History
Arthroscopic techniques have revolutionized surgery, and hip arthroscopy in particular has greatly advanced knowledge of the normal and pathologic hip. Compared with other joints, however, arthroscopy of the hip has faced obstacles in application. The essential factor underlying the relatively slow development of hip arthroscopy is the anatomic constraint inherent in the hip joint. A thick, muscular, soft tissue envelope overlies the hip, and a thick fibrous capsule encompasses the joint. The femoral head is deeply recessed circumferentially into the acetabulum, limiting access to intraarticular structures. In the first account of hip arthroscopy in cadavers in 1931, Burman acknowledged these challenges, writing, “it is manifestly impossible to insert a needle between the head of the femur and the acetabulum.” The first clinical application, reported in 1939 by Takagi, was for cases of Charcot disease, tuberculosis, and septic arthritis.
Whereas development of arthroscopic procedures for the knee and subsequently the shoulder progressed quickly in the later part of the twentieth century, hip arthroscopy lagged because of the technical demands and lack of indications. In the late 1980s, however, bolstered by improved recognition of intraarticular hip pathology and advances in technique such as the routine utilization of traction, hip arthroscopy emerged as a key component of the armamentarium for the diagnosis and treatment of hip disorders, as popularized by authors such as Glick, Byrd, and McCarty in North America and Villar in England. Increased utilization of hip arthroscopy contributed to a more comprehensive understanding of conditions that affect the hip joint. Many common hip conditions that were previously unrecognized and left untreated, such as femoroacetabular impingement (FAI) and structural instability, were elucidated by hip arthroscopy. The indications and technology have continued to expand during the past two decades through the contributions of surgeons such as Byrd, Philippon, Sampson, and Ilizaliturri.
With ever-expanding indications, improvements in technique, and innovative arthroscopic instrumentation, hip arthroscopy has become more standardized and reproducible. The procedure has quickly grown from a diagnostic instrument to a powerful tool to treat hip pathology.
Indications and Purpose of the Treatment
The minimally invasive nature of hip arthroscopy is attractive to patients, surgeons, and the medical providers involved in patients’ recovery and rehabilitation. Open hip surgery requires a comparatively large incision and dissection, and the morbidity associated with the exposure may slow recovery. Use of the arthroscopic technique allows improved visualization of the labrum, articular cartilage of the femoral head, and acetabulum, as well the fovea, ligamentum teres, hip capsule, and adjacent synovia. Surgical tools developed specifically for hip arthroscopy can be used to provide the diagnosis and treatment of conditions involving the aforementioned structures.
Currently, the primary indications for hip arthroscopy include symptomatic labral tears ( Fig. 82-1 ), focal symptomatic chondral lesions, loose bodies, ligamentum teres lesions, and capsular laxity. A better understanding of the pathologic mechanism underlying FAI has expanded the role of arthroscopy in the treatment of this condition as well. Arthroscopic treatment of pigmented villonodular synovitis and synovial chondromatosis has been reported. Other potential roles for hip arthroscopy include avascular necrosis and hip instability. Arthroscopic and endoscopic access to structures in the area of the hip has also been introduced, and gluteus medius/minimus, iliotibial, and iliopsoas pathology may be addressed, as well as some nerve entrapment conditions.
Like any surgical intervention, preoperative planning and careful patient selection is mandatory and should be considered the most important element in successful arthroscopy of the hip. The suspected diagnosis based on the history and physical examination should be confirmed by imaging. Magnetic resonance imaging (MRI) has proved useful for intraarticular disorders, although it has limitations. In the case of labral pathology, a magnetic resonance arthrogram (MRA) is the best imaging study ( Fig. 82-2 ). Computed tomography (CT) and three-dimensional reconstruction may help the surgeon understand bony deformities.
The hip arthroscopist needs to be familiar with the anatomy in the area of the hip, as well as the normal arthroscopic anatomy and its variations. Hip arthroscopy is associated with a steep learning curve, and training in hip arthroscopy before performing one’s first case is mandatory to avoid complications. Training opportunities range from courses, cadaver laboratories, and symposiums to a formal dedicated fellowship.
Operative Room Setup and Positioning
Patient positioning is the first step to success in hip arthroscopy. Two positions have been described for hip arthroscopy: supine and lateral. We prefer the lateral position with use of regional anesthesia, image intensifier control, and traction. Other physicians perform the procedure with the patient in the supine position. Patient positioning and the site of arthroscopic portals differ among authors. Regardless of the position used, the positioning technique must be exact and reproducible. Poor patient positioning will result in inadequate distraction, with poor access to the central compartment or inadequate hip mobilization, limiting access to the hip periphery. The setup must provide the capability of applying and releasing traction throughout the case. Dynamic assessment of hip motion may help the surgeon in evaluating the clearance of hip mobility.
