今日の臨床サポート 今日の臨床サポート

著者: 星野裕信 浜松医科大学 整形外科

監修: 酒井昭典 産業医科大学 整形外科学教室

著者校正/監修レビュー済:2021/06/02
患者向け説明資料

改訂のポイント:
  1. 日本股関節学会のFAI診断指針ならびに変形性股関節症診療ガイドライン改訂第2版の内容を盛り込んだ。

概要・推奨   

  1. 世界的にコンセンサスの得られたFAIの明確な診断基準はない。
  1. わが国における狭義のFAI診断指針が提唱されている。
  1. Cam変形は変形性股関節症の発生の危険因子になる(推奨度C)
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病態・疫学・診察 

疾患情報(疫学・病態)  
  1. 大腿骨寛骨臼インピンジメント(femoroacetabular impingement、FAI)は、股関節の動きに伴って大腿骨と寛骨臼が衝突して種々の臨床症状を引き起こす病態のことである[1]
  1. 以前は原因不明の股関節痛といわれていたが、病態の認知度の向上や画像診断の進歩により診断が可能となった。
  1. 大腿骨側の形態異常によるものをcam type、寛骨臼側の形態異常によるものをpincer type、両者の合併するものをcombined typeまたはMixed typeという[2]
 
FAIのタイプ

FAIにはcam type(a)とpincer type(b)があり、cam typeは大腿骨側の形態異常、pincer typeは寛骨臼側の形態異常によって起こる。

 
  1. スポーツや外傷に伴って生じる場合と、日常生活動作における繰り返す衝突によって症状を引き起こす場合がある。
  1. 臨床症状は、股関節唇損傷の程度、軟骨損傷の程度によって異なる。
  1. 寛骨臼形成不全を伴わない1次性変形性股関節症の原因の1つとされている[3]
 
前外側股関節唇損傷

12歳女児。FAIによる左股関節唇損傷。前方ポータルより30°斜視鏡にて鏡視。プローベにて関節唇の寛骨臼縁付着部をゆっくり外側に引くと断裂部がみえる。

出典

著者提供
 
前方股関節唇損傷

28歳女性。FAIによる前方股関節唇損傷。前方ポータルより30°斜視鏡にて鏡視。

出典

著者提供
 
  1. 股関節唇損傷の誘因(参考文献:[4]
  1. 開排などの軽微な日常生活動作に起因するものや、スポーツによるものも多いため、詳細な問診が重要である。しかしFitzgeraldは55例の関節唇損傷患者を調査した結果、34例は受傷機転が明らかであったが、21例は原因が不明であったとしている。当科においても寛骨臼形態異常を伴わず、臨床所見、放射状MRIにより股関節唇損傷と診断した23例23関節について調査した結果、明らかな受傷機転が判明したものが15関節であり、8関節は受傷機転が不明であった。これらの症例は医療機関受診から診断がつくまでの期間は平均18.8カ月もかかっており、初診医の診断は「X線で異常はない」7関節、「打撲」5関節、「筋肉痛」2関節、「腰椎椎間板ヘルニア」9関節であった。
 
  1. FAIにおけるスポーツの関与(参考文献:[5][6]
  1. 前向き研究で、FAIの70%がsportsに起因するもので、そのうち30%がelite sportsであった。
  1. 症状の出現は徐々に生じ、活動性に応じて間欠的に生じる。
  1. 診断がつくまで数カ月から数年スポーツを休まなくてはならない。
  1. 鼠径部にするどい痛みや持続する痛みが生じる。
  1. 割れるようなまたはひっかかるような痛みが短時間持続する。
  1. 座った姿勢で不安で不快な感じがする(特に低い椅子)。
  1. ある特定の姿勢や股関節の角度で再現される。
  1. その再現性は変化することもある。
  1. 長時間座った後立ち上がるときに再現される。
  1. しばしば歩くときは痛くない。
  1. 股関節を強制的に屈曲するスポーツで多い。
 
FAIにおけるスポーツの関与

ある施設において、股関節鏡視下にFAIの治療を受けた200人の患者のスポーツの内訳を示す。

出典

J W Thomas Byrd, Kay S Jones
Arthroscopic management of femoroacetabular impingement in athletes.
Am J Sports Med. 2011 Jul;39 Suppl:7S-13S. doi: 10.1177/0363546511404144.
Abstract/Text BACKGROUND: Hip pathology is a significant source of pain and dysfunction among athletic individuals and femoroacetabular impingement is often a causative factor. Arthroscopic intervention has been proposed to address the joint damage and underlying impingement.
HYPOTHESIS: Arthroscopy may be effective in the management of symptomatic femoroacetabular impingement in athletes.
STUDY DESIGN: Case series, Level of evidence, 4.
METHODS: All patients undergoing hip arthroscopy at 1 institution were prospectively assessed with a modified Harris hip score obtained preoperatively and postoperatively at 3, 12, 24, 60, and 120 months. This report consists of a cohort of 200 patients identified who underwent arthroscopic management of femoroacetabular impingement, participated in athletic activities, and had achieved minimum 1-year follow up.
RESULTS: There was 100% follow-up at an average of 19 months (range, 12-60 months). A total of 116 athletes had achieved 2-year follow-up. For the entire cohort, the average age was 28.6 years (range, 11-60 years) with 148 males and 52 females. There were 159 cam, 31 combined, and 10 pincer lesions. There were 23 professional, 56 intercollegiate, 24 high school, and 97 recreational athletes. The male:female ratio was 2.8:1 among cam lesions and 1:1 among pincer lesions. The median preoperative score was 72 with a postoperative score of 96 and the median improvement was 20.5 points, which was statistically significant (P < .001). Ninety-five percent of professional athletes and 85% of intercollegiate athletes were able to return to their previous level of competition. There were 5 transient neurapraxias (all resolved) and 1 minor heterotopic ossification. One athlete (0.5%) underwent conversion to total hip arthroplasty and 4 (2%) underwent repeat arthroscopy. For the group with minimum 2-year follow up, the median improvement was 21 points with a postoperative score of 96.
CONCLUSION: The data substantiate successful outcomes in the arthroscopic management of femoroacetabular impingement with few complications and most athletes were able to resume activities.

