Introduction

Advances in arthroscopic techniques and the tools available have made hip arthroscopy an increasingly attractive alternative to longer, more invasive open approaches to address pathology within the hip joint. In particular, the challenges of femoroacetabular impingement have brought hip arthroscopy to the forefront of the current orthopedic literature in an attempt to address both the soft tissue and the bony pathology involved with this difficult diagnosis. Several authors have published their techniques, and their short-term results have demonstrated the efficacy of this approach. However, further efforts need to be made to make arthroscopic labral repair and femoroacetabular impingement surgery a further refined and more reproducible procedure.

The main controversy regarding the treatment of femoroacetabular impingement is whether it can be addressed more effectively with an open dislocation of the hip joint or with less invasive arthroscopic techniques. The work of Ganz and others has demonstrated excellent results with open dislocation. However, the morbidity associated with this procedure—in addition to the possible risks associated with the tenuous blood supply to the femoral head—in our opinion makes an open dislocation unnecessarily risky when considering recent improvements in arthroscopic techniques.

The purpose of this chapter is to discuss in detail the technique of labral repair and rim trimming in the setting of femoroacetabular impingement. Our goals are to describe our unique approach to this challenging diagnosis and to offer the orthopedic surgeon new tools with which to return patients and athletes to their daily lives and to their respective sports.

Indications

Proper patient selection is the key to excellent outcomes. There are no absolute indications for rim resection and labral repair. However, it is important that any pathologic findings on plain radiographs or magnetic resonance images be correlated with the findings of the physical examination to determine the true cause of the patient’s pain and dysfunction. The typical patients who undergo rim resection are those with coxa profunda or a relative retroversion to the acetabulum. These patients have either an acetabulum that is too deep and thus restrictive to motion or an abnormal amount of bone at the anterior lip of the acetabulum. The radiographic findings that demonstrate these two distinct pathologies will be discussed later in this chapter. These two patient populations have pincer-type impingement, and it can only be addressed by the resection of bone from the acetabular rim.

For labral repair, the indications are more varied. Labral tears can be caused by relatively minor to very extreme trauma. In the setting of pincer impingement, it is common to find a labral tear at the site of the excessive bone on the acetabulum. After this bone has been removed, it will be necessary to reattach the labrum to the acetabular rim. However, there are those cases in which a full-thickness tear of the labrum has not yet occurred; it is still possible to see dysfunction of the chondrolabral junction in these patients. In this setting, it is necessary to create a separation at the chondrolabral junction to remove the excessive acetabular bone.

The final indication would be the presence of an os acetabuli or a rim fracture at the acetabular rim. This piece of bone can either become painful itself as it moves with hip motion, or it can become fixed in place and create an external impingement source to the hip joint. There is debate among experts in the field regarding whether resection or fixation is the adequate approach in this patient population. The decision about which approach to use is typically made at the time of surgery, when the fragment of bone can be probed and evaluated in the natural environment of the hip joint.

Brief history and physical examination

The patient with pincer impingement or a labral tear may have had a multitude of varying diagnoses before the current evaluation. Typical patients will have prior diagnoses of sciatica, sports hernia, piriformis syndrome, coxa saltans, or various lumbar spine pathologies. It is important to elucidate from the patient the nature and quality of the pain when he or she first noticed his or her symptoms, any exacerbating conditions or positions, and his or her response to previous treatments. Each of these questions will help the surgeon to zero in on the cause of the patient’s pain and dysfunction.

The physical examination is very important and very effective for determining the source of the patient’s symptoms. First, an evaluation of the patient’s lumbar spine and a focused neurologic evaluation should be performed; this allows the surgeon to rule out any non-hip pathologies that could be causing the patient’s pain. In our practice, we then perform a series of tests that address the range of motion and strength of the musculature around the hip. It is common to see a reduction of internal rotation and pain during testing among patients with impingement. In addition, we will perform anterior and posterior impingement tests to further stress the labrum and to determine if there is a tear present. Finally, we will perform a hip dial test to determine the integrity of the anterior capsule and the iliofemoral ligament. With the patient in a supine position, we will evaluate the position of the lower extremity with respect to the long axis of the body. By pressing on the inside of the patient’s foot and watching for rebound, we can determine how tight or lax this capsular tissue has become.

It is very important with any of these provocative tests to determine whether the pain that the patient is experiencing is the same pain that has brought that patient to your clinic. One effective way that this can be accomplished is to perform a lidocaine and Kenalog injection in the office. After sterile preparation, an 18-gauge spinal needle is placed within the hip capsule, and the steroid and lidocaine mixture is administered. After approximately 5 minutes, we repeat the physical examination tests and quantify the improvement in the patients’ symptoms. This is typically diagnostic, and it can also be therapeutic during the time that the patient is awaiting surgical intervention.

Technique

All of our arthroscopic hip techniques are performed with the patient in the supine position. After a lumbar plexus block and a general anesthetic are administered to the patient, we are very meticulous with our setup. The patients’ feet are wrapped in protective boots and placed in leather foot holders at the foot of the bed. Each lower extremity is attached to a bar that is freely mobile for abduction, adduction, flexion, and extension. The nonoperative extremity is placed in approximately 60 degrees of abduction, whereas the operative extremity will eventually be placed in neutral abduction. Before the feet are wrapped, electromyography monitors are placed near the tibial nerve for continuous monitoring during the procedure. After baseline signals are achieved, we are ready to begin the distraction of the operative extremity for optimal portal site placement. A C-arm fluoroscopy device is used to verify the amount of joint distraction that is achieved. The foot is internally rotated 90 degrees and then locked in place; this allows us to place the proximal femur nearly parallel with the floor. After the radiographic verification of adequate distraction is attained, we remove the C-arm and prepare the patient in a standardized fashion. A picture of our standard setup is shown in Figure 20-1.

