Surgical Management of CAM-Type FAI: A Technique Guide

Fig. 8.1

Operating room setup. (Left) The operating table setup with a perineal foam post and traction setup. (Right) Patient’s foot wrapped in protective foam pad and tightly secured to the traction boots

The patient, now supine on the fracture table, has foam pads applied to their feet (Fig. 8.1). The patient is positioned on the operating table so that the large, well-padded perineal post (to prevent injury to the perineal soft tissue and pudendal nerve) is positioned to be an effective countertraction measure to a medially/adducted force (Fig. 8.2). The padded feet are securely fastened to the traction table using the appropriate straps and the operative leg positioned in full abduction. For lateral decubitus position, the fracture table is then rotated 90° so that the operative extremity is superior to the rest of the patient (Fig. 8.2, right). On occasion, an examination under anesthesia is performed to assess for hypermobility of the hip in all planes of motion in cases where clinically indicated (connective tissue disorders).

Fig. 8.2

Patient positioning. (Left) Perineal foam pad positioning to prevent pudendal nerve injury. (Center) Patient has been transported down the bed to allow the perineal foam pad to be an effective countertraction force. Note the fluoroscopic device positioned over the operative extremity from the opposite side of the surgeon. (Left) Patient and fluoroscopic device positioning if performing hip arthroscopy in the lateral decubitus position

For the supine position, the fluoroscopic device is brought in from the opposite side of the operative extremity, at a 45° angle (Fig. 8.2, middle). In-line longitudinal traction (with the femoral neck) is then applied (Fig. 8.3, top), and the operative extremity is adducted 5–10° at a time (Fig. 8.3, bottom center), with sequential fluoroscopic images confirming progressive joint distraction (Fig. 8.3, bottom right and left). Approximately 11–22 kg of traction is required to distract the operative joint 8–10 mm, looking for a “loss of seal” effect and often audible “pop.” The final operative extremity should be in neutral abduction, slight internal rotation (i.e., approximately 5°), and a maximum 5–10° of flexion. The nonoperative extremity should be in 45–50° of abduction and slight external rotation (i.e., approximately 5°), serving as countertraction. This is usually completed prior to prepping and draping the hip.

Fig. 8.3

Application of traction to distract the hip joint. (Top) Application of longitudinal traction in line with the femoral neck with the extremity in full abduction to provide distraction at the hip joint. (Bottom, right) Intraoperative fluoroscopic image prior to application of any hip traction. (Bottom, center) With longitudinal traction applied, the surgeon next sequentially adducts the operative extremity 5–10° at a time, with intermitted fluoroscopic images confirming appropriate distraction at the hip joint. (Bottom, left) Intraoperative fluoroscopic image with the extremity in the optimal operative position demonstrating distraction at the hip joint

When operating in the lateral decubitus position, traction is applied with 10° of flexion, 20° of abduction, and neutral rotation of the hip. Similar to above, adequate separation of the femoral head from the acetabulum is verified with fluoroscopy. Usually 40–50 kg of traction force is enough to create adequate 1–1.5 cm distraction.

Limiting traction time to 90–120 min maximum decreases the risk of traction-related complications.

8.2.2 Draping

Draping techniques vary, but it is standard practice to drape in sterile fashion and allow for complete exposure of the entire hemi-pelvis of the operative side. Adhesive clear dressing (such as Ioban) is applied to the hip region only to allow for preservation of landmarks drawn on the hip. This draping technique generally exposes the hip from above the inguinal ligament to the mid-thigh anteriorly. Care is also taken to expose the hip posteriorly to allow for a posterolateral portal placement (exposing approximately 5 cm posterior to the posterior border of the greater trochanter). Finally, the operative leg, below the knee, is free of draping to allow for a manual dynamic assessment of the hip when needed (Fig. 8.4).

