- Email: [email protected]
Hip Labral Repair Options
Hip Labral Repair Options Brett M. Cascio, MD Labrum repair is an important part of hip arthroscopy. Multiple short-term and biomechanical studies have shown that restoring the function of the labrum by repair is preferable to debridement in appropriate situations. There are multiple options for devices to repair the labrum and accessory devices to assist in repair. Options include traditional suture-loaded anchors and newer knotless anchors. There are absorbable, all-suture, and nonabsorbable anchors. This article reviews the anchors, techniques, and accessory devices that are available to the surgeon to facilitate labrum repair. Some of the pitfalls associated with labrum repair and how to avoid them are also discussed. Accessory devices include cannulas and a variety of suture passers. Oper Tech Sports Med 19:125-128 © 2011 Elsevier Inc. All rights reserved. KEYWORDS hip arthroscopy, labrum repair, anchors
H
ip acetabular labrum tears place patients at risk for hip arthritis.1 The decision to debride or repair the torn labrum depends on multiple factors, including the quality of the labrum, the age of the patient, and the presence or absence of a pincer lesion.2,3 Multiple biomechanical and shortterm clinical studies support preserving the labrum when possible.3 Studies indicate that labral repair is preferable to labral debridement.4-6 The biomechanical data also indicate that labrum function is important, is worth preserving, and can be preserved with repair.7,8 Among other things, the acetabular labrum provides support to the articular cartilage, thus shielding the cartilage from shear forces at the edge of the acetabulum.9 Cartilage changes usually begin in the same area of the labrum tear, and over time, these changes can lead to full-thickness acetabular lesions and “kissing” lesions on the femoral head, eventually leading to significant osteoarthritis. Labrum repair rather than debridement attempts to halt or slow this progression. The treatment of pincer-type femoroacetabular impingement requires the destabilization or complete detachment of the completely or partially torn labrum to adequately remove the bony lesion.10,11 Partially detatching the labrum also improves access to either debriding, microfracturing, or removing cartilage lesions associated with labrum tears. The labrum should be repaired after iatrogenic detatchment. Labrum reconstruction involves the use of autograft or allograft tissue as a substitute for the labrum. In this situation, the tissue is held with anchors in the location of the absent labrum. Lake Charles Memorial Hospital, Lake Charles, LA. Address reprint requests to Brett M. Cascio, MD, 1717 Oak Park Boulevard, Lake Charles, LA 70601. E-mail: [email protected]
1060-1872/11/$-see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1053/j.otsm.2010.09.009
Unfortunately, no classification system exists describing labral tears, chondral changes, or the extent of the pincer lesions to guide a surgeon’s decision. The essential question is whether it is worth the extra surgical time, the risk of chondral injury, the risk of implant breakage, or the implant cost to repair the labrum rather than debride it.12 When done without iatrogenic injury, the preponderance of short-term evidence and expert opinion is that the preservation of the labrum is worth the risk. The purpose of this article was to summarize the options available to the surgeon for labral repair so the surgeon can make a more informed decision when faced with the choice to repair or to debride. I review many of the available anchors and other devices that make suture repair possible.
General Categories The standard options for repair include the use of anchors. Anchors can be grossly divided into knotless or knotted hip anchors. There are also various size options and absorbable and nonabsorbable versions. It is the responsibility of the surgeon to assure that implants used are Food and Drug Administration approved.
Knotted Anchors There are several options in this category. Each system uses a drill or punch to make a pilot hole for the anchor, and then the anchor is either tapped or screwed into the acetabular bone. 125
B. M. Cascio
126
Raptor Series The knotted anchor series by Smith and Nephew (Andover, MA) consists of several options. The Osteoraptor anchor is an absorbable anchor comprised of a hydroxyapatite composite and comes in 2.3-mm and 2.9-mm versions. Both versions are loaded with an Ultrabraid suture. The 2.9-mm version also comes in a double-loaded option. Another Smith and Nephew knotted anchor is called the Bioraptor PK and is a nonabsorbable 2.9-mm anchor comprised of poly-ether ketone (PEEK) Optima material double loaded with 2 Ultrabraid sutures (Fig. 1). The Bioraptor also comes in a knotless version, which is discussed later. The insertion of these anchors is via a drill and tap-in method. There is a drill guide that the surgeon keeps in place, removes the drill, and inserts the anchor. Risks include anchor breakage, joint penetration, and the fact that the 2.3-mm Osteoraptor anchors are single loaded so if one suture fails during passage or tying, an additional anchor must be used.
