AOA Symposium. Hip Disease in the Young Adult: Current Concepts of Etiology and Surgical Treatment

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1 This is an enhance PDF from The Journal of Bone an Joint Surgery The PDF of the article you requeste follows this cover page. AA Symposium. Hip Disease in the Young Ault: Current Concepts of Etiology an Surgical Treatment John C. Clohisy, Paul E. Beaulé, Aran 'Malley, Marc R. Safran an Perry Schoenecker J Bone Joint Surg Am. 2008;90: oi: /jbjs.g This information is current as of May 11, 2011 Reprints an Permissions Publisher Information Click here to orer reprints or request permission to use material from this article, or locate the article citation on jbjs.org an click on the [Reprints an Permissions] link. The Journal of Bone an Joint Surgery 20 Pickering Street, eeham, MA

2 2267 CPYRIGHT Ó 2008 BY THE JURAL F BE AD JIT SURGERY, ICRPRATED the rthopaeic forum AA Symposium Hip Disease in the Young Ault: Current Concepts of Etiology an Surgical Treatment* By John C. Clohisy, MD, Paul E. Beaulé, MD, FRCSC, Aran Malley, MD, Marc R. Safran, MD, an Perry Schoenecker, MD The unerstaning, iagnosis, an treatment of arthritic hip isease in young patients are rapily evolving. A variety of new an refine surgical techniques are now being utilize worlwie, an continue progress in this realm of orthopaeics is inevitable. *This report is base on a symposium presente at the Annual Meeting of the American rthopaeic Association on June 13-16, 2007, in Asheville, orth Carolina. evertheless, there are major challenges to optimize the introuction an utilization of these proceures on a more wiesprea basis. In this American rthopaeic Association (AA) symposium, the attenees were aske whether the overall quality of iagnostic evaluation an surgical treatment of prearthritic an early arthritic hip isease in the Unite States is optimal, acceptable or eficient 1. Fifty-seven percent of the responents answere that iagnostic an surgical care is eficient, inicating a nee for improve meical management of these patients. Progress in this subspecialty area is epenent on the evelopment of improve methos of patient evaluation an selection for surgery, effective issemination of new knowlege, an the clinical investigation of refine an new surgical interventions. Young ault patients pose a unique challenge in that they present to the orthopaeic surgeon Disclosure: In support of their research for or preparation of this work, one or more of the authors receive, in any one year, outsie funing or grants in excess of $10,000 from Zimmer, Inc an the Washington University Institute of Clinical an Translational Sciences. either they nor a member of their immeiate families receive payments or other benefits or a commitment or agreement to provie such benefits from a commercial entity. o commercial entity pai or irecte, or agree to pay or irect, any benefits to any research fun, founation, ivision, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immeiate families, are affiliate or associate. J Bone Joint Surg Am. 2008;90: oi: /jbjs.g.01267

3 2268 T HE J URAL F B E &JIT S URGERY JBJS. RG VLUME 90-A UMBER 10 CTBER 2008 H IP D ISEASE I THE YUG A DULT:CURRET C CEPTS F E TILGY AD S URGICAL T REATMET with hip symptoms that originate from a wie range of isease processes, an the patient age range spans from aolescence through mile age. Perhaps most notable is that these patients present to a variety of orthopaeic surgeons with ifferent treatment perspectives. These inclue general orthopaeists as well as peiatric, sports meicine, ault reconstruction, an trauma subspecialists. The purposes of this report are to escribe the spectrum of hip isease encountere in young ault patients an to review the contemporary concepts of the etiology an surgical treatment of such isorers. Importantly, there is a relative lack of high-level clinical evience for alternative hip proceures. The majority of reports regaring these interventions are Level IV, an many of the technical aspects of treatment continue to evolve without the support of strong clinical outcomes research. This fact unerscores the nee for surgeons to carefully consier the utilization of new proceures in these patients an to perform higher-level clinical stuies to assess the true value of these interventions. I. Etiology of Hip Disease Mechanical hip ysfunction is a major cause of early hip egeneration an osteoarthritis 2-8. A variety of structural hip isorers have been propose as etiologies of joint pathomechanics. These inclue evelopmental ysplasia of the hip, Perthes isease, slippe capital femoral epiphysis, an impingement isorers 3,4,9. Mechanical isorers of the hip can be ivie into two major categories: structural instability (ysplasia) an femoroacetabular impingement, or combinations of the two (Fig. 1). steoarthritis most commonly occurs seconary to repetitive an/or chronic shear stress at the acetabular rim 10,11. Acetabular ysplasia an femoroacetabular impingement are the two most common causes of excessive shear stress an acetabular rim synrome 10. In evelopmental ysplasia of the hip, inaequate osseous coverage of the femoral hea results in mechanical Fig. 1 A iagram epicting the most common etiologies of hip isease. It is important to note that many patients have a combination of factors that play a role in the pathophysiology of hip isease. DDH = evelopmental ysplasia of the hip. (Reprouce, with moification, from: Beaulé PE. Young ault with hip pain monograph. Rosemont, IL: American Acaemy of rthopaeic Surgeons; p 2. Reprinte with permission.) overloa of the anterolateral acetabular rim an labrum. As a result, patients with evelopmental ysplasia of the hip commonly have the evelopment of anterolateral labral tears, anterolateral acetabular chonromalacia, acetabular rim fractures, an synovial cysts. This acetabular rim overloa synrome progresses to arthrosis with time unless the hip joint pathomechanics are correcte 12. Femoroacetabular impingement is characterize by ecrease clearance an abnormal contact between the femoral hea-neck junction an the acetabular rim 3,9 (Fig. 2). These isorers are ue to proximal femoral an/or acetabular rim eformity an are now recognize