlarge the Approach

Local Measures

Superficial Surgical Dissection. Detach the origins of the tensor fasciae latae and the sartorius.

Deep Surgical Dissection. Detach the origins of the gluteus medius and minimus from the outer wing of the ilium by blunt dissection. (This procedure is always necessary during pelvic osteotomies.) Bleeding from the raw exposed surface of the ilium can be controlled if you pack the wound with gauze sponges. Individual bleeding points can be controlled by the application of bone wax. There is no other way to stop bleeding.

Extensile Measures

The skin incision may be extended posteriorly along the iliac crest to expose that bone. In theory, the extension allows the taking of bone graft, but it is rarely used.

To extend the approach distally, lengthen the skin incision downward along the anterolateral aspect of the thigh. Incise the fascia lata in line with the skin incision; underneath it lies the interval between the vastus lateralis and the rectus femoris. Try to stay in the interval; you will have to split muscle fibers to expose the anterior aspect of the femur. This extension gives excellent exposure of the entire shaft of the femur (see Fig. 8-13).

Figure 8-16 The gluteus minimus, medius, and maximus have been resected to reveal the hip joint capsule and the reflected head of the rectus femoris.

The approach can be extended to allow visualization of both the inner and outer walls of the pelvis at the level of the hip joint to allow pelvis osteotomy. To obtain visualization of the outer part of the ilium, gently strip the muscular coverings from the bone at the level of the origin of the reflected head of rectus. Using blunt instruments stay in contact with bone. This dissection will lead you into the sciatic notch. Take great care that any instrument inserted into the notch remains firmly on the bone, since the sciatic nerve is also emerging through the notch. Detach the straight head of the rectus femoris from the anterior inferior iliac spine, and carefully lift off the iliacus muscle from the inside of the pelvis, again sticking very carefully to the bone. A blunt instrument will gradually lead you into the greater sciatic notch. At this stage, both instruments should be in contact with each other and with the bone of the sciatic notch. Retraction on both instruments will allow visualization of the entire thickness of the pelvis at the level of the top of the acetabulum, permitting an accurate osteotomy to be carried out.

Figure 8-17 The iliopsoas tendon has been retracted medially; the rectus femoris has been resected and the joint capsule opened to reveal the joint.