The Journal of Bone & Joint Surgery

The Journal of Bone & Joint Surgery, Volume 92, Issue 15

Scientific Articles | November 03, 2010

Vascular Supply to the Acetabular Labrum

Morteza Kalhor, MD¹; Kevin Horowitz, MD²; Martin Beck, MD³; Bashir Nazparvar, MD⁴; Reinhold Ganz, MD³

¹ Department of Orthopedic Surgery, Iran University of Medical Sciences, Firouzgar Medical Center, Behafarin Street, Tehran 15934, Iran
² Department of Orthopaedic Surgery, Baylor College of Medicine, 6701 Fannin Street, CC 670.01, Houston, TX 77030. E-mail address: kshorowi@texaschildrens.org
³ Department of Orthopedic Surgery, University of Bern, Inselspital CH-3010, Bern, Switzerland
⁴ Department of Anatomy, Legal Medicine Research Center, Behesht Street, Khayyam Avenue, Tehran 11144, Iran

View Disclosures and Other Information

Disclosure: The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity.

Investigation performed at the Department of Orthopedic Surgery, Iran University of Medical Sciences, Firouzgar Medical Center, and the Department of Anatomy, Legal Medicine Research Center, Tehran, Iran

J Bone Joint Surg Am, 2010 Nov 03;92(15):2570-2575. doi: 10.2106/JBJS.I.01719

5 Recommendations (Recommend) | 3 Comments | Saved by 3 Users Save Case

Article

Comments (0)

text A A A

Abstract

Background:

The acetabular labrum plays an important role in hip joint stability and protection of the articular cartilage of the hip. Despite this, few investigators have evaluated its microscopic vasculature and, to our knowledge, none has assessed its macroscopic blood supply. The purposes of this study were to identify the origin and course of the vascular supply to the acetabular labrum to determine if this blood supply is affected by a labral tear.

Methods:

Colored silicone was injected into the vascular tree proximal to thirty-five hips in twenty-eight fresh cadavers. Twenty-four hours after injection, anatomic dissection was performed and the vessels supplying the labrum were followed from their origin to their final distribution. Additionally, labral segments of fifteen randomly selected hips were resected to assess the acetabular rim's vascular contribution, and fifteen hips were dislocated for complete intra-articular inspection of the labrum.

Results:

Radial branches of a previously described periacetabular periosteal vascular ring were identified as the source of labral blood supply in all thirty-five hips. These branches coursed toward the hip joint on the periosteal surface, penetrated the joint capsule near its innominate insertion, and continued within a loose connective-tissue layer on the capsular surface of the labrum. No contribution from the hip capsule, synovial lining, or osseous acetabular rim could be demonstrated. An intact vascular supply was identified in all seven hips with a labral tear.

Conclusions:

The acetabular labrum receives its blood supply from radial branches of a periacetabular periosteal vascular ring that traverses the osseolabral junction on its capsular side and continues toward the labrum's free edge. The hip capsule, the synovial lining, and the osseous acetabular rim do not appear to provide substantial contributions to the labral blood supply.

Clinical Relevance:

The blood supply to the acetabular labrum probably remains intact in the majority of hips with labral tears, which are typically partial-thickness tears on the articular side. An improved understanding of labral vasculature may have implications for the surgical treatment of labral tears and associated osseous abnormalities.

Figures in this Article

Introduction

The acetabular labrum is a fibrocartilaginous structure attached to the periphery of the osseous acetabular rim. It increases joint depth, stability, and congruity¹ and provides a seal that is critical for protection of the articular cartilage of the hip².

Damage to the labrum has been identified as a factor in the development of coxarthrosis^3-7. Outcomes of open treatment of femoroacetabular impingement have been shown to be superior when the labrum is reattached, compared with when it is resected⁸. Therefore, the current philosophy in joint preservation surgery is to maintain and repair the labrum whenever possible^8-12.

Despite the importance of the acetabular labrum, only a few investigators have evaluated its vascularity^13-15. These investigators used histologic cross sections to assess the location and density of vessels within and adjacent to the labrum. We are aware of no report, however, that has described the precise pattern of blood supply to the labrum.