as common causes of prearthritic hip pain an seconary osteoarthritis 3,9. Abnormal femoroacetabular abutment, particularly in positions of hip flexion an internal rotation, preispose affecte patients to labral tears, articular cartilage amage, an premature osteoarthritis. Impingement abnormalities can be ivie into two major categories, namely, cam-type an pincer-type impingement isorers (Fig. 2) 9. Cam femoroacetabular impingement results from eformities of the proximal part of the femur. Most commonly, the anterolateral hea-neck junction has an insufficient hea-toneck offset, creating a relative prominence at the anterolateral hea-neck junction. This results in repetitive trauma of the anterolateral hea-neck junction with the anterosuperior acetabular rim an results in shear stresses at the chonrolabral junction that can eventually prouce chonrolabral separation, labral etachment, an articular cartilage amage 13 (Figs. 3-A through 3-D). Pincer impingement isease results from acetabular overcoverage of the femoral hea, resulting in repetitive abutment of the femoral neck against the labrum an prominent acetabular rim. The acetabular labrum is com-

4 2269 T HE J URAL F B E &JIT S URGERY JBJS. RG VLUME 90-A UMBER 10 CTBER 2008 H IP D ISEASE I THE YUG A DULT:CURRET C CEPTS F E TILGY AD S URGICAL T REATMET Fig. 2 Femoroacetabular isease patterns. The reuce clearance uring joint motion leas to repetitive abutment between the proximal part of the femur an the anterior acetabular rim. A: The normal clearance of the hip. B: Reuce femoral hea an neck offset (cam impingement). C: Excessive overcoverage of the femoral hea by the acetabulum (pincer impingement). D: A combination of reuce hea an neck offset an excessive anterior overcoverage (combine impingement). (Reprouce, with moification, from: Lavigne M, Parvizi J, Beck M, Siebenrock KA, Ganz R, Leunig M. Anterior femoroacetabular impingement. Part I. Techniques of joint preserving surgery. Clin rthop Relat Res. 2004;418:61-6. Reprinte with permission.) presse between the neck an rim, causing both labral an articular cartilage amage. Retroversion of the acetabulum, coxa profuna, an protrusio 14,15 are the major pathomechanic etiologies of pincer impingement. These abnormalities can also be combine with cam femoral eformities, creating a combine impingement isorer 13. In aition to structural isorers of the hip, osteonecrosis of the femoral hea with the potential for collapse an joint eterioration is a common cause of hip ysfunction in young patients. Aitional patient-specific factors can also contribute to early hip isease an subsequent egeneration (Fig. 1). These inclue sports activities, patient age, soft-tissue laxity, previous injury or trauma, an so-calle biologic susceptibility 16 of the joint. All of these factors alone or in combination can contribute to the onset an progression of hip isease. II. Clinical Evaluation A etaile patient evaluation is focuse on ientifying the specific etiology of the patient s symptoms, carefully efining the structural anatomy of the hip joint, an assessing the extent of joint egeneration 2. Patient-specific factors, such as age, activity level, comorbiities, an physical conition, are also important eterminants in the final treatment plan. Patient Interview The meical history shoul inclue the age an overall health of the patient, a etaile escription of the pain characteristics, the activity level, associate comorbiities, an any previous hip isease or relate treatments. Care shoul be taken to carefully etermine the specific pattern of symptoms. It shoul be clarifie whether the symptoms are primarily associate with weight-bearing activities or hip flexion positions such as sitting. Hip pain exacerbate by sitting is commonly associate with femoroacetabular impingement. A history of true locking or catching can be inicative of an intraarticular mechanical problem such as an acetabular labral tear or chonral flap. Physical Examination n examination, the overall physical conition of the patient is observe. The sitting posture an gait pattern shoul be note. Abuctor strength, limb lengths, an neurovascular status are etermine. An assessment of hip range

5 2270 T HE J URAL F B E &JIT S URGERY JBJS. RG VLUME 90-A UMBER 10 CTBER 2008 H IP D ISEASE I THE YUG A DULT:CURRET C CEPTS F E TILGY AD S URGICAL T REATMET Fig. 3-A Fig. 3-B Figs. 3-A through 3-D A thirty-one-year-ol woman with cam impingement that was manage arthroscopically. At arthroscopy, the anterolateral acetabular rim cartilage was elaminate (arrow) (Fig. 3-A), an the acetabular labrum was torn along the articular margin (Fig. 3-B). FH = femoral hea, A = acetabulum, an L = labrum. of motion is extremely important in elineating an accurate iagnosis an for selecting the most appropriate surgical intervention. Specifically, the range of hip flexion must be measure accurately. Internal rotation shoul be assesse at 90 of flexion as a screening maneuver for anterior femoroacetabular impingement. Patients with so-calle classic evelopmental ysplasia of the hip ten to have goo hip flexion an internal rotation in flexion. Patients with femoroacetabular impingement have restricte hip flexion an reuce internal rotation in flexion. An aitional examination maneuver that is noteworthy is the anterior impingement test, which is performe by passively placing the hip in flexion, auction, an internal rotation. A positive test reprouces the patient s groin pain. It is a sensitive screening test for patients with acetabular labral isease an impingement. It can also be utilize as a nonspecific screening tool for intraarticular isease an hip joint irritability. In the setting of an uncertain iagnosis, the physical examination can be expane to inclue a fluoroscopically guie, iagnostic hip injection an an examination after the injection. Imaging The goals of imaging are to assess the structural anatomy of the hip, the congruency of the articulation, an the Fig. 3-C Fig. 3-D The impingement lesion of the femoral hea-neck junction (arrows) can be note (Fig. 3-C), an the prominence of the anterolateral hea-neck junction was remove with an arthroscopic burr (Fig. 3-D) to relieve anterior femoroacetabular impingement.

