Acetabular Labral Repair: Current Concepts

Nick Mohtadi M.D., MSc, FRCSC
Calgary, AB

 

Repair of the acetabular labrum is a technically demanding procedure, with controversial indications and mixed results. Nevertheless, it is clear that the labrum in the hip is an important structure that has functions including: 1) shock absorption, 2) facilitation of joint lubrication by providing a seal between the central and peripheral compartments, 3) pressure distribution and 4) stability1-3. The labrum of the hip is unique. It is both analogous to the meniscus in the knee and the labrum in the shoulder. It is also distinctive in the respect that it is intimately associated with the adjacent articular cartilage in most patients, however, a variety of normal sulci may be present at this interface1-5. Therefore, we can think of the labrum in the hip as the anatomical structure which provides the transition between the capsule and articular cartilage.

 

Pathology in the labrum is difficult to determine clinically, radiographically and with MRI. This is due to the fact that most labral tears are associated with or secondary to a variety of other problems. These include traumatic subluxation/dislocation, instability, femoroacetabular impingement (FAI), developmental dysplasia of the hip, osteoarthritis and simply aging2. However, patients typically present with pain and clicking or other mechanical symptoms of an insidious nature with physical findings that are sensitive indicators but definitely non-specific6. The impingement sign is usually positive in patients with a labral tear but this sign is also positive with patients with arthritis, femoroacetabular impingement and many other hip disorders.

Patients should be evaluated by confirming that they have a hip joint problem on history and physical examination, with X-rays including a standing AP of the pelvis and at a minimum, a frog leg lateral view of the hip7-9. The Dunn lateral view is more sensitive in identifying asphericity of the femoral head when looking for FAI10. Magnetic resonance imaging with an arthrogram is the investigation of choice for most centres. However, MRI or MRA is not indicated if the X-rays show an obvious problem such as osteoarthritis.

Indications for labral repair are difficult to deduce from the literature since there are no studies comparing resection/debridement to labral repair. The only published studies compare labral repair/refixation compared with resection in patients undergoing surgery to correct femoroacetabular impingement11,12. These authors suggested that FAI surgery combined with labral repair/refixation is better than labral resection. However, neither study was prospective, randomized, took into account the quality of labral tissue nor used validated outcome measures for this type of patient population.

At the present time there is no quality clinical data to support repairing the labrum compared to labral debridement. However, the basic principle of preservation of good quality labral tissue cannot be questioned. Animal research suggests that healing of the labrum is likely, but healing is incomplete and occurs with fibrocartilage13. Whether the same applies to humans is yet to be completely determined.

Techniques of arthroscopic labral repair have been described by several authors14-19. The pre-requisites to perform a labral repair can be divided into three categories: the surgeon, the patient and the technique. The surgeon must be very comfortable and experienced with hip arthroscopy, including knowledge and skills to visualize the central and peripheral compartments, use of anchors, arthroscopic suture tying and have an understanding of accessory portals. The patient must have appropriate clinical and radiological findings and most importantly, labral pathology which is amenable to repair. The technical pre-requisites include adequate but safe distraction to gain easy access to the central compartment of the hip, an arthroscopic capsulotomy to allow for correct insertion of instruments, secure anchor placement in bone with accurate suture positioning and tying. A detailed description of an arthroscopic labral repair is beyond the scope of this brief article. Video reproductions of hip labral tear are available on-line however this procedure should only be performed with careful attention to the above requisite principles.

In summary, arthroscopic repair of the labrum in the hip is important from the perspective of preservation/restoration of "normal" anatomy and therefore function of the hip joint. The technique is difficult; the indications for repair are evolving and good evidence for the effectiveness of repair has yet to be determined.

References

  1. Bedi, A., et al., The management of labral tears and femoroacetabular impingement of the hip in the young, active patient. Arthroscopy, 2008. 24(10): p. 1135-45.
  2. Groh, M.M. and Herrera J., A comprehensive review of hip labral tears. Curr Rev Musculoskelet Med, 2009. 2(2): p. 105-17.
  3. Petersen, W., Petersen F., and Tillmann B., Structure and vascularization of the acetabular labrum with regard to the pathogenesis and healing of labral lesions. Arch Orthop Trauma Surg, 2003. 123(6): p. 283-8.
  4. Cashin, M., et al., Embryology of the acetabular labral-chondral complex. J Bone Joint Surg Br, 2008. 90(8): p. 1019-24.
  5. Saddik, D., et al., Prevalence and location of acetabular sublabral sulci at hip arthroscopy with retrospective MRI review. AJR Am J Roentgenol, 2006. 187(5): p. W507-11.
  6. Burnett, R.S., et al., Clinical presentation of patients with tears of the acetabular labrum. J Bone Joint Surg Am, 2006. 88(7): p. 1448-57.
  7. Clohisy, J.C., et al., A systematic approach to the plain radiographic evaluation of the young adult hip. J Bone Joint Surg Am, 2008. 90 Suppl 4: p. 47-66.
  8. Clohisy, J.C., et al., Radiographic evaluation of the hip has limited reliability. Clin Orthop Relat Res, 2009. 467(3): p. 666-75.
  9. Clohisy, J.C., et al., The frog-leg lateral radiograph accurately visualized hip cam impingement abnormalities. Clin Orthop Relat Res, 2007. 462: p. 115-21.
  10. Meyer, D.C., et al., Comparison of six radiographic projections to assess femoral head/neck asphericity. Clin Orthop Relat Res, 2006. 445: p. 181-5.
  11. Larson, C.M. and Giveans M.R., Arthroscopic debridement versus refixation of the acetabular labrum associated with femoroacetabular impingement. Arthroscopy, 2009. 25(4): p. 369-76.
  12. Philippon, M.J., et al., Outcomes following hip arthroscopy for femoroacetabular impingement with associated chondrolabral dysfunction: minimum two-year follow-up. J Bone Joint Surg Br, 2009. 91(1): p. 16-23.
  13. Philippon, M.J., Arnoczky S.P., and Torrie A., Arthroscopic repair of the acetabular labrum: a histologic assessment of healing in an ovine model. Arthroscopy, 2007. 23(4): p. 376-80.
  14. 1Hernandez, J.D. and McGrath B.E., Safe angle for suture anchor insertion during acetabular labral repair. Arthroscopy, 2008. 24(12): p. 1390-4.
  15. Kelly, B.T., et al., Arthroscopic labral repair in the hip: surgical technique and review of the literature. Arthroscopy, 2005. 21(12): p. 1496-504.
  16. Larson, C.M., et al., Advanced techniques in hip arthroscopy. Instr Course Lect, 2009. 58: p. 423-36.
  17. Murphy, K.P., et al., Repair of the adult acetabular labrum. Arthroscopy, 2006. 22(5): p. 567 e1-3.
  18. Philippon, M.J., 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: p. 309-16.
  19. Philippon, M.J. and Schenker, M.L. A new method for acetabular rim trimming and labral repair. Clin Sports Med, 2006. 25(2): p. 293-7, ix.

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