Lateral Position
Glick introduced the lateral position for hip arthroscopy. The patient is positioned in the lateral decubitus position on the operating table with the operative side upward ( Fig. 82-3 ). Only the foot of the operative side is fixed to the traction device, and pelvic tilt is avoided by means of the patient’s body weight. The opposite leg rests freely on the operating table with knee and hip flexion between 10 and 20 degrees. The operative hip is positioned in neutral abduction and flexion of 20 degrees to relax the anterior hip capsule. Flexion of more than 20 degrees does not improve distraction of the hip joint and increases the possibility of injury to the sciatic nerve. Neutral rotation is preferred while establishing arthroscopic portals to maximize the distance between the posterior edge of the greater trochanter and the sciatic nerve.
When the lateral position is used, the perineal post has extra padding, is oversized (with an outer diameter of 10 to 12 cm), has a horizontal orientation, and is positioned in the groin of the operative leg, which is not the case when the supine position is used. Elevation of the post provides lateralization of the force, and as a result, the traction direction is more in line with the femoral neck. Before traction is applied, the patient’s genitalia should be inspected to verify that it is not being compressed. After a successful traction test is completed, the hip is taken through range of motion. Flexion of at least 40 degrees is important to adequately relax the anterior hip capsule and permit access the hip periphery. Flexion of at least 90 degrees along with internal and/or external rotation, as well as abduction and/or adduction, may be necessary to ensure complete decompression of impinging deformities. It is important to perform this test before draping because the operating room staff who have not undergone scrubbing will manipulate the table accessories, and they must be familiar with the manipulation of the traction device. In our experience a dedicated lateral hip distractor is preferred by the operating room staff because it is easier to manipulate under the drapes.
The surgeon stands in front of the patient to have better access to the anterior aspect of the hip (most of the pathology in the hip joint is anterior). The surgeon’s assistant stands at the back side of the patient to facilitate participation in the procedure. We believe that the arthroscopy tower should be positioned across from the surgeon on the back side of the patient. Placing the tower proximally toward the patient’s head affords a direct view for the surgical assistant. An arthroscopy suite with multiple monitors would provide the assistant with an even better view.
Intraoperative fluoroscopy with a C-arm should be used for identification of the anatomic references to localize portal positions. The C-arm is covered by sterile drapes and is positioned horizontally under the operating table to provide an anteroposterior (AP) fluoroscopic view of the hip. In larger patients, the arch of the C-arm may not be big enough to reach the area of the hip joint from under the table, in which case it can be positioned over the table, focusing on the area of the hip joint with the arch tilted over the patient’s head. The C-arm may be moved proximally toward the head when not in use. A lateral view is achieved by moving the hip joint rather than the C-arm. The screen of the image intensifier is also positioned at the back side of the patient adjacent to the feet to provide a direct unobstructed view to the surgeon and assistant. The scrub nurse with all the arthroscopic instrumentation is on the same side of the surgeon toward the feet of the patient.
Special operating table accessories are required to position a patient in the lateral decubitus position for hip arthroscopy on a fracture table. These accessories often are unavailable, which has made the supine approach more popular. More recently, dedicated distractors for hip arthroscopy in the lateral approach have been developed (McCarthy Type Distractor, Inomed, Boston, MA, and Smith & Nephew Lateral Distractor, Smith & Nephew Endoscopy, Andover, MA). These dedicated distractors may help make the lateral position more accessible to surgeons, especially in the surgery center setup.
Supine Position
Thomas Byrd developed supine positioning for hip arthroscopy. He describes the merits of supine positioning as follows: it is the simplest and fastest positioning method; the orientation of the joint is familiar to the orthopaedic surgeon; it provides reliable access for all standard portals; it easily accommodates repositioning for arthroscopy of the peripheral compartment; and it permits other procedures to be performed, such as iliopsoas bursoscopy. An important advantage of the supine approach is a reduced risk of intraabdominal fluid extravasation, which has been reported only in the lateral position. Philippon has described the modified supine position in which the hip is in slight internal rotation (15 degrees), with 10-degree flexion, neutral abduction, and 10 degrees of lateral tilt.