SutureTak This labrum anchor by Arthrex (Naples, FL) comes in an absorbable version, the Bio-SutureTak, and a nonabsorbable version, the PEEK SutureTak. Both versions are 3.0 mm in diameter and 14-mm long. A hole is drilled in the bone, and the anchor is tapped in. The anchors come double loaded with either 1 or 2 permanent # 2 Fiberwire suture. The implantation system includes a drill and drill guide. Risks include anchor breakage or joint penetration.
Conmed Linvatec The 3.1-mm Bio Mini-Revo Anchor by Conmed Linvatec (Utica, NY) offers a single-loaded, screw-in absorbable andchor called the Bio Mini-Revo anchor. The anchor is 3.1 mm in diameter and is made of 96 L/4 D polylactic acid. The implant is preloaded on a disposable driver and is prethreaded with 1 #2 Hi-Fi high-strength suture.
Figure 1 The 2.9-mm Bioraptor PK nonabsorbable anchor by Smith and Nephew (http://www.smith-nephew.com).
Figure 2 The JuggerKnot all-suture permanent anchor by Biology of Metals (http://www.biomet.com).
JuggerKnot The JuggerKnot by Biomet (Warsaw, IN) is an all-suture anchor system (Fig. 2). A 1.4-mm drill is used to create a hole, which is significantly smaller than the hole needed to implant a more traditional-type anchor. The all-suture anchor is comprised of a # 5permanent polyester suture and is loaded with a MaxBraid suture (Fig. 3). The anchor folds or balls up and
Figure 3 The JuggerKnot anchor deployed. The anchor expands approximately 30%, providing resistance to pullout (http://www. biomet.com).
Hip labral repair options
127 The Bio version is comprised of a PEEK eyelet and poly-l-lactic acid (PLLA) anchor, whereas the PEEK anchor has a PEEK anchor and eyelet. Suture is passed around the labrum and loaded through the anchor eyelet, and the anchor is then placed into a predrilled hole and deployed by tapping with a mallet. Suture tension usually increases as the anchor is deployed.
Knotless BioRaptor
expands about 30% when deployed and thus resists pulling back through the original drill hole.
The knotless version of the BioRaptor anchor by Smith and Nephew has become available recently for use in the hip. The anchor has a 2.9-mm inner diameter and an outer diameter approximately 3.5 mm (Fig. 5). The anchor is inserted by a tap in mechanism once the repair suture is passed around the labrum and loaded onto the anchor. The benefit of this anchor is that once the anchor is implanted, tissue tension is adjustable. Once tissue tension is optimized by pulling on the suture strands 1 at a time, then an internal screw mechanism is advanced and compresses the suture to prevent slippage.
Knotless
Capsulotomy
Similar to shoulder anchors, hip knotless anchors have benefits and drawbacks when compared with knotted anchors. Benefits include the lower profile of knotless anchors because of the elimination of the knot and the ability to pass the suture first, thus avoiding the potential need for an additional anchor if the suture on a suture-loaded knotted anchor somehow fails during labral passage or knot tying. Potential drawbacks of knotless anchors include the presence of metal in some versions and the potential for anchor breakage when inserting the anchor at a slightly different angle than the drill hole. This drill angle-insertion angle mismatch occurs because, as opposed to suture-loaded anchors, which are inserted through a drill guide immediately after drilling, the knotless anchor is usually inserted without a guide. There are also a few moments between the drilling of the pilot hole for the knotless anchor and the insertion of the knotless anchor during which the surgeon loads the suture that has been passed around the labrum. These few moments allow for the potential to lose sight of the pilot hole and thus introduce the opportunity for drill angle-insertion angle mismatch. This can cause catastrophic anchor failure when the surgeon attempts to tap the anchor into hard acetabular bone. Ultimately, the use of knotted or knotless anchors depends on surgeon preference because no studies show the superiority of either type of anchor. I use approximately half knotted and half knotless anchors. Visualization of the acetabular bone must be excellent to use a knotless anchor because the drill hole needs to be located to insert the anchor.