PMID 21709026
 
  1. 股関節唇損傷の発生機序(参考文献:[3][7][8][9][10][11][12][13]
  1. FAIは股関節の形態異常に基づいて生じる大腿骨と寛骨臼縁の衝突によって生じる障害である。これは大腿骨側の形態異常と寛骨臼側の形態異常およびその両者の形態異常が存在すると、股関節可動域が生理的範囲を超えなくても、日常生活動作における股関節の可動時に、大腿骨頭や大腿骨頚部が寛骨臼縁に衝突を来すために関節唇損傷や軟骨損傷を生じるものである。
  1. cam impingement
  1. 特に大腿骨頭から頚部の形態異常により股関節屈曲時に大腿骨頭の隆起部に股関節唇が挟み込まれたり、大腿骨頭が寛骨臼縁で外側から内側にかけての剪断力を生じることにより、寛骨臼縁軟骨移行部において関節唇損傷を来す。大腿骨頭変形は先天性股関節脱臼、ペルテス病、大腿骨頭すべり症や外傷後に2次的に生じるものや、明らかな原因がなく大腿骨頭から頚部にかけてのoffsetの減少または骨性隆起によりに生じるものがある。この大腿骨頭の形態異常の指標として、pistol-grip deformityの有無、頚部オフセットが7mm以下であったり、Nötzliらの提唱しているα角が50°以上である場合に形態異常ありとする報告がある。また、2038人の健常若年者のデータから、単純X線正面像での角の正常上限を97.5パーセンタイルとすると、男性93°、女性94°、側面像では男性68°、女性56°という報告もあり。
  1. pincer impingement
  1. 寛骨臼側の形態異常により関節唇が挟み込まれることにより生じるものはpincer impingementといい、寛骨臼が後方へ捻れている状態(acetabular retroversion)であったり、寛骨臼の前後方向への捻れは正常であるが、寛骨臼縁が前方に張り出している状態(anterior over coverage)や、深い寛骨臼(coxa profunda)であるために、過度でない股関節の屈曲可動域において、大腿骨頚部と寛骨臼縁が衝突することによって生じる関節唇の断裂または寛骨臼縁軟骨移行部におけるdetachmentを来す。単純X線上cross-over signやPRIS signを呈することが多いと報告されている。
 
pistol-grip deformity

cam typeに特有の大腿骨の変形。股関節正面または側面X線像にて骨頭を円形に見立てた場合、外側または前方のhead-neck junctionにおいて、円からはみでる張り出しのあるもの。

出典

著者提供
 
cross-over sign

pincer type に特有の単純X線所見。
寛骨臼の前縁線が深く張り出して、後縁線と交差する。寛骨臼のretroversionを示唆する。
AP pelvic viewでのみ評価、股関節中心像ではない。
・前縁後縁の線が不鮮明な場合、罹患側を空気圧迫して立位で撮影するとよい。
・cross-over pointは寛骨臼の上方1/4で起こる。

出典

著者提供
 
prominence of the ischial spine (PRIS)sign

PRISは股関節単純X線正面像で坐骨棘が突出してみえる。
寛骨臼のretroversionを示唆する所見。
・pincer type FAIのリスクの1つとなる。

出典

著者提供
 
posterior wall sign

骨頭の中心が寛骨臼後縁より外側にある。
寛骨臼のretroversionを示唆する所見。
・pincer type FAIのリスクの1つとなる。

出典

著者提供
 
  1. 股関節唇損傷におけるFAIの関与(参考文献:[14]
  1. 股関節唇損傷にFAIがどの程度関与しているかは、現在のところ画像上FAIの指標をどの程度有していたかで判断せざるを得ない。Wengerらは31名の股関節唇損傷患者の骨形態異常の頻度を調査した結果、36%に寛骨臼後捻、41%に大腿骨頚部offsetの減少を認め、FAIの骨形態異常を示さなかったのは13%であったと報告している。また、Guevaraらは、78名の寛骨臼形成不全のない股関節唇損傷患者の単純X線上のFAIの指標を調査した結果、cross-over signは44%にみられたと報告している。当科においても、寛骨臼形成不全がなく、放射状MRI、股関節造影、キシロカインテストにより股関節唇損傷と診断した44関節を対象としてFAIの関与と受傷機転の有無を調査した結果、約6割にFAIの関与が認められた。またpincer群と正常群では受傷機転を有する例が多い傾向であり、この2つのタイプのFAIは関節唇損傷に際して損傷機転が異なる可能性があると思われる。
 
  1. FAI疫学(参考文献:[6][15]
  1. 典型的なFAIは20~50歳にみられ、男性が2/3であった。
  1. フランスで16~50歳までの股関節痛の患者292名の前向き多施設試験で、FAIが原因だったものは58%(うち2/3がOA、35%が寛骨臼形成不全)。
 
  1. FAIが変形性股関節症の原因(参考文献:[3][6][16][17][18]
  1. 前方FAIが早期の変形性股関節症の原因となる
  1. cam lesionの寛骨臼前上方への刺激が繰り返し生