For supine hip arthroscopy, the patient is positioned on the operating table with both feet fixed to avoid pelvic tilt when traction is applied to the operative side. The surgeon, assistant, and scrub nurse work from the side of the operative hip, and the arthroscopy tower is positioned across the patient from the surgeon, with the fluoroscopy monitor at the foot. An oversized perineal post with extra padding (with an outer diameter of 12 cm) is vertically attached and positioned against the medial thigh of the operative leg, providing a lateralizing vector to the traction force. The resulting direction of the traction is not in line with the femoral shaft but instead is more parallel to the femoral neck. The operative hip joint is positioned in extension, abduction (25 degrees), and neutral rotation during portal placement for proper orientation. The setup should allow easy rotation of the foot for intraoperative visualization of the femoral head. The contralateral leg is abducted in the traction apparatus to neutralize the force on the pelvis. The C-arm is brought in between the legs in a vertical position over the operative side to provide an AP image of the hip. Slight traction is applied first to the contralateral extremity to stabilize the torso and pelvis on the table. After the pelvis is stabilized, traction is applied to the surgical leg, and adequate distraction of the joint line is confirmed by fluoroscopy.
Traction
Access to the hip joint for arthroscopy is provided by traction. The fundamental advantage of traction is opening of the joint line to allow entrance of the instruments ( Fig. 82-4 ). Traction affords a thorough exploration of the central compartment with reduced risk of iatrogenic chondral or labral damage. The main disadvantages of traction include stretching of soft tissue structures such as the lateral femoral cutaneous nerve, compression of perineal structures against the post, and pressure on the foot. In a patient who has not been anesthetized, forces of up to 900 N may be necessary to open the joint 10 mm (see Fig. 82-4, B ). This traction may be reduced to 300 N with inducement of proper anesthesia and muscle relaxation. According to Byrd and Glick, necessary traction force to obtain appropriate visualization may approach 80 lb (25 to 30 kg). Special traction devices are available for both supine and lateral approaches.
A traction test is always performed before preparing and draping the patient to confirm effective separation of the femoral head from the acetabulum at the image intensifier. This separation should be at least 10 mm. When separation does not occur, the foot fixation should be verified, because a poorly secured foot is the most common cause of ineffective traction. The foot must be well padded to avoid compression injuries. Different options are available for foot fixation to the traction device. A “ski boot” design was introduced by McCarthy and is very effective in providing foot fixation to the traction device. Most fracture tables have “booties” that fix the foot with use of Velcro straps or belt buckles.
Preparing and Draping
After the traction test is performed, the hip is brought back to the starting position without traction and the surgical area is prepared for surgery. When applying sterile drapes, we first start by covering both ends of the C-arm using sterile bags. Waterproof adhesive sterile drapes are then placed in a standard fashion. The surgeon should be careful not to cover portal sites with the drapes. The medial drape should be slightly medial to the anterior superior iliac spine, the posterior drape should be behind the posterior edge of the greater trochanter, the superior drape should be above the level of the anterior superior iliac spine, and the distal drape should be at least 10 to 15 cm below the tip of the greater trochanter. After drapes are in position, sterile gauze is placed over the area where the portals will be established, and an adhesive transparent surgical drape is placed over the surgical area (including the gauze). This seal will prevent fluid from leaking under the drapes to the patient when the procedure starts.
After cables and tubes for arthroscopy are ready, traction is applied (traction starting time should be recorded to monitor its duration). With the traction established, the gauze is removed from the surgical area with the adhesive drape that covers it and landmarks are identified and marked on the skin with a skin marker (we prefer to mark the skin after traction is applied to avoid migration of the marks).
Hip Arthroscopy Equipment and Instrumentation
Use of a set of dedicated hip arthroscopy instruments is mandatory when attempting arthroscopic access to the hip joint. The use of standard arthroscopy equipment for access to the hip joint will increase the possibility of iatrogenic damage to structures inside and around the hip joint.
An arthroscopy tower should contain the monitor, digital camera, high-flow/low-pressure arthroscopy pump, shaver and radiofrequency control console, and an image processing system. Specially designed extra-long arthroscopic instruments are used, which include a long spinal needle and a specially designed flexible guide wire to reach the depth of the hip joint. We use a specially designed hip arthroscopy instrument set (Hip Access System, Smith & Nephew) that is based on a slotted cannula and is designed to be used in combination with standard length 4.0-mm arthroscopes of 30 and 70 degrees. The scissors and graspers used for hip arthroscopy also should be longer than conventional ones. Although most patients can be treated using standard-length shaving tips and burrs, use of extra-long instruments is recommended. Curved instruments are needed to accommodate the spherical anatomy of the hip. Flexible radiofrequency devices are also very helpful. Cannulated instruments are the workhorse of hip arthroscopy and are included in every commercially available hip arthroscopy instrument set. Standard cannulas may limit access of curved devices, and thus slotted cannulas may be used for these devices.
