Hip Labral Disorders

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Clinically Relevant Anatomy 

The hip labrum is a dense fibrocartilagenous structure, mostly composed of type 1 collagen that is typically between 2-3mm thick that outlines the acetabular socket and attaches to the bony rim of the acetabulum. The labrum has an irregular shape as it is wider and thinner in the anterior region of the acetabulum and thicker in the posterior region. Hip labral disorders are pathologies of this structure; in most cases this is caused by a tear in the labrum but it can also be caused by a dislocation, misalignment from bony structures ore a not optimal angle of the caput femoris.

As for the blood supply, it is thought that the majority of the labrum is avascular with only the
outer third being supplied by the obturator, superior gluteal, and inferior gluteal arteries. There is
controversy as to whether there is a potential for healing with the limited blood supply and this is an important clinical consideration. The superior and inferior portions are believed to be innervated and contain free nerve endings and nerve sensory end organs (giving the senses of pain, pressure, and deep sensation).

The labrum functions as a shock absorber, joint lubricator, and pressure distributor. It resists
lateral and vertical motion within the acetabulum along with aiding in stability by deepening the joint by 21%. The labrum also increases the surface area of the joint by 28% allowing a wider area of force distribution and is accomplished by creating a sealing mechanism to keep the synovial fluid within the articular cartilage.

Acetabular Labrum copyright and courtesy of Primal Pictures Ltd.

Labral tears can be classified by their location (anterior, posterior, or superior/lateral),
morphology (radial flap, radial fibrillated, longitudinal peripheral, and unstable), or etiology. It is generally accepted that most labral tears occur in the anterior, anterior-superior, and superior regions of this acetabulum.

Epidemiology/Etiology

The labrum is susceptible to traumatic injury from shearing forces that occur with twisting, pivoting and falling. The most common mechanism is an external rotation force in a hyperextended position. In some cases pain develops over time. It is believed the microtraumata are responsible of the labral lasions in these cases.

Hip dysplasia is an important risk factor. Hip dysplasia is a general term used to describe certain abnormalities of the femur or the acetabulum, or both that result in inadequate containment of the femoral head within the acetabulum. A shallow acetabulum, a femoral or acetabular anteversion, and a decreased head offset or perpendicular distance from the center of the femoral head to the axis of the femoral shaft are a few of those bony abnormalities.

With the advent of arthroscopic surgery as an accurate means of diagnosis (magnetic resonance arthrography), hip labral injuries have become of growing interest to the medical profession. Direct trauma, including motor vehicle accidents and slipping or falling with or without hip dislocation, are known causes of acetabular labral tears. Additional causes of labral tears may include acetabular impingement, joint degeneration, and childhood disorders such as Legg-Calve-Perthes disease, congenital hip dysplasia, and slipped capital femoral epiphysis. While most tears occur in the anteriosuperior quadrant, a higher than normal incidence of posterosuperior tears appear in the Asian population due to a higher tendency toward hyperflexion or squatting motions.

According to a systematic review by Leiboid et al,

• Hip labral tears commonly occur between 8 to 72 years of age and on average during the fourth decade of life.
• Women are more likely to suffer than Men.
• 22-55% of patients that present with symptoms of hip or groin pain are found to have an acetabulular labral tear.
• Up to 74.1% of hip labral tears cannot be attributed to a specific event or cause.
• In patients who identified a specific mechanism of injury, hyperabduction, twisting, falling, or direct blow from a car accident were common mechanisms of injury . Women, runners, professional athletes, participants in sports that require frequent external rotation and/or hyperextension,
• Those attending the gym 3 times a week all have an increased risk of developing a hip labral tear. 
  

