FAI: An emerging problem in orthopedics

Last month our esteemed panelists gave us a diverse yet balanced presentation laying the foundation for this month’s Round Table discussion on current and emerging surgical procedures for patients afflicted with femoroacetabular impingement (FAI) and labral tears.

This Round Table began, quite honestly, as a reaction to an arthroscopic labral reconstruction procedure (with gracilis autograft) that was presented at this year’s Orthopedics Today Hawaii conference. Some questions were related to technique; many were justifiably related to rationale.

With the interest, research, and literature rapidly expanding, my hope is to allow our expert panel to continue in stride as they tackle the topic of what can be done and what should be done — which are not necessarily the same — as all of us learn, often from each other, about the rapidly evolving management of young adults with hip pain.

Dean K. Matsuda, MD
Moderator

Round Table Participants Moderator Dean K. Matsuda, MD Director of Hip Arthroscopic Surgery Co-Chair of Sports Medicine Kaiser-Permanente WLA Medical Center Los Angeles, Calif. Philip C. Noble, PhD Professor Department of Orthopedic Surgery Baylor College of Medicine Houston, Texas Marc J. Philippon, MD Orthopedic Surgeon, Partner Steadman Hawkins Clinic Vail, Colo. Thomas G. Sampson, MD Medical Director, Total Joint Center Saint Francis Memorial Hospital Medical Director of Hip Arthroscopy Post Street Surgery Center San Francisco, Calif. Robert T. Trousdale, MD Professor of Orthopedics Mayo Clinic College of Medicine Rochester, Minn.

Dean K. Matsuda, MD: What are your indications for surgical intervention in cases of FAI?

Marc J. Philippon, MD: Patients usually present for treatment of disabling hip pain. They have usually failed conservative treatment and come to our facility for surgical intervention. Patients are encouraged to seek early intervention. Time from onset to surgery does correlate with outcomes following hip arthroscopy.

Our study showed that patients who waited more than 1 year and who had an alpha angle greater than 55· were 9.5 times more likely to have grade III/IV chondral defects. This suggests that early intervention may lead to improved patient outcomes in patients with debilitating hip pain.

Other indications for surgery included physical exam and radiographic diagnosis of FAI.

Thomas G. Sampson, MD: My indication for arthroscopic hip surgery is anyone who has pain from the hip joint for more than 6 months with or without a specific diagnosis and has failed any conservative care. For FAI, there is no known conservative treatment unless it is due to hyperlordosis of the lumbar spine, which can be treated by a physical therapist.

I reserve a steroid injection for those who are extremely symptomatic and hesitant to have surgery or, for some reason, delay it. The fact that symptoms may abate in FAI doesn’t mean the problem has gone away. There is still an ongoing destructive process that may cause symptoms to wax and wane.

Robert T. Trousdale, MD: Our general indications for surgical intervention include pain bad enough to warrant surgery and structural problems that one can improve upon in the presence of reasonable articular cartilage. That includes an acetabular osteotomy if the dysplasia problem is worse on the pelvic side, a femoral osteotomy if the deformity is worse on the femoral side or, on occasion, a combination of both femoral and acetabular osteotomies.

If a young patient has structural problems of impingement on the acetabular side or femoral side we try to solve all the structural problems that are present. I think the patient who is middle-aged — older than 40 or 50 years — we are less likely to do a major open intervention in light of the fact that the secondary chondral problems are often marked. The younger the patient, the more likely we are going to accept more significant arthritic problems in the joint.

Matsuda: What procedures do you typically perform in the management of hip labral pathology?

Philippon: To treat labral pathology, you must treat all factors that may have caused the pathology and all concomitant pathologies which may limit the patient’s full recovery.

The femoral head and neck are resected with a 5.5-mm burr prior to labral repair in order to assess the repair during dynamic exam. The decision to repair or debride the labral pathology is made intraoperatively. Degenerative labral tears are debrided using thermal and/or shaving techniques. Frayed, flap, and small labral tears with enough viable healthy tissue remaining to provide anatomic function are also debrided.

