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Clinical Presentation of Patients with Tears of the Acetabular Labrum
R. Stephen J. Burnett, Gregory J. Della Rocca, Heidi Prather, Madelyn Curry, William J. Maloney and John C.
Clohisy
J. Bone Joint Surg. Am. 88:1448-1457, 2006. doi:10.2106/JBJS.D.02806
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BY
THE JOURNAL
OF
BONE
AND JOINT
SURGERY, INCORPORATED
Clinical Presentation of
Patients with Tears
of the Acetabular Labrum
BY R. STEPHEN J. BURNETT, MD, FRCS(C), GREGORY J. DELLA ROCCA, MD, PHD,
HEIDI PRATHER, DO, MADELYN CURRY, RN, WILLIAM J. MALONEY, MD, AND JOHN C. CLOHISY, MD
Investigation performed at the Department of Orthopaedic Surgery,
Barnes-Jewish Hospital at Washington University School of Medicine, St. Louis, Missouri
Background: The clinical presentation of a labral tear of the acetabulum may be variable, and the diagnosis is often
delayed. We sought to define the clinical characteristics associated with symptomatic acetabular labral tears by reviewing a group of patients who had an arthroscopically confirmed diagnosis.
Methods: We retrospectively reviewed the records for sixty-six consecutive patients (sixty-six hips) who had a documented labral tear that had been confirmed with hip arthroscopy. We had prospectively recorded demographic factors, symptoms, physical examination findings, previous treatments, functional limitations, the manner of onset, the
duration of symptoms until the diagnosis of the labral tear, other diagnoses offered by health-care providers, and
other surgical procedures that these patients had undergone. Radiographic abnormalities and magnetic resonance
arthrography findings were also recorded.
Results: The study group included forty-seven female patients (71%) and nineteen male patients (29%) with a mean
age of thirty-eight years. The initial presentation was insidious in forty patients, was associated with a low-energy
acute injury in twenty, and was associated with major trauma in six. Moderate to severe pain was reported by fiftyseven patients (86%), with groin pain predominating (sixty-one patients; 92%). Sixty patients (91%) had activityrelated pain (p < 0.0001), and forty-seven patients (71%) had night pain (p = 0.0006). On examination, twenty-six
patients (39%) had a limp, twenty-five (38%) had a positive Trendelenburg sign, and sixty-three (95%) had a positive
impingement sign. The mean time from the onset of symptoms to the diagnosis of a labral tear was twenty-one
months. A mean of 3.3 health-care providers had been seen by the patients prior to the definitive diagnosis. Surgery
on another anatomic site had been recommended for eleven patients (17%), and four had undergone an unsuccessful operative procedure prior to the diagnosis of the labral tear. At an average of 16.4 months after hip arthroscopy,
fifty-nine patients (89%) reported clinical improvement in comparison with the preoperative status.
Conclusions: The clinical presentation of a patient who has a labral tear may vary, and the correct diagnosis may not
be considered initially. In young, active patients with a predominant complaint of groin pain with or without a history
of trauma, the diagnosis of a labral tear should be suspected and investigated as radiographs and the history may be
nonspecific for this diagnosis.
Level of Evidence: Diagnostic Level IV. See Instructions to Authors for a complete description of levels of evidence.
orrell and Catterall1 introduced the concept of degenerative labral tears of the hip in association with
developmental dysplasia and secondary degenerative
osteoarthritis. The acetabular labrum also has been found to
be abnormal in association with other hip disorders, including
D
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an aspherical femoral head2-5, slipped capital epiphysis6,7, LeggCalvé-Perthes disease, and hip trauma8,9. Athletic activities
that involve repetitive pivoting movements or repetitive hip
flexion are now recognized as additional causes of acetabular
labral injury10,11, and tears of the acetabular labrum have become an increasingly recognized disorder in young adult and
middle-aged patients12-16. More recently, anterior femoroacetabular impingement has been associated with labral injury,
articular cartilage damage, and secondary osteoarthritis2-5.
Collectively, these studies indicate that acetabular labral di-
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sease may be concomitant with many degenerative conditions
of the hip.
Labral tears may be considered as a source of hip-related
symptoms, yet a definitive diagnosis is often delayed12. A lack
of familiarity with this diagnosis, the absence of major radiographic findings13,17, and limited information on the clinical
syndrome associated with this disorder may contribute to this
delay. Thus, there is a need for enhanced awareness and improved diagnostic information to effectively recognize and
treat symptomatic labral tears.
The purpose of the present study was to perform a retrospective analysis of the clinical, radiographic, and treatment histories of a group of patients who had arthroscopically
confirmed tears of the acetabular labrum.
Materials and Methods
ll patients provided informed consent to participate in
the present study, which was approved by our institutional review board. Between January 2000 and June 2003,
sixty-six patients had an arthroscopically confirmed acetabular labral tear. During this same time-period, 264 primary
total hip arthroplasty procedures, 112 revision hip procedures, and 111 additional nonarthroplasty procedures were
performed by the senior author (J.C.C.). The additional nonarthroplasty procedures included sixty-four periacetabular
osteotomies, twenty-two proximal femoral osteotomies (eleven
of which were combined with a periacetabular osteotomy),
ten hip joint osteoplasties, five core decompressions, four
psoas tendon lengthenings, four hip fusions, and two
Chiari pelvic osteotomies. Patients who required reconstructive or salvage procedures for the treatment of major
structural abnormalities such as developmental dysplasia of
the hip, prior Legg-Calvé-Perthes disease, slipped capital
femoral epiphysis, or femoroacetabular impingement were
excluded from the study. The sixty-six patients (sixty-six
hips) with lesser degrees of osseous abnormality and with
symptoms and signs consistent with a torn acetabular labrum formed the study group. These hips were radiographically normal or had mild osseous abnormalities that were
not thought to be sufficient to warrant either osteotomy or
osteoplasty. The sixty-six arthroscopies compromised 12%
of the hip procedures performed by the senior author during this time-period.
