Marc J Philippon MDab Mara L Schenker BSa

aSteadman-Hawhins Research Foundation, 181 W. Meadow Drive, Suite 1000, Vail, CO 81657, USA Steadman-Hawhins Clinic, 181 W. Meadow Drive, Suite 1000, Vail, CO 81657, USA

Our previously reported technique of labral repair has shown promising clinical outcomes [1,2]. However, the surgical technique is technically demanding and provides less than optimal visualization for anchor placement. As a result, the senior author (MJ.P.) has developed a new technique using the lateral portal. This technique permits better visualization and arthroscopic access to the entire anterior and posterosuperior acetabular rim. The suture anchor can be placed higher on the acetabular rim and at a more precise location and angle (closer to 90°) under direct visualization to avoid anchor penetration into the articulating surface.

Using the previously reported modified supine position for hip arthroscopy [1,2], the patient is placed on a standard fracture table with the operative hip in 10° of flexion, 15° of internal rotation, 10° of lateral tilt, and neutral abduction. To provide for instrument clearance and to avoid iatrogenic damage to the labrum or chondral surfaces, approximately 8 to 10 mm of joint distraction is required. Three arthroscopic portals (anterolateral, anterior, distal lateral accessory) are used and have been previously described [1,2].

Upon joint entry, a systematic examination should be performed of the entire acetabular labrum. The fibrocartilaginous labrum is normally adherent to the acetabular rim and transitions to the hyaline articular cartilage in a zone of approximately 1 to 2 mm [3] (Fig. 1). The labrum is widest anteriorly and thickest superiorly, corresponding to the weight-bearing region of the acetabulum [4]. The labrum has been shown to provide approximately 5 mm of additional femoral head coverage [4], and primarily function as a physiologic joint seal [5,6]. A torn labrum is thought to alter load transmission in the joint and increase articular cartilage consolidation [6,7].

In our practice, we observe five types of labral tears: detached, midsubstance longitudinal, flap, frayed, and degenerative. Seldes et al [3] have described the histology of these tears in cadaveric specimens. The authors defined a separation

* Corresponding author. Steadman-Hawkins Research Foundation, 181 W. Meadow Drive, Suite 1000, Vail, CO 81657. E-mail address: [email protected] (M.J. Philippon).

0278-5919/06/$ - see front matter © 2006 Elsevier Inc. All rights reserved.

doi:10.1016/j.csm.2005.12.005 sportsmed.theclinics.com

Fig. 1. Arthroscopic view of the normal anterior triangle. L, labrum; AC, anterior capsule; FH, femoral head.

between the labrum and the hyaline cartilage as a detached tear and a cleavage plane within the substance of the fibrocartilage as a midsubstance tear. The authors of this study observed a high incidence of labral tears in the aging hip and concluded that they may be an early precursor to hip osteoarthritis [3]. Given what is currently understood about the vascular pattern and function of the labrum, we believe that, in patients with labral tears, preservation of any healthy labral tissue may improve the overall integrity of the hip joint. Thus, it is thought that repair of detached and certain healthy midsubstance labral tears (in the capsular one third section of fibrocartilage) may effectively delay or prevent the onset of hip osteoarthritis. Recently, an in vivo ovine model has been established, to compare labral repair versus labral resection. At 12 weeks post-labral repair, the labrum has shown early evidence of healing (Philippon MJ. Unpublished data, 73rd Annual Meeting of the American Academy of Orthopaedic Surgeons, 2006).

The first steps to addressing labral tears are to assess the type(s) of tear present and to define the borders of the tear with a flexible instrument. Controlled application of monopolar radiofrequency energy to the margins of the tear will contract the fibrocartilage and better define the tear. The goal of arthroscopic debridement of a torn labrum should be to remove the impinging tissue that causes pain and mechanical symptoms. A flexible ligament chisel detaches the torn portion of the labrum from the intact healthy labrum, and a motorized angled shaver helps define the appropriate plane and removes the debrided tissue from the joint (Fig. 2). As previously mentioned, we believe it is important to avoid overresection and preserve as much of the healthy fibrocarti-lage as possible.