The use of capsulotomies in hip arthroscopy allows 2 main benefits. The first is that hip arthroscopy fluid can escape through the capsulotomy through the path of least resistance and thus decrease the risk of fluid extravasation and complications associated with this phenomenon. The second benefit of performing capsulotomies is increased visualization. A capsulotomy allows increased movement of the scope and thus improved visualization. Other benefits include the increased ability to move instruments for completing particular tasks as in suture passage and retrieval for instance. Another benefit of the capsulotomy is potentially decreased iatrogenic injury because freedom of movement allows the surgeon to avoid the femoral head cartilage. I use a beaver blade to perform capsulotomies, and I usually connect the lateral and anterior capsulotomies into 1 large capsulotomy. A potential
Figure 4 The Pushlock knotless nonabsorbable anchor by Arthrex (http://www.Arthrex.com).
Pushlock The Pushlock anchor system by Arthrex uses compression between the anchor and bone to prevent suture slippage and provide the security of the repair. The Pushlock anchors come in 2.9 mm ⫻ 15.5 mm and 3.5 mm ⫻ 19.5 mm versions. Both sizes are available in regular and Bio versions (Fig. 4).
Figure 5 The Bioraptor knotless nonabsorbable anchor by Smith and Nephew. Note the internal screw mechanism that allows tissue tension after anchor insertion. (Courtesy of Smith and Nephew.)
B. M. Cascio
128 downside to performing a capsulotomy includes hip instability in patients, especially in dysplastic patients.
Cannulae I use cannulae extensively to protect my portals. Reestablishing a lost portal during hip arthroscopy can cost valuable traction time. Multiple cannulae exist. Cannulae can also be used to help retract capsule and to direct drill bits, guides, and anchors into the joint at the appropriate angle. Problems can arise when cannulae are not long enough to reach the joint, which happens in larger and more muscular people.
Suture Passers Multiple options for passing suture exist. I use a variety of bird beak suture passers. I usually fold the end of the suture on itself 3 or 4 times in approximately 3-mm lengths. I pass this fold of suture through the labral tear and then release it. The fold of suture unfolds and allows multiple areas of suture at different angles to grab with a grasper. Another option is to use a rotator cuff repair suture passer to pass suture. There are also multiple, variable angled suture shuttles that can be used.
Conclusions Labrum repair is an important part of hip arthroscopy. Multiple anchors exist to repair the labrum and preserve its function. Options include knotless, knotted, absorbable, and nonabsorbable anchors.
References 1. McCarthy JC, Noble PC, Schuck MR, et al: The Otto E Aufranc award: The role of labral lesions to development of early degenerative hip disease. Clin Orthop Relat Res 393:25-37, 2001 2. Bharam S: Labral tears, extra-articular injuries, and hip arthroscopy in the athlete. Clin Sports Med 25:279-292, 2006 3. Robertson WJ, Kadrmas WR, Kelly BT: Arthroscopic management of labral tears in the hip: A systematic review of the literature. Clin Orthop Relat Res 455:88-92, 2007 4. Espinosa N, Rothenfluh DA, Beck M, et al: Treatment of femoro-acetabular impingement: Preliminary results of labral refixation. J Bone Joint Surg Am 88:925-935, 2006 5. Larson CM, Giveans MR: Arthroscopic debridement versus refixation of the acetabular labrum associated with femoroacetabular impingement. Arthroscopy 25:369-376, 2009 6. Philippon MJ, Briggs KK, Yen YM, et al: Outcomes following hip arthroscopy for femoroacetabular impingement with associated chondrolabral dysfunction: minimum two-year follow-up. J Bone Joint Surg Br 91:16-23, 2009 7. Greaves LL, Gilbart MK, Yung AC, et al: Effect of acetabular labral tears, repair and resection on hip cartilage strain: A 7T MR study. J Biomech 43:858-863, 2010 8. Philippon MJ, Arnoczky SP, Torrie A: Arthroscopic repair of the acetabular labrum: A histologic assessment of healing in an ovine model. Arthroscopy 23:376-380, 2007 9. Groh MM, Herrera J: A comprehensive review of hip labral tears. Curr Rev Musculoskelet Med 2:105-117, 2009 10. Philippon MJ, Weiss DR, Kuppersmith DA, et al: Arthroscopic labral repair and treatment of femoroacetabular impingement in professional hockey players. Am J Sports Med 38:99-104, 2010 11. Philippon MJ, Yen YM, Briggs KK, et al: Early outcomes after hip arthroscopy for femoroacetabular impingement in the athletic adolescent patient: A preliminary report. J Pediatr Orthop 28:705-710, 2008 12. Ilizaliturri VM Jr: Complications of arthroscopic femoroacetabular impingement treatment: a review. Clin Orthop Relat Res 467:760-768, 2009