These sixty-six patients represent a consecutive series.
All patients had failed a course of nonoperative therapy before undergoing arthroscopy. Preoperatively, they completed
a comprehensive interview to detail their history. Demographic data were recorded, and all patients were asked to
characterize their pain with regard to severity, location, character, duration, mechanical symptoms, aggravating factors,
and modes of relief. The activity level (sedentary, active, recreational athletics, or high-level athletics)14 was self-reported,
and the manner of onset of symptoms (traumatic, acute, or
insidious)15 was also assessed. The effect of symptoms on daily
activities was solicited through questions regarding limping,
the use of assistive devices, and the ability to walk various dis-
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tances, to ascend and descend stairs, to don shoes and socks,
to sit for extended periods of time, and to utilize public
transportation18. Prior diagnoses, the number of health-care
providers (including physicians, chiropractors, physical therapists, and nurse practitioners) who had been seen for the
problem, and the time from the onset of symptoms to a definitive diagnosis of an acetabular labral tear were recorded, as
were alternative diagnoses for the symptoms, treatment recommendations that had been made by other physicians prior
to the diagnosis of a labral tear, and previous treatments that
had been performed.
On physical examination, the presence or absence of a
limp and the Trendelenburg sign were noted and the results
of an impingement test19 were recorded. The impingement
test is positive when, with the hip flexed to 90°, adduction
and internal rotation produce groin pain19. The modified
Harris hip scoring system as described by Byrd and Jones for
patients managed with hip arthroscopy15 was also administered preoperatively and at each follow-up visit. Patients
were seen in the clinic for follow-up visits at six weeks, three
months, twelve months, and annually thereafter. The patient’s subjective improvement was also assessed at each visit
and at a minimum of one-year of follow-up and was characterized as “improved,” “not improved,” or “equivocal/unsure.” Twenty-two patients (33%) had an injection to assist
in the diagnostic evaluation.
All patients were evaluated with standing anteroposterior pelvic, frog-leg lateral, and cross-table lateral radiographs.
Thirty-five patients also were evaluated with a false-profile
radiograph20 to assess anterior femoral head coverage. The
preoperative extent of degenerative changes was classified into
four grades according to the criteria of Tönnis21 (see Appendix). Measurements that were used to evaluate hip dysplasia
included the acetabular index20-24, the lateral center-edge angle
of Wiberg23, and the anterior center-edge angle of Lequesne20
as measured on a false-profile radiograph21,22,24. Radiographic
findings associated with anterior femoroacetabular impingement also were evaluated. Acetabular version was determined
with use of the anteroposterior pelvic radiograph21,25-29. Femoral head-neck offset was determined on the cross-table lateral
radiograph according to the method described by Eijer et al.30.
All patients underwent magnetic resonance arthrography preoperatively as part of our standard protocol to evaluate
acetabular labral disease31. The magnetic resonance arthrographic images were interpreted by musculoskeletal radiologists who were not routinely blinded to the clinical history of
the patients.
All patients were personally evaluated by the senior author, who then performed hip arthroscopy and confirmed an
acetabular labral tear in all sixty-six hips. All hip arthroscopy
procedures were performed with the patient in the supine position on a standard fracture table32. Joint distraction (8 to 10
mm) was obtained with fracture table traction, and fluoroscopy was utilized to facilitate portal placement. Three standard
arthroscopic portals (anterior, anterolateral, and posterolateral) were used, and the joint was systematically inspected with
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70° and 30° arthroscopes. The location of the labral tear was
recorded16, and the tear was classified arthroscopically with use
of the staging system described by Wardell et al.33. Unstable
portions of the labrum were débrided in all cases with a Ligament Chisel (Smith and Nephew, Andover, Massachusetts)
and/or an arthroscopic shaver. No labral tears were repaired.
The stable, capsular labral remnant was preserved whenever
possible.
No patient in the present series was lost to follow-up. All
patients were followed for at least twelve months, and the
mean duration of follow-up was 16.4 months (range, twelve to
forty-seven months). Three patients were contacted by telephone to obtain the most recent modified Harris hip score15
for this study.
Statistical analysis was accomplished with use of chisquare analysis, which tested the proportionality of symptoms. Random probability dictates that each category for a
symptom would contain roughly the same number of patients. The level of significance was set at p ≤ 0.05. The Wilcoxon signed-rank test was used to compare modified Harris
hip scores before and after surgery.
Results
he average age of the sixty-six patients at the time of diagnosis was thirty-eight years (range, fifteen to sixty-four
years). Forty-seven patients (71%) were female, and nineteen
patients (29%) were male. The labral tear was present on the
right side in forty patients (61%) and on the left side in
twenty-six patients (39%).
The preoperative symptoms are presented in Table I.
