Anatomy of the Hip
Bony Structures
The Acetabulum is a shallow socket made by the junction of the three pelvic bones
· Ilium
· Ischium
· Pubis
acetabulum.gif

Labrum and Ligaments
The labrum is a layer of cartilage that is attached to the inside of the acetabulum and acts as a shock absorber, joint lubricator, and pressure distributor. The thickness of the labrum varies, but is normally 2-3 mm thick. The labrum is wider and thinner in the anterior portion and thicker in the posterior region. The labrum is believed to deepen the acetabulum by approximately 21% and increases the surface area by 28%. This helps to distribute the stress from the femoral head and decrease the contact stress on the articular surfaces. It also acts as a pressure seal for the synovial fluid and by maintaining this pressure the fluid will bear some of the stress from the femur. A study showed that without the labrum the contact stress in the hip increased by as much as 92% (Groh et al., 2007).

Ligaments of hip include the iliofemoral, pubocapsular, and ischiocapsular ligaments. The iliofemoral ligament is the strongest in the body and prevents hyperextension, controls external rotation and adduction, and limits the pelvis during backward rolling of the femoral head while weight bearing. The pubofemoral ligament prevents excessive abduction while the ischiocapsular ligament prevents excessive internal rotation and adduction (Prentice, 2006).

hip_anatomy_ligaments01.jpg

Musculature
The muscles can be divided into 2 groups, the anterior and posterior groups.
Anterior group:
· Iliacus
· Psoas
These two muscles merge to create the iliopsoas and it flexes the thigh and can assist with external rotation and adduction.
psoas_image.jpg
Posterior group:
· Tensor fasciae latae – tenses the fascia lata and assists with flexion, abduction, and internal rotation
· Gluteus maximus – extends and externally rotates
· Gluteus medius – abducts and internally rotates
· Gluteus minimus – abducts and internally rotates
· Piriformis – externally rotates and assists with extension and abduction
· Gemellus superior – externally rotates
· Gemellus inferior – externally rotates
· Obturator internus – externally rotates
· Obturator externus – externally rotates
· Quadratus femoris – externally rotates
(Prentice, 2006)
200px-Posterior_Hip_Muscles_1.PNG

glutes.jpg

Nerves and Vasculature
The anterior and superior portions of the labrum are thought to be the most innervated parts which contain free nerve endings and sensory nerve end organs. This creates feelings of pain, pressure, and deep sensation.
The vessels that provide blood flow are the obturator, superior gluteal, and inferior gluteal arteries. The outer 1/3 of the labrum is believed to be vascular while the remaining inner 2/3 is avascualar (Groh et al., 2007).

Classification
Labral tears have been classified into 4 types: radial flap, radial fibrillated, longitudinal peripheral, and abnormally mobile. Radial flap tears were the most common type and defined them as having a disruption of the free margin of the labrum (Lage et al., 1996). Radial fibrillation involves fraying of the free margin and was associated with degenerative joint disease. Abnormally mobile tears can result from a detached labrum, similar to a Bankart lesion in the shoulder. The least common type were tears occurring in a longitudinal direction in the peripheral aspect of the labrum. Labral tears most commonly
occur in an anterior and anterosuperior location on the inner aspect of the labrum (Burnett et al., 2006).