All other labral pathologies are repaired using suture anchors with either circumferential or mid-substance capture. In the cases of pincer-type FAI, it was sometimes necessary to extend the labral tear using an arthroscopic knife entered precisely at the chondro-labral junction. The labral tear can then be carefully extended to allow adequate access for the 5.5-mm motorized burr to decompress the underlying pincer lesion.

In most cases, the labrum can then be reattached and repaired using suture anchors to restore an anatomic labral seal and femoroacetabular labral articulation. If a short segment of the labrum is involved with the pincer lesion, then the labrum can remain attached. However, we have seen in revision cases that the segment was too long and the labrum became unstable.

If the labrum is unstable on dynamic exam, then extend the detachment and rim trimming. In order to prevent over trimming the rim and the potential of dysplasia, we measure the depth of the lunate surface at the 12 o’clock position before and after rim trimming. This depth is related to the change in the center-edge (CE) angle by the following formula: Change in CE angle = 1.8 + (0.64 × rim reduction in millimeters). The formula is to be applied only in instances in which a rim trimming is performed and at least 1 mm of rim is resected. A measurement of less than 1 mm lacks accuracy in determining the relationship.

When a chondral defect is near the chondro-labral junction, rim trimming can also be used to decrease the size of the chondral defect.

We then use the microfracture technique to treat the chondral defect. The chondral defect on the femoral head is also treated with microfracture if the cartilage rim around the defect is of adequate depth to hold the clot. Synovectomy and lysis of adhesions should also be addressed, as they are possible pain generators following surgery. The capsule is sutured at the site of the initial capsulotomy.

There are occasions, however, in which the labrum cannot be repaired primarily. The labral tear pattern can be complex and completely disrupt the longitudinal fibers, which leaves little functional material to repair. In these cases, we use an autograft illiotibial band to reconstruct the labrum.

Sampson: The surgical treatment for non-FAI labral pathology varies depending on the tear type, the association with degenerative joint disease (DJD), and the age and activity level of the patient.

In most of my cases, it simply requires partial labrectomy. I think there are rare cases after trauma in a young patient where a bucket handle usually associated with a posterior subluxation or dislocation benefits from a repair, however most that I have seen were too frayed for repair and were debrided. I have found it rare to perform a labral repair in my patient population, which averages in the 30 to 40 year-old age range.

Trousdale: If the patient is younger and has major structural problems, we will solve the structural problem about the hip joint and deal with the labral pathology. In the vast majority of patients we try to repair the labrum if it is a repairable lesion — a tear from the osseous surface. If there is peripheral tearing, we will debride that tear.

In patients with dysplasia, we will solve the dysplastic problem. In patients with a retroverted acetabulum in the face of poor posterior wall coverage, we will do an anteversion periacetabular osteotomy. In classic dysplasia we will do a classic periacetabular osteotomy. If there are impingement problems we will try to solve the impingement situation.

In patients with pincer-type acetabular impingement, if they have a deep socket (coxa profunda) or protrusio defect we will lessen the depth of the socket. In patients with a retroverted socket, if they have adequate posterior wall coverage, we will do a labral take-down and anterior rim trimming. In patients who, as mentioned above, have a retroverted socket in the face of poor posterior wall coverage, we will do a reverse (anteverting) periacetabular osteotomy.

We have done, and recently published in Clinical Orthopaedics and Related Research, our technique for labral reconstruction. We have taken the round ligament and used that as a reconstructive tissue for the labrum. That, I think, should be considered experimental as there is really no long-term outcome.

Matsuda: Dr. Philippon, could you describe your arthroscopic supine approach?

Philippon: The patient is placed in a modified supine position with a combination of general anesthesia and a lumbar plexus sciatic regional block with complete muscular paralysis. The perineum is positioned against an extra-wide, padded bolster with care taken to protect the genitalia. Both legs are positioned in 40· of adduction, 20· of flexion, and neutral rotation.

