Capsulotomy First: A Novel Concept for Hip Arthroscopy

Abstract

Capsulotomy during hip arthroscopy improves the mobility of arthroscopic instruments and helps gain greater access to key areas of the hip. During the past decade, its use has expanded dramatically as the complexity of hip arthroscopy has advanced. We report a novel approach for hip arthroscopy that consists of performing an extra-articular capsulotomy under endoscopic control before exploration of the hip joint. The principle of this new concept is to replicate an anterior Hueter approach of the hip joint. We describe the surgical technique and discuss its advantages compared with conventional hip arthroscopy techniques using either a peripheral- or central-compartment starting point. This new approach is easy to master, can be performed with a 30° optic system, does not require fluoroscopic assistance, allows a reduction in both the force and duration of traction, and reduces the risk of labral or chondral damage.

Arthroscopy is increasingly used to address hip pathology. Capsulotomy, which is commonly performed in hip arthroscopy, assists visualization and instrument navigation.¹ Capsulotomy in conjunction with hip arthroscopy is indicated in treating femoroacetabular impingement or when large loose bodies need to be removed from the joint, among other indications. The optimal technique, amount of resection, and indications for capsulotomy remain unknown. We propose a novel approach for hip arthroscopy that consists of performing an extra-articular longitudinal capsulotomy from outside to inside before exploring the hip joint. The principle of this new concept is to replicate an anterior Hueter anterior approach under endoscopic control.² It involves first making a longitudinal capsular incision along the neck of the femur and extending it, if required, over the labrum and along the acetabular rim with an electrocoagulation electrode. The purpose of this technical note is to describe the surgical steps of this new approach and to discuss its advantages over conventional techniques with either a peripheral- or central-compartment starting point.

Surgical Technique

The patient is placed supine on a surgical table with the feet well padded and placed into traction boots (Fig 1A). The hip is placed in slight flexion without any traction. Instrumentation comprises a 70° arthroscope (but the procedure can be equally performed with a 30° arthroscope); an FMS Duo+ pump (Fluid Management System; DePuy Mitek, Raynham, MA), which can control inflow and outflow to maintain a constant pressure (set at 50 mm Hg); a VAPR electrode (DePuy Mitek); and a 3.5-mm 90° hook electrode (DePuy Mitek). To improve vision, 1 mg/L of epinephrine is added to the irrigation fluid.

Fig 1.

Patient position and portal placement. (A) The patient is placed supine on a surgical table, and the feet are well padded and placed into traction boots. (B) The first portal is located 2 cm anterior and distal to the superior tip of the greater trochanter (GT). A 4-mm blunt trocar is introduced and directed medially underneath the tensor fascia lata and anteriorly to the gluteus minimus muscle in the direction of the anterior iliac spine (AIS). (C, D) The instrumental portal is then created medially to the tensor fascia lata and is located at least 2 inches from the first portal to triangulate more easily.

Only 2 portals are usually required. The first portal is located 2 cm anterior and distal to the superior tip of the greater trochanter (Fig 1B). A 4-mm blunt trocar is introduced and directed medially underneath the tensor fascia lata and anteriorly to the gluteus minimus muscle. The surgeon must feel the bone contact with the upper part of the femoral neck (Fig 2A). Once the bone contact is felt, the trocar is slid in front of the femoral neck to place it parallel to the anterior surface of the femoral neck. The arthroscope is then introduced into this portal following the same direction. The anterior surface of the femoral neck is the only area of the capsule where there is no muscle insertion. Instead, a precapsular fatty tissue is seen, which can be easily debrided to show the white fibers of the capsule (Figs 2B and 3A). This is the only white structure in the whole area, and this white structure must be identified with the arthroscope. The arthroscope is then in contact with the capsule and positioned medially to the gluteus minimus and laterally to the iliocapsularis muscle. The instrumental portal is created medially to the tensor fascia lata and is located at least 4 to 5 cm from the first portal to triangulate more easily (Fig 1 C and D). Both portals can be easily interchanged during the operation if required. In our experience, a third portal is rarely useful.

Fig 2.

Outside-in capsulotomy technique. (A) The anterior surface of the femoral neck, underneath the tensor fascia lata (TFL), is the only area of the capsule where there is no muscle insertion. (B) Instead, a precapsular fatty tissue is seen, which can be easily debrided to show the white fibers of the capsule between the gluteus medius muscle (GM) and the iliocapsularis muscle (ICM). (C) The capsular incision is performed along the neck of the femur and, only if necessary, is extended over the labrum and then along the acetabular rim so as to expose the area from the base of the femoral neck to the supra-acetabular ilium.

Fig 3.

Arthroscopic views of outside-in capsulotomy technique. (A) After the anterior aspect of the capsule (C) has been identified (white structure), the precapsular fatty tissue (PCF) is removed with an electrode. (B) The capsular incision is performed along the neck of the femur. (C) Labral fibers (L) are perpendicular to those of the capsule, which is pearly white and easily identifiable. (D) A simple debulking of the capsule with the shaver along the acetabular rim provides sufficient exposure, and a T-shaped capsulotomy is usually not necessary. (E) The longitudinal capsulotomy allows exposure of the area from the base of the femoral head (FH) to the supra-acetabular ilium. (F) Anatomic side-to-side reduction of the capsule can be obtained with an automated suture passer.