H
ip acetabular labrum tears place patients at risk for hip arthritis.1 The decision to debride or repair the torn labrum depends on multiple factors, including the quality of the labrum, the age of the patient, and the presence or absence of a pincer lesion.2,3 Multiple biomechanical and shortterm clinical studies support preserving the labrum when possible.3 Studies indicate that labral repair is preferable to labral debridement.4-6 The biomechanical data also indicate that labrum function is important, is worth preserving, and can be preserved with repair.7,8 Among other things, the acetabular labrum provides support to the articular cartilage, thus shielding the cartilage from shear forces at the edge of the acetabulum.9 Cartilage changes usually begin in the same area of the labrum tear, and over time, these changes can lead to full-thickness acetabular lesions and “kissing” lesions on the femoral head, eventually leading to significant osteoarthritis. Labrum repair rather than debridement attempts to halt or slow this progression. The treatment of pincer-type femoroacetabular impingement requires the destabilization or complete detachment of the completely or partially torn labrum to adequately remove the bony lesion.10,11 Partially detatching the labrum also improves access to either debriding, microfracturing, or removing cartilage lesions associated with labrum tears. The labrum should be repaired after iatrogenic detatchment. Labrum reconstruction involves the use of autograft or allograft tissue as a substitute for the labrum. In this situation, the tissue is held with anchors in the location of the absent labrum. Lake Charles Memorial Hospital, Lake Charles, LA. Address reprint requests to Brett M. Cascio, MD, 1717 Oak Park Boulevard, Lake Charles, LA 70601. E-mail: [email protected]
1060-1872/11/$-see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1053/j.otsm.2010.09.009
Unfortunately, no classification system exists describing labral tears, chondral changes, or the extent of the pincer lesions to guide a surgeon’s decision. The essential question is whether it is worth the extra surgical time, the risk of chondral injury, the risk of implant breakage, or the implant cost to repair the labrum rather than debride it.12 When done without iatrogenic injury, the preponderance of short-term evidence and expert opinion is that the preservation of the labrum is worth the risk. The purpose of this article was to summarize the options available to the surgeon for labral repair so the surgeon can make a more informed decision when faced with the choice to repair or to debride. I review many of the available anchors and other devices that make suture repair possible.
General Categories The standard options for repair include the use of anchors. Anchors can be grossly divided into knotless or knotted hip anchors. There are also various size options and absorbable and nonabsorbable versions. It is the responsibility of the surgeon to assure that implants used are Food and Drug Administration approved.
Knotted Anchors There are several options in this category. Each system uses a drill or punch to make a pilot hole for the anchor, and then the anchor is either tapped or screwed into the acetabular bone. 125
B. M. Cascio
126
Raptor Series The knotted anchor series by Smith and Nephew (Andover, MA) consists of several options. The Osteoraptor anchor is an absorbable anchor comprised of a hydroxyapatite composite and comes in 2.3-mm and 2.9-mm versions. Both versions are loaded with an Ultrabraid suture. The 2.9-mm version also comes in a double-loaded option. Another Smith and Nephew knotted anchor is called the Bioraptor PK and is a nonabsorbable 2.9-mm anchor comprised of poly-ether ketone (PEEK) Optima material double loaded with 2 Ultrabraid sutures (Fig. 1). The Bioraptor also comes in a knotless version, which is discussed later. The insertion of these anchors is via a drill and tap-in method. There is a drill guide that the surgeon keeps in place, removes the drill, and inserts the anchor. Risks include anchor breakage, joint penetration, and the fact that the 2.3-mm Osteoraptor anchors are single loaded so if one suture fails during passage or tying, an additional anchor must be used.