 

Mechanism of Injury

There are five possible etiologies of labral tears that are currently recognized: Femoroacetabular impingement (FAI),trauma,capsular laxity, dysplasia, and degeneration. ^1,2 FAI has been categorized into two types: cam and pincer. Cam type impingment exists with a large femoral head with resulting abdnormal junction between the femoral head and neck. This causes impingement between the femur and acetabular rim, particularly during hip flexion and internal rotation.¹
Pincer impingement occurs with an acetabular overcoverage, causing abutment of the femoral head into the acetabulum.Cam impingement is the proposed etiology of atererosuperior labral tears, and pincer type is thought to be on eof the causes posterioinferior chondral lesions.² Traumatic injury to the hip labum is thought to occur with a shearing force associated with twisting and falling. This can lead to joint instabililty resulitng in abnormal movment patterns with eventual degenerative changes and labral fraying.² Capsular laxity with resulting labral pathology is thought to occur in one of two ways; cartilage disorders (ie. Ehlers-Danlos syndrome) or rotational laxity resulting from excessive external rotation. These forces are often seen in certain sports including ballet,hockey,and gymnastics. ² Hip dysplasia occurs with development of a shallow acetabular socket resulting in decreased coverage of the femoral head. This places increased stress into the anterior portion of the hip joint, resulting in impingement and possible tears over time. ¹

Characteristics/Clinical Presentation

Patients with pain deep in the groin, instability of the hip, a "clicking" or "locking" feeling and stiffness of the hip might be suffering from an acetabular labral tear. These symptoms can increase when the patient's bearing weight or performing twisting movements of the hip. Pain may also occur while climbing stairs. Most patients (90%) diagnosed with acetabular labral tears have had complaints of pain in the anterior hip or groin. This can be an indication for an anterior labral tear, whereas buttock pain is more consistent with posterior tears and less common. 

Labral tears have been classified into 4 types:
- radial flap: most common, disruption of free margin of the labrum
- radial fibrillated: fraying of the free margin, associated with degenerative joint disease
- longitudinal peripheral: least common
- abnormally mobile: can result from a detached labrum

There is some variation in the presentation of hip labral tears.  Frequently patients present with anterior hip and groin pain, although some do present with GT, buttock, and/or medial knee pain. Mechanical symptoms associated with a tear are clicking, popping,giving way,catching,and stiffness. Patients offent describe a dull ache which increases with activities such as running or brisk walking. ¹
Some special tests performed are: FABER test,scour test, resisted SLR, and  anterior hip impingement test^1,2

Due to difficulties in identifying specific mechanisms of injury for hip labral tears, generalizing typical signs and symptoms proves to be a rather challenging task. Ninety percent of patients with a hip labral tear have complaints of anterior hip and/or groin pain.  Less common areas of pain include anterior thigh pain, lateral thigh pain, buttock pain, and radiating knee pain. Pain patterns and additional symptoms reported in studies include insidious onset of pain, pain that worsens with activity, night pain, clicking, catching, or locking of the hip during movement . Functional limitations may include prolonged sitting, walking, climbing stairs, running, and twisting/pivoting .

According to a 2008 study by Martin et al, symptoms of groin pain, catching, pinching pain with sitting, FABERs test, flexion-internal rotation, adduction impingement test, and trochanteric tenderness were found to have low sensitivities (.6-.78) and low specificities (.10-.56) in identifying patients with intra-articular pain.

Differential Diagnosis

A variety of pathologies have to be taken into account when facing hip pain. In most cases this pain is situated in the anterior hip or goin region. Some patients might also complain about pain in the lateral region or deep in the posterior buttocks, but this is less common. Pain in the hip region van be due to hip joint contusion, strain, athlethis pubalgia, osteitis pubis, inflammatory arthritis, osteoarthritis, septic arthritis, piriformis syndrome, snapping hip syndrome, bursitis, femoral head avascular necrosis, fracture, dislocation, tumor, hernia, slipped femoral capital epiphysis, Legg-Calve-Perthes disease, or referred pain from the lumbosacral and sacroiliac areas. 

The current gold standard for diagnosing labral tears is arthroscopy. There has been favorable results reported utilizing MRA, however studies have reported wide ranges of sensitivity from 60%- 100% and specificity from 44% - 100%. ² 

Given the etiology of this condition it is very important to obtain a good history, paying close attention to childhood problems such as Legg-Calve-Perthes disease, congenital hip dysplasia, slipped femoral capital epiphysis and trauma.