6 2271 T HE J URAL F B E &JIT S URGERY JBJS. RG VLUME 90-A UMBER 10 CTBER 2008 H IP D ISEASE I THE YUG A DULT:CURRET C CEPTS F E TILGY AD S URGICAL T REATMET integrity of the cartilage space. A supine or staning anteroposterior pelvic raiograph can provie the majority of information regaring structural anatomy. The anteroposterior pelvic raiograph epicts the acetabular coverage of the femoral hea, hea sphericity, acetabular inclination, horizontal position of the joint center, loss of joint space, an the version of the acetabulum. The egree of inclination (the Tönnis angle) of the sourcil (the weight-bearing ome of the acetabulum) is measure, with normal values being between 0 an 10 from the horizontal 17. The lateral centerege angle assesses lateral acetabular coverage of the femoral hea, an normal values are between 25 an 35 11,17. Specific lateral raiographs can be consiere to better efine the osseous anatomy of the proximal part of the femur, the anterior an posterior joint spaces, an acetabular rims, not all of which may be well visualize with the anteroposterior pelvic raiograph. Lateral raiographs inclue the falseprofile 18, true cross-table lateral, frogleg lateral 19, or Dunn raiographs 20. The false-profile raiograph emonstrates the anterior coverage of the femoral hea, joint space integrity of the anterosuperior an posteroinferior aspects of the joint, an anterior acetabular rim osteophytosis (Fig. 4). The other lateral raiographs are most valuable for efining the structural anatomy of the anterolateral hea-neck junction. Ieally, an initial raiographic screening by a general orthopaeist inclues an anteroposterior pelvic raiograph an a lateral raiograph of choice. If aitional evaluation an imaging is require, this may be best orchestrate by the treating surgeon. Magnetic resonance imaging, magnetic resonance arthrography, an compute tomography scanning are effective in excluing other sources of hip symptoms an in efining the etaile intra-articular an extraarticular abnormalities about the hip. A stanar magnetic resonance imaging scan is most useful as a screening mechanism to iagnose osteonecrosis of Fig. 4 Schematic rawing emonstrating the false-profile raiographic technique. The right hip is being image. (By permission of the Mayo Founation.) the femoral hea, stress fractures, neoplasm, an infection. Magnetic resonance arthrography with a small fiel of view centere on the hip has been popularize for more etaile evaluation of intra-articular structures. Paraaxial magnetic resonance arthrography imaging has been enorse as an optional imaging strategy for visualization of the anatomy of the femoral hea-neck junction an evaluation of impingement abnormalities 21,22. The GEMRIC (elaye gaoliniumenhance magnetic resonance imaging of cartilage) imaging technique hols promise in assessing the integrity of articular cartilage an quantitating early arthritic isease. This imaging moality assesses the glycosaminoglycan content of the articular cartilage an has been shown to be of prognostic value in preicting the response of ysplastic hips to joint-preserving osteotomies 23. Compute tomography scanning has assume a larger role for etaile evaluation of osseous hip anatomy 24, an it can be utilize to better characterize osseous impingement lesions, assess acetabular version, an elineate structural anatomy in severely eforme hips. Three-imensional reconstructions are particularly informative in characterizing an localizing osseous impingement lesions an in planning the etails of impingement lesion resection. III. pen Treatment of Femoroacetabular Impingement Surgical treatment for symptomatic femoroacetabular impingement (Table I) shoul primarily aress relief of the mechanical impingement an consier treatment of any seconary intraarticular isease. The specific type of treatment epens on the pattern an extent of impingement isease. Less invasive surgical techniques are most commonly consiere for focal cam impingement, while more invasive open proceures are most suitable to treat nonfocal or combine cam-pincer isease patterns. pen interventions inclue anteversion periacetabular osteotomy, surgical islocation of the hip, an anterior arthrotomy tech-

7 2272 T HE J URAL F B E &JIT S URGERY JBJS. RG VLUME 90-A UMBER 10 CTBER 2008 H IP D ISEASE I THE YUG A DULT:CURRET C CEPTS F E TILGY AD S URGICAL T REATMET TABLE I Common Finings in the Evaluation of Femoroacetabular Impingement Patient history Preominant anterior inguinal (groin) pain Pain exacerbation with activity an hip flexion (sitting) Mechanical symptoms Physical examination Limite passive hip flexion ( 105 ) Limite internal rotation at 90 of hip flexion ( 15 ) Positive anterior impingement test Raiographic evaluation Anteroposterior pelvic raiograph Cam impingement: aspherical femoral hea an insufficient hea-neck offset Pincer impingement: excessive hea coverage (acetabular retroversion, protrusio, or profuna) Lateral raiographs (cross-table, Dunn, or frog-leg lateral) Aspherical femoral hea an insufficient hea-neck offset Imaging Magnetic resonance arthrography Acetabular labral tears, acetabular rim chonromalacia, an insufficient hea-neck offset Compute tomography Cam impingement: aspherical femoral hea an insufficient hea-neck offset Pincer impingement: acetabular retroversion, overcoverage, an rim fractures niques. Less invasive options inclue a limite anterior approach to the hip alone or in combination with hip arthroscopy. Isolate hip arthroscopy techniques to aress intra-articular isease components an associate impingement lesions have also evolve. Anteversion periacetabular osteotomy is an uncommonly performe proceure that is inicate in the setting of major acetabular retroversion an posterior wall insufficiency 15. This technique can provie anteversion correction of the acetabulum an improve mechanics between the femoral heaneck junction an the acetabular rim. This proceure is inicate in a small subgroup of patients with pincer impingement. A trochanteric slie osteotomy with surgical islocation of the hip is the most well-ocumente surgical strategy for the treatment of impingement isease This surgical approach preserves the bloo supply to the femoral hea, yet it allows complete islocation of the hip with circumferential exposure of the acetabulum an the femoral hea-neck junction. Care is taken to preserve the eep branch of the meial femoral circumflex artery 28. This proceure allows irect visualization an correction of impingement isease that can encompass osteochonroplasty of the femoral hea-neck junction, osteochonroplasty of the acetabular rim, repair of the acetabular labrum, relative femoral