Back when I was a high-school tailback 150 lbs soaking wet
the only hip problems I remember were groin pulls and hip pointers.
Decades later, everything became a labral tear. Sure, dysplasia was recognized
as a cause of hip pain and labral tears. But not until relatively recently has
the connection between athletes, hip problems and labral tears come together
with femoroacetabular impingement (FAI). It is difficult to talk about labral
tears without mentioning impingement in the same breath, and vice versa.
FAI has emerged as an entity with profound clinical impact, sidelining
weekend and professional athletes alike, perhaps even being the number one
recognizable cause of early hip osteoarthritis. The condition and its current
treatment options span hip reconstructive surgery and sports medicine.
I decided to gather two hip arthroscopic surgeons who shaped my own
practice (one arthroscopically shaped my hips), a joint reconstruction surgeon
with extensive expertise in open FAI surgery, and one of the foremost
authorities in basic science orthopedic research, particularly as it applies to
the hip. In this first of a two-part Round Table discussion, I ask these
experts to teach us about the latest concepts and controversies in the
management of hip labral tears and FAI.
Dean K. Matsuda, MD
|Round Table Participants
Dean K. Matsuda, MD
Director of Hip
Co-Chair of Sports Medicine
Los Angeles, Calif.
Philip C. Noble, PhD
of Orthopedic Surgery
Baylor College of Medicine
Thomas G. Sampson, MD
Total Joint Center
Saint Francis Memorial Hospital
of Hip Arthroscopy
Post Street Surgery Center
San Francisco, Calif.
Marc J. Philippon, MD
Partner Steadman Hawkins Clinic
Robert T. Trousdale, MD
Mayo Clinic College of Medicine
Dean K. Matsuda, MD: We are hearing that isolated hip labral
tears are quite uncommon. What are your thoughts?
Philip C. Noble, PhD: By isolated labral tears, I
assume that we are referring to lesions of the labrum or the
labro-cartilaginous junction that occur in the absence of morphologic
abnormalities of the femur or the acetabulum. Naturally this statement could be
completely true or completely false, depending how critically we define the
morphologically normal hip.
We know that labro-cartilaginous lesions are common, especially in old
age, with a prevalence of 60% to 80% reported in postmortem studies. Similarly,
morphologically abnormal hips seem to have become remarkably common over the
last decade with the increasing interest of musculoskeletal radiologists in
In a recent study we found that the normal femur, as
conventionally defined, was relatively rare in men. Yet, in adults older than
55 years of age, the prevalence of symptomatic hip osteoarthritis (OA) is
reported to be only 5% to 7%. This suggests that many individuals have silent
labral pathology and silent, or clinically insignificant, bony abnormalities of
the pelvis and femur. It is the connection between the two that appears to be
In circumstances where physical activities place abnormal loads on the
labrum, usually at the extremes of the motion arc, labral pathology can be
generated or exacerbated and lead to hip symptoms. If these activities are
repetitive, joint degeneration may develop.
Our experiments on joint positions and labral strains show that in
extension and mild flexion, large strains can develop at the anterior-superior
labralchondral junction without bony impingement. This correlates nicely
with McCarthys observations that labral lesions commonly occur without
FAI in a population of athletic patients. Conversely, Philippon has shown that
in groups of patients who routinely load the hip in a flexed position (eg,
hockey goalies), labral injury is associated with chronic femoroacetabular
This concept of multiple mechanisms leading to hip OA is supported by
cadaver studies of degenerated hips. We have examined a series of subjects with
early degenerative joint disease (DJD) in which the majority have clear
limitation of hip motion secondary to FAI, but approximately one-third of the
cases have normal hip motion with labral pathology arising from some cause
other than bony impingement.
Based on these observations, I believe that hip OA is a multifactorial
disease which occurs when a series of risk factors coincide, including
acetabular and femoral dysmorphia, soft-tissue laxity, the mechanical
properties of the cartilage and labrum, the immunologic susceptibility of each
patient to inflammatory mediators, and imposed loading and posture. The most
important of these factors are the loads and positions imposed on the joint by
Marc J. Philippon, MD: In our database of over 1,700 hip
arthroscopies, we have no documented cases of isolated labral tears in primary
hip arthroscopies. We found that 86% of all labral tears are associated with
mixed cam- and pincer-type impingement, 9% were associated with isolated cam
impingement, and 5% associated with isolated pincer impingement. Forty-percent
of the labral tears were associated with hip instability; however, we are
currently trying to identify which type of instability is associated with
certain labral tears.