We usually use an optical 70° arthroscope, but the use of a conventional 30° arthroscope is equally feasible. The precapsular fatty tissue is cleaned (Fig 3B), and a longitudinal capsulotomy is performed (Fig 3C). During the capsulotomy, the surgeon must always keep the hand feeling the bone contact between the electrode and the femoral neck. Ideally, the capsulotomy is performed with a 3.5-mm 90° hook electrode. Care should be taken to avoid a capsular entry point that is too far proximal because this can damage the labrum. Labral fibers are perpendicular to those of the capsule, which is pearly white and easily identifiable (Fig 3C). When the surgeon is approaching the labrum, it is preferable to use a shaver. It is important to remember that the joint capsule of the hip is quite thick, and with the usual optical magnification of an arthroscope, this may seem quite impressive. The capsule is opened in a longitudinal fashion following the axis of the neck so as to maintain the stabilizing function of the iliofemoral ligament. A T-shaped capsulotomy can be performed, if needed, depending on the type of lesion to be addressed (Figs 2C and 3E) but is rarely necessary because a simple debulking of the capsule with the shaver along the acetabular rim provides sufficient exposure (Fig 3D). The longitudinally oriented capsulotomy facilitates procedures such as labral repair or grafting because the capsule is lifted up and over the labrum and held close to the rim in the process and does not compromise the iliofemoral ligament. A traction suture can be passed through 1 of the 2 capsular flaps to improve the exposure. Hip arthroscopy is then performed in a routine manner. Confirmation of the required resection can be obtained through fluoroscopy and visual dynamic assessment by performing the impingement test.

At completion of the hip arthroscopy work, the operated limb is brought back to a neutral hip position free from traction, flexion, or rotation. Approximation of both sides of the capsule is tested, ensuring that anatomic side-to-side reduction can be obtained. Side-to-side stitches are retrieved with an automated Scorpion suture passer (Arthrex, Naples, FL) and tied in a standard fashion (Fig 3F, Video 1).

Discussion

Hip arthroscopy is now a common procedure. The procedure usually described starts in the central compartment.³ A chief concern of the central-compartment starting point is the potential for iatrogenic chondral or labral injury. Because the hip capsulotomy has not yet been performed, a tight hip joint increases the risk of chondral scuffing and labral penetration, as well as the need for increased traction.⁴ Dienst et al.⁵ described a peripheral-compartment starting point in hip arthroscopy with the advantages of safe entry into the central compartment and reduced traction time. However, this procedure is technically demanding, the first portal must be made under fluoroscopic control, and specific instrumentation with dilatators and a nitinol guidewire is required.

A peripheral starting point is attractive because the arthroscopic instrumentation is introduced along the anterior femoral neck region, which is devoid of articular cartilage and is a safe distance from the labrum. The senior author (F.L.) started treating femoroacetabular impingement in 1999 and developed an arthroscopically assisted minimally invasive Hueter anterior approach.² He started to develop the outside-in endoscopic anterior approach with a capsulotomy in 2006, as a response to difficulties locating arthroscopic punctures when changing instruments, and has used it as a routine procedure since 2010. Some authors advocate performing an extensive capsulotomy to optimize exposure and treatment in hip arthroscopy.¹ Capsulotomy allows safer entry to over-covered or tight hips, as well as better exposure for complex procedures, and improves mobility of instruments. Moreover, it allows greater ease of access by the arthroscope and instruments to most of the hip joint's central and peripheral compartments than through traditional capsular punctures.¹ The longitudinal capsulotomy is performed in an area devoid of muscle insertion. It can be performed in a variety of ways depending on the anticipated pathology and can be easily closed at the end of the procedure. Traction is applied only for access into the central compartment, and the traction strength required is decreased because the capsulotomy has already been performed. Our new technique allows for the use of a conventional 30° optic system, does not require fluoroscopy, and is less technically challenging than the conventional method.⁶ No specific instrumentation is required, avoiding the use of expensive single-use sets or nitinol guidewires that can break in the joint (Table 1).

Table 1.

Advantages of Outside-In Capsulotomy for Hip Arthroscopy

No need for specific hip instrumentation, including a 70° arthroscope, cannulated trocars, or dilatators

Less costly procedure with no need for single-use instrument sets, a nitinol guidewire, or a specific needle

No risk of nitinol guidewire breakage in the joint

No need for fluoroscopic assistance

Reduced traction time and less risk of labral or chondral damage compared with a technique with a central-compartment starting point

Technically easier than a technique using a peripheral-compartment starting point

However, the described procedure is not without disadvantages, and having a good understanding of the bony and ligamentous anatomy of the anterior hip capsule is critical to executing the technique well. In inexperienced hands, a surgeon could take the dissection medially, missing the capsule completely and going into the neurovascular structures. The presence of circumflex vessels that cross the joint in the innominate fascia has not caused any problems so far because these vessels are positioned more distally and superficially than the capsule, but care must be taken when removing the precapsular fatty tissue to recognize and treat any source of bleeding. Moreover, this technique can be considered extensive relative to the traditional minimally invasive hip arthroscopic technique, and complications such as fluid extravasation and dislocation can be major. However, these complications are rare, and capsular repair should be considered when indicated because of concerns of instability.⁷

An early capsulotomy from the outside may seem surprising, but with very little practice, it is easy to master and it represents an undeniable progress in our practice. No specific instrumentation or fluoroscopy is required. A capsulotomy-first incision reduces both the force of traction and the traction time, and it reduces the risk of chondral and labral injuries. No specific complications related to this new approach have occurred in our experience. A good knowledge of extracapsular hip anatomy is required.

Supplementary Data

Video 1

Detailed demonstration of capsulotomy-first surgical technique for hip arthroscopy, which consists of performing an extra-articular capsulotomy under endoscopic control before the hip joint exploration. The principle of this new concept is to replicate an anterior Hueter approach of the hip joint.