neck lengthening, trochanteric avancement, an articular cartilage proceures of the femoral hea an acetabulum. Less invasive surgical proceures are now being evelope an refine to aress impingement isease. The goals of these proceures are to treat intraarticular isease precisely with arthroscopic techniques an to correct the cam an/or pincer structural abnormalities either arthroscopically or through irect visualization by less invasive open proceures. Access to the anterolateral femoral hea-neck junction, acetabular labrum, an acetabular rim can be obtaine through the Smith-Petersen interval or the Heuter anterior approach. The anterolateral hea-neck junction is contoure to create a more normal hea-neck offset. The acetabular labrum can be inspecte an repaire, an acetabular rim trimming can be performe if neee. Hip arthroscopy can be use as an ajunct to the anterior approach to aress acetabular labral tears, articular cartilage isease, an synovitis. Hip arthroscopy techniques are now evolving to the point at which a variety of impingement isease patterns can be treate arthroscopically evertheless, extensive arthroscopic experience an unerstaning of hip pathomechanics are neee to apply these surgical techniques effectively. Disease components in the central compartment are treate, an then the peripheral compartment of the joint is visualize an femur-base cam impingement abnormalities are correcte (Figs. 3-A through 3-D). Aitionally, techniques have been evelope for acetabular labral takeown, repair, an trimming of the acetabular rim 32. Presently, publishe clinical follow-up on arthroscopic impingement proceures is very limite, an there is a nee for stuies to efine the efficacy of these proceures. IV. pen Treatment of Developmental Dysplasia of the Hip Hip-preserving acetabular reorientation osteotomies allow a major correction of ysplasia an great improvement in clinical function 28, For example, the periacetabular an rotational acetabular osteotomy can provie major, multiimensional acetabular correction for the mechanically jeoparize ysplastic hip. Aitionally, acetabular reorientation can be augmente by a variety of other surgical techniques to optimize the proceure 11,34,35,37,40. Acetabular labral repair or partial resection, femoral hea recontouring, femoral hea-neck junction osteochonroplasty, relative femoral neck lengthening, trochanteric avancement, an proximal femoral osteotomy are now part of the surgeon s

8 2273 T HE J URAL F B E &JIT S URGERY JBJS. RG VLUME 90-A UMBER 10 CTBER 2008 H IP D ISEASE I THE YUG A DULT:CURRET C CEPTS F E TILGY AD S URGICAL T REATMET armamentarium an can be utilize to refine the hip reconstruction. With use of these surgical techniques an strategies, the symptomatic ysplastic hip can be preserve, an relief of pain an improve function is preictable 34,37,40,41,43,44. ptimal caniates have no or minimal seconary osteoarthritis an a highly congruent hip joint while maintaining hip range of motion. Although there are several osteotomy techniques to reorient the acetabulum, incluing rotational acetabular osteotomies an triple innominate osteotomies, the Bernese periacetabular osteotomy 37 has been wiely aopte. Surgical correction is irecte at the restoration of joint stability while minimizing seconary impingement 11. Surgical Technique Concepts for Periacetabular steotomy The periacetabular osteotomy is usually performe through a moifie Smith-Petersen abuctor-sparing approach 11,35,45. The funamental goal is correction of the acetabular insufficiency by repositioning the weightbearing surface laterally an anteriorly to enhance femoral hea coverage. The abnormal lateral position of the hip joint center can also be correcte by meial translation of the acetabulum 46. In aressing ysplasia, the en goal is to achieve stability an meialization without retroverting the acetabulum an potentiating impingement. The stanar reuction maneuver is a combination of internal rotation, forwar tilt (extension), an meial translation. Intraoperatively, the surgical correction obtaine must be carefully scrutinize with plain raiographs or fluoroscopy (Table II). Following acetabular reirection, there shoul be a minimum of 90 of flexion an 30 of abuction. n completion of the periacetabular osteotomy, we routinely perform an anterior arthrotomy to assess both the labrum an the anterolateral heaneck offset. Degenerative labral tears, unstable flaps, or entire etachments may be ébrie an/or repaire. Alternatively, if labral isease is suspecte from the history, physical examination, TABLE II Periacetabular steotomy Assessment* 1 Acetabular sourcil (weight-bearing surface) is repositione in a more horizontal orientation with a superolateral inclination of 0 to 10 2 Lateral femoral hea coverage is improve with a goal of achieving 25 to 35 3 The hip joint center is translate meially (if neee) to place the meial aspect of the femoral hea to within 5 to 10 mm of the ilioischial line 4 Version is correct; look for unesirable retroversion as etecte by crossover of the anterior an posterior rims 5 Anterior femoral hea coverage is improve to 20 to 25 on the false-profile raiograph (an is not excessive) 6 The correction maintains or prouces a congruent joint space, an subluxation is correcte 7 Aequate hea-neck offset is present or has been restore with osteochonroplasty 8 Aequate internal fixation with acceptable screw position 9 Hip flexion of 90 an hip abuction of 30 *These are optimal parameters, an the correction obtaine will vary epening upon the severity an characteristics of the eformity. an magnetic resonance arthrography, it may be avantageous to combine hip arthroscopy with the acetabular osteotomy. Commonly, there is insufficient anterolateral femoral hea-neck offset 47, an an osteochonroplasty may be performe as an ajunct to acetabular reorientation. This minimizes seconary hip-joint impingement. If relative coxa valga preclues the restoration of satisfactory lateral coverage an resiual instability remains, a proximal femoral varus osteotomy is performe. When a Perthes-like eformity (instability with impingement) is aresse, it is typically necessary to combine the periacetabular osteotomy with a valgus flexion-proucing proximal femoral osteotomy an/or extensive recontouring of the hea-neck junction an trochanteric avancement. This enhances the range of motion in abuction an flexion an prevents seconary femoroacetabular impingement 36. The Bernese periacetabular osteotomy (an other acetabular reorientation techniques) preictably relieves pain an increases the function of the involve hip (Fig. 5). The reporte outcomes of surgical treatment for symptomatic