Thomas G. Sampson, MD: In my practice of hip arthroscopy going
back to 1984 we have treated many labral tears, however, in most cases these
were accompanied with other pathologies. I believe what we called labral tears
were in many cases labro-cartilaginous tears of the acetabulum as well as
delaminations of the articular cartilage. Isolated tears were seen in less than
10% of the patients. We saw many tears associated with DJD.
Shown here, what
was thought to be a radial labral tear in 1999. On further analysis it proved
to be a delamination of the acetabular cartilage.
Image: Sampson TG
Prior to 2001, we did not scrutinize X-rays as we do today looking for
the elements of FAI. Today, labral tear is the most common
diagnosis on MRIs in my referred patients. Many MRIs are of inadequate quality
and have to be repeated; however, most often I spent a great deal of time
showing the patient that what they really have is a labral-cartilage junctional
tear or degeneration form of FAI and not an isolated labral tear. MRA with
gadolinium may be helpful, but I prefer to see an MRI so I can determine if the
painful side has an effusion.
Regarding the relationship of developmental dysplasia of the hip and
FAI, remember that plain X-rays may show a narrow center-edge angle or false
profile, however, the impinging rim is anterior where it is difficult to image.
At surgery, whether I have or have not imaged the rim osteophyte with X-rays,
CT or MRI, I will always look for an anterior rim lesion and have found it more
often than not even if it was not seen with imaging.
Robert T. Trousdale, MD: We feel that the majority of labral
tears are secondary to structural problems about the hip joint and have some
data published in the orthopedic literature that support this fact. We
retrospectively looked at all the labral tears at the Mayo Clinic over a period
of time and found that more than eight out of 10 patients had concurrent
structural problems. One can easily envision both impingement problems and
dysplasia putting more stress on the labrum and leading to labral pathology.
Matsuda: What is the relevant basic science to support or refute
labral preservation surgery?
Noble: The hip labrum plays a critical role in keeping the head
of the femur reduced within the acetabulum, in maintaining lubrication of the
joint and in serving as a soft bumper at the limits of motion. Nerves within
the labrum also provide potential for proprioception.
As in the shoulder, venting of the labrum greatly reduces the resistance
to distraction and frank dislocation. The mechanism of labral stabilization has
been demonstrated in our experiments and in several elegant studies by Ferguson
and Ganz. They show that labrum forms a seal for joint fluid through contact
against the femoral head, and the effectiveness of this sealing function is
reflected in the force needed to displace the head within the socket.
As the labral seal keeps synovial fluid between the articulating
surfaces, a healthy labrum increases the hydrodynamic component of lubrication
which keeps friction to a minimum. It also protects against overload of the
chondral surface and the underlying bone during episodes of sudden impact as
larger instantaneous loads can be supported before fluid is displaced from the
zone of articulation.
Our experiments have shown that the labrum also undergoes significant
strain during activities involving abduction and external rotation around the
neutral position. Once the labrum is vented and torn, micro-instability ensues
with 1-mm to 1.5-mm increased anterior displacement of the femoral head within
the acetabulum. This change in the mechanical environment may directly lead to
cartilage overload and the onset of DJD, although the relationship between
micro-instability and cartilage health is not well understood.
These observations and the clinical results of Beck and Espinosa support
the conclusion that labral excision is undesirable and should be regarded as
the meniscectomy of the hip. However, from a basic science
perspective, labral reattachment poses some unique challenges because of the
lack of vascularity, the frequency of secondary hip deformities and the
different patterns of labral pathology.
Studies of labral vascularity report differing conclusions; however, all
authors agree that the more central (articular) two-thirds of the cross-section
of the labrum are avascular. Whether the remainder of the labrum has any
vascularity is a subject of debate; however, it is agreed that the fibrous
tissue covering the capsular surface is a potential source of blood supply
Given this situation, it is conceivable that reattachment of the labrum
will only occur along the capsular edge of the tissue and that the strength of
the reattachment will be determined primarily by the sutures rather than the
bridging tissue. Although Phillipon has reported encouraging results in
professional athletes in the short term, the properties of the labral
reconstruction remain unknown.