Fig. 8.4

Sterile draping of the operative site. (Top, left) Large approach sheets placed on the leg and torso and operative hip squared off. (Top, right) Extremity drape applied. (Bottom, left) Marking pen used to delineate anatomy and potential portal sites (see Fig. 8.5). (Bottom, right) Sterile skin adhesive dressing applied

8.2.3 Portal Placement for Supine Position

Upward of nine different central and peripheral arthroscopic portals have been described [5], and the ones that follow are those of the senior author’s preference. Proper portal placement is essential for ease of execution of the surgical plan, and inadequate portal placement can predispose to complications such as damage to periarticular structure such as the sciatic nerve injury. Of note, there exists wide variability between patients of different weight, body mass index, and the locations of at-risk neurovascular structures to the arthroscopic portals used, and so great caution must be exercised [6]. Traditionally, four portals are used: anterolateral, anterior/mid-anterior portal, distal anterolateral portal, and posterolateral portal (Fig. 8.5). The majority of central compartment procedures however can be done through the anterolateral and anterior/mid-anterior portals, with the posterolateral portal serving mainly as an outflow portal. In general, do not hesitate to make additional portals if necessary or reposition already made ones for ease, remembering not to go medial of a line drawn vertically from the anterior superior iliac spine (ASIS), so as to avoid injury to the neurovascular bundle.

Fig. 8.5

Surgical landmarks of the operative extremity in supine position. Anatomy and possible portal sites marked on the operative site (left hip) with a sterile marking pen. AL anterolateral portal, PL posterolateral portal, DP accessory (distal) anterolateral portal, MAP mid-anterior portal, GT greater trochanter of femur, ASIS anterior superior iliac spine, NVB neurovascular bundle (lies medial to a vertical line originating at the ASIS)

First, the standard anterolateral portal is created using a Seldinger technique. Using the anterior superior iliac spine (ASIS) and the most proximal tip of the greater trochanter (GT) as landmarks, the anterolateral portal (risk to superior gluteal nerve) is made using a skin entry that is 1 cm anterior and superior to the tip of the GT. The trajectory for the spinal needle is 15° cephalad and 15° posterior. Another method to obtain this portal is to insert the spinal needle at the level of the joint line approximately 1 cm anterior to the GT tip and direct the spinal needle 15–20° posterior. The muscle interval used is the tensor fasciae latae/gluteus maximus with rectus femoris/hip flexors. Once the spinal needle penetrates the joint, a loss of resistance is appreciated. The needle insert is withdrawn, and fluoroscopy is used to visualize an air arthrogram. Saline (approximately 10 cc) is then injected intra-articularly, and a flashback or backflow of fluid is visualized, confirming the correct location. Next, a long guidewire is passed through the cannulated spinal needle and advanced to the acetabular fossa. The spinal needle is withdrawn, and a scalpel is used to create a 1 cm skin incision for portal creation. The scope trochar is advanced over the guidewire and through the capsule, with caution taken to ensure the guidewire does not bend or break. Fluoroscopy is used to ensure the guidewire does not damage intra-articular structures. Once the trochar is placed correctly, the guidewire is withdrawn (Figs. 8.6 and 8.7).

Fig. 8.6

Hip arthroscopy instruments. Instruments used to establish the portals (from left to right): spinal needles (×2), arthroscopic scalpel, scalpel, syringe with saline, snaps (×2), scope trochars (×2), half pipes, ruler, and marking pen. The guidewire and switching stick are located at the top of the sheet

Fig. 8.7

Arthroscopic portal creation demonstrating surgical and fluoroscopic set up. The Seldinger technique is used to create the arthroscopic portals

The 70° arthroscope is inserted, and the anterior/mid-anterior portal (risks to lateral femoral cutaneous nerve (LFCN), femoral nerve, femoral artery, femoral vein, ascending branch of lateral circumflex artery) is made under direct visualization with fluoroscopic guidance as needed. The capsular triangle (Fig. 8.8), formed by the femoral head and acetabulum, is the target for spinal needle insertion to create this portal (approximate 3 o’clock position viewing from anterolateral portal). Again, a Seldinger technique is employed. We use a mid-anterior portal for the decreased risk of LFCN injury. The skin landmark is approximately 2–3 cm anterior and 2–3 cm distal to the anterolateral portal. The spinal needle trajectory is 45° cephalad and 10–15° medially. Once intra-articular confirmation is directly visualized, the inserter is withdrawn, a scalpel is used to make a 1 cm skin incision, care is taken to cut the skin only (and avoid branches of LFCN), the guidewire is passed through the cannulated spinal needle, the spinal needle is withdrawn, and the trochar is advanced over the guidewire – again, taking caution not to deform the wire.