hip ysplasia have been very satisfactory as recently reporte by Millis an Murphy 11, Matheney et al. 40, an Siebenrock et al. 41. The utilization of this proceure is now expaning to encompass severely ysplastic hips, acetabular ysplasia with associate Perthes-like femoral eformities, an hips that have ha a previous osteotomy 34,36,48. V. Hip Arthroscopy The number of hip arthroscopy proceures is increasing on an annual basis. With appropriate inications, soun patient selection criteria for surgery, an realistic patient expectations, hip arthroscopy can be a reliable intervention for the iagnosis an treatment of intraarticular an periarticular isease. evertheless, it is important to realize that the majority of clinical evience is Level IV an Level V, with relatively shortterm follow-up in most stuies. Clearly, there is a major nee for higher-level clinical evience to etermine the true efficacy of hip arthroscopy proceures. Inications an Contrainications The most common inications inclue acetabular labral isease, focal articular cartilage lesions, femoroacetabular impingement, loose boies, an synovial isorers Absolute contrainica-

9 2274 T HE J URAL F B E &JIT S URGERY JBJS. RG VLUME 90-A UMBER 10 CTBER 2008 H IP D ISEASE I THE YUG A DULT:CURRET C CEPTS F E TILGY AD S URGICAL T REATMET Fig. 5 Anteroposterior raiographs of a seventeen-year-ol girl with symptomatic bilateral acetabular ysplasia an acetabular rim fractures (a). She was treate with stage periacetabular osteotomies an ha an excellent clinical result with both hips (b). tions to hip arthroscopy inclue any clinical situation that prevents safe istraction of the hip joint. Relative contrainications inclue altere anatomy precluing safe portal placement (previous surgery), open wouns, severe obesity, an infection (other than to wash out a hip that has an active joint infection). Aitionally, arthroscopic treatment alone is rarely appropriate in the setting of major, uncorrecte structural eformities an is unlikely to benefit patients with avance osteoarthritis or osteonecrosis with femoral hea collapse. onstructural Intra-Articular Disorers In its most basic form, hip arthroscopy serves as a iagnostic tool. Given that both magnetic resonance imaging an magnetic resonance arthrography have limite sensitivity for etecting certain intra-articular isorers 54, hip arthroscopy occasionally plays a iagnostic role in evaluating hip pain of unknown etiology. evertheless, in the large majority of patients, the iagnosis an unerlying pathomechanics of the joint are eluciate prior to surgery. Current concepts suggest that labral tears in young to mile-age patients are often the result of other intrinsic isorers, such as evelopmental ysplasia of the hip, femoroacetabular impingement, an hip instability 6,7,55. Thus, an effort shoul be mae to ientify an correct the unerlying etiology of the labral tear in aition to treating the tear itself.

10 2275 T HE J URAL F B E &JIT S URGERY JBJS. RG VLUME 90-A UMBER 10 CTBER 2008 H IP D ISEASE I THE YUG A DULT:CURRET C CEPTS F E TILGY AD S URGICAL T REATMET Hip arthroscopy is increasingly use to treat acetabular labral tears an associate abnormalities, yet the iagnosis of these lesions an the selection of appropriate surgical caniates are still evolving. Stuies have foun the most common locations for labral isease are the anterior or anteriorsuperolateral regions 51, Partial arthroscopic resection of symptomatic acetabular labral tears has a reporte success rate of between 68% an 84% 50,51,55,59,60, with less preictable results in the setting of more extensive articular cartilage isease 51,61. Arthroscopic acetabular labral repair is technically feasible, although the inications an clinical outcomes nee to be efine. Interest in labral repair is increasing as there is clinical an basic-science evience that supports the importance of the labrum for normal hip function by acting as a gasket, maintaining joint flui pressure, an proviing structural stability 27,62. Short-term preliminary reports with this type of tear pattern have suggeste that outcomes are equivalent to those of partial labrectomy 63,64. Arthroscopic treatment for focal chonral amage has been reporte, with mixe results 52,65. As iscusse previously, chonral amage is highly associate with labral tears, an the preoperative iagnosis of chonral amage remains a consierable challenge 54,66. Although microfracture an abrasion chonroplasty of the hip are also possible, the inications an outcomes nee to be efine 65. Symptomatic soft-tissue instability of the hip is an uncommon entity that has recently been propose as a cause of hip symptoms. The iagnosis is challenging, an there is an incomplete unerstaning of this iagnosis an the role of surgical treatment. It may present as chronic hip pain in athletes (incluing gymnasts an ballet ancers), after a traumatic episoe, or more commonly in active iniviuals with unerlying hyperlaxity states. These patients may respon to capsulolabral repair 67. Recent reviews of the topic have suggeste that arthroscopic examination is inicate when hip instability is suspecte an the patient gets relief from an intra-articular anesthetic injection but fails to respon to six months of conservative treatment 68,69. There is an obvious nee to more clearly efine the iagnosis, inications, an results of treating softtissue laxity about the hip, as current evience for intervention is primarily Level V. Arthroscopic treatment is possible for other uncommon conitions of the hip such as rupture of the ligamentum teres 70 an synovial isorers 53,71,72.Arthroscopic management of ahesive capsulitis an of infection have also been reporte Mil Structural Disorers The optimal treatment strategies for intra-articular hip isease associate with mil structural abnormalities remains controversial. Specifically, the necessity for an egree of eformity correction nee to be etermine. Avances in hip arthroscopy have le to the evelopment of specific techniques for the treatment of hip impingement isorers 30-33, yet further evaluation of the clinical results of these techniques is necessary to accurately establish the avantages an isavantages of these proceures. The role of hip arthroscopy in the ysplastic hip remains quite controversial, as an arthroscopic proceure cannot correct the unerlying pathomechanics of the joint an may even accelerate the egenerative process 51. Therefore, comprehensive correction of the unerlying structural abnormality of the hip shoul be strongly consiere. evertheless, arthroscopy has been use successfully in the treatment of some intra-articular isease patterns (labral tears, chonral