Etiology of Labral Tears

Isolated labral tears occur in about only 5% of cases and are usually the result of a traumatic event (Martin et al., 2005). Acetabular labral tears are commonly associated with functional acetabular impingement (FAI), capsular laxity, articular cartilage degeneration, and dysplasia.
  • Injury due to trauma
    • Often a result of shearing forces with twisting, pivoting, and falling.
    • Fun Fact: In North America the majority of tears are located anterosuperiorly and are a result of sudden twisting and pivoting (Baber, Robinson, & Villar, 1999). Meanwhile in the Asian population, tears are located posteriorly and are a result of hyperflexion and squatting motions (Mason, 2001).
  • Functional Acetabular Impingement
    • Decreased joint space between the femur and the acetabulum.
    • Cam impingement: radius of femoral head is large and there is a loss of the normal spherical junction between the femoral head and neck.
      • Impingement during hip flexion combined with adduction and internal rotation.
      • Anterosuperior lesions
      • More common in young athletic males (Lavigne et al., 2004)
    • Pincer impingement: increased overcoverage due to an abnormal acetabulum
      • Continuous contact of the femoral head into the acetabulum
      • Posteroinferior lesion
      • More common in middle aged athletic women (Lavigne et al., 2004)
      • Also seen after hip replacements (Iida et al.,1999)
  • Capsular Laxity
    • Global laxity
      • Connective tissue disorder (i.e. Down's, Marfan's)
    • Focal rotational laxity
      • Usually from excessive forceful hip external rotation (golf, ballet, gymnastics, martial arts, hockey, and baseball (Philippon & Schenker, 2005)) which leads to decreased iliofemoral ligament function
      • Ligament has decreased ability to absorb stress which can be transferred to the labrum
  • Dysplasia
    • Shallow acetabular socket that results in decreased coverage of the femoral head
    • Stability of the hip is compromised and increased stress is put on the anterior capsule and labrum (Bellabarba, Sheinkop, & Kuo, 1998)
  • Articular cartilage degeneration
    • Patients with labral pathology have chondral damage due to increased contact pressure and articular cartilage consolidation (McCarthy et al., 2001)

‍Clinical Examination
Little information exists regarding the sensitivity, specificity, and/or likelihood associated with a single clinical test or a number of tests in diagnosing an acetabular labral tear. Findings remain inconsistent due to common misdiagnosis and a difficult differential diagnosis, as well as the variable locations of labral tears at the hip. Most of the tests (as shown below) provide more general information regarding the potential for intra-articular and extra-articular pathologies, with possible lumbosacral issues as well.

Intra-articular Examination: May be positive for labral tear, but may also include (but is not limited to) OA, loose bodies, chondral lesions, synovitis, avascular necrosis and osteonecrosis (Burnett et. al, 2006).


  • ‍FABER or Patrick test:
Sensitivity of .57-.60; Specificity of .18-.88 (Jones, 2011)

In a study done by Mitchell et al, it was reported that the FABER test elicited pain in 88% of patients (15 of 17) with intra-articular pathology, but they did not find any correlation between a positive FABER test result and different types of hip joint pathology (Burnett et. al, 2006).

  • Scour test:
Sensitivity of .62-.91; Specificity of .43-.75 (Jones, 2011)


  • Resisted SLR test


If the history, symptoms, and signs are consistent with a labral tear, the next step is to assess for potential associated factors such as 1) Femoral-Acetabular-Impingement (FAI), 2) capsular and ligament laxity, 3) articular cartilage degeneration and 4) dysplasia. With this in mind, various special tests (as shown below) can be performed to distinguish among these impingement, capsular and/or general ligament laxity, and decreased hip ROM issues. Positive tests may include: sharp hip and/or groin pain, clicking and/or popping, muscle guarding, apprehension, and hypermobility. History of clicking/popping: sensitivity of .5-1.0; specificity of .85 (Jones, 2011).
1) ‍FAI‍: A positive anterior hip impingement test is currently the most consistent physical exam finding in patients with labral tears. The most common test involves the combined motions of hip flexion, adduction, and internal rotation (Groh & Herrera, 2009).
In a study done by Beck et. al, it was demonstrated that impingement occurs at 80 to 90 degrees of hip flexion and was further increased by adduction and internal rotation. In this study, all 19 subjects who underwent surgery for FAI had a positive FADIR test pre-operatively as well as evidence of impingement during surgery (Burnett et. al, 2006).
In a similar study done by Ito et al, 24 out of 25 individuals with arthroscopically confirmed FAI and labral tears had a positive FADIR test. A study done by Narvani et al, however, reported limited usefulness of the FADIR test in identifying individuals with a labral tear diagnosed by MRA (sensitivity, 75%; specificity, 43%) (Burnett et. al, 2006).
In 6 professional soccer players with anterior labral tears, Saw and Villar found that all of the players had significant pain with combined hip flexion, internal rotation, and adduction (FADIR). The wide range of provocative tests may be attributable to differences in the location of the tear.
In a study conducted by Fitzgerald, they performed two different clinical tests that provoked symptoms in 54 patients, depending on tear location. To identify an anterior labral tear, the patient’s leg is brought into full flexion, external rotation, and full abduction, and is then extended with internal rotation and adduction (FADIR). To identify a posterior labral tear, the patient’s leg is brought into extension, abduction, and external rotation, and is then flexed with internal rotation and adduction. If a labral tear is present, these tests will result in sharp pain with or without a click (Burnett et. al, 2006).