Schmerl and colleagues provide a thorough list for differential diagnosis of labral injury causing hip pain:

• Contusion (especially over bony prominences)
• Strains Athletic pubalgia
• Osteitis pubis
• Inflammatory arthridites
• Piriformis syndrome
• Snapping hip syndrome Bursitis (trochanteric, ischiogluteal, iliopsoas)
• Osteoarthritis of femoral head
• Avascular necrosis of femoral head
• Septic arthritis
• Fracture or dislocation
• Tumors (malignant and benign)
  
• Hernia (inguinal or femoral)
• Slipped capital femoral epiphysis
• Legg-Calve-Perthes disease
• Referred pain from lumbosacral structures and the sacroiliac joint

Magnetic resonance arthrography (MRA) is the diagnostic of choice for hip labral tears. In a systematic review, Burgess et al, reported that the majority of studies (11/12) found the sensitivity of MRA to be .63 - .1. Magnetic resonance imaging (without arthrography) and computed tomography (CT) have been shown to be unreliable diagnostic tests. 

Diagnostic Procedures

Imaging from plain radiographs, computed tomography (CT) and magnetic resonance imaging (MRI) are rather useless when identifying labral tears. The magnetic resonance arthrography (MRa) on the other hand is proven to be more succesful. MRa uses a dye injection into the hip capsule before imaging several planes with an MR. Although an MRa can give some indications for labral tears, studies have indicated that the sensitivity and specificity of the test varies. Diagnosis is there for best based on the combination of MRa, physical examination and arthroscopy. Arthroscopy is considered the golden standard and can be used for diagnostic as well as therapeutic means.

Outcome Measures

add links to outcome measures here (also see Outcome Measures Database)

hip Outcome Measures

Harris Hip score

Lower Extremity Functional Scale (LEFS)

Lequesne Hip Score

Examination 

Hip labral disorders can be diagnosed during a thorough physical examination. In some cases the first signs can be spotted while observing the patient. During a brief walk the knee on the side of the affected hip might be slightly bend to absorb the shocks and lowering the weight bearing on that side. the step length of the affected leg may also be shortened to lower the pain. Aside from simple observation there are a number of provocative tests that can be performed. Because each test stresses a particular part of the acetabular labrum, they can also give an indication of where the tear is located.

for the McCarthy test, both hips have to be in a flexed position. The affected hip needs to be brought into extension. If this movement reproduces a painful click, the patient is suffering from a labral tear.

The flexion-abduction-external rotation test(FABER) test elicates 88% of the patient with an articular pathology, But the FABER test didn’t find any correlation between the pisitive test result and the tipes of hip joint pathology.

To identify an anterior labral tear, the patient's leg has to be brought into full flexion, lateral rotation and full abduction. Then the leg has to be extended with medial rotation and adduction. Patients with an anterior labral tear will experience sharp catching pain and in some cases there might be a "clicking" of the hip.

A posterior Labral tear is identified by bringing the patient's leg into extension, abduction and lateral rotation followed by an extension with medial rotation and adduction of the leg. Sharp catching pain with or without a "click" will be an indication for a posterior labral tear.

The following are special tests for the acetabular labrum:

Impingement Test (Flexion-Adduction-Internal Rotation Test)

The hip impingement test is the most widely used and consistent physical exam procedure used to identify patients with a hip labral tear. The patient is placed in supine and the examiner passively flexes the hip to 90 degrees while performing adduction and internal rotation. The test is considered to have a positive finding if the patient experiences pain in the groin region. However, test positions and operational definitions of a positive test vary in literature. The Impingement test (Flexion-Adduction-Internal Rotation Test) has a sensitivity of .75. 

Fitzgerald Test

The Fitzgerald test utilizes 2 different test positions to determine if the patient has an anterior or posterior labral tear. To test for a anterior labral tear, the patient lies supine while the physical therapist (PT) performs flexion, external rotation, and full abduction of the hip, followed by extending the hip, internal rotation, and adduction. To test for a posterior labral tear, the PT performs passive extension, abduction, external rotation, from the position of full hip flexion, internal rotation, and adduction while the patient is supine. Tests are considered to be positive with pain reproduction with or without an audible click.  The Fitzgerald test has a sensitivity of .98. 

Other tests

Other tests found to have high specificities but lacking high-quality study designs and supportive literature include the Flexion-Adduction-Axial Compression test and palpation to the greater trochanter. Flexion-Internal Rotation-Axial Compression test, Thomas test, Maximum Flexion-External Rotation Test, and Maximum Flexion-Internal Rotation Tests were found to have poor diagnostic measures.