SutureTak This labrum anchor by Arthrex (Naples, FL) comes in an absorbable version, the Bio-SutureTak, and a nonabsorbable version, the PEEK SutureTak. Both versions are 3.0 mm in diameter and 14-mm long. A hole is drilled in the bone, and the anchor is tapped in. The anchors come double loaded with either 1 or 2 permanent # 2 Fiberwire suture. The implantation system includes a drill and drill guide. Risks include anchor breakage or joint penetration.
Conmed Linvatec The 3.1-mm Bio Mini-Revo Anchor by Conmed Linvatec (Utica, NY) offers a single-loaded, screw-in absorbable andchor called the Bio Mini-Revo anchor. The anchor is 3.1 mm in diameter and is made of 96 L/4 D polylactic acid. The implant is preloaded on a disposable driver and is prethreaded with 1 #2 Hi-Fi high-strength suture.
Figure 1 The 2.9-mm Bioraptor PK nonabsorbable anchor by Smith and Nephew (http://www.smith-nephew.com).
Figure 2 The JuggerKnot all-suture permanent anchor by Biology of Metals (http://www.biomet.com).
JuggerKnot The JuggerKnot by Biomet (Warsaw, IN) is an all-suture anchor system (Fig. 2). A 1.4-mm drill is used to create a hole, which is significantly smaller than the hole needed to implant a more traditional-type anchor. The all-suture anchor is comprised of a # 5permanent polyester suture and is loaded with a MaxBraid suture (Fig. 3). The anchor folds or balls up and
Figure 3 The JuggerKnot anchor deployed. The anchor expands approximately 30%, providing resistance to pullout (http://www. biomet.com).
Hip labral repair options
127 The Bio version is comprised of a PEEK eyelet and poly-l-lactic acid (PLLA) anchor, whereas the PEEK anchor has a PEEK anchor and eyelet. Suture is passed around the labrum and loaded through the anchor eyelet, and the anchor is then placed into a predrilled hole and deployed by tapping with a mallet. Suture tension usually increases as the anchor is deployed.
Knotless BioRaptor
expands about 30% when deployed and thus resists pulling back through the original drill hole.
The knotless version of the BioRaptor anchor by Smith and Nephew has become available recently for use in the hip. The anchor has a 2.9-mm inner diameter and an outer diameter approximately 3.5 mm (Fig. 5). The anchor is inserted by a tap in mechanism once the repair suture is passed around the labrum and loaded onto the anchor. The benefit of this anchor is that once the anchor is implanted, tissue tension is adjustable. Once tissue tension is optimized by pulling on the suture strands 1 at a time, then an internal screw mechanism is advanced and compresses the suture to prevent slippage.
Knotless
Capsulotomy
Similar to shoulder anchors, hip knotless anchors have benefits and drawbacks when compared with knotted anchors. Benefits include the lower profile of knotless anchors because of the elimination of the knot and the ability to pass the suture first, thus avoiding the potential need for an additional anchor if the suture on a suture-loaded knotted anchor somehow fails during labral passage or knot tying. Potential drawbacks of knotless anchors include the presence of metal in some versions and the potential for anchor breakage when inserting the anchor at a slightly different angle than the drill hole. This drill angle-insertion angle mismatch occurs because, as opposed to suture-loaded anchors, which are inserted through a drill guide immediately after drilling, the knotless anchor is usually inserted without a guide. There are also a few moments between the drilling of the pilot hole for the knotless anchor and the insertion of the knotless anchor during which the surgeon loads the suture that has been passed around the labrum. These few moments allow for the potential to lose sight of the pilot hole and thus introduce the opportunity for drill angle-insertion angle mismatch. This can cause catastrophic anchor failure when the surgeon attempts to tap the anchor into hard acetabular bone. Ultimately, the use of knotted or knotless anchors depends on surgeon preference because no studies show the superiority of either type of anchor. I use approximately half knotted and half knotless anchors. Visualization of the acetabular bone must be excellent to use a knotless anchor because the drill hole needs to be located to insert the anchor.
The use of capsulotomies in hip arthroscopy allows 2 main benefits. The first is that hip arthroscopy fluid can escape through the capsulotomy through the path of least resistance and thus decrease the risk of fluid extravasation and complications associated with this phenomenon. The second benefit of performing capsulotomies is increased visualization. A capsulotomy allows increased movement of the scope and thus improved visualization. Other benefits include the increased ability to move instruments for completing particular tasks as in suture passage and retrieval for instance. Another benefit of the capsulotomy is potentially decreased iatrogenic injury because freedom of movement allows the surgeon to avoid the femoral head cartilage. I use a beaver blade to perform capsulotomies, and I usually connect the lateral and anterior capsulotomies into 1 large capsulotomy. A potential
Figure 4 The Pushlock knotless nonabsorbable anchor by Arthrex (http://www.Arthrex.com).