  • FADIR/Anterior hip impingment test:
Sensitivity of .78; Specificity of .10-.43 (Jones, 2011)


  • Posterior hip impingement test


2) Capsular laxity: Hip capsular and general ligament laxity can be evaluated primarily by performing the log roll test and long-axis femoral distraction. General ligament laxity may predispose an individual to symptomatic hip instability. Beighton’s scale is used for hypermobility to assess general ligament laxity. This scale includes assessing opposition of the thumb to forearm, elbow hyperextension, knee hyperextension, extension of the fifth metacarpophalangeal joint, and the ability to rest the palms on the floor with straight knees (Burnett et. al, 2006).
  • Log roll test


  • Long-axis femoral distraction


3) Articular cartilage degeneration: Assessing hip ROM can be used to identify individuals with diffuse articular cartilage degeneration associated with intra-articular pathologies such as labral tears and OA (Burnett et. al, 2006).

4) Dysplasia
  • Ortolani's and Barlow's tests performed on infants with suspected hip instability; used for developmental hip dysplasia.
  • Craig's test: Shows an excessive amount of anteversion greater than 15 degrees of motion between the neck and shaft of the femur, and the patient typically presents with their toes pointed inward.

Extra-articular Examination
Extra-articular structures should be addressed because conditions can coexist. Palpation may provide knowledge into extra-articular symptoms. If the source of pain is solely from intra-articular origin, palpable pain is rarely present. Individuals with muscle strains and/or tendonitis have pain with palpation, stretching, and resisted movements directed at the involved muscle and/or tendon. Examination of the lumbar spine and pelvis at the lumbosacral joint may also be required in an individual with hip pain and a potential labral tear (Burnett et. al, 2006).
In a study done by Brown et al, it was found that the presence of limp, groin pain, and limited hip internal rotation ROM was useful in distinguishing between individuals with a hip-only disorder or a combined hip-spine disorder from a spine-only disorder. Positive likelihood ratios for the presence of these findings in identifying individuals with hip-only disorders or hip-spine disorders from individuals with spine-only disorders were 7, 7, and 14, respectively. If tests are positive for a lumbosacral disorder, treatment can be directed there and its effect on hip pain can be evaluated (Burnett et. al, 2006).

Summary differentiating between intra-articular vs extra-articular hip pathologies (Burnett et. al, 2006)
Table 1 Labra Tear.jpg

Summary of clinical findings from various studies outlining symptoms of potential labral tears (Burnett et. al, 2006)
Labral Chart 1.jpg

Narvani et al.

Two maneuvers previously reported to have been successful in the diagnosis of acetabular labrum tears. The first one involves internal rotation, flexion and compression of the hip joint. Three out of the four patients with acetabular labrum tears complained of discomfort with this manoeuvre (sensitivity=75%). However, eight out of the fourteen patients without the labral tear also had discomfort with this manoeuvre (specificity of 43%).
"...even though the number of the patients is small this study suggests that acetabular labrum tears can be a common cause of groin pain in athletes presenting with groin pain, and sports clinicians have to be well aware of the condition. Clinical features do not appear to be very reliable in diagnosis of labrum tears. Magnetic resonance arthrography and hip arthroscopy must be utilised more in management of athletes with groin pain, especially those whom have not responded to other forms on intervention, as previous research shows that this could be a treatable condition (Narvani et al., 2003)"

Labral Chart 2.jpg

Diagnosis and Misdiagnosis

Burnett et al. (2006) retrospectively looked at 66 patients who had a documented acetabular labral tear that had been confirmed with hip arthroscopy. Twenty-two patients were diagnosed initially with something other than a labral tear. Eight of the ten patients that were diagnosed with "osteoarthritis" had plain radiographs performed that did not show any degenerative changes.
Labral Table Mis-Diagnosis.jpgTable 4 Labral Tear.jpg


