[Orthopedic Arthroscopy] Detailed Explanation of Hip Arthroscopy Surgical Approach

With significant advancements in surgical techniques and equipment, hip arthroscopy has become increasingly common, and its indications are constantly expanding. During hip arthroscopy, patients can be positioned supine or laterally, each with its advantages. The supine position is more familiar to surgeons and more comfortable for patients, and it is also more suitable for standard fracture operating tables. The lateral position is more suitable for obese patients, and it is also easier to enter the joint cavity from behind the greater trochanter for patients with large anterolateral osteophytes.

Supine arthroscopic surgery utilizes three standard approaches: the anterolateral approach, the anterior approach, and the posterolateral approach (Figures 1 and 2). The anterolateral approach is typically established first under fluoroscopic guidance. The posterolateral and anterior approaches are established under direct visualization of the anterolateral approach. After establishing additional approaches, the arthroscope is positioned in the anterior approach to determine the location of the anterolateral inlet. Because the anterolateral approach is established without direct visualization, observation is necessary to ensure that the labrum is not penetrated. Several additional auxiliary approaches can be visually established according to the procedure (Figure 3).

Figure 1. Surface landmarks: femoral artery, vein, and nerve; greater trochanter and anterior superior iliac spine.

Figure 2. Three standard approaches: anterior, anterolateral, and posterolateral.

Figure 3. Additional approaches. AL. Anterolateral approach; AP. Anterior approach; MAP. Mid-anterior approach; PMAP. Proximal mid-anterior approach; PALA. Proximal supplementary lateral approach; PSP. Posterosuperior approach.

Standard surgical approach for hip arthroscopy

Anterolateral Approach

The puncture site is approximately 1 cm anterosuperior to the anterior border of the greater trochanter of the femur. The puncture orientation is 0°–15° cephalic and 20°–30° posterior. The anterolateral approach passes through the gluteus medius muscle to reach the anterior joint capsule of the hip joint (Figure 4). The closest neurovascular structures are the superior and sciatic nerves. The anterolateral approach allows for observation of the central chamber (especially the anterior and superior), clearing of the working channel or placement of screws, and observation of the peripheral chamber and operating channel (Figure 5).

Anterior Approach

Located at the intersection of the tangent line to the tip of the greater trochanter and the extended line below the anterior superior iliac spine. The puncture angle is 40°–45° cephalic and 25°–30° midline. The anterior approach passes through the sartorius and rectus femoris muscles, descends through the joint capsule, and is close to the lateral femoral cutaneous nerve and the ascending branch of the lateral circumflex femoral artery (Figure 6). The anterior approach allows observation of the intermediate chamber and the operating channel (labial dissection, repair, and cleaning, etc.) (Figure 7).

Posterolateral Approach

Located 1 cm above and behind the apex of the greater trochanter. The posterolateral approach passes through the gluteus medius and gluteus minimus muscles to reach the posterolateral joint capsule of the hip joint. The nearest neurovascular structure is the sciatic nerve (Figure 8). The posterolateral approach allows visualization of the intermediate chamber and repair of the posterior labrum (Figure 9).

Supine Hip Arthroscopy Technique

The patient lies supine on a fracture operating table or a standard operating table with traction, and a perineal column is placed.

The affected hip joint is in extension, slight abduction, and neutral rotation. Traction is applied to the operated lower limb, and fluoroscopy confirms joint retraction.

First, an anterolateral approach is established using a 6-inch 17-gauge needle under fluoroscopy. The approach is located in a safe zone.

Care should be taken not to puncture the labrum when establishing each hip arthroscopy approach. If excessive resistance occurs during puncture, the needle direction should be adjusted under fluoroscopy, ensuring the needle is parallel to the femoral head and kept at a distance from the acetabular rim. The joint cavity is infused with saline. The guidewire is inserted into the joint cavity through the needle and then withdrawn. The cannula assembly is introduced into the joint cavity along the guidewire. Care should be taken not to damage the femoral head articular surface or puncture the labrum during cannula introduction.

Establish an anterior and posterolateral approach. Insert an epidural needle into the joint cavity and confirm its position under fluoroscopy with 70° arthroscopy.

Determine the location of the anterior approach. The incision should only cut the skin layer to avoid damaging the lateral femoral cutaneous nerve.