The purpose of this cadaveric study was to describe the macroscopic vascular supply to the acetabular labrum from its origin to its termination. A secondary purpose was to determine whether the labral blood supply is interrupted in the presence of a labral tear.

Materials and Methods

The Legal Medicine Research Center in Tehran in cooperation with the Iran University of Medical Sciences provided the specimens for this study. The selection and preparation of the cadavers were overseen by the autopsy service of the Legal Medicine Research Center and were supervised by a forensic medicine specialist. Formal institutional review board approval was not required, but the study had the support and approval of our orthopaedic department and hospital administration. This investigation was part of a more extensive cadaveric study being performed to examine the overall vasculature within and surrounding the hip joint.

Thirty-five hips in twenty-eight fresh cadavers (twenty-five male and three female) were evaluated. The approximate ages of the donors at the time of death ranged from twenty to fifty years, although the precise ages as well as the clinical histories were not available. The cadavers of younger people were selected when possible because of the ease of vascular filling and better definition of the dissected structures. In all specimens, the hip region was intact with no signs of previous surgery.

With use of large syringes, 150 to 180 mL of green silicone was injected into the common iliac artery of the first twenty-one cadavers, which subsequently underwent unilateral hip dissection. Manual pressure was applied to the syringes until further passage of the silicone was not possible. In the final seven cadavers, which underwent bilateral hip dissection, the aorta was injected with approximately 240 mL of silicone. The technique of injection has been described previously¹⁶.

Twenty-four hours after silicone injection, the hips were approached both anteriorly and posteriorly. All dissections were performed by one of the authors (M.K.). The ilioinguinal approach with a vertical femoral limb was used for anterior access and a transtrochanteric approach was used for posterior access. The injected vessels were followed from their proximal origin to their distal termination. Muscles covering the periacetabular bone and hip capsule were removed, while the periosteum was preserved. With use of sharp dissection, it was relatively easy to separate the muscle fibers from the periosteum and to preserve the underlying vessels. However, it was more difficult to separate these muscles from the hip capsule because of the presence of perforating vessels and the lack of a clear dissection interval, particularly at the location of their tendinous attachments. A circumferential capsulotomy near the acetabular rim was performed, with care taken to not damage the soft tissues overlying the labrum or the traversing vessels.

In fifteen randomly selected hips, a 5 to 10-mm segment of intact labrum was resected and was visually assessed for vessels entering the substance of the labrum from its osseous attachment. These sections were taken from the posterior aspect of the labrum in eight cases, the superior aspect of the labrum in four, and the anterior aspect of the labrum in three. For the first twenty dissections, the hip was subluxated but not completely dislocated. For the final fifteen dissections (all in male cadavers), the hip was fully dislocated and the articular surfaces of the labrum were evaluated.

Source of Funding

There was no external source of funding for this study.

Results

In all specimens, the acetabular labrum was supplied by radial branches of a periacetabular vascular ring. This ring, which has been described previously^16,17, receives its primary supply from the superior and inferior gluteal arteries, with lesser contributions from the medial and lateral circumflex femoral arteries. In addition, the anterior portion of the ring receives a minor contribution from the intrapelvic vasculature. The radial branches from this ring ran on the periosteal surface toward the hip capsule (Fig. 1-A). They penetrated the capsule near its innominate insertion, ran perpendicularly across the osseolabral junction, continued on the labrum's capsular surface, and terminated near its free edge (Fig. 1-B). Once they were intracapsular, these vessels were contained within a loose connective-tissue layer that was continuous with the synovial lining of the hip capsule.

Fig. 1-A

Fig. 1-A Posterolateral aspect of a left hip after detachment of the muscles from the capsule and acetabular bone and before capsulotomy, demonstrating the radial branches of the periacetabular vascular ring arteries running on the periosteum toward the hip capsule. 1 = greater trochanter. 2 = dashed line showing the free edge of the labrum beneath the capsule. 3 = dashed line showing the periacetabular origin of the capsule. 4 = radial branches to the acetabular bone and labrum. Fig. 1-B Posterolateral aspect of the same hip shown in Fig. 1-A after capsulotomy, demonstrating the radial branches traversing the capsular surface of the labrum. 1 = greater trochanter. 2 = femoral head. 3 = labrum. 4 = radial branches to the acetabular bone and labrum. 5 = periacetabular vascular ring.

