Acetabular labral tears, as the name implies, are tears involving the acetabular labrum of the hip.
With the increasing use of hip arthroscopy in orthopedic surgery since the 1970s pathologies of the acetabular labrum as a possible cause of chronic hip and groin pain have become more familiar to a wider medical audience.
Acetabular labral tears are not infrequent. They are found in 55% of arthroscopies for intractable hip pain 1.
- pain on weight-bearing, flexion and internal rotation
- microinstability, painful audible clicking, transient locking, giving way of the hip
- mismatch between clinical symptoms and radiographic findings
- delayed diagnosis
- long-standing labral tears contribute to premature osteoarthritis 1,2
Major trauma (e.g. hip dislocation) may cause a labral tear. However, there is no history of previous trauma in most cases. Structural osseous abnormalities are often found 3,4.
- cam deformity
- femoroacetabular impingement
- hip dysplasia
- capsular laxity
- cartilage damage
- paralabral cysts
Plain radiograph / CT
- normal appearance in most cases
- structural skeletal abnormalities
- osteoarthritis (advanced cases)
Labral tears may manifest as abnormal labral morphology, hypoechoic cleft and/or labral detachment from the acetabular rim. Paralabral cysts may also be visible 7.
- may show perilabral cysts or advanced cartilage lesions
- labrum integrity can be assessed only in the presence of joint effusions
- intrasubstance high T1 or PD signal is not considered as pathologic
- high T2 signal may be interpreted as mucoid or cystic degeneration.
Direct MR arthrography
- most accurate imaging study (91vs 36% on native MRI)
- minimally invasive compared with arthroscopy
- highly diluted intra-articular Gd-injection (0.0025 mmol/ml) with joint distension (10-20 ml) allows optimal assessment of the labrum on fatsat T1 sequences
- triangular cross-section
- rounded/flattened labral cross-section
- perilabral cleft
- insertional cleft on transverse ligament
- communicating iliopsoas bursa (15%)
- absent antero-superior labrum
- sublabral sulcus
- labral tears (marked by intrasubstance contrast entry)
- bucket handle
- labral detachment
- cartilage delamination
- loose bodies 1
Treatment and prognosis
Acetabular labral tears are the main indication for hip arthroscopy.
Partial labrectomy and labral repair are the current surgical options.
Preliminary scientific data suggest that labral repairs can heal and patients can expect both symptomatic and functional improvement. However, valid prospective studies are needed to determine the long-term outcome of labral repair 5,6.
On arthrography for small clefts consider
- labral sulci: sulci have smooth labral edges, whereas labral tears tend to have irregular edges
- 1. Petersilge CA. From the RSNA Refresher Courses. Radiological Society of North America. Chronic adult hip pain: MR arthrography of the hip. Radiographics. 2000;20 Spec No : S43-52. Radiographics (link) - Pubmed citation
- 2. Mccarthy J, Noble P, Aluisio FV et-al. Anatomy, pathologic features, and treatment of acetabular labral tears. Clin. Orthop. Relat. Res. 2003;(406): 38-47. doi:10.1097/01.blo.0000043042.84315.17 - Pubmed citation
- 3. Petersilge CA. MR arthrography for evaluation of the acetabular labrum. Skeletal Radiol. 2001;30 (8): 423-30. doi:10.1007/s0025610300423 - Pubmed citation
- 4. Beaulé PE, O'neill M, Rakhra K. Acetabular labral tears. J Bone Joint Surg Am. 2009;91 (3): 701-10. doi:10.2106/JBJS.H.00802 - Pubmed citation
- 5.Safran MR. The acetabular labrum: anatomic and functional characteristics and rationale for surgical intervention. J Am Acad Orthop Surg. 2010;18 (6): 338-45. J Am Acad Orthop Surg (full text) - Pubmed citation
- 6. Robertson WJ, Kadrmas WR, Kelly BT. Arthroscopic management of labral tears in the hip: a systematic review of the literature. Clin. Orthop. Relat. Res. 2007;455 : 88-92. doi:10.1097/BLO.0b013e31802c7e0f - Pubmed citation
- 7. Lungu E, Michaud J, Bureau NJ. US Assessment of Sports-related Hip Injuries. (2018) Radiographics : a review publication of the Radiological Society of North America, Inc. 38 (3): 867-889. doi:10.1148/rg.2018170104 - Pubmed
- 8. Mike S. Nguyen, Valeriy Kheyfits, Brian D. Giordano, Gregory Dieudonne, Johnny U. V. Monu. Hip Anatomic Variants That May Mimic Abnormalities at MRI: Labral Variants. (2013) American Journal of Roentgenology. 201 (3): W394-400. doi:10.2214/AJR.12.9860 - Pubmed