Diagnosis of Labral Tears by PT vs. OS vs. OR
PT vs OR Table.png
"Using arthroscopy as the reference standard, hip labral tears in the subjects were clinically suspected with 80–85% accuracy among the examining clinicians. Clinical diagnostic accuracy of an experienced physical therapist, orthopaedic surgeon, and orthopaedic residents on patients with hip labral pathology was excellent with no significant difference among examiners. This study further strengthens the evidence that the use of Army PTs in the role of managing, evaluating, and treating patients with neuromusculoskeletal dysfunction is a successful model (Springer et al., 2009)."
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2953315/

Summary of Hip Diagnostic Tests (Burnett et al)
Table 5 Labral Tear.jpg

Imaging and articular injections are often used for diagnosing hip pain. For acetabular labral tears, magnetic resonance arthrogram (MRA) is considered to be the diagnostic imaging of choice. MRI has been found to be less reliable than MRA. In a 2004 study by Byrd and Jones, they found that an MRI had a sensitivity of 25% and a specificity of 67% while MRA had a sensitivity of 66% and a specificity of 75%.

Computed tomography scans are unable to reliably detect labral tears. Standard magnetic resonance imaging produces both false-positive results and an underestimation of labral pathology and has only a 30% sensitivity and a 36% accuracy. Magnetic resonance arthrography produces better results, with reported accuracies as high as 91%. Magnetic resonance arthrography does continue to have difficulty correctly identifying patients without labral tears, with a reported specificity of about 70%. Bone scintigraphy, more commonly known as the “bone scan,” recently was proposed as a way of detecting a labral tear, as scans in patients with tears showed characteristic patterns of increased uptake in the superior aspect of the acetabulum. However, this method warrants further testing to determine its diagnostic value. Direct observation of the labrum by arthroscopy, although invasive, continues to be the gold standard for diagnosis (Groh & Herrera, 2009).

MRA produces better results, as the intraarticular or systemic infusion of gadolinium is required to obtain the detail necessary to study the labrum. The principle of the procedure relies upon capsular distension, thereby outlining the labrum with contrast and filling any tears that may be presen. A study by Czerny et al. showed the sensitivity and accuracy for nondistended joints were 30% and 36%, respectively, while the sensitivity and accuracy increased to 90% and 91%, respectively, after joint distention, proving the importance of capsular distension. An MRA is also helpful to rule out other abnormalities within the differential, which include but are not limited to stress fractures, neoplasm, avascular necrosis, osteitis pubis, synovitis, ligamentum teres rupture, and other extraarticular soft tissue abnormalities, such as sports hernias and tendon avulsions (Groh & Herrera, 2009).

MRA has its limitations in regard to sensitivity for diagnosis of acetabular labral and articular cartilage abnormalities. Studies have compared MRA with surgical findings and have shown a range of sensitivity from 60% to 100% and that of specificity from 44% to 100% for acetabular labral pathology as compared to direct surgical visualization. These studies demonstrate that a negative scan does not fully rule out a labral tear and that hip arthroscopy remains the gold standard. A potential pitfall in diagnosing labral tears is false positives, such as those which may occur when there is the normal anatomic variant of recesses or sulci.

MRA may also be less effective in identifying posterior and lateral tears. Whereas, McCarthy et al. showed a 74% sensitivity for detecting anterior tears, the sensitivity for the detection of posterior tears was 20% and for lateral tears was 11%.
    • North American population vs. Asian population.

BOTTOM LINE:
  • Arthroscopy, which is considered the gold standard, can be a diagnostic and therapeutic medium.
  • When used for diagnosis, it is reserved for those patients with an intra-articular source of pain without a clear diagnosis after careful history, physical exam, and radiographic studies.
  • MRI have been seen to miss or misdiagnose labral tears.
  • If a labral tear is found:
    • Conservative treatment as related to PT
      • Yazbek et al. found that patients demonstrated decreased pain, functional improvement, and correction of muscular imbalance with the following treatment protocol: Phase 1 emphasized pain control, education in trunk stabilization, and correction of abnormal joint movement. Phase 2 focused on muscular strengthening, recovery of normal range of motion (ROM), and initiation of sensory motor training. Phase 3 emphasized advanced sensory motor training, with sport-specific functional progression. ROM, flexibility, pain, special tests, and level of function were assessed, and strength was measured with handheld dynamometry (Yazbek et al, 2011).
    • Previously, the treatment method of choice was excision, now surgeons perform arthroscopic debridement of labral tears to preserve as much healthy labral tissue as possible (Groh & Herrera, 2009).