Another question which will only be answered with long-term follow-up is
the fate of the joint after labral reattachment. Espinoza and Leunig have shown
that hip symptoms and function dramatically improve with labral preservation.
It is unknown whether this beneficial outcome arises from increased stability
of the joint, or improvements in lubrication and the distribution of articular
pressures. An even more important question is whether it can be assumed that
these symptomatic improvements necessarily indicate that the onset of OA has
been significantly delayed and, if so, for how long?
One explanation of the connection between labral pathology and chondral
degeneration is that separation of the labral-chondral junction provides access
for joint fluid to the subchondral boundary which serves as a breach of the
protective outer layer of the cartilage. This often leads to chondral
delamination and rapid development of an unsalvageable joint. If the key event
in this scenario is access of fluid to the chondro-labral junction, formation
of a mechanically stable labral reconstruction may be sufficient to minimize
mechanical symptoms but may not block the progression of joint degeneration.
It has still to be demonstrated that current methods of labral
reattachment restore the original fluid barrier formed by the junction between
the labrum and the articular surface, thereby protecting the subchondral
boundary from ingress of pressurized joint fluid.
Matsuda: What is the relevant clinical science to support or
refute labral preservation surgery?
Philippon: The literature continues to grow to support labral
preservation. Ferguson and colleagues showed that contact stresses in
acetabular cartilage increase with time, and are up to 92% higher in the
absence of the labrum.
Another study shows labral disruption and DJD of the hip were related.
Espinosa and colleagues showed that labral repair resulted in 80% excellent
outcomes, while debridement only had excellent outcomes in 28%.
Supine arthroscopic image 3 years
after arthroscopic femoral osteoplasty in a patient with FAI and continued
pain. Note neo-corticalization around femoral osteoplasty area (blue arrow).
This patient underwent recent rim trimming and labral refixation (black arrow)
to treat the pincer component. Surgeon began arthroscopic rim trimming and
labral refixation soon after this patients first surgery.
Image: Matsuda DK
Labral debridement was compared to refixation in patients with FAI in a
recent study by Larson and colleagues who found good to excellent results in
66.7% of the patients in the labral debridement group vs. 89.7% in the labral
refixation group. They concluded based on their early results, labral
refixation resulted in better outcomes.
We recently completed a study on 112 patients with FAI and labral
pathology at a minimum of 2 years postoperative. Their preoperative modified
Harris Hip score (MHHS) was 58. Fifty-eight patients underwent labral repair
and 54 underwent debridement. The labral repair group had a postoperative MHHS
score of 87 compared to 81 in the labral debridement group. Labral repair was
identified as an independent predictor of improved MHHS in this group. The
median patient satisfaction in this cohort was nine on a scale of 1 to 10 with
10 being very satisfied.
As new studies show the importance of labral tissue, we have set a
threshold of 7 mm of labral width that needs to be present for a repair. As the
width of the labral tissue decreases (due to previous debridement or
degeneration), so do the changes in the joint and treatment options. On these
data, we think it is critical to preserve the native labrum using repair
techniques when possible.
Trousdale: The relative clinical data to support labral
preservation vs. labral debridement is actually quite scant. There are some
retrospective data with relatively small numbers that suggest labral
preservation is better than labral debridement, but we really do not have good
long-term outcome studies to support the fact that labral refixation is better
than labral debridement.
Yet, from a theoretical sense it is a good judgment to try to preserve
the labrum when possible. The labrum serves an important function including
deepening the socket and preserving the fluid seal in the hip joint which is
probably important for long-term cartilage viability. Certainly in young active
patients it is reasonable to consider trying to save the labrum whenever
Matsuda: How do you diagnose labral tears and FAI?
Philippon: We perform a standard physical exam, range of motion
and specific tests to diagnose labral tears and FAI. Tests for FAI include: the
anterior impingement test, posterior impingement test, and the Faber distance
examination a measurement of the distance from the lateral genicular
line in the knee to the exam table. These are complemented by radiographs:
cross-table lateral radiographs to assess the anterior femoral head-neck offset
(alpha angle) and AP pelvis radiographs to evaluate the acetabulum for the
amount of coverage of the femoral head and the degree of version.