Medical Management

The most commen treatment uses anti-inflammatory drugs. Hip Labral Disorders can also be treated with débridement or with churgical ripair. There is a bioabsorbeble suture angor placed witch is needed to stabilize the fibrocartilaginous tissue back to the rim of the acetabulum when the labrum is detached from the bone. The goal of this artoscopic theatment is to releave the pain by eliminating the unstable flap tear that causes this discomfort. Pelvic osteotomies is a surgical treatment that is used when the alignment of the bone structures isn’t optimal. Due to this misalignment of the socket, witch is usually created by a disease during childhood the hip is going to wear out prematurely. When the angel of the caput femoris isn’t optimal a femoral osteotomy can be done. A femoral osteotomy is a surgical treatment where the femur is cut and angled differently in an attempt to improve the mechanics of the leg. As last resort an arthodesis can be used. Witch this churgical treatment an artificial induction of joint ossification is placed between two bones.

Conservative management includes rest,NSAIDS, physical therapy. There is not a great deal of evidnece supprting a speicifc protocol for PT, however it has been suggested to address joint motion, recruitment patterns of the hip musculature, avoiding pivoting and shearing motions across the hip joint, and analyzing/correcting gait patterns.²If conservative treatment fails arthroscopic treatment is often indicated. Procedures include labral repair, osteoplasty,rim trimming, microfracture, and capsular modifications. ³ A post operative course of phyiscal therapy has been suggested with intial restrictions in range of motion to allow for appropriate healing. Gradual motion, weightbearing, and strengthening is initiated based primarily on tissue healing times.³

Physical Therapy Management

So far there has been no research on the efficacy of hip mobilization or manipulation in the treatment of labral disorders. Although it is suggested that the therapy should focus on optimizing the alignment of the hip joint and the precision of joint motion, avoiding pivoting motions and correcting gait patterns. 

Conservative treatment for a diagnosis of an acetabular labral tear typically consists of non-steroidal anti-inflammatory drugs, limited weight-bearing, and physical therapy. During this time of limited activity, the patient’s pain may be reduced; however, the pain often reoccurs when the patient returns to normal activities.

When conservative treatment does not resolve symptoms, surgical intervention is often appropriate. The most common procedure is an excision or debridement of the torn tissue by joint arthroscopy. However, studies have demonstrated mixed post-surgical results. Fargo et al, found a significant correlation between outcomes and presence of arthritis on radiography. Only 21% of patients with detectable arthritis had good results from surgery, compared with 75% of patients without arthritis. Arthroscopic detection of chondromalacia was an even stronger indicator of poor long-term prognosis.

Surgical treatment has been shown to have short-term improvements, however the long-term outcomes remain unknown.

Physical Therapy Management

The goal during PT management of an acetabular labral tear is to optimize the alignment of the hip joint and the precision of joint motion . This can be done by

1. Reducing anteriorly directed forces on the hip
2. Addressing abnormal patterns of recruitment of muscles that control the hip .
3. Instructing patients to avoid pivoting motions, especially under load, since the acetabulum rotates on a loaded femur, thus increasing force across the labrum .

Because of abnormal recruitment patterns of the hip muscles in individuals with acetabular labral tears, PT treatment should optimize control of these muscles, specifically the hip adductors, deep external rotators, gluteus maximus, and iliopsoas muscles . Additionally, if quadriceps femoris and hamstring muscles dominate, this should be corrected, as decreased force contribution from the iliopsoas during hip flexion and from the gluteal muscles during active hip extension results in greater anterior hip forces .

Through gait and foot motion analysis, the PT can discover any abnormalities, such as knee hyperextension causing hip hyperextension, walking with an externally rotated hip, or stiffness in the subtalar joint that need to be corrected through taping, orthotics, or strengthening . Gait analysis may also uncover decreased hip abduction during both the stance and swing phase, as well as decreased hip extension during swing phase -- characteristics that may be part of a hip joint stabilization strategy used by patients to compensate for deficient hip musculature functionality.

Additionally, patients need to be educated regarding modification of functional activities to avoid any positions that cause pain, such as sitting with knees lower than hips or with legs crossed, getting up from a chair by rotating the pelvis on a loaded femur, hyperextending the hip while walking on a treadmill, etc.