The onset of symptoms was insidious in forty patients (61%)
(p < 0.0001), acute in twenty (30%), and secondary to a
major traumatic episode in six (9%). The traumatic episodes
included a motor-vehicle collision (two patients), a workrelated injury (three), and sports-related trauma (one). In
fifty-seven patients (86%), the severity of symptoms was rated
as moderate (thirty-three patients, 50%) or severe (twenty-four
patients, 36%) (p = 0.001). Sixty-one patients (92%) localized
the predominant pain to the groin (p < 0.0001), while associated anterior thigh or knee pain (thirty-four patients, 52%)
(p = 0.81) and lateral hip pain (thirty-nine patients, 59%)
(p = 0.14) were also reported. Twenty-five patients (38%) reported associated posterior (buttock) pain (p = 0.05). No patient had isolated buttock pain; the presence of buttock pain
was always associated with groin pain. Preoperatively, the
quality of hip pain was characterized as sharp in fifty-seven
patients (86%) (p < 0.0001) and dull in fifty-three patients
(80%) (p < 0.0001); a combination of dull aching pain with
intermittent episodes of sharp pain was present in fortysix patients (70%) (p = 0.001). Activity-related pain was
present in sixty patients (91%) (p < 0.0001). Symptoms
were aggravated by walking in forty-six patients (70%) (p =
0.001), by pivoting on the affected side in forty-six patients
(70%) (p = 0.001), by impact activities in forty-one patients
(62%) (p = 0.05), and by prolonged sitting in forty patients
(61%) (p = 0.08). Pain was reported as constant in thirty-six
T
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TABLE I Summary of Hip Symptoms Associated
with Labral Tears
Clinical Parameter
Onset of symptoms
Insidious
Acute
Trauma
Moderate/severe symptoms
Number of
Patients
40 (61%)
P Value
<0.0001*
20 (30%)
6 (9%)
57 (86%)
0.001*
Groin
Anterior thigh/knee
61 (92%)
34 (52%)
<0.0001*
0.81
Lateral hip
Buttock
39 (59%)
25 (38%)
Location of pain
0.14
0.05*
Quality of pain
Sharp pain
57 (86%)
<0.0001*
Dull pain
53 (80%)
<0.0001*
Combination of sharp and dull pain
Activity-related pain
46 (70%)
60 (91%)
0.001*
<0.0001*
Constant pain
Intermittent pain
36 (55%)
30 (45%)
0.46
0.46
Night pain
Mechanical snapping/popping/
locking
47 (71%)
35 (53%)
0.0006*
0.062
Mechanical locking
27 (77%) of 35
Painful mechanical locking
24 (89%) of 27
0.06
Pain during walking
Pain during pivoting
46 (70%)
46 (70%)
0.001*
0.001*
Pain during impact activities
Pain during sitting
41 (62%)
40 (61%)
0.05
0.08
<0.0001*
*Significant (p ≤ 0.05).
hips (55%) (p = 0.46) and intermittent in thirty hips (45%)
(p = 0.46). Forty-seven patients (71%) reported pain at night
(p = 0.0006). Sixty-five patients (98%) characterized themselves as athletic or active. Mechanical symptoms were reported in approximately one-half of the patients surveyed.
Thirty-five patients (53%) reported snapping or popping.
Twenty-seven patients (41%) reported true locking (or catching and unlocking) of the involved hip, and twenty-four of
these patients reported pain associated with the locking episodes (p < 0.0001).
Data on functional limitations are presented in Table II.
Most notably, 89% of the patients reported limping, 46% reported limitation of walking distance, 67% used a banister for
stairs, and 25% could not sit for periods of more than thirty
minutes.
There had been frequent delays in diagnosis, inaccurate
diagnoses, and ineffective treatments. The average time from
the initial onset of symptoms to the definitive diagnosis was
twenty-one months (range, two to 156 months; median,
twelve months). An average of 3.3 health-care providers
(range, zero to eleven health-care providers) had been seen
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TABLE II Functional Limitations Associated with
Labral Tears
Number of Hips
(N = 66)
Limitation
Limp at any time during symptoms
59 (89%)
Severity of limp
Slight/mild
51 (77%)
Moderate
Severe
5 (8%)
3 (5%)
Use of cane, crutches, or assistive device
at any time during symptoms
Limitation in walking distance
6 (9%)
24 (36%)
Limited to 6 blocks
10 (15%)
Limited to 2 blocks
11 (17%)
Limited to household
3 (5%)
Stairs
Requires use of banister
44 (67%)
Unable
1 (2%)
Sitting
<30 minutes
Unable/short duration
17 (26%)
3 (5%)
Donning shoes and socks
Difficult
Unable
Unable to use public transportation
21 (32%)
3 (5%)
6 (9%)
prior to the establishment of a definitive diagnosis. Diagnoses by other health-care providers varied markedly (Table
III). Twenty-two (33%) of the sixty-six patients recalled
having received a diagnosis other than a labral tear. Eighteen
different diagnoses were reported to describe the clinical
symptoms experienced by these patients prior to our initial
assessment. Many patients had received more than one diagnosis. Fourteen patients (21%) had been diagnosed with
a “soft-tissue injury” that was not otherwise specified. Ten
patients (15%) had been told that they had “osteoarthritis,”
although plain radiographs had not demonstrated degenerative changes in eight of the ten hips. Four patients had been
diagnosed with a spinal disorder, and three had been diagnosed with a snapping psoas tendon. Other diagnoses that
had been suggested by previous health-care providers are
listed in Table III.
Treatment recommendations that had been made by
other health-care providers most often included nonsteroidal
anti-inflammatory drugs (fifty-five patients, 83%) (p < 0.0001)
and physical therapy (forty-two patients, 64%) (p = 0.03).
Narcotic pain relievers had been recommended for more than
one-third (twenty-six [39%]) of the patients. Surgical intervention at an anatomic site other than the hip joint had been
recommended to eleven patients (17%). These recommendations included lumbar discectomy (two), an ovarian cyst
procedure or laparoscopy (two), an open iliotibial band or trochanteric bursal procedure (three), hernia exploration (two),
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and psoas or musculotendinous release (two). Unsuccessful
surgery at another anatomic site actually had been performed
in four of these eleven patients. The four unsuccessful procedures had included inguinal herniorrhaphy (one patient),
psoas release (one patient), and diagnostic laparoscopy (two
patients). None of these four patients had relief of clinical
symptoms following these procedures.
Sixty-three patients (95%) had a positive impingement
test. In contrast, a limp while walking a short distance
(twenty-six patients; 39%) and a positive Trendelenburg sign
(twenty-five patients; 38%) were present less commonly. Diagnostic hip injection provided major relief of symptoms in
twenty of twenty-two patients.
Preoperative radiographic analysis demonstrated a relatively high prevalence of early degenerative changes and mild
structural hip abnormalities. Thirty-six hips (55%) had no
degenerative changes (Tönnis grade 0), yet twenty-two (33%)
had mild (grade-1) changes and eight (12%) had moderate
(grade-2) changes. No hip had advanced degenerative disease.