flaps, an ligamentum teres tears) in patients with mil evelopmental ysplasia of the hip an mechanical symptoms 77. Arthroscopy shoul be consiere only for patients with mil ysplasia or as a relatively short-term solution for symptom relief in patients who are not appropriate caniates for an osteotomy. For example, ébriement of an irreparable labral tear for temporary symptom relief may be appropriate in certain patients. In contrast, we woul not recommen labral repair without concurrent structural eformity correction. The role of hip arthroscopy in the treatment of femoral hea osteonecrosis or establishe osteoarthritis is very limite. Uncommonly, it may offer the potential for relief of mechanical symptoms by ébriement of chonral or labral flaps 61, The results clearly eteriorate with increasing levels of chonral amage an joint involvement. Surgical Technique General Principles Hip arthroscopy is performe with the patient in either the supine or lateral position, epening on surgeon preference 81,82. The key requirement for both positions is aequate joint istraction (8 to 10 mm) to allow safe access to the central compartment (the area between the acetabulum an the femoral hea). The peripheral compartment (the intracapsular space outsie the acetabulum) can be accesse without traction. Almost all surgeons utilize the anterior an anterolateral portals, while some surgeons also avocate the routine use of a posterolateral portal. An anterior capsulotomy or partial capsular resection facilitates visualization in the peripheral compartment. If it is neee, an accessory anterolateral portal can be establishe approximately 4 to 5 cm istal to the anterolateral portal 83. For the correction of a cam impingement eformity, the arthroscope is place in the peripheral compartment an an arthroscopic burr is use to resect the prominent, nonspherical area on the anterolateral femoral hea-neck junction. Care is taken to avoi amage to the bloo supply to the femoral hea by protecting the posterolateral retinacular vessels that originate from the meial circumflex femoral artery 84. For correction of a pincer impingement eformity, the arthroscope is place in the central compartment an the anterolateral an

11 2276 T HE J URAL F B E &JIT S URGERY JBJS. RG VLUME 90-A UMBER 10 CTBER 2008 H IP D ISEASE I THE YUG A DULT:CURRET C CEPTS F E TILGY AD S URGICAL T REATMET anterior portals are use to perform an acetabular rim trimming. The amage labrum in the area of excess acetabular rim can be etache while the joint is istracte. It is important to emphasize that the takeown of an intact chonrolabral junction is controversial an of uncertain benefit. After release of the amage labrum, a burr is then use to resect the area of overhanging acetabulum. After resection, the labrum is repaire with suture anchor fixation or, alternatively, is resecte. Recent evience 27 has inicate that, with open treatment of impingement isease, labral repair is associate with improve clinical outcomes compare with a full-thickness resection. VI. Treatment ptions for En-Stage Hip Disease Despite the innovation an positive clinical results with various surgical techniques for joint preservation, many young patients present for treatment with en-stage egeneration of the hip an are not caniates for jointpreserving surgery. In this clinical setting, joint replacement proceures are consiere with the goals of relieving pain, maintaining activity levels, restoring hip function, an enhancing quality of life. The introuction of alternative prosthetic bearing surfaces an improve hip-resurfacing implants suggests that there is potential for improve function an survivorship of prosthetic hip reconstructions. The major challenges going forwar are to ientify the optimal prosthetic bearing surfaces, etermine the clinical efficacy of contemporary hip replacement an hip resurfacing implants, an elineate the mi-term to long-term survivorship of these two proceures. In choosing between hip replacement an hip resurfacing, the surgeon shoul consier a variety of factors incluing patient age, sex, activity level, boy-mass inex, an comorbiities 85. Proximal femoral bone quality an a history of surgery shoul also be assesse as these variables may impact the success of the surgical proceure. Total Hip Replacement The excellent clinical results of total hip replacement in all age groups are well known, an, with the use of improve wear-resistant bearing couples, these results will most likely continue to improve over time. Total hip replacement has several avantages. These inclue broaer criteria for patient selection, less invasive surgical techniques, implant moularity, ocumente long-term efficacy, protection from proximal femoral fracture, an technical ease. Total hip replacement is appropriate in the vast majority of young patients, even in the setting of poor proximal femoral bone stock (cystic egeneration, osteonecrosis, an osteoporosis), femoral hea-neck eformity, compromise acetabular bone stock, inflammatory arthritis, limb-length iscrepancy, an obesity. Aitionally, less invasive surgical techniques 86 an multimoality pain management protocols have quickene patient recovery an reuce perioperative pain associate with the proceure. The implant-relate versatility of hip replacement is also avantageous with respect to bearing surface materials (ceramics, highly cross-linke polyethylene, an metals), femoral hea-neck iameter sizes an lengths, an acetabular liner options (elevate lips, offset, an constraine). Implant fixation characteristics with contemporary evices are excellent an urable. With aging, the femoral neck an intertrochanteric region of the proximal part of the femur are protecte from fracture by the femoral implant. Technically, primary total hip arthroplasty is a straightforwar proceure performe with a variety of surgical approaches an techniques. Arguable isavantages of total hip replacement relative to total hip resurfacing inclue islocation (with stanar femoral hea sizes), compromise of proximal femoral bone stock with component insertion, the potential for excessive lengthening 87, proximal femoral stress-shieling over long perios of time 88, an perceive activity limitation. It shoul be note that prosthesis survivorship as a means of measuring outcome has limitations in terms of assessing health-relate quality of life 89, especially in active, high-eman patients. Consequently, integrating patient activity level in the assessment of total hip arthroplasty function provies relevant qualitative information that is not containe in current hip-scoring systems 90,91. Using the University of California at Los Angeles (UCLA) activity