Conclusion
The‍ appropriate physical therapy intervention ‍for a patient with an acetabular labral tear has yet to be determined, and no published articles on treating labral tears have been established. Hickman and Peters concluded that “physical therapy has not proved to be of significant benefit and is not recommended” for patients with a labral tear. However, from our (Sahrmann & Lewis, 2006) clinical experience, physical therapy can be beneficial when appropriately used. According to Sahrmann and Lewis, appropriate intervention should focus on reducing anteriorly directed forces on the hip by addressing the patterns of recruitment of muscles that control hip motion, by correcting the movement patterns during exercises such as hip extension and during gait, and by instruction in the avoidance of pivoting motions in which the acetabulum rotates on the femur, particularly under load. Thus, the initial examination is designed to identify any clinically detectable impairments in the precision of both active and passive hip motions. The most common examination finding is subtle increases in accessory joint motions, particularly during flexion and lateral rotation. The general goal of the intervention is to optimize the alignment of the hip joint and the precision of joint motion, particularly avoiding excessive forces into the anterior hip joint. The control of the hip abductor, deep lateral rotator, gluteus maximus, and iliopsoas muscles should be optimized, and dominant participation of the quadriceps femoris and hamstring muscles should be corrected. (Sahrmann & Lewis, 2006)

In general, a physical therapist should suspect an acetabular labral tear when a patient with normal radiographs complains of a long duration of anterior hip or groin pain and clicking, pain with passive hip flexion combined with adduction and medial rotation, and pain with an active straight leg raise and has minimal to no restriction in ROM.

Future research must investigate the long-term outcomes of partial labrectomy, as well as the efficacy of conservative approaches to care (Schmerl, Pollard, & Hoskins, 2005).

Evidence has suggested that information obtained from patient history and clinical examination can be used to identify those patients with possible labral tears. The signs and symptoms, however, have a great deal of overlap with other hip disorders, consequently resulting in incorrect diagnoses such as iliotibial band syndrome, snapping psoas syndrome, lumbar radicular pain, osteonecrosis, trochanteric bursitis, hip stress fracture, and inguinal or femoral hernia (Burnett et al., 2006). The examination must include screening of the lumbosacral spine and an evaluation of the intra-articular and extra-articular structures to narrow down the possible pathologies. If a labral tear is suspected the four areas mentioned before that are associated with labral tears: 1) FAI, 2) Capsular laxity, 3) articular cartilage degeneration, and 4) dysplasia must be considered. Along with these considerations, the common signs and symptoms gathered from research that suggests labral tears must be acknowledged: 1) Groin pain, 2) Activity related pain, 3) Mechanical locking or clicking, and 4) Limping during symptoms. For conclusive evidence diagnostics such as an MRA are necessary to establish the diagnosis of an acetabular labral tear.


labral table.jpg


Systematic Review Chart.jpg

Take home message of the systematic review:
1. Health professionals must be cautious in interpreting the study results for use in clinical practice.
2. MRA consistently outperformed MRI (CT may also be a useful technique)
3. Symptoms likely to be present are anterior groin pain and mechanical hip symptoms.