We are currently proposing a new technique for the repair of a detached labrum. Based on our surgical experience and the reports of Ganz et al [8], detached labra are common findings in patients with cam-type femoroacetabular impingement. In this condition, a bony abnormality at the junction of the femoral head and neck abuts the acetabular rim, particularly during flexion, internal rotation, and abduction. As a result of the shear forces generated by this impingement,

a separation is thought to be created between the fibrocartilaginous labium and the articular cartilage at the transition zone. Additionally, in patients with large pincer-type femoroacetabular impingement, it may be necessary to surgically detach the labrum in a "rim trimming" procedure for full resection of the bony overhang. In these cases, an arthroscopic osteotome placed through the lateral portal removes small sections of the anterosuperior acetabular rim. A motorized burr through the lateral portal then removes the remaining overhang and contours normal acetabular rim morphology. Following the rim trimming procedure, reattachment of the labrum to the acetabular rim is necessary, and may now also be performed through the lateral portal.

For the repair of a detached labrum, at least one bioabsorbable suture is needed to stabilize the fibrocartilage back to the acetabular rim. After appropriately defining the margins of the tear, the arthroscope is placed in the anterior portal, providing a view of the anterosuperior acetabular rim. A clear 8.25-mm cannula is then introduced through the lateral portal. A sleeve for the anchor is used to establish the appropriate angle for the anchor (Fig. 3A). Fluoroscopy may be used during the procedure to ensure optimal placement. We recommend tapping the sleeve slightly into the acetabular rim and then manually driving the anchor into place using tactile sensation as guidance. While tapping the path of the anchor, it is critical to visualize the articular surface of the acetabulum to assure that the articular surface is not being compromised. If bulging of the articular surface is noticed, the angle of the anchor must be redirected. To avoid penetration into the articular surface, the anchor is typically driven at an approximate angle of 15° to the vertical (Fig. 4). Once the anchor is in place, the articular surface should again be visualized to verify that it has not been penetrated.

The next step is to deliver a limb of suture between the labrum and the acetabular rim with a suture passer (Fig. 3B). Using an arthropierce (bird beak), the suture is retrieved over the labrum (Fig. 3C). As the suture is pulled out through the clear cannula, it is important to visualize the anchor to assure that the correct suture limb is being retrieved. A disadvantage to this labral repair

Fig. 3. Sequence of repair for a detached acetabular labrum. (A) A sleeve is placed on the anterosuperior acetabular rim. L, labrum; A, acetabulum. (B) An arthropierce passes the suture between the acetabular rim and the detached labral tissue. (C) An arthropierce grabs the suture to pull back around the labral tissue. FH, femoral head. (D) Arthroscopic view of completed repair of a detached labrum. L, labrum; A, acetabulum.

Fig. 3. Sequence of repair for a detached acetabular labrum. (A) A sleeve is placed on the anterosuperior acetabular rim. L, labrum; A, acetabulum. (B) An arthropierce passes the suture between the acetabular rim and the detached labral tissue. (C) An arthropierce grabs the suture to pull back around the labral tissue. FH, femoral head. (D) Arthroscopic view of completed repair of a detached labrum. L, labrum; A, acetabulum.

approach is that the suture cannot be easily visualized with the arthroscope in the anterior portal. The cannula must then be pulled back slightly for improved visualization, and the suture is tied down using standard arthroscopic knot-tying techniques (Fig. 3D).

Depending on the size of the labral detachment, a second or third anchor may be necessary. The camera should then be returned to the lateral portal to visualize the labral repair. A flexible radiofrequency probe may then be used to contour the edges of the labrum. At the conclusion of the labral repair, traction should be released and dynamic testing of the labral repair should be performed to confirm adequate repair.

Following repair of the detached labrum, it may be necessary to address pathologies commonly associated with detached labra. Osteoplasty of cam-type femoroacetabular impingement or microfracture of acetabular or femoral chon-dral defects may be performed as needed.

In conclusion, a novel technique for the suture anchor repair of a detached labrum has been described. Detachment of the labrum can result from cam-type femoroacetabular impingement or may be necessitated for full resection of the

Fig. 4. To avoid penetration into the articulating surface, the anchor should be driven at an approximate angle of 15° to the vertical.

pincer-type acetabular overhang. The senior author has performed this new technique in over 140 patients and has noticed a few key advantages over the previously described technique. This approach allows direct visualization of the anterosuperior acetabular rim. The suture anchor may then be placed higher and at a more precise location and angle through the lateral portal. This technique appears to be easier to master and more reproducible when compared to the former technique [1,2].

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