Fluoroscopy is used to obtain an AP view of the operative hip. Gentle traction is applied through the operative hip with moderate counter-traction through the nonoperative hip until the development of a “vacuum sign” in the joint space. Once this has been visualized, the operative leg is adducted to neutral and the foot is maximally internally rotated to bring the femoral neck parallel to the floor.

Joint distraction is assessed with fluoroscopy and additional traction, usually 25 to 50 pounds total, is applied to achieve approximately 10-mm total distraction. Once final traction is established, the operative table is tilted 10· toward the nonoperative side.

All images are of supine patient viewed from the anterolateral portal. Figure 'a' shows anterosuperior acetabular rim after rim trimming and suture anchor drill hole (yellow arrowheads) preparation. Figure 'b' shows the gracilis tendon autograft being attached via the modified mid-anterior portal. Figure 'c' shows the labral reconstruction prior to release of intermittent hip distraction. Image: Matsuda DK

Matsuda: What is the future of hip preservation surgery?

Philip C. Noble, PhD: A disturbing number of patients seek treatment when chondral damage has occurred and less successful treatments, like microfracture, are all that can be offered. In some of these cases, early detection of labral and chondral pathology may help preserve the joint through guiding earlier intervention.

Clearly, we need to know more about the success of osteochondroplasty and labral refixation in terms of long-term joint health and not simply short-term symptomatic relief. Rigorous work-up of cases already performed using newer imaging modalities can provide valuable insights into the success of attempts to reattach the labrum and restore the chondral seal, and the response of the articular surface to improved lubrication and a reduction of chronic inflammation. Modalities including ultrasound imaging and functional magnetic resonance imaging (FMRI) should be utilized to learn more about what we have achieved to date as a springboard for the next advances.

Unfortunately, we have limited options for improving labral fixation and chondral repair as most of the challenges are biological and not mechanical. The greatest problem confronting us is the management of chondral delamination, especially where lesions are present on both the femoral head and the mating acetabulum.

It is also unclear whether labral reattachment will be successful in the long-term when performed on a broader scale than at present given the technical demands of the procedure. Solutions to tissue attachment which look promising include:

• the use of tissue scaffolds for articular repair and attachment;
• the incorporation of angiogenic growth factors into the reattached labrum and the chondro-labral junction to stimulate vascular ingrowth;
• the use of surgical adhesives, especially those based on artificially engineered proteins, to restore the integrity of the chondro-labral and cartilage-bone interfaces; and
• the development of an artificial labrum as an option to prolong the natural joint before resorting to prosthetic replacement of the articulating surfaces.

Sampson: To predict the future of hip preservation, we need to understand how hips are destroyed. Let us use the modal of osteoarthritis (OA). It has become more accepted that OA may be caused by abnormal morphology of the hip joint such as FAI, developmental dysplasia (DDH) or coxa magna from old Perthes disease. All of these conditions cause mechanical destruction of the articular cartilage and labrum by a high concentration of forces on mismatched articular surfaces. The reaction to the generated particulate matter is a physiologic response with synovitis and the secretion of digestive enzymes and scavenger cells which cause further destruction of the joint.

The goals of joint preservation surgery are to correct the abnormal morphology to create a concentric articulation, and reverse the destructive biologic response to eliminate the synovitis.

I advocate performing a correction of cam bumps, rim osteophytes and excess head mass — using arthroscopic means whenever possible, especially in those who already have OA and are young with Harris Hip scores greater than 60. We have found that good predictors of success are both hip rotation and joint space greater than 50% of the unaffected hip. Poor predictors include X-ray or MRI evidence of large acetabular cysts, complete overgrowth of the notch by osteophyte, complete ossification of the transverse ligament, and large inferior and posterior femoral head osteophytes. All of the predictors indirectly reflect the nature or the remaining articular hyaline cartilage cells and their matrix.

The challenges are to restore the morphology before the mechanical forces have caused irreversible cartilage cell death and inability for cartilage matrix regeneration.

