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.

Figure 20–5 Anteroposterior pelvic radiograph that shows a retroverted acetabulum and a crossover sign.

Before any bone removal occurs, the junction between the capsule and the labral tissue must be developed. This will allow for the removal of an adequate amount of bone without causing further damage to the labrum or disturbing the capsular integrity at this site. It is also important to maintain a meticulous dissection at the anterosuperior aspect of the rim as a result of the close proximity of the reflected head of the rectus. If this area is damaged, postoperative adhesions can cause significant dysfunction.

We perform the rim trimming with the use of a 5.5-mm motorized burr. With the labrum detached and safely out of the way, we slowly begin to remove bone from the anterosuperior margin of the rim. We continually stop and get a profile view of the acetabular rim with the arthroscope to determine the extent of our resection. This process is repeated until we have a normal acetabular profile and a healthy bed of tissue for reattaching the labrum. If the labral tear extends beyond the zone of the pincer lesion, we will also trim a small portion of the bone in that region as well to provide a good surface for our labral repair. An example of a typical rim resection is shown in Figure 20-6. It is not uncommon to encounter subchondral cysts during the rim resection; these cysts are evidence of chronic impingement and should be completely resected. If they are not addressed, it is possible to drill into them during suture anchor placement and thus achieve substandard fixation.

Figure 20–6 Arthroscopic view of the burring of a pincer lesion. A, Acetabulum; L, labrum.

Labral repair

One of the most important aspects of this procedure—and also the most challenging arthroscopically—is the labral repair. The proper reattachment of the labrum to the acetabular rim provides the appropriate seal for the hip joint, the proper tracking of the labrum on the femoral head cartilage, and the surface area for pressure distribution within the hip joint. Failure in any one these three areas will cause subsequent pain, potential instability, and further degeneration of the cartilage.

Our technique requires the use of a very-small-diameter suture anchor. Because the acetabular rim can be both shallow and narrow, larger anchor devices are not as efficacious with this application. We use the 2.3-mm PEEK BioRaptor (Smith & Nephew, Andover, MA) for our fixation. We use a specially designed trocar with very sharp wings at the distal tip that help with the proper placement of the anchor; this allows us to get as close to the acetabular rim as possible without penetrating the joint (Figure 20-7).

Figure 20–7 Suture anchor guide device in place on the acetabular rim.

Depending on the size of the tear, we will typically use two to three anchors to adequately fix the labrum down to the rim. We usually start at the most anterior aspect of the tear and work posteriorly. The anchor placement is the only time during the procedure that we will use a plastic cannula. A 10-mm cannula is placed through the mid-anterior portal, and the trocar is subsequently passed and placed in an optimal position on the rim. After the drilling and seating of the anchor, we test its integrity by pulling on the free limbs of the suture. We use an arthroscopic suture passer to pass the suture closest to the rim around the intra-articular portion of the labrum and to retrieve both limbs through the cannula. It is possible to tie the labrum with too much force and to strangulate the tissue; it is also possible to have the suture too loose and to have it become a secondary source of impingement during the procedure. An example of the appearance of an appropriately tensioned knot is shown in Figure 20-8. A standard arthroscopic suture cutter is placed as close to the knot as possible to reduce the potential size of any foreign material within the hip joint. We will repeat these steps with subsequent anchors until the labrum is well fixed.

Figure 20–8 Dynamic evaluation after labral repair, rim trimming, and osteochondroplasty that shows normal tracking of the labrum with the femoral head.

After we have completed the labral repair, we test its integrity and its ability to seal the hip joint. By releasing the traction and moving the arthroscope into the peripheral compartment, we can evaluate the labral repair. From the peripheral compartment, it is possible to see the entire labrum and its interaction with the femoral head and neck as it moves through a full range of motion (see Figure 20-8). We also perform a dynamic examination by testing the hip joint in full flexion and abduction to ensure that the labrum does not demonstrate excessive motion and that there is no evidence of impingement present.

If there is any component of cam impingement present, this must be addressed at the time of the initial arthroscopic intervention. We use the same 5.5-mm motorized burr to remove the excess bone from the femoral head–neck junction. After an adequate osteoplasty has been performed, we will again perform a dynamic examination to ensure that the labral tissue is not impinged during full flexion and abduction.

Postoperative rehabilitation

Postoperatively, early emphasis is placed on preventing the formation of adhesions and regaining internal rotation. The prevention of adhesion formation consists of passive range-of-motion exercises and the use of a continuous passive motion machine for 2 weeks. Patients may also begin stationary biking as soon as it is tolerable to them. External rotation is restricted during the first 18 days in most cases, with this restriction being extended if more capsular work was performed. To protect the repaired labrum, a brace is worn while ambulating for the first 10 postoperative days to limit flexion to 90 degrees and to prevent abduction. Passive external rotation exercises are begun 21 days postoperatively. Pneumatic foot pumps are worn while at rest for the first 2 weeks to prevent deep venous thrombosis.