Rotate the arthroscope 70° posteriorly. Under arthroscopic monitoring and fluoroscopy, establish the posterolateral approach. The approach should be slightly cephalic and anterior, merging with the anterolateral approach. Maintaining the hip joint in a neutral rotational position is crucial for this approach to avoid sciatic nerve injury.

After establishing all three approaches, use the posterolateral approach as the perfusion pathway.

To allow visualization of the acetabulum, labrum, and femoral head from all three approaches, alternate between using 70° and 30° arthroscopes on the anterolateral and anterior approaches. Rotate the lens and internally and externally rotate the hip joint. 70° arthroscopy is best used for observing the labrum, acetabulum, and periphery of the femoral head, while 30° arthroscopy is typically used for observing the central compartment of the acetabulum, the femoral head, and the upper part of the acetabular fossa.

Insert the arthroscopic scalpel through a cannula and make a slight transverse incision in the joint capsule to increase the operating space for surgical instruments (Figures 10A and 10B).

Use a flexible cannula with interchangeable instruments to introduce the curved shaving head into most of the femoral head and acetabulum. Extended instruments can also be used to remove the labrum or loose body fragments.

Large loose bodies can be crushed and removed; careful observation is necessary when retracting the instruments through the cannula.

After completing the arthroscopic procedure on the central compartment, traction on the operated lower limb can be released and the hip flexed to 45°. This relaxes the joint capsule, facilitating exploration of the surrounding compartments.

Adjust the original anterior and anterolateral approaches to the femoral neck position. Alternatively, an auxiliary approach can be established 4-5 cm distal to the anterolateral approach (Figure 11). The femoral neck is located under fluoroscopic guidance.

Lateral Decubitus Hip Arthroscopy Technique

The patient lies on their side on a fracture operating table or a specific traction bed, with the surgical side up. A perineal column is placed. The perineal column should be positioned as close as possible to the lateral thigh of the surgical side to protect the pudendal nerve and improve traction force on the hip joint.

The hip joint is abducted 20°–45° and extended. The hip joint is placed in a slightly abducted, flexed, and externally rotated position. Fluoroscopy is used to assess the traction status and guide the instruments in. Sufficient traction is applied to create a large enough joint space to accommodate the 5mm arthroscope and surgical instruments.

Traction is applied to the surgical lower limb; fluoroscopy ensures a traction space of 8–10mm. If greater traction force is required to open the joint, a puncture needle can be inserted into the joint cavity under fluoroscopic guidance to inject a small amount of air, thus relieving the vacuum seal effect of the hip joint and making it easier to obtain the required traction force.

Mark anatomical landmarks, including the femoral artery, anterior superior iliac spine, inguinal ligament, and the anterior, posterior, and superior borders of the greater trochanter.

Surgical approaches in the lateral decubitus position typically include the anterior greater trochanter approach, the posterior greater trochanter approach, and the direct anterior approach. Additional approaches may be used depending on the specific surgical procedure.

The anterior greater trochanter approach is usually established first. Under fluoroscopic guidance, a 6-inch 18-gauge needle is inserted into the joint cavity from the anterior border of the greater trochanter. Ensure that the labrum is not punctured.

Air or saline may be injected to dilate the joint capsule. A guidewire is introduced into the joint cavity through the needle. Fluoroscopy confirms correct guidewire placement.

Make a skin incision at the needle insertion site. Insert the arthroscopic cannula into the joint cavity along the guidewire. Perform fluoroscopy again. Avoid bending or breaking the guidewire.

Establish an anterior approach as an irrigation port. An anterior approach is also necessary for visualizing the anterior structures of the hip joint.

Insert a lumbar puncture needle at the intersection of the sagittal line of the anterior superior iliac spine and the horizontal line at the proximal apex of the greater trochanter of the femur, with the needle pointing 45° cephalic and 20° medial. Guided by fluoroscopy and arthroscopy.

Make a small skin incision at the insertion point and insert a 5.25-inch irrigation cannula. The branches of the lateral femoral cutaneous nerve are close to this approach; the incision only cuts through the skin layer, bluntly dissecting the subcutaneous tissue to avoid nerve injury. The cannula and stylet will push the nerve laterally as they pass through.

Establish a posterior approach to the greater trochanter using a similar procedure at the posterior margin of the apex.

Incise the joint capsule between the two approaches. Alternating between the two approaches as needed for the procedure facilitates manipulation and optimizes the field of vision.