Pushlock The Pushlock anchor system by Arthrex uses compression between the anchor and bone to prevent suture slippage and provide the security of the repair. The Pushlock anchors come in 2.9 mm ⫻ 15.5 mm and 3.5 mm ⫻ 19.5 mm versions. Both sizes are available in regular and Bio versions (Fig. 4).
Figure 5 The Bioraptor knotless nonabsorbable anchor by Smith and Nephew. Note the internal screw mechanism that allows tissue tension after anchor insertion. (Courtesy of Smith and Nephew.)
B. M. Cascio
128 downside to performing a capsulotomy includes hip instability in patients, especially in dysplastic patients.
Cannulae I use cannulae extensively to protect my portals. Reestablishing a lost portal during hip arthroscopy can cost valuable traction time. Multiple cannulae exist. Cannulae can also be used to help retract capsule and to direct drill bits, guides, and anchors into the joint at the appropriate angle. Problems can arise when cannulae are not long enough to reach the joint, which happens in larger and more muscular people.
Suture Passers Multiple options for passing suture exist. I use a variety of bird beak suture passers. I usually fold the end of the suture on itself 3 or 4 times in approximately 3-mm lengths. I pass this fold of suture through the labral tear and then release it. The fold of suture unfolds and allows multiple areas of suture at different angles to grab with a grasper. Another option is to use a rotator cuff repair suture passer to pass suture. There are also multiple, variable angled suture shuttles that can be used.
Conclusions Labrum repair is an important part of hip arthroscopy. Multiple anchors exist to repair the labrum and preserve its function. Options include knotless, knotted, absorbable, and nonabsorbable anchors.
References 1. McCarthy JC, Noble PC, Schuck MR, et al: The Otto E Aufranc award: The role of labral lesions to development of early degenerative hip disease. Clin Orthop Relat Res 393:25-37, 2001 2. Bharam S: Labral tears, extra-articular injuries, and hip arthroscopy in the athlete. Clin Sports Med 25:279-292, 2006 3. Robertson WJ, Kadrmas WR, Kelly BT: Arthroscopic management of labral tears in the hip: A systematic review of the literature. Clin Orthop Relat Res 455:88-92, 2007 4. Espinosa N, Rothenfluh DA, Beck M, et al: Treatment of femoro-acetabular impingement: Preliminary results of labral refixation. J Bone Joint Surg Am 88:925-935, 2006 5. Larson CM, Giveans MR: Arthroscopic debridement versus refixation of the acetabular labrum associated with femoroacetabular impingement. Arthroscopy 25:369-376, 2009 6. Philippon MJ, Briggs KK, Yen YM, et al: Outcomes following hip arthroscopy for femoroacetabular impingement with associated chondrolabral dysfunction: minimum two-year follow-up. J Bone Joint Surg Br 91:16-23, 2009 7. Greaves LL, Gilbart MK, Yung AC, et al: Effect of acetabular labral tears, repair and resection on hip cartilage strain: A 7T MR study. J Biomech 43:858-863, 2010 8. Philippon MJ, Arnoczky SP, Torrie A: Arthroscopic repair of the acetabular labrum: A histologic assessment of healing in an ovine model. Arthroscopy 23:376-380, 2007 9. Groh MM, Herrera J: A comprehensive review of hip labral tears. Curr Rev Musculoskelet Med 2:105-117, 2009 10. Philippon MJ, Weiss DR, Kuppersmith DA, et al: Arthroscopic labral repair and treatment of femoroacetabular impingement in professional hockey players. Am J Sports Med 38:99-104, 2010 11. Philippon MJ, Yen YM, Briggs KK, et al: Early outcomes after hip arthroscopy for femoroacetabular impingement in the athletic adolescent patient: A preliminary report. J Pediatr Orthop 28:705-710, 2008 12. Ilizaliturri VM Jr: Complications of arthroscopic femoroacetabular impingement treatment: a review. Clin Orthop Relat Res 467:760-768, 2009