Outcomes

There are few reports that discuss the long-term outcomes of hip arthroscopy for labral dysfunction and associated femoroacetabular impingement (Table 20-1). We have recently reported about the outcomes of 45 professional athletes after arthroscopic intervention for femoroacetabular impingement and labral pathology. We used return to sport as an indicator for function, because these 45 professional athletes were unable to participate at the professional level before intervention. After arthroscopy, 93% of these patients returned to full competitive professional competition, and 78% remained active at the professional level an average of 1.6 years later.

We also looked at the early outcomes after arthroscopic acetabular labral repair. In this study, 52 patients underwent arthroscopic acetabular labral repair by a single surgeon. At an average follow-up length of 9 months (range, 6 to 15 months), patients showed significant improvement as measured by three clinical outcomes measures: the Modified Harris Hip Score, the Non-Arthritic Hip Score, and the Hip Outcome Score activities of daily living and sports subscales. The average patient satisfaction rate was 8.5 out of 10. This study showed that, during early follow up, patients exhibited significant improvement and high rates of satisfaction after arthroscopic acetabular labral repair.

In another study, early outcomes were documented after microfracture procedures in the hip. Nineteen patients underwent microfracture procedure for the treatment of grade 4 chondral defects on either the femoral head, the acetabulum, or both. At 1 year of follow up, patients showed significant improvements in all four of the previously mentioned clinical outcome measures, and the average patient satisfaction rate was 8.6 out of 10. Younger patients also experienced better outcomes. This study showed that patients who undergo micro-fracture for the treatment of grade 4 chondral defects in the hip can have good function, significant improvement, and high levels of patient satisfaction.

A continuation of the previous study looked at the ability of the microfracture clot to produce repair tissue. Nine patients underwent a microfracture procedure of acetabular chondral defects and had a subsequent hip arthroscopy in which the chondral defect fill could be quantified. The average time from the primary arthroscopy to the second look was 20 months. The average percentage of fill that was noted was 91% (range, 25% to 100%). Eight patients had a grade 1 or 2 repair product during the second look. The one patient who had 25% fill had diffuse osteoarthritis on both surfaces at the time of arthroscopy. This study showed that microfracture for the treatment of grade 4 acetabular chondral lesions shows an excellent ability to produce repair tissue as demonstrated during a second look at the area.

The reason that a patient requires revision surgery is important for delineating the proper indications for hip arthroscopy. The purpose of this study was to report the major reasons that patients present for revision hip arthroscopy. Thirty-seven revision hip arthroscopies were performed by the senior surgeon. The most common reason that patients underwent revision hip surgery was for unaddressed or inadequately addressed impingement at the time of index arthroscopy, persistent labral pathology, chondral defects, and capsulolabral adhesions. The outcomes of this study showed that patients regained some of their lost function within the first year after revision hip arthroscopy and that the major reason that patients underwent revision hip arthroscopy was for persistent impingement.

Complications

Unfortunately, there are no surgical interventions that are complication free, including hip arthroscopy. The keys to having successful outcomes are to recognize the potential complications and to take extraordinary steps to avoid them if at all possible.

In our practice, the most common complication after surgery has been postoperative tendonitis of the hip flexor. This will typically start to cause anterior groin pain with hip flexion approximately 6 weeks after surgery. Two interventions have been made to decrease the frequency of this complication. First, we changed the position of our anterior portal in an effort to move farther away from the hip flexor musculature. The mid-anterior portal allows for excellent visualization, and it is farther lateral than the anterior portal and thus farther from the hip flexors. Since the use of this portal, we have seen a dramatic improvement in hip flexor tendonitis. Second, we made multiple adjustments to the postoperative rehabilitation process with respect to the hip flexors. By limiting active flexion for the first 2 to 3 weeks after the procedure, patients have noted less pinching in the anterior groin.

Capsulolabral adhesions are also more frequent complications among our postoperative hip scope patients than we would prefer. Clinically, we will see a reduction in the previously attained range of motion. This reduction in motion then creates a vicious cycle of reduced motion, pain, deconditioning of the hip musculature, and then a further reduction of motion. The use of circumduction exercises postoperatively has limited the occurrence of postoperative adhesions. The addition of platelet-rich plasma (PRP) as part of our surgical intervention has been very beneficial with respect to this complication. The hemostatic properties of this injection directly at the site of the head–neck resection has reduced the frequency of capsulolabral adhesions among our patients.

There have been other complications described in the literature, including perineal numbness, transient neurologic symptoms (both motor and sensory), impotence, and bruising of the genitalia. Proper attention to detail during the setup of the operative theater is very important for avoiding these complications, and paying close attention to the amount of traction time is very effective for reducing them. Furthermore, the use of continuous nerve monitoring during the procedure is a good indicator of the amount of stress that is being placed on the nerves and on all of the associated structures within the lower extremities.

Conclusions

Hip arthroscopy has provided the orthopedic surgeon with the ability to address pathologies related to the acetabular rim and the labral tissue with great effectiveness. The relatively low complication rates and the very high success rates are the driving forces behind the recent focus on this approach that have been seen in the orthopedic literature and at national meetings across the globe. Continuing innovations developed by pioneering orthopedic surgeons will further advance the successes that have been seen during the past 5 to 7 years.