The mean lateral center-edge angle of Wiberg measured 29°
(range, 14° to 44°), the mean acetabular index was 14° (range,
5° to 22°), and the mean anterior center-edge angle was 29°
(range, 10° to 45°). If we define developmental dysplasia as a
lateral center-edge angle of <25° and/or an anterior centeredge angle of <20°, fifteen hips (22.7%) had dysplasia. The lat-
TABLE III Other Diagnoses Offered by Health-Care
Providers as Recalled by the Patient
Condition
Number of
Patients Who
Received Diagnosis*
Soft-tissue injury, nonspecified
14
Osteoarthritis
10
Lumbar spine/low-back disorder, nonspecified
4
Psoas or other tendonitis
3
Rheumatoid arthritis
2
Lupus
2
Bursitis
1
Iliotibial band syndrome
1
Stress fracture
1
Ischiitis
1
Pelvic pain, unspecified
1
Overuse syndrome
1
Hip dislocation/instability
1
Nerve injury following hysterectomy
1
Hip misalignment
1
Sciatica
1
Osteonecrosis
1
Inguinal hernia
2
*Several patients received more than one diagnosis.
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Fig. 1-A
Figs. 1-A through 1-E Radiographic, magnetic resonance arthrographic, and arthroscopic images
for an active, twenty-seven-year-old woman with a two-year history of insidious-onset right groin
pain. Figs. 1-A and 1-B Anteroposterior pelvic radiograph (Fig. 1-A) and false-profile radiograph of
the right hip (Fig. 1-B). The patient had mild acetabular dysplasia (lateral center-edge angle, 18°;
anterior center-edge angle, 22°; acetabular inclination, 17°).
eral center-edge angle measured 14° in two hips, and it measured between 15° and 25° in the remaining thirteen hips. The
mean femoral head-neck offset measured 10 mm (range, 6 to
14 mm), and a reduced offset (<9 mm)30 was noted in ten hips
(15%). The mean offset ratio measured 0.189 (range, 0.105 to
0.270), and a reduced offset ratio30 was noted in thirteen hips
(19.7%). Sixty-one (92%) of the anteroposterior pelvic radiographs showed acetabular anteversion, and five (8%) demonstrated a minimal or equivocal amount of retroversion.
Collectively, twenty-five (38%) of the sixty-six hips had thirtythree radiographic abnormalities, with fifteen hips having acetabular dysplasia and eighteen hips having lesions consistent
with anterior impingement (a reduced offset ratio or retroversion) (Figs. 1-A through 1-E). Eight hips had both types of radiographic abnormality. Importantly, only twenty-four hips
(36.3%) had completely normal radiographic findings, with
no structural abnormality and no degenerative changes.
The preoperative magnetic resonance arthrogram was
interpreted as positive for a labral tear in forty-eight (73%) of
the sixty-six hips. In the remaining eighteen hips (27%), it was
equivocal or was interpreted as negative. The sensitivity of
magnetic resonance arthrography in the present study was
79%. The specificity was not calculated because all patients
had a labral tear (that is, there were no false-negative results).
Similarly, the positive predictive value was 1.0 (that is, all patients with a positive finding on magnetic resonance arthrography had a labral tear) whereas the negative predictive value
was not determined because all patients had a labral tear.
Arthroscopy revealed that the labral tear was anterior in
Fig. 1-B
forty-two hips (64%), anterosuperolateral in ten (15%), superolateral in nine (14%), both anterior and posterior in three
(5%), and posterior in two (3%). Ninety-two percent of the
tears were anterior, anterosuperolateral, or superolateral. Ac-
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cording to the staging system of Wardell et al.33, thirty-two
tears (48%) were classified as stage 1, one (1.5%) was classified
as stage 2, twenty-one (32%) were classified as stage 3A, five
(7.6%) were classified as stage 3B, and seven (10.6%) were
classified as stage 4.
The modified Harris hip score improved from a mean of
62 points (range, 27 to 92 points) preoperatively to a mean of
83 points (range, 33 to 100 points) (p < 0.0001) at a minimum
of one year of follow-up. One year after arthroscopy, sixty-two
(94%) of the patients noted subjective improvement in symptoms compared with the preoperative status. At the time of
the most recent follow-up, at an average of 16.4 months
(range, twelve to forty-seven months), the mean modified
Harris hip score was 80 points (range, 33 to 100 points) (p <
0.001) and fifty-nine patients (89%) continued to have improved hip function and diminished symptoms. At the time of
the most recent follow-up, the subjective improvement in
overall symptoms was characterized as “improved” for fiftynine hips (89%).
Seven patients (seven hips; 11%) had persistent, recurrent, or progressive symptoms after arthroscopic treatment.
Three of the seven hips had a grade-1 labral tear, three had a
grade-3 tear, and one had a grade-4 tear. In addition, three
hips had Tönnis grade-2 osteoarthritis, three had grade-1
osteoarthritis, and one had no degenerative changes radiographically (grade 0). Three hips (two with a grade-3B tear
and one with a grade-4 tear) had progressive symptomatic
osteoarthritis and were considered to be candidates for total
hip arthroplasty. All three of these hips had had Tönnis
grade-1 osteoarthritis preoperatively. Two of these hips had
mild acetabular dysplasia, and the third hip had a large fullthickness chondral defect of the anterosuperior aspect of the
femoral head. Two of these three patients (both of whom
had mild acetabular dysplasia) reported major relief of
symptoms for two years following the arthroscopic labral
débridement.
Fig. 1-D
Fig. 1-E
Fig. 1-C
Sagittal, fat-suppressed T1-weighted magnetic resonance arthrogram,
made after the intraarticular injection of gadolinium, demonstrating an
anterior labral tear (arrow). The patient was counseled regarding the
treatment options of periacetabular osteotomy or hip arthroscopy. She
was managed with hip arthroscopy because of the mild nature of the
acetabular dysplasia, the relatively normal anterior femoral head coverage, and her preference for arthroscopic treatment.