Figure 20–1 Operative setup and patient positioning.

Our portal placement has evolved after extensive experience with hip arthroscopy and the complications that can be related to portal placement. Although our lateral portal has remained mostly unchanged, we have changed the position of the standard anterior portal in an attempt to reduce the morbidity associated with the rectus muscles and the nearby nerves. In particular, the lateral femoral cutaneous nerve and the smaller branches of the femoral nerve can potentially be irritated by the close proximity of the anterior portal.

We draw out specific landmarks on the patient’s leg to properly identify the ideal location for our portals. The anterosuperior iliac spine and the outline of the greater trochanter are the most important of these landmarks. From the tip of the greater trochanter, we measure proximally 1 cm and anteriorly 1 cm; this is the ideal location for our lateral portal. From that site, we measure a distance between 5 cm and 6 cm distal and anterior on a 60-degree plane from horizontal for the placement of our unique mid-anterior portal (Figure 20-2). In our experience, these two portals are all that are necessary to achieve the adequate visualization of the most important aspects of both the central and peripheral compartments of the hip joint. We have also substantially reduced the morbidity associated with portal placement over the past year with the new position of our mid-anterior portal.

Figure 20–2 Arthroscopic portal placement. The anterosuperior iliac spine and the outline of the greater trochanter are shown at the top and bottom of the image. A line is drawn through the tip of the greater trochanter. The lateral portal is placed 1 cm proximal from the greater trochanter and 1 cm superior. The mid-anterior portal is placed 5 cm to 7 cm distal to the lateral portal and at an angle of 45 degrees to 60 degrees from the longitudinal axis of the leg.

After our surgical team performs our standardized timeout for proper extremity identification, a No. 11 blade is used to incise the previously marked incision sites for our two portals. We place a standard hip arthroscopy needle into the hip joint through our lateral incision first. The needle is directed 20 degrees inferior and 20 degrees caudal for optimal placement within the central compartment. We no longer use C-arm fluoroscopy for this portion of the procedure; however, during the learning curve portion of hip arthroscopy, it may be useful to verify the position of the needle before entry into the hip joint while you are becoming comfortable with the procedure to lessen the chance that the femoral head or the labrum will be violated during needle placement. After the needle is placed within the hip joint, we insufflate the joint with approximately 30 ml of sterile fluid. We can positively identify the position within the hip joint by the presence of a sudden increase in pressure after an adequate amount of fluid is placed. The brisk outflow of fluid from the needle verifies needle placement. A guidewire is placed through the needle, and a 5-mm cannula is passed over the Nitinol wire. After the arthroscope is introduced into the hip joint through the lateral cannula, we place the mid-anterior portal with the use of direct visualization to lessen the risk of the cartilage of the femoral head and the labrum being violated. In our experience, C-arm fluoroscopy is not helpful during the placement of the mid-anterior portal.

Now that we have established a portal for the arthroscope and a working portal, we can begin the diagnostic portion of the arthroscopy to visualize all aspects of both the central and peripheral compartments. Our attention is first directed to the chondrolabral junction. We use a probe to determine if there are any areas in which the labrum has been separated from the acetabular rim. It is typical with cam-type impingement to see delamination of the acetabular cartilage at the site of the labral detachment. With the use of the blunt end of a shaver or with a probe, it is possible to see a “wave sign”: the cartilage will buckle at sites where the labrum is damaged but not yet detached from the acetabular rim (Figure 20-3). It is very important to inspect these areas carefully. If they are not addressed at the time of the initial surgery, they can be the source of recurrent pain and disability as the junction between the labrum and the delaminated cartilage degenerates.

Figure 20–3 Chondrolabral dysfunction “wave sign.”

Before we perform our rim trimming and any necessary labral work, we measure the distance from the cotyloid fossa to the acetabular rim at the 3, 6, and 9 o’clock positions. We also measure the labral width at these three positions. This information, in combination with our preoperative x-rays and the measurement of the center-edge angle, provide us with a roadmap for our rim resection and the subsequent labral repair. Attention to detail during this portion of the procedure is essential to avoid the over- or under-resection of bone during the preparation of the acetabular rim.

Rim trimming

The typical pincer lesion is produced as a result of an abnormal growth of bone at the anterosuperior portion of the acetabulum (Figure 20-4). The pincer can be either primary or secondary to the chronic abutment of the femoral neck on the acetabular rim. With respect to the normal anatomy and position of the acetabulum, this area creates a relative retroversion to the acetabulum. The x-rays in Figure 20-5 show this crossover sign. This is an area in which the anterior wall is farther lateral than the posterior acetabular rim. The goals of the rim resection should be to remove this area of bone and to restore the normal anatomy and relative position of the acetabulum with respect to the pelvis and the femoral neck. If this area is not addressed, subsequent labral damage and delamination of the cartilage will continue. Typically, this anterosuperior region of the acetabular rim also corresponds with the area of labral pathology. If the tear does not extend to this region, it is necessary to detach the labrum at this site for the proper resection of bone. After this has been completed, the labrum can then be reattached with the use of suture anchors.

Figure 20–4 Bruised acetabular labrum with associated pincer impingement.