View Large | Download Slide(.ppt)
Add to My JBJS

The radial supply vessels were not uniformly spaced around the circumference of the labrum. The highest concentration of vessels was found posteriorly, with roughly two-thirds of the radial branches located in the posterior half of the labrum (Fig. 2). The posterosuperior quadrant appeared to have a slightly higher density of vessels (see Appendix) than the posteroinferior quadrant, and the anteroinferior quadrant had a higher concentration of radial branches than the anterosuperior quadrant. The branches supplying the superior and posterosuperior portions of the labrum arose from the portion of the periacetabular ring supplied primarily by the superior gluteal artery (see Appendix), while those supplying the posterior and posteroinferior parts of the labrum arose from the portion of the ring supplied primarily by the inferior gluteal artery (see Appendix).

Fig. 2

Schematic drawing of the lateral aspect of the right innominate bone and acetabulum, demonstrating the periacetabular vascular ring and the approximate concentration of the radial arterial branches around the circumference of the labrum. 1 = superior gluteal artery. 2 = inferior gluteal artery. 3 = anterior superior iliac spine. 4 = anterior inferior iliac spine. 5 = stump of the reflected head of the rectus femoris. 6 = periacetabular vascular ring. White arrowheads = contribution of the medial femoral circumflex artery to the periacetabular vascular ring. Black arrowhead = contribution of the lateral femoral circumflex artery to the periacetabular vascular ring. Black arrows = contribution of the intrapelvic vascular system to the periacetabular vascular ring.

View Large | Download Slide(.ppt)
Add to My JBJS

In all cadavers, the labrum was triangular in cross section with its base attached to the osseous acetabular rim and continuous with the acetabular cartilage. Visual inspection of the cut surfaces of the resected labral segments failed to show any vessels entering the labrum from the adjacent subchondral bone (Fig. 3). Labral separation from the acetabular cartilage was found in seven of the fifteen hips (all in males) in which full dislocation had been performed. Regardless of the depth and extent of the separation, the capsular side of the labrum in these seven hips was in continuity with the acetabular rim and the overlying vascular connective-tissue layer remained intact. We did not observe any difference in the number of labral vessels between hips with an intact labrum and those with chondrolabral separation, although a very slight and focal synovitis was seen in the two hips with the most severe labral damage. No overt signs of advanced osteoarthritis or other intra-articular disease were apparent in any hip.

Fig. 3

Posterior aspect of a right hip following resection of a segment of the labrum. The arrow points to the osseolabral junction and shows the absence of visible vessels traversing this boundary. The radial vessels on the labrum can be seen embedded in a layer of loose connective tissue. 1 = femoral head. 2 = labrum. The arrowhead points to a radial vessel on the labrum, which can be seen embedded in a layer of loose connective tissue.

View Large | Download Slide(.ppt)
Add to My JBJS

Discussion

The results of this investigation support the finding in prior studies that the blood supply to the acetabular labrum is located on its capsular surface. Seldes et al.¹³ assessed labral cross sections histologically and found highly vascular loose connective tissue lining a recess between the hip capsule and the capsular surface of the labrum. Petersen et al.¹⁴ also described this connective-tissue layer and, using immunohistochemical methods, identified the presence of blood vessels only within the capsular third of the labrum. Kelly et al.¹⁵ graded labral cross sections for vascular density and found a substantially increased concentration of vessels within the capsular half of the labrum.

Unlike these prior studies, however, our study identified the origin of the capsular-sided blood supply. This blood supply was found to be a series of radial arteries originating from the periacetabular vascular ring and not vessels on the capsular surface or within the synovial lining. This finding is in contrast to the conclusion of Petersen et al.¹⁴ that the labrum was nourished by a well-vascularized joint capsule and the statement by Kelly et al.¹⁵ that the hip capsule provided the major contribution to the vascularity of the labrum. Since these investigators did not follow the source of the blood supply proximally, their conclusions were likely based on the presence of highly vascular tissue on the capsular side of the labrum.