Figs. 1-D and 1-E At the time of arthroscopy, an anterior labral tear was identified (arrows) (Fig. 1-D) and was débrided back to a stable labral remnant (arrows) (Fig. 1-E). After three years of follow-up, the patient had a good clinical result, with slight, occasional pain.
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One of the seven patients with persistent pain had development of, and received treatment for, complex regional
pain syndrome/reflex sympathetic dystrophy following hip
arthroscopy. Another one of these seven patients, who had residual deformity due to Legg-Calvé-Perthes disease, had improvement in terms of pain and mechanical symptoms after
arthroscopy but experienced recurrent pain twelve months
later. He underwent a surgical dislocation, osteoplasty, and
trochanteric advancement to address anterior femoroacetabular impingement. A third patient in this group had mild acetabular dysplasia and had major improvement in symptoms
for twelve months postoperatively yet had a recurrence of
pain. This patient was offered a periacetabular osteotomy. A
fourth patient, who had recurrent pain twelve months postoperatively, was being evaluated at the time of the most recent
follow-up.
Discussion
here is a growing body of knowledge regarding the etiology and treatment of acetabular labral tears12,16,34-37. The
development of magnetic resonance arthrography31,38-40 and
the refinement of hip arthroscopy have contributed to the
understanding34,41-43 and treatment13,14 of this disorder. Nevertheless, definitive diagnosis of this condition can be difficult as
the clinical symptoms and physical findings may be varied and
subtle. Plain radiographic analysis also has major limitations
in contributing to the diagnosis12.
The results of the present study provide insight into the
diagnosis and treatment of acetabular labral tears. The average
age of our patients undergoing hip arthroscopy for a labral
tear was thirty-eight years. Other reports have suggested a
similar age range, with young adults from twenty-five to forty
years old being affected most commonly12,14-16. The onset of
symptoms of a labral tear, while occasionally traumatic or
acute, occurred in an insidious fashion in almost twothirds of the patients in the current study. When acute and insidious categories were combined, >90% of the labral tears
in the present study fell into one of these two categories,
whereas major trauma to the hip was less frequently responsible for the labral tear. These findings are in agreement with
previous reports11,12,15,35,42. Fitzgerald12 retrospectively evaluated
the records for fifty-five patients who had undergone open arthrotomy or arthroscopy for the treatment of a labral tear and
reported similar findings: twenty-five patients had no history
of trauma, twenty-three patients had experienced minor trauma
or twisting injuries, and seven had been involved in a serious
motor-vehicle accident.
The severity of symptoms associated with labral tears
has not been well documented. We found it concerning that
86% (fifty-seven) of our patients had moderate or severe hip
pain. The use of narcotic analgesics for the relief of hip symptoms had been recommended to more than one-third of the
patients, emphasizing the magnitude of the discomfort that
the patients experienced. Additionally, the mean delay in establishing the correct diagnosis (twenty-one months) and the
finding that patients had been evaluated by an average of 3.3
T
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health-care providers before obtaining the correct diagnosis
indicates the need for improved medical recognition of this
disorder. The difficulty and timing of making the diagnosis of
a labral tear in our patients appear to be similar to the findings
reported by others12,14,15.
The quality and description of pain associated with a labral tear are important first steps in establishing a diagnosis.
Symptoms often may be diffuse and indistinct10, leading to
several differential diagnostic possibilities. The most common
site of pain in our patients was the groin. Buttock, lateral hip,
and thigh pain were present less often. Other reports also have
suggested that the presence of painful symptoms localized to
the groin is one factor that is commonly associated with labral
tears10,12,13,16,35. Nevertheless, many hip disorders can be associated with groin pain, which adds to the difficulty of diagnosing a labral tear. We found that the pain characteristics that
occurred most commonly in the present study included both
sharp and dull pain in the groin, which was activity-related in
>90% (sixty) of the patients. In addition, night pain and pain
with pivoting or walking were common complaints. Thus, the
diagnosis of a labral tear must be considered for active patients
who present predominantly with groin pain that is worsened
by activity and impact even though these symptoms and signs
are associated with no or minor radiographic evidence of hip
disease.
We wish to emphasize the frequency with which these
patients were misdiagnosed. Fourteen patients (21%) had received a diagnosis of a nonspecified soft-tissue injury prior to
our evaluation. We recommend that patients with a suspected
soft-tissue injury should be followed clinically and, if symptoms persist for longer than two months, further diagnostic
evaluation should be performed.
Given the presenting symptoms, it is not surprising that
other diagnoses (iliotibial band syndrome, snapping psoas
syndrome, lumbar radicular pain, osteonecrosis, trochanteric
bursitis, hip stress fracture, inguinal or femoral hernia) were
made in some of these patients. We recognize that these conditions certainly can present with symptoms similar to those
of a labral tear and may even coexist with a labral tear. Similarly, abdominal or gynecologic conditions also were offered
as diagnoses for some of our patients. Overall, 17% of our patients had received a recommendation to undergo surgery at
an alternative anatomic site and 6% of our patients had actually undergone surgery, without improvement of their symptoms. This finding highlights the need for enhanced awareness
of this condition. In equivocal cases, we found that a diagnostic hip injection was very helpful for distinguishing intraarticular disease from extra-articular disease44.