score 92, one recent stuy compare the outcome of total hip replacement an hip resurfacing. That prospective ranomize trial showe that patients with hip resurfacing ha a higher mean activity score than their total hip counterparts at twelve months of follow-up. This potential isavantage of total hip replacement must be confirme with longer-term follow-up stuies an must be interprete in the context of a lower risk of revision surgery after total hip replacement evertheless, these ata are consistent with the concept that patients with a high activity level may be the most appropriate caniates for a hip-resurfacing proceure. These ata also unerscore the nee for improve, valiate activity scores for high-eman patients. Such scores will facilitate surgical ecision-making an will be the basis for comparison stuies of total hip replacement an resurfacing. Hip Resurfacing Resurfacing arthroplasty of the hip has experience a resurgence in popularity over the last ecae 96. With improvement in esign technology an metallurgy, many of the problems that plague early esigns, such as massive bone loss with cemente acetabular components 97 an high polyethylene wear rates associate with larger femoral hea sizes, have been overcome Current hip-resurfacing systems utilize a hybri esign, with a press-fit acetabular component an a cemente femoral component 96,102. Early an mi-term results have been reporte an are favorable compare with early esigns of hip-resurfacing implants Asin other alternative hip proceures, careful patient selection helps to minimize

12 2277 T HE J URAL F B E &JIT S URGERY JBJS. RG VLUME 90-A UMBER 10 CTBER 2008 H IP D ISEASE I THE YUG A DULT:CURRET C CEPTS F E TILGY AD S URGICAL T REATMET complications an the nee for early reoperation 85. Conversely, because of the improve survivorship of total hip replacement 107 an the excellent shortterm performance of new bearing couples 108,109, one may rightly question the role of hip resurfacing in toay s armamentarium of replacement proceures. Several potential avantages are emphasize by the proponents of hip resurfacing. These inclue preservation of proximal femoral bone stock, more physiologic stress transfer in the proximal part of the femur 110, more normal hip kinematics 96, a low islocation rate, an easy femoral revision proceures 111. Perhaps the most emphasize potential benefit is the tolerance of high activity levels that may enhance quality of life or patient-perceive quality of life. Thus, there is a major nee for investigation of activity levels an quality of life after hip resurfacing. An aitional theme in hipresurfacing reports is that careful patient selection is important to optimize clinical results an avoi complications. The surface arthroplasty risk inex 85 (Table III) is useful in guiing the treatment ecision-making process when contemplating hip resurfacing compare with total hip replacement 103. The isavantages of hip resurfacing inclue a larger surgical exposure an a technically more emaning proceure, limitations in the setting of compromise femoral bone quality, a lack of moularity, limitations with regar to lengthening the extremity, early femoral neck fracture, an metal ion-associate problems. ver longterm follow-up perios, the potential complications of recurrent femoroacetabular impingement an proximal femoral fracture also nee to be investigate. In a practical sense, hip resurfacing has not been within the training curriculum of orthopaeic surgeons for the last two ecaes an a learning curve will likely occur as the proceure is utilize more commonly. For example, the failure mechanisms of femoral loosening 103, seconary to malalignment an femoral neck fractures are commonly relate to surgical technique. The prevalence of femoral neck fracture TABLE III Surface Arthroplasty Risk Inex 92 Points Femoral hea cyst of >1 cm in size 2 Patient weight of <82 kg 2 Previous hip surgery 1 UCLA activity level of >6 1 Maximum score 6 has been reporte to range from 0.8% to 1.45% 105,112, an these fractures ten to occur within the first six months after surgery, with osteonecrosis an femoral neck notching being implicate as potential causes 113,116,117. n the other han, the prevalence of failures seconary to femoral component loosening has been reporte to range from 6% to 10% 103,114,115. An aitional controversial aspect of hip resurfacing is the importance of metal ion release from the bearing surface. The major concern is for patients with compromise renal function since metal ions generate from a metal-on-metal bearing are excrete through the urine, an the lack of clearance of these ions may lea to excessive levels in the bloo 118,119. Currently, the only clear complication from exposure to metal ions is a hypersensitivity reaction, which occurs in approximately 0.3% of patients 120,121. The clinical finings associate with this phenomenon are persistent pain an periprosthetic osteolysis with or without component loosening 120,121. More importantly, a recent paper examining metal ions in umbilical cor bloo showe that cobalt an chromium ions cross the placental barrier 122 an may be a source of concern for women of chilbearing age who are contemplating a resurfacing proceure. Clearly, a major isavantage of hip resurfacing remains the associate release of metal ions, which leaves the patient expose to elevate ion levels for ecaes. The key aspects to the surgical technique for hip resurfacing can be ivie into three steps: the choice of the surgical approach, selection of implant size, an positioning of the implant 103,123. In terms of surgical approach, the vascularity of the proximal aspect of the femur shoul be consiere because the femoral component rests on the reame femoral hea. Disruption of the bloo flow to the femoral hea via the posterior approach coul cause an osteonecrotic event that isrupts the bone-cement interface an leas to premature loosening or, in extreme cases, neck fracture 116. evertheless, several centers have reporte excellent short-term to meium-term results using the posterior approach. With respect to implant sizing, it is recommene that referencing shoul be off the femur in orer to avoi neck notching. nce the femoral component size is selecte, then one verifies that the matching acetabular component is appropriate for the patient s anatomy. If the anatomy necessitates an in-between size, it is better to go up one size with the acetabular implant than to notch the femoral neck when preparing it for a smaller femoral component. Finally, implant positioning in hip resurfacing is more emaning since the margin for acceptable implant positioning is narrower. n the acetabular sie, it is critical to avoi excessively vertical placement because of the risk of runaway wear. ne shoul aim for an abuction angle of 40 to 45. Alternatively, an excessively horizontal position of the acetabular component can be a source of anterior femoroacetabular impingement an shoul also be avoie. n the femoral sie, slight valgus orientation relative to the femoral neck is favorable to implant survivorship by mini-