Fig. 8.8

Creation of the mid-anterior portal. Arthroscopic view of the hip joint for creation of the mid-anterior portal. The intraoperative landmark is an inverted triangle of hip capsule between the femoral head and labrum

Once anterolateral and mid-anterior portals are created, an interportal capsulotomy is created from 3 o’clock to 11 o’clock anterolaterally is made by connecting the two portals with an arthroscopic scalpel. The technique involves a coordinated use of the half pipe and switching stick to switch the arthroscope and arthroscopic scalpel between portals while protecting the surrounding soft tissue and maintaining portal placement. The limited capsulotomy is essential for instrument mobility, anchor placement, and arthroscopic knot tying and can be a “bailout” for a suboptimally positioned portal. The capsulotomy itself starts approximately 5–8 mm from the labrum and measures approximately 15–20 mm in total length [7]. This allows for repair of the capsule when indicated.

The distal anterolateral portal for the osteochondroplasty is made 3–5 cm distal to the anterolateral portal (Fig. 8.5, DP), using a similar trajectory and technique as that for creation of the anterolateral portal. The posterolateral portal (risk to sciatic nerve) is made 1–3 cm posterior to the greater trochanter, in line with the anterolateral portal (Fig. 8.5, PL).

8.2.4 Portal Placement for Lateral Decubitus Position

The portal placement in the lateral decubitus position is very similar to the supine portal placement as described above. One of the senior authors (MS), who operates in the lateral decubitus position, normally uses the same four described portals: an anterolateral or lateral (ALP), a modified mid-anterior (MMAP), a distal anterolateral or distal (DALP), and a posterolateral portal (PLP) (Fig. 8.9).

Fig. 8.9

Surgical landmarks of the operative extremity in lateral decubitus position. (Top) Anatomy and possible portal sites marked on the operative site (right hip) with a sterile marking pen. The GT has been outlined. HORZ horizontal line from the level of the superior border of the GT, VERT vertical line descending from the ASIS (anterior superior iliac spine). (Bottom) Anatomy and possible portal sites marked on the operative site (left hip) with a sterile marking pen. GT and ASIS have been outlined. The lateral portal (anterolateral), the distal portal (distal anterolateral), and the modified mid-anterior portal are marked

As in the supine technique, the GT and ASIS are landmarked and drawn onto the patient with a marking pen [8]. A vertical, medial line is drawn down from the ASIS that indicates where no incisions should be made in order to avoid the femoral artery and nerve [8]. The first portal that is made is the LP which is approximately halfway between the ALP and PLP (Fig. 8.9).

To distract the joint, a 17-gauge spinal needle (tip away from the femoral head and blunt wedge to the cartilage) is introduced to the central compartment from the site of the PLP. The spinal needle is introduced 35° medial and 20° cephalad. Space between the acetabulum and femoral head should be at least 10 mm, but not more than 15 mm, after the first needle is introduced into the joint capsule and the vacuum is released. Another 17-gauge spinal needle is introduced to the central compartment from the site of the LP in the same manner. A flexible metal guidewire is introduced through the spinal needle, and adequate position of the guidewire is verified with fluoroscopy. The switching stick and arthroscopy cannulas are introduced with help of the guidewire. The arthroscopy pump is connected to the arthroscopy cannula and a 70° arthroscope is inserted. The PLP can then be created. A posterior portal is necessary for posterior labral sutures and posterior rim trimming. The MMAP can then be created using direct visual control where the site of the skin incision is approximately 7 cm medial and 2 cm distal from the LP [9].

8.2.5 Diagnostic Arthroscopy

Diagnostic arthroscopy is first completed to examine the entirety of the labrum, looking for areas of injection and associated pathology. Any pathology is appropriately dealt with as outlined in previous chapters. The chondrolabral junction is also examined and areas of detachment and tearing identified. The femoral head is examined for evidence of foveal and/or articular cartilage damage. The ligamentum teres is next examined and the capsule diffusely examined as well.

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