Plain radiographs and magnetic resonance arthrography of the hip provide critical information when evaluating
patients who have signs and symptoms indicative of labral
disease. These studies assist in the identification of structural
abnormalities that may be important in the etiology and surgical treatment of the disease, and also they can eliminate several alternative diagnoses. We emphasize that we excluded
patients with major structural abnormalities of the hip that
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required osteotomy or osteoplasty procedures. The sixty-six
patients who constituted our study group were judged to have
structurally normal hips or minor deformities that did not
necessarily require a reconstructive procedure. Nevertheless,
many of these sixty-six hips had radiographic abnormalities
such as mild acetabular dysplasia and anterior femoroacetabular impingement. In addition, 45% of the hips had mild
(33%) or moderate (12%) osteoarthritic changes. Only 36%
of the hips were classified as having normal radiographic
findings. In the context of the senior author’s entire experience in treating hip disease during the study period, an acetabular labral tear in the setting of normal radiographic
findings was relatively uncommon, representing just 4% of all
cases. These data are consistent with other studies that have
demonstrated a high incidence of structural hip abnormalities in association with labral tears17,45. The use of magnetic
resonance arthrography to evaluate labral tears in our cohort
of patients yielded a sensitivity of 79%. In 27% of the patients
who had an arthroscopically verified tear, preoperative magnetic resonance arthrography failed to detect the lesion. Despite this limited sensitivity, we continue to perform these
studies for all patients. This test frequently confirms the diagnosis and reliably rules out other uncommon conditions (e.g.,
osteonecrosis, stress fracture, neoplasm) that could present
with hip symptoms suggestive of labral disease.
Selection of the optimal surgical treatment strategy depends on a variety of patient-related factors as well as the findings of physical examination and imaging studies46-49. It is our
impression that nonoperative treatment is usually unsuccessful for symptomatic labral tears. The optimal treatment of
a labral tear in the setting of mild acetabular dysplasia, mild
asphericity of the femoral head, or mild retroversion of the
acetabulum remains unresolved. Additionally, the evolving
concept of reduced femoral head-neck offset and anterior impingement was not fully appreciated during the time-period
of the present study, and we did not routinely address impingement lesions surgically.
Previous work has demonstrated that it is uncommon
for early degenerative changes to develop in dysplastic hips
with a lateral center-edge angle of >16° and an acetabular inclination of <15°22. Thus, for very mildly dysplastic hips with a
symptomatic labral tear, we will consider arthroscopic treatment alone50,51, but this is dependent on several patient-related
factors46. Most commonly, we prefer arthroscopy alone for patients with hip dysplasia who are not good candidates for osteotomy surgery because of relatively advanced age and/or
medical comorbidities. For patients with femoroacetabular
impingement disorders, we select the surgical procedure according to the anatomic location of the lesion and the extent
of the disease. For example, for patients with focal (anterolateral) cam impingement that is diagnosed early, we prefer
treatment with hip arthroscopy and a combined limited open
arthrotomy and osteoplasty of the head-neck junction52. In
contrast, hips with circumferential disease or associated posterior osteophytosis are better treated with surgical dislocation
and débridement as previously reported53,54. In our cohort,
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none of the patients had an osteoplasty for the treatment of
anterior femoroacetabular impingement.
In the present study, seven patients had a failure of
treatment within twelve months (four patients) or sixteen
months (three patients) after the index procedure. All seven
patients had initial improvement in terms of pain and mechanical symptoms followed by later deterioration. Three of
these patients had higher-grade labral tears and articular cartilage defects. The symptoms progressed, resulting in a recommendation for total hip replacement. These three patients
all had had mild (Tönnis grade-1) osteoarthritis preoperatively. While it is certainly possible that one or more of these
seven patients may have been misdiagnosed or had an alternative etiology of symptoms, the preoperative clinical examination findings, the imaging and arthroscopic findings, and
the early clinical results were consistent with intra-articular
hip disease in each case.
The present study had a number of limitations. First,
the data were based on a subjective recollection of the onset
of symptoms and time-courses by the patients themselves.
It is conceivable that patients with long-standing disease may
not accurately recall the duration or cause of their symptoms.
Second, there was no age-matched control set of data from
patients with hip pain without an acetabular labral tear.
Therefore, it is difficult to describe a symptom as pathognomonic for this syndrome alone. In the current study, however,
all data were collected prospectively for a series of sixty-six
consecutively diagnosed labral tears that were treated and
evaluated by one surgeon. Third, we cannot exclude the possibility that these same symptoms and signs represented coexisting extra-articular conditions such as hip flexor tendonitis,
bursitis, capsular injury, or muscular abnormality. However,
the improvement in hip scores (average, 20.1 points) and the
rate of subjective patient-reported improvement (94%) at one
year after arthroscopic treatment strongly support the assumption that the preoperative clinical symptoms were directly related to the labral tear.
The clinical presentation, radiographic analysis, and
magnetic resonance arthrographic findings associated with
symptomatic acetabular labral tears provide useful information for the diagnosis and treatment of this condition. Acetabular labral tears are frequently the manifestation of primary
structural hip disease17,45. It is therefore imperative for the surgeon to determine the specific etiology of the labral tear and to
contemplate all treatment options, including hip arthroscopy,
osteotomy, and osteoplasty. With an increasing knowledge
and recognition of femoroacetabular impingement and mild
acetabular dysplasia, our indications for proceeding with a
surgical reconstruction (rather than hip arthroscopy alone)
are expanding. Nevertheless, acetabular labral tears also can
occur in the absence of a structural hip disorder. Therefore,
optimal treatment is achieved by means of diagnosis of the labral tear, determination of the absence or presence of an associated structural abnormality, and selection of a surgical plan
that addresses both the labral disease and the underlying
structural abnormality, if present.