13 2278 T HE J URAL F B E &JIT S URGERY JBJS. RG VLUME 90-A UMBER 10 CTBER 2008 H IP D ISEASE I THE YUG A DULT:CURRET C CEPTS F E TILGY AD S URGICAL T REATMET mizing tensile stresses on the femoral neck 124. Metal-on-metal hip-resurfacing arthroplasty will continue to play a role in the treatment of en-stage hip arthritis in young patients. Currently, the ieal caniate is an active male patient who is less than sixty years of age with a iagnosis of osteoarthritis. Since we now have hip resurfacing implants with goo-to-excellent clinical results at short-term to mi-term follow-up, it is imperative that future stuies better efine optimal patient selection criteria for surgery, investigate the true qualityof-life benefit, an etermine longerterm complications an survivorship. Future clinical stuies shoul focus on comparing the results of resurfacing proceures an total hip replacement in similar patient cohorts. Hip Arthroesis Arthroesis, although uncommonly carrie out, is inicate for young patients with en-stage unilateral hip arthritis who have contrainications for both joint preserving an joint replacement proceures. Hip arthroesis preserves bone stock an can provie pain relief inefinitely 125. The ultimate goal for these patients is a return to an active lifestyle with minimal restrictions. The ieal caniate is an aolescent or young ault (less than thirty years of age) with a history of multiple hip surgeries, posttraumatic arthritis, an/ or postinfectious hip isease. Activity emans are high, an the patient shoul not have preexisting isease of the lumbar spine, ipsilateral knee, or contralateral hip 126. The surgical approach chosen for the fusion shoul attempt to minimize trauma to the abuctor muscle mass 127 in case total hip arthroplasty is subsequently performe. With proper patient selection an with the hip fuse in an optimal position, the onset of notable pain in ajacent joints can be elaye for up to twenty-five years 126,128. VII. verview The care of hip isease in aolescent an young ault patients has engenere recent interest associate with a number of factors, which inclue an improve unerstaning of the mechanical etiology of isease in many patients an of the effectiveness of mechanically base treatment in many situations. This realm of orthopaeics is now experiencing rapi growth an high levels of interest because of the improve unerstaning of hip isease an innovation in surgical techniques. It is imperative that the orthopaeic community eucate other health-care proviers regaring the iagnosis an treatment of early hip isease. Specifically, we shoul target peiatricians, primary care physicians, raiologists, an physical therapists with the message that early iagnosis an referral for specialize care may optimize clinical outcomes an alter the natural history of these isorers. Surgical strategies for joint preservation shoul be viewe as esirable alternatives compare with persistent hip ysfunction an progressive joint egeneration. As we move forwar, it is critical that these interventions be evaluate with soun clinical research. Specifically, hip arthroscopy an surgical techniques in joint preservation nee to be analyze with respect to symptom relief, activity tolerance, quality of life, an survivorship. Low-wear implant bearings an resurfacing implants nee to be followe for longer terms in orer to istinguish their clinical benefit an wear characteristics. There is great nee for improve valiate activity an quality-of-life scores for these high-eman patients. In aition, etermining the role of genetic factors in hip isease an eveloping effective screening protocols for various hip isorers may lea to an earlier iagnosis an preventive care. Collectively, progress in these areas will lea to continue improvements in the orthopaeic care of this traitionally unerserve patient group. John C. Clohisy, MD Washington University School of Meicine, 660 South Eucli, Campus Box 8233, St. Louis, M aress: clohisyj@wuosis.wustl.eu Paul E. Beaulé, MD, FRCSC University of ttawa, 501 Smyth Roa, Suite 5004, ttawa, K1H 8LC, Canaa Aran Malley, MD Marc R. Safran, MD Stanfor University, 300 Pasteur Avenue, R-105, Ewars Builing, Stanfor, CA Perry Schoenecker, MD Shriners Hospital for Chilren2St. Louis Chilren s Hospital, ne Chilren s Place, St. Louis, M References 1. Clohisy JC, Safran MR, Schoenecker PL, Beaule PE. The young ault with hip arthrosis: there are finally options. Rea at the Annual Meeting of the American rthopaeic Association; 2007 Jun 13-16; Asheville, C. 2. Clohisy JC, Keeney JA, Schoenecker PL. Preliminary assessment an treatment guielines for hip isorers in young aults. Clin rthop Relat Res. 2005;441: Ganz R, Parvizi J, Beck M, Leunig M, otzli H, Siebenrock KA. Femoroacetabular impingement: a cause for osteoarthritis of the hip. Clin rthop Relat Res. 2003;417: Harris WH. Etiology of osteoarthritis of the hip. Clin rthop Relat Res. 1986;213: Millis MB, Kim YJ. Rationale of osteotomy an relate proceures for hip preservation: a review. Clin rthop Relat Res. 2002;405: Peelle MW, Della Rocca GJ, Maloney WJ, Curry MC, Clohisy JC. Acetabular an femoral raiographic abnormalities associate with labral tears. Clin rthop Relat Res. 2005;441: Wenger DE, Kenell KR, Miner MR, Trousale RT. Acetabular labral tears rarely occur in the absence of bony abnormalities. Clin rthop Relat Res. 2004;426: Ganz R, Leunig M, Leunig-Ganz K, Harris WH. The etiology of osteoarthritis of the hip: an integrate mechanical concept. Clin rthop Relat Res. 2008; 466: Lavigne M, Parvizi J, Beck M, Siebenrock KA, Ganz R, Leunig M. Anterior femoroacetabular impingement: part I. Techniques of joint preserving surgery. Clin rthop Relat Res. 2004;418: Klaue K, Durnin CW, Ganz R. The acetabular rim synrome. A clinical presentation of ysplasia of the hip. J Bone Joint Surg Br. 1991;73: Millis MB, Murphy SB. Periacetabular osteotomy. In: Callaghan JJ, Rosenberg AG, Rubash HE, eitors. The ault hip. 2n e, vol 1. Philaelphia: Lippincott, Williams an Wilkins; p Murphy SB, Ganz R, Muller ME. The prognosis in untreate ysplasia of the hip. A stuy of raiographic factors that preict the outcome. J Bone Joint Surg Am. 1995;77: Beck M, Kalhor M, Leunig M, Ganz R. Hip morphology influences the pattern of amage to the