Classifications of cam- and pincer-type impingement are based on
radiographic images and MRI. Acetabular retroversion or coxa profunda indicate
pincer-type impingement and an alpha angle of greater than 42º is
considered positive for cam impingement.
Joint space is measured preoperatively on an AP pelvis radiograph at
three locations: the lateral, center and medial edge of the sourcil. This is a
crucial step in the evaluation process. Joint space of less than 2 mm is
considered a relative contraindication for most hip arthroscopies. In our
study, those with joint space less than 2 mm were 39 times more likely to
progress to total hip arthroplasty.
A special sequence alpha angle MRI is also completed to further document
the alpha test. Our research has shown that the MRI alpha angle is more
accurate than radiographs. Currently we use a 3T MRI and are determining the
sensitivity and specificity of this instrument for the diagnosis of labral
We also use a pain test, where lidocaine is injected into the hip joint
to determine if symptoms are intra-articular or extra-articular. A functional
sports test is performed before and after surgery to see if symptoms affect
performance and function.
Sampson: I diagnose labral tears and FAI by first listening to
the patients history of insidious onset of groin pain, which may or may
not have some related old sprain. Usually the patient will have positional
pain, mostly with sitting, that is relieved with hip extension. He or she may
have an unpredictable pop on occasion and little pain with walking; however,
when performing sports that involve twisting and flexing, the hip becomes
Second, I notice that the exam is mostly normal except for loss of
internal rotation and abduction compared to the opposite hip. The patient may
have a positive impingement sign with flexed internal rotation. Those with a
partial delamination defect may also have pain in the same location when
bringing the leg up from extension, internal rotation to flexion external
Imagine when doing the impingement test that the acetabulum is like the
face of a clock. In a right hip, if directly lateral from the tip of the
trochanter is 12 oclock, the clock face from 1 oclock to 4
oclock may be zones 1 and 2 where most delaminations are seen. If the
delamination is attached at 4 oclock, then with clockwise rotation the
cam bump will catch it, cause pain and snap. On the other hand,
counterclockwise rotation may cause pain but no snap will occur.
Along with these findings, plain radiographs including a proper AP
pelvis X-ray including hip-to-below-the-lesser-trochanters with the coccyx 1 cm
to 2 cm from the pubis symphysis, and frog and cross-table laterals should give
clues to the cam and pincer morphology.
CT scans are great, but involve a lot of radiation. They help map out
the lesions. I like a high-quality MRI of the affected hip only not a
pelvis MRI, which is essentially worthless. I order MRAs if the hip has no
effusion to act as contrast.
I do an injection test if I am not clear as to whether the pain is from
the hip. If a patient has a gadolinium MRA with anesthetic and says he or she
had no relief from the test, you need to follow up with the right question
Did you have any relief of the hip pain at the time of the MRA or
directly afterwards? Also, it needs to be determined if a long-acting, instead
of short-acting, anesthetic agent was used.
Trousdale: The role of history, physical examination, and
appropriate imaging studies, all are important. In general, the history and
physical examination are relatively nonsensitive and nonspecific tests.
Catching, locking, groin pain, pain with flexion and internal rotation, and
pain with apprehension of the hip all indicate potential labral problems,
impingement problems, or dysplasia and are relatively nonspecific findings.
The plain radiographs, which in our center include a good AP pelvic, a
true lateral, an oblique, and a false-profile view, are the gold standard for
diagnosing bony abnormalities.
For labral and chondral pathology, the best test in our minds is an MRI
with intra-articular gadolinium. There are centers that are looking at the
sensitivity and specificity of MRI without intra-articular gadolinium. In the
future with appropriate software technology, this may become very reliable.
Presently we get both sagittal, coronal, and radial MRI views of the hip joint
which is probably the most sensitive and specific for labral and chondral
A note from the editor:
Part 2 of this Round Table discussion will appear in the July
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:
email@example.com. 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: firstname.lastname@example.org. 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:
He receives royalties from Smith & Nephew and Bledsoe; is on the
speakers 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; ew-mail: email@example.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:
receives research or institutional support, miscellaneous funding and royalties
from and is a consultant to DePuy and he is a consultant to Wright Medical