After addressing abnormal movement patterns, focused muscle strengthening work and recovery of normal range of motion, patients eventually need to be progressed to advanced sensory-motor training and functional exercises, sport specific if applicable .

If surgery is performed, usually the first 6 weeks post-surgery are NWB or TTWB. Active and active assisted exercises are appropriate in gravity-minimized positions to maintain motion of the hip. Stationary bike, not recumbent bicycle, is appropriate; end range hip flexion should be done passively rather than actively. Rehabilitation protocols are currently based on surgeon and PT experience and can follow either labral debridement or repair guidelines, depending on the procedure performed, and move through 4 basic phases. The four basic phases follow the general progression of initial exercises, intermediate exercises, advanced exercises and sports specific training .

Key Research

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Austin A, Meyer J, Powers C, Souza R. Identification of abnormal hip motion associated with acetabular labral pathology. J Orthop Sports Phys Ther. 2008;38(9):558-565.

Steadman Hawkins Research Foundation, Vail, Colorado, USA. New frontiers in hip arthroscopy: the role of arthroscopic hip labral repair and capsulorrhaphy in the treatment of hip disorders. Instr Course Lect. 2006;55:309-16.

Concurrent Criterion-Related Validity of Physical Therapy Examination Tests for Hip Labral Tears

A comprehensive review of hip labral tears

Clinical Bottom Line

Between a quarter and a half of all patients experiencing hip or groin pain are diagnosed with an acetabular labral tear; however this disorder is difficult to diagnose, and patients, on average, wait two years or longer before a diagnosis is made.  The options for treatment include both conservative (physical therapy) and non-conservative (surgery) approaches. PT can benefit patients by strengthening and re-educating neuromuscular control of the hip musculature, thus lending stability to the hip joint, while surgical excision or debridement of the torn labrum may be indicated for patients that do not reach desired outcomes conservatively.

Resources

Groh M, Herrera J. A comprehensive review of hip labral tears. Curr Rev Musculoskelet Med 2009;2:105-117

Enseki K, Martin R, Draovitch P, Kelly B, Philippon M, Shunker M. The hip joint: Arthroscopic procedures and postoperative rehabilitation. J Orthop Sports Phys Ther. 2006;36(7):516-525.

Lewis CL, Sahrmann SA. Acetabular labral tears. Physical Therapy. 2006;89:110-21.

Schmerl M, Pollard H, Hoskins W. Labral Injuries of the hip: a review of diagnosis and management. J Manipulative Physiol Ther. 2005;28(8):632.

Resources

1. Groh M,Herrera J. A comprehensive review of hip labral tears.Curr Rev Musculoskelet Med 2009;2:105-117

2. Martin R,Enseki K,Draovitch P,Trapuzzano T,Philippon M. Acetabular labral tears of the hip:examination and diagnostic challenges.JOSPT 2006;36(7):503- 515

3. Enseki K,Martin R, Draovitch P,Kelly B,Philippon M, Schenker M. The hip joint: arthroscopic procedures and postoperative rehabilitation. JOSPT 2006;36(7):516-525

Case Studies

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References

1. Groh M,Herrera J. A comprehensive review of hip labral tears.Curr Rev Musculoskelet Med 2009;2:105-117 

2. Martin R,Enseki K,Draovitch P,Trapuzzano T,Philippon M. Acetabular labral tears of the hip:examination and diagnostic challenges.JOSPT 2006;36(7):503- 515

3. Enseki K,Martin R, Draovitch P,Kelly B,Philippon M, Schenker M. The hip joint: arthroscopic procedures and postoperative rehabilitation. JOSPT 2006;36(7):516-525

Recent Related Research (from Pubmed)

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References

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Martin R, Enseki K, Draovitch P, Trapuzzano T, Philippon M. Acetabular labral tears of the hip: Examination and diagnostic challenges. J Orthop Sports Phys Ther. 2006:36(7):503-515. Enseki K, Martin R, Draovitch P, Kelly B, Philippon M, Schenker M. The hip joint: Arthroscopic procedures and postoperative rehabilitation. J Orthop Sports Phys Ther. 2006;36(7):516-525.
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