Although the intraosseous penetration of injected silicone is limited, we found no evidence of vessels entering the labrum from the acetabular rim. Previous investigators who have assessed the contribution of the osseous acetabulum to labral vasculature have reported inconsistent findings. All of the intralabral vessels that Seldes et al.¹³ identified were adjacent to the osseous acetabular projection; this was true for both the circumferential small-caliber vessels in the intact labrum and the increased microvascularity that they found in the torn labrum. The proximity of these vessels to the acetabular rim likely led to those authors’ hypothesis that one possible source of labral neovascularization was the adjacent subchondral bone. Kelly et al.¹⁵ reported an inconsistent contribution of vascular supply from the osseous acetabulum, although they found no substantial difference in vessel concentration between portions of the labrum adjacent to and those distant from the osseous acetabular projection.

Of the fifteen cadaveric hips that were fully dislocated in this study, seven were found to have articular-sided discontinuity between the labrum and the acetabular cartilage. The capsular side of the osseolabral junction as well as the terminal supply vessels remained intact in every hip. The extent of labral damage did not appear to influence the blood supply, although slight and very focal synovitis was seen in the two hips with the most severe labral damage. Other investigators have reported variable findings regarding the vascular response to labral tears. Seldes et al.¹³ reported increased microvascularity while Kelly et al.¹⁵ found no difference in the vascular pattern.

The concentration of radial vessels identified in this study was not uniform around the circumference of the labrum. Although there was some variability among specimens, the anterior aspect of the labrum showed the lowest density of vessels in all hips. This finding is in contrast to that of Kelly et al.¹⁵ who found no substantial difference in vascularity patterns within the anterior, superior, posterior, and inferior regions of the labrum. The paucity of the radial vessels identified anteriorly may be a result of the attachment of the strong iliofemoral ligament and the reflected head of the rectus femoris muscle, which may act as barriers to the entrance of the extracapsular radial arteries.

Our findings suggest that the blood supply to the acetabular labrum likely remains intact in the majority of hips with labral tears, which typically occur on the articular side^13,18. This finding may have implications for the techniques used for surgical repair of labral tears. A popular treatment protocol for acetabular overcoverage or retroversion seen in pincer-type femoroacetabular impingement consists of labral detachment, rim-trimming, and labral refixation with suture anchors^8,9,11,12. These procedures can be performed via a surgical hip dislocation approach or by arthroscopic means. Our anatomic dissections indicate that labral detachment transects the vessels that supply the labrum. Early results⁸ of this labral refixation technique have been shown to be superior to those of labral resection, but long-term results and verification of labral healing are lacking. Although Philippon et al.¹¹ showed evidence of healing after releasing short segments of the ovine labrum, it is unclear what length of separation will heal in humans and whether the circumferential vessels described by Seldes et al.¹³ provide vascular supply between the remaining feeding vessels.

This study was limited by the ability of injected silicone to penetrate deeply into intraosseous vessels and those within the substance of the labrum. In addition, no histologic evaluation was performed to demonstrate how the supply vessels enter the labral tissue. Lastly, the density of radial vessels that was reported was based on the observations of one author (M.K.) during the dissections and his subsequent review of photographs of the cadaveric dissections. Our findings, however, demonstrate that the blood supply to the labrum is from extra-articular radial branches of a periacetabular vascular ring that cross the capsular side of the osseolabral junction. Therefore, performing a capsulotomy of any configuration should leave the vascular supply to the labrum intact provided that the adjacent periosteum and overlying loose connective tissue are not disrupted. Complete release of the labrum, however, necessarily damages labral supply arterioles, which may affect healing. This shortcoming may promote the development of novel techniques of rim-trimming and labral repair in which the capsular-sided connective tissue is preserved. Although such techniques have not been investigated, maintaining the vasculature to the labrum would likely optimize the healing environment. Creating new methods to improve the survival of labral tissue is important considering the increasing evidence of the labrum's vital role in normal hip function^1,2,19-21 and the prevention of osteoarthritis^3-5,7,8,10.