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Appendix
A table showing the Tönnis classification system is available
with the electronic versions of this article, on our web site at
jbjs.org (go to the article citation and click on “Supplementary
Material”) and on our quarterly CD-ROM (call our subscription
department, at 781-449-9780, to order the CD-ROM). R. Stephen J. Burnett, MD, FRCS(C)
Heidi Prather, DO
Madelyn Curry, RN
John C. Clohisy, MD
Suite 11300–West Pavilion, 1 Barnes-Jewish Hospital Plaza, St. Louis,
MO 63110. E-mail address for J.C. Clohisy: jclohisy@wustl.edu
Gregory J. Della Rocca, MD, PhD
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Department of Orthopaedic Surgery, University of MissouriColumbia, Mc213 Mchaney Hall, Columbia, MO 65211
William J. Maloney, MD
Stanford Hospital and Clinics, Edwards Building, Room 209,
300 Pasteur Drive, Stanford, CA 94305
In support of their research for or preparation of this manuscript, one or
more of the authors received grants or outside funding from Zimmer. None
of the authors received payments or other benefits or a commitment or
agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or
nonprofit organization with which the authors are affiliated or associated.
doi:10.2106/JBJS.D.02806
References
1. Dorrell JH, Catterall A. The torn acetabular labrum. J Bone Joint Surg Br.
1986;68:400-3.
19. MacDonald SJ, Garbuz D, Ganz R. Clinical evaluation of the symptomatic
young adult hip. Semin Arthroplasty. 1997;8:3-9.
2. Ganz R, Parvizi J, Beck M, Leunig M, Notzli H, Siebenrock KA. Femoroacetabular impingement: a cause for osteoarthritis of the hip. Clin Orthop Relat Res.
2003;417:112-20.
20. Lequesne M, de Seze. [False profile of the pelvis. A new radiographic incidence for the study of the hip. Its use in dysplasias and different coxopathies].
Rev Rhum Mal Osteoartic. 1961;28:643-52. French.
3. Notzli HP, Wyss TF, Stoecklin CH, Schmid MR, Treiber K, Hodler J. The contour
of the femoral head-neck junction as a predictor for the risk of anterior impingement. J Bone Joint Surg Br. 2002;84:556-60.
21. Tonnis D, Heinecke A. Acetabular and femoral anteversion: relationship with
osteoarthritis of the hip. J Bone Joint Surg Am. 1999;81:1747-70.
4. Siebenrock KA, Wahab KH, Werlen S, Kalhor M, Leunig M, Ganz R. Abnormal
extension of the femoral head epiphysis as a cause of cam impingement. Clin Orthop Relat Res. 2004;418:54-60.
5. Ito K, Minka MA 2nd, Leunig M, Werlen S, Ganz R. Femoroacetabular impingement and the cam-effect. A MRI-based quantitative anatomical study of the femoral head-neck offset. J Bone Joint Surg Br. 2001;83:171-6.
6. Goodman DA, Feighan JE, Smith AD, Latimer B, Buly RL, Cooperman DR. Subclinical slipped capital femoral epiphysis. Relationship to osteoarthrosis of the
hip. J Bone Joint Surg Am. 1997;79:1489-97. Erratum in: J Bone Joint Surg Am.
1999;81:592.
7. Leunig M, Casillas MM, Hamlet M, Hersche O, Notzli H, Slongo T, Ganz R.
Slipped capital femoral epiphysis: early mechanical damage to the acetabular cartilage by a prominent femoral metaphysis. Acta Orthop Scand. 2000;71:370-5.
8. Paterson I. The torn acetabular labrum; a block to reduction of a dislocated
hip. J Bone Joint Surg Br. 1957;39:306-9.
9. Dameron TB Jr. Bucket-handle tear of acetabular labrum accompanying posterior dislocation of the hip. J Bone Joint Surg Am. 1959;41:131-4.
22. Murphy SB, Ganz R, Muller ME. The prognosis in untreated dysplasia of the
hip. A study of radiographic factors that predict the outcome. J Bone Joint Surg
Am. 1995;77:985-9.
23. Wiberg G. The anatomy and roentgenographic appearance of a normal hip
joint. Acta Chir Scand. 1939;83 Suppl 58:7-38.
24. Delaunay S, Dussault RG, Kaplan PA, Alford BA. Radiographic measurements
of dysplastic adult hips. Skeletal Radiol. 1997;26:75-81.
25. Siebenrock KA, Schoeniger R, Ganz R. Anterior femoro-acetabular impingement due to acetabular retroversion. Treatment with periacetabular osteotomy. J
Bone Joint Surg Am. 2003;85:278-86.
26. Mast JW, Brunner RL, Zebrack J. Recognizing acetabular version in the radiographic presentation of hip dysplasia. Clin Orthop Relat Res. 2004;418:48-53.
27. Reynolds D, Lucas J, Klaue K. Retroversion of the acetabulum. A cause of hip
pain. J Bone Joint Surg Br. 1999;81:281-8.
28. Giori NJ, Trousdale RT. Acetabular retroversion is associated with osteoarthritis of the hip. Clin Orthop Relat Res. 2003;417:263-9.
10. De Paulis F, Cacchio A, Michelini O, Damiani A, Saggini R. Sports injuries in
the pelvis and hip: diagnostic imaging. Eur J Radiol. 1998;27 Suppl 1:S49-59.
29. Reikeras O, Bjerkreim I, Kolbenstvedt A. Anteversion of the acetabulum and
femoral neck in normals and in patients with osteoarthritis of the hip. Acta Orthop Scand. 1983;54:18-23.
11. Mason JB. Acetabular labral tears in the athlete. Clin Sports Med.
2001;20:779-90.
30. Eijer H, Myers SR, Ganz R. Anterior femoroacetabular impingement after femoral neck fractures. J Orthop Trauma. 2001;15:475-81.
12. Fitzgerald RH Jr. Acetabular labrum tears. Diagnosis and treatment. Clin Orthop Relat Res. 1995;311:60-8.
31. Keeney JA, Peelle MW, Jackson J, Rubin D, Maloney WJ, Clohisy JC. Magnetic
resonance arthrography versus arthroscopy in the evaluation of articular hip pathology. Clin Orthop Relat Res. 2004;429:163-9.
13. McCarthy JC. Hip arthroscopy: applications and technique. J Am Acad Orthop
Surg. 1995;3:115-22.
14. Farjo LA, Glick JM, Sampson TG. Hip arthroscopy for acetabular labral tears.
Arthroscopy. 1999;15:132-7.