For the future, we need a method to determine whether the joint has crossed an irreversible threshold so we may determine which hips will have predictably good outcomes with surgery.

With arthroscopic hip surgery, we have all of the tools and abilities to examine the hip, biopsy pathologic and normal-appearing tissues, and change the morphology using current techniques described in treating FAI in an outpatient setting with minimal morbidity and an easier rehabilitation than open techniques.

The addition of cartilage cellular analysis preoperatively using noninvasive imaging, and intraoperatively with biopsy or probes, would satisfy our abilities to predict and prognosticate outcomes from hip preserving surgery in those who already have OA.

Chemical labeling PET scans and high resolution MRI is still in its early stages of identifying cartilage integrity, however, it is already useful, if available.

Trousdale: I think we have a reasonable handle on the structural problems that lead to impingement and arthritis. What we don’t know is the long-term outcome of various operations. We do not know if the interventions that we do are going to change the natural history of the disease.

The future involves cartilage restoration techniques.

Matsuda: I predict that we will trend towards more minimally invasive options in the management of focal, eg, acetabular retroversion, and even global, eg, coxa profunda or protrusio acetabulae, FAI. Improved techniques and instruments are on the horizon. Labral reconstruction in select patients will play a role in hip preservation.

We will better understand the biomechanical effects and consequences of our acetabular procedures; this will enable us to determine who should have a rim trimming procedure and who may fare better with a reverse periacetabular osteotomy (PAO).

Moreover, I predict that endoscopic Bernese PAO will become a possible —perhaps even preferred — management for select patients with dysplasia and/or focal FAI.

Arthroscopic techniques will expand their utility in the trauma setting. Treatment of displaced femoral head fractures and acetabular rim stress fractures have recently been published. And although not necessarily hip preservation our expertise will expand into the area of the central pelvis as we learn more about the multitude of conditions that contribute to athletic pubalgia, thus making us more complete surgeons.

For more information:

• Dean K. Matsuda, MD, can be reached at Southern California Permanente Medical Group, Kaiser West Los Angeles Medical Center, 6041 Cadillac Ave., Los Angeles, CA; 323-857-4477; e-mail: dean.k.matsuda@kp.org. He has intellectual property rights with ArthroCare.
• Philip C. Noble, PhD, can be reached at Institute of Orthopedic Research & Education, 6550 Fannin-Smith Tower, Ste. 2512, Houston, Texas 77030; 713-441-3010; e-mail: pnoble@bcm.tmc.edu. He receives royalties from Smith & Nephew, Stryker and Zimmer; is a paid consultant or employee of, and receives research or institutional support from Smith & Nephew and Zimmer; and receives miscellaneous non-income support from Biomet, Smith & Nephew and Zimmer.
• Marc J. Philippon, MD, can be reached at 181 W Meadow Drive, Ste. 400, Vail, CO 81657; 970-476-1100; e-mail: drphilippon@steadman-hawkins.com. He receives royalties from Smith & Nephew and Bledsoe; is on the speaker’s bureau and is a paid or unpaid consultant for and receives non-income support from Smith & Nephew and receives institutional or research support from Smith & Nephew and Ossur.
• Thomas G. Sampson, MD, can be reached at Post Street Orthopaedics and Sports Medicine, 2299 Post St., Suite 107, San Francisco, California 94115-3443; 415-345-9400; e-mail: tgsampsonmd@yahoo.com. He receives royalties from Smith & Nephew.
• Robert T. Trousdale, MD, can be reached at Mayo Clinic, 200 First St. SW E14B, Rochester, MN 55905; 507-284-3663; e-mail: trousdale.robert@mayo.edu. He receives research or institutional support, miscellaneous funding and royalties from and is a consultant to DePuy and he is a consultant to Wright Medical Technology.

Reference:

• Sierra RJ, Trousdale RT. Labral reconstruction using the ligamentum teres capitis: report of a new technique. Clin Orthop Relat Res. 2009;467(3):753-759.