Appendix

Additional images showing the vascular supply to the acetabular labrum are available with the electronic version of this article on our web site at jbjs.org (go to the article citation and click on "Supporting Data").

References

Ferguson SJ; Bryant JT; Ganz R; Ito K. The influence of the acetabular labrum on hip joint cartilage consolidation: a poroelastic finite element model. J Biomech. 2000;33:953-60.[PubMed][CrossRef]

Ferguson SJ; Bryant JT; Ganz R; Ito K. The acetabular labrum seal: a poroelastic finite element model. Clin Biomech (Bristol, Avon). 2000;15:463-8.[PubMed]

Altenberg AR. Acetabular labrum tears: a cause of hip pain and degenerative arthritis. South Med J. 1977;70:174-5.[PubMed]

Harris WH; Bourne RB; Oh I. Intra-articular acetabular labrum: a possible etiological factor in certain cases of osteoarthritis of the hip. J Bone Joint Surg Am. 1979;61:510-4.[PubMed]

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;393:25-37.[PubMed]

Leunig M; Beck M; Woo A; Dora C; Kerboull M; Ganz R. Acetabular rim degeneration: a constant finding in the aged hip. Clin Orthop Relat Res. 2003;413:201-7.[PubMed]

Ganz R; Parvizi J; Beck M; Leunig M; Nötzli H; Siebenrock KA. Femoroacetabular impingement: a cause for osteoarthritis of the hip. Clin Orthop Relat Res. 2003;417:112-20.[PubMed]

Espinosa N; Rothenfluh DA; Beck M; Ganz R; Leunig M. Treatment of femoro-acetabular impingement: preliminary results of labral refixation. J Bone Joint Surg Am. 2006;88:925-35.[PubMed]

Kelly BT; Weiland DE; Schenker ML; Philippon MJ. Arthroscopic labral repair in the hip: surgical technique and review of the literature. Arthroscopy. 2005;21:1496-504.[PubMed]

Murphy KP; Ross AE; Javernick MA; Lehman RA Jr. Repair of the adult acetabular labrum. Arthroscopy. 2006;22: 567.e1-3.

Philippon MJ; Arnoczky SP; Torrie A. Arthroscopic repair of the acetabular labrum: a histologic assessment of healing in an ovine model. Arthroscopy. 2007;23:376-80.[PubMed]

Philippon MJ; Schenker ML. A new method for acetabular rim trimming and labral repair. Clin Sports Med. 2006;25:293-7, ix.[PubMed]

Seldes RM; Tan V; Hunt J; Katz M; Winiarsky R; Fitzgerald RH Jr. Anatomy, histologic features, and vascularity of the adult acetabular labrum. Clin Orthop Relat Res. 2001;382:232-40.[PubMed]

Petersen W; Petersen F; Tillmann B. Structure and vascularization of the acetabular labrum with regard to the pathogenesis and healing of labral lesions. Arch Orthop Trauma Surg. 2003;123:283-8.[PubMed]

Kelly BT; Shapiro GS; Digiovanni CW; Buly RL; Potter HG; Hannafin JA. Vascularity of the hip labrum: a cadaveric investigation. Arthroscopy. 2005;21:3-11.[PubMed]

Kalhor M; Beck M; Huff TW; Ganz R. Capsular and pericapsular contributions to acetabular and femoral head perfusion. J Bone Joint Surg Am. 2009;91:409-18.[PubMed]

Beck M; Leunig M; Ellis T; Sledge JB; Ganz R. The acetabular blood supply: implications for periacetabular osteotomies. Surg Radiol Anat. 2003;25:361-7.[PubMed]

Larson CM; Giveans MR. Arthroscopic management of femoroacetabular impingement: early outcomes measures. Arthroscopy. 2008;24:540-6.[PubMed]