Irrigation should be always assisted by a fluid pump to provide clear visualization without the need for excessive pressure. Because of the possibility of intraabdominal extravasation of fluid, the amount of fluid and the intraarticular pressure must be monitored. We recommend a low pressure (50 to 60 mm Hg) and high flow pump.
Landmarks and Topographic Anatomy of the Hip Joint
Surface landmarks around the hip joint and their relationship to anatomic structures are the road map of hip arthroscopy. Understanding portal placement in relation to these landmarks and the anatomic structures around the portal path in every anatomic layer is paramount in performing safe and successful hip arthroscopy.
The most important and apparent surface landmarks are the greater trochanter and the anterior superior iliac spine ( Fig. 82-5 ). These landmarks should always be marked before the surgery is started.
Byrd et al. performed a cadaveric anatomic study and described the relation of the classic central compartment portals, skin landmarks, and the anatomic structures around the hip joint. The sciatic nerve lies about 1.5 cm posterior to the posterior aspect of the greater trochanter. The femoral neurovascular bundle lies medial to the vertical line coming down from the anterior superior iliac spine. Two or three branches of the lateral femoral cutaneous nerve traverse the anterior hip and are at most risk of injury when anterior portals are established.
An image intensifier is used for all cases, and surface landmarks are verified with fluoroscopy, which is important to ensure precise portal placement and minimize the risk of iatrogenic damage. Once displacement of the joint line of at least 10 mm is achieved with traction, the first portal (in our practice, the anterolateral portal) can be placed.
Portals
Most hip arthroscopies can be performed through a visualization portal and working portal, although some surgeons use additional portals as needed depending on the pathology. Three standard portals are described for hip arthroscopy: anterolateral, anterior, and posterolateral. Several accessory portals are also used.
Anterolateral
The anterolateral portal is also known as the anterior peritrochanteric portal because of its location at the anterosuperior corner of the greater trochanter. The anterolateral portal is considered the easiest and safest portal to establish because it is located most centrally in the “safe zone,” and for this reason, we establish it first. This portal penetrates the gluteus medius before entering the lateral aspect of the capsule. Entrance into the hip is monitored closely with fluoroscopy to minimize iatrogenic chondral injury or penetration of the labrum. The superior gluteal nerve travels an average of 4.4 to 5 cm superior to this portal.
Anterior
The anterior portal site is established at the intersection of a vertical line extending distally from the anterior superior iliac spine and a horizontal line extending medially from the greater trochanter ( Fig. 82-6 ). The trajectory of this portal from the skin into the hip is approximately 45 degrees cephalic and 30 degrees toward the midline. Branches of the lateral femoral cutaneous nerve (LFCN) are at risk when the anterior portal is established. The portal courses through the sartorius and rectus muscles en route to the hip joint. Some surgeons prefer to position the direct anterior portal 1 cm lateral to vertical line from the anterior superior iliac spine to avoid penetrating the rectus femoris tendon and limit risk of injury to branches of the LFCN. This portal is typically created under arthroscopic visualization to ensure appropriate position within the joint ( Fig. 82-7 ).
Posterolateral
The posterolateral portal is located at posterosuperior corner of the greater trochanter and is also known as the posterior peritrochanteric portal. The posterolateral portal penetrates both the gluteus medius and minimus before entering the lateral capsule at its posterior margin. Its route is superior and anterior to the piriformis tendon. This portal lies closest to the sciatic nerve at the level of the capsule with an average distance of 2.9 to 3 cm. Approximately 4.4 cm separates the posterolateral portal from the superior gluteal nerve.
Accessory Portals
To accommodate some central compartment instrumentation and to access the hip periphery, variations of the original portals and other accessory portals have been introduced. Robertson and Kelly described the anatomic relationships of eight different skin incisions (including the traditional anterolateral, posterolateral, and direct anterior portal) with 11 different portal trajectories that have been used for hip arthroscopy and the peritrochanteric space by different authors, using a study design similar to that of the study by Byrd ( Fig. 82-8 ).