32. Byrd JW. Hip arthroscopy in the supine position. Oper Tech Sports Med.
2002;10:184-95.
15. Byrd JW, Jones KS. Prospective analysis of hip arthroscopy with 2-year followup. Arthroscopy. 2000;16:578-87.
33. Wardell SR, McCarthy JC, Mason JB, Stamos VP, Bono JV. Injuries to the acetabular labrum: classification, outcome, and relationship to degenerative arthritis. Read at the Annual Meeting of the American Academy of Orthopaedic
Surgeons. 13-17 Feb 1997; San Francisco, CA. p 36.
16. McCarthy J, Noble P, Aluisio FV, Schuck M, Wright J, Lee JA. Anatomy, pathologic features, and treatment of acetabular labral tears. Clin Orthop Relat Res.
2003;406:38-47.
34. Ikeda T, Awaya G, Suzuki S, Okada Y, Tada H. Torn acetabular labrum in young
patients. Arthroscopic diagnosis and management. J Bone Joint Surg Br.
1988;70:13-6.
17. Peelle MW, Della Rocca GJ, Maloney WJ, Curry MC, Clohisy JC. Acetabular
and femoral radiographic abnormalities associated with labral tears. Clin Orthop
Relat Res. 2005;441:327-33.
35. Byrd JW. Labral lesions: an elusive source of hip pain case reports and literature review. Arthroscopy. 1996;12:603-12.
18. Harris WH. Traumatic arthritis of the hip after dislocation and acetabular fractures: treatment by mold arthroplasty. An end-result study using a new method of
result evaluation. J Bone Joint Surg Am. 1969;51:737-55.
36. Horii M, Kubo T, Hirasawa Y. Radial MRI of the hip with moderate osteoarthritis. J Bone Joint Surg Br. 2000;82:364-8.
37. DeAngelis NA, Busconi BD. Assessment and differential diagnosis of the
Downloaded from www.ejbjs.org on February 26, 2007
1457
THE JOUR NAL
OF BONE & JOINT SURGER Y · JBJS.ORG
VO L U M E 88-A · N U M B E R 7 · J U L Y 2006
painful hip. Clin Orthop Relat Res. 2003;406:11-8.
38. Leunig M, Werlen S, Ungersbock A, Ito K, Ganz R. Evaluation of the acetabular labrum by MR arthrography. J Bone Joint Surg Br. 1997;79:230-4. Erratum in:
J Bone Joint Surg Br. 1997;79:693.
39. Czerny C, Hofmann S, Urban M, Tschauner C, Neuhold A, Pretterklieber M, Recht MP, Kramer J. MR arthrography of the adult acetabular capsular-labral complex:
correlation with surgery and anatomy. AJR Am J Roentgenol. 1999;173:345-9.
40. Locher S, Werlen S, Leunig M, Ganz R. [MR-Arthrography with radial sequences for visualization of early hip pathology not visible on plain radiographs].
Z Orthop Ihre Grenzgeb. 2002;140:52-7. German.
41. Suzuki S, Awaya G, Okada Y, Maekawa M, Ikeda T, Tada H. Arthroscopic diagnosis of ruptured acetabular labrum. Acta Orthop Scand. 1986;57:513-5.
42. Hase T, Ueo T. Acetabular labral tear: arthroscopic diagnosis and treatment.
Arthroscopy. 1999;15:138-41.
43. Hickman JM, Peters CL. Hip pain in the young adult: diagnosis and treatment
of disorders of the acetabular labrum and acetabular dysplasia. Am J Orthop.
2001;30:459-67.
44. Byrd JW, Jones KS. Diagnostic accuracy of clinical assessment, magnetic resonance imaging, magnetic resonance arthrography, and intra-articular injection in
hip arthroscopy patients. Am J Sports Med. 2004;32:1668-74.
45. Wenger DE, Kendell KR, Miner MR, Trousdale RT. Acetabular labral tears
rarely occur in the absence of bony abnormalities. Clin Orthop Relat Res.
2004;426:145-50.
C L I N I C A L PR E S E N T A T I O N O F PA T I E N T S
TE A R S O F T H E A C E T A B U L A R L A B R U M
WITH
46. Clohisy JC, Keeney JA, Schoenecker PL. Preliminary assessment and treatment guidelines for hip disorders in young adults. Clin Orthop Rel Res. 2005;
441:168-79.
47. McCarthy JC. Early hip disorders: advances in detection and minimally invasive treatment. New York: Springer; 2003.
48. Millis MB, Kim YJ. Rationale of osteotomy and related procedures for hip
preservation: a review. Clin Orthop Relat Res. 2002;405:108-21.
49. Troum OM, Crues JV 3rd. The young adult with hip pain: diagnosis and medical treatment, circa 2004. Clin Orthop Relat Res. 2004;418:9-17.
50. McCarthy JC, Lee JA. Acetabular dysplasia: a paradigm of arthroscopic examination of chondral injuries. Clin Orthop Relat Res. 2002;405:122-8.
51. Byrd JW, Jones KS. Hip arthroscopy in the presence of dysplasia. Arthroscopy. 2003;19:1055-60.
52. Clohisy JC, McClure JT. Treatment of anterior femoroacetabular impingement
with combined hip arthroscopy and limited anterior decompression. Iowa Orthop
J. 2005;25:164-71.
53. Beck M, Leunig M, Parvizi J, Boutier V, Wyss D, Ganz R. Anterior femoroacetabular impingement: part II. Midterm results of surgical treatment. Clin Orthop
Relat Res. 2004;418:67-73.
54. Ganz R, Gill TJ, Gautier E, Ganz K, Krugel N, Berlemann U. Surgical dislocation of the adult hip: a technique with full access to the femoral head and acetabulum without the risk of avascular necrosis. J Bone Joint Surg Br. 2001;
83:1119-24.
Downloaded from www.ejbjs.org on February 26, 2007