Konrath GA; Hamel AJ; Olson SA; Bay B; Sharkey NA. The role of the acetabular labrum and the transverse acetabular ligament in load transmission in the hip. J Bone Joint Surg Am. 1998;80:1781-8.[PubMed]

Tan V; Seldes RM; Katz MA; Freedhand AM; Klimkiewicz JJ; Fitzgerald RH Jr. Contribution of acetabular labrum to articulating surface area and femoral head coverage in adult hip joints: an anatomic study in cadavera. Am J Orthop (Belle Mead NJ). 2001;30:809-12.[PubMed]

Crawford MJ; Dy CJ; Alexander JW; Thompson M; Schroder SJ; Vega CE; Patel RV; Miller AR; McCarthy JC; Lowe WR; Noble PC. The 2007 Frank Stinchfield Award. The biomechanics of the hip labrum and the stability of the hip. Clin Orthop Relat Res. 2007;465:16-22.[PubMed]

Topics

vascular ring ; cadaver ; tissue dissection ; hip joint ; silicones ; blood supply, arterial ; acetabular labrum ; hip joint capsule ; acetabular rim

Username

Password

Access for Patients

Forgot Password?

Have a subscription to the print edition?

Not a Subscriber?

Buy this Article

Get online access for 30 days for $35

New to JBJS?

Subscribe to the online edition for 30 days for $75

Register for a FREE limited account to get full access to all CME activities, to comment on public articles, or to sign up for alerts.

Have a subscription to the print edition?

Current subscribers to The Journal of Bone & Joint Surgery in either the print or quarterly DVD formats receive free online access to JBJS.org.

Activate your online account now

Forgot your password?

Enter your username and email address. We'll send you a reminder to the email address on record.

Username:*

Email Address:*

Forgot your username or need assistance? Please contact customer service at subs@jbjs.org. If your access is provided
by your institution, please contact you librarian or administrator for username and password information. Institutional
administrators, to reset your institution's master username or password, please contact subs@jbjs.org

References

Accreditation Statement

These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.

CME Activities Associated with This Article

Submit a Comment

Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
Comments are moderated and will appear on the site at the discretion of JBJS editorial staff.

* = Required Field

Comment Author(s) * (if multiple authors, separate names by comma)

Example: John Doe

Affiliation & Institution*

Comment Title*

Comment*

Cancel

Print
PDF
Email

Recipient(s) will receive an email with a link (good for 5 days) to 'Vascular Supply to the Acetabular Labrum'.
Your Name:*
Example: John Doe

Email Address:* CC Me:
Enter your valid email address. Example: jdoe@example.com

Recipient's Email Address:*

Separate multiple email address with semi-colons (up to 5).

Subject:* 's The Journal of Bone & Joint Surgery: 'Vascular Supply to the Acetabular Labrum'
Subject for your email.

Message:

(Optional, message will truncate at 1000 characters)

Processing your request... Please Wait...

Copyright © in the material you requested is held by The Journal of Bone & Joint Surgery, Inc. (unless otherwise noted). This email ability is provided as a courtesy, and by using it you agree that that you are requesting the material solely for personal, non-commercial use, and that it is subject to Journal of Bone & Joint Surgery, Inc.'s Terms of Use. The information provided in order to email this topic will not be used to send unsolicited email, nor will it be furnished to third parties. Please refer to The Journal of Bone & Joint Surgery Inc.'s Privacy Policy for further information.

Copyright © The Journal of Bone & Joint Surgery Inc. All rights reserved.
Share
Get Citation

Morteza Kalhor, Kevin Horowitz, Martin Beck, Bashir Nazparvar, Reinhold Ganz; Vascular Supply to the Acetabular Labrum. The Journal of Bone & Joint Surgery. 2010 Nov;92(15):2570-2575.

Download citation file:

RIS (Zotero)

EndNote

BibTex

Medlars

ProCite

RefWorks

Reference Manager

Copyright © The Journal of Bone and Joint Surgery, Inc.
Rights & Permissions
Article Alerts

Processing your request... Please Wait.
Submit a Comment
Data Supplements