References
  1. Baber YF, Robinson AH, Villar RN. Is diagnostic arthroscopy of the hip worthwhile? A prospective review of 328 adults investigated for hip pain. J Bone Joint Surg Br. 1999;81:600-603. http://www.bjj.boneandjoint.org.uk/content/81-B/4/600.long
  2. Bellabarba C, Sheinkop MB, Kuo KN. Idiopathic hip instability. An unrecognized cause of coxa saltans in the adult. Clin Orthop Relat Res. 1998;261-271.
  3. Burgess RM, Rushton A, Wright C, & Daborn C. The validity and accuracy of clinical diagnostic tests used to detect labral pathology of the hip: a systematic review. Manual Therapy 2011;16:318-326. http://www.sciencedirect.com/science/article/pii/S1356689X11000038
  4. Burnett R, Della RG, Prather H, Curry M, Maloney W, Clohisy J. Clinical presentation of patients with tears of the acetabular labrum. Journal of Bone and Joint Surgery 2006;88(7):1448-57. http://users.rowan.edu/~cecis85/PDFs/21330919.pdf and http://jbjs.org/article.aspx?articleid=27566
  5. Groh MM & Herrera J. A comprehensive review of hip labral tears. Curr Rev Musculoskelet Med. 2009; 2(2): 105-117. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697339/
  6. Iida H, Kaneda E, Takada H, Uchida K, Kawanabe K, Nakamura T. Metallosis due to impingement between the socket and the femoral neck in a metal-on-metal bearing total hip prosthesis. A case report. J Bone Joint Surg Am. 1999;81:400-403. http://jbjs.org/article.aspx?articleid=2426
  7. Jones, Brandy. "Evidence-based evaluation of the hip." North Georgia College and State University. 2011.http://www.northgeorgia.edu/uploadedFiles/Academics/School_of_Education/
  8. Lage LA, Patel JV, Villar RN. The acetabular labral tear:an arthroscopic classification. Arthroscopy. 1996;12:269-272. http://www.sciencedirect.com/science/article/pii/S0749806396900572
  9. Lavigne M, Parvizi J, Beck M, Siebenrock KA, Ganz R, Leunig M. Anterior femoroacetabular impingement: part I. Techniques of joint preserving surgery. Clin Orthop Relat Res. 2004;61-66.
  10. Lewis CL & Sahrmann SA. Acetabular labral tears. Journal of the American Physical Therapy Association 2006;86(1):110-121. http://ptjournal.apta.org/content/86/1/110.short
  11. Martin RL, Kelly BT, Philippon MJ. A classification system for labral tears of the hip [abstract]. J Orthop Sports Phys Ther. 2005;35:A23. http://rehabeducation.com/main/wp-content/uploads/Hip-Acetabular%20labral%20tests.pdf
  12. Mason JB. Acetabular labral tears in the athlete. Clin Sports Med. 2001;20:779-790.
  13. McCarthy JC, Noble PC, Schuck MR, Wright J, Lee J. The Otto E. Aufranc Award: The role of labral lesions to development of early degenerative hip disease. Clin Orthop Relat Res. 2001;25-37.
  14. McCarthy JC, Noble PC, Schuck MR, Wright J, Lee J. The watershed labral lesion: its relationship to early arthritis of the hip. J Arthroplasty. 2001;16:81-87.
  15. Narvani AA, Tsiridis E, Kendall S, Chaudhuri R, Thomas P. A preliminary report on prevalence of acetabular labrum tears in sports patients with groin pain. Knee Surg Sports Traumatol Arthrosc. 2003;11:403-408. http://link.springer.com/article/10.1007%2Fs00167-003-0390-7
  16. Philippon MJ, Schenker ML. Athletic hip injuries and capsular laxity. Oper Tech Orthop. 2005;15:261-266.
  17. Prentice, W. (2006). Arnhiem's principles of athletic training. (12 ed., pp. 667-671). New York, NY: McGraw Hill.
  18. 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.
  19. Springer BA, Gill NW, Friedman BA, Ross AE, Javernick MA, & Murphy KP. Acetabular labral tears: diagnostic accuracy of clinical examination by a physical therapist, orthopedic surgeon, and orthopaedic residents. North American Journal of Sports Medicine 2009;4(1):38-45.
  20. Yazbek PM, Ovanessian V, Martin RL, & Fukuda TY. J Orthop Sports Phys Ther 2011;41(5):346-353, Epub 18 February 2011. doi:10.2519/jospt.2011.3225
  21. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2953315/
  22. http://www.youtube.com/watch?v=5UzAvGTmdMw
  23. http://www.youtube.com/watch?v=WKEgvnGJRCs
  24. http://www.youtube.com/watch?v=jjLsFZRYZgA
  25. http://www.youtube.com/watch?v=XA1VSK5NBCk
  26. http://www.youtube.com/watch?v=1r3OZeGX1kQ
  27. http://www.youtube.com/watch?v=CTKWi2qidP0
  28. http://www.youtube.com/watch?v=nUohlWSO7To
  29. http://www.youtube.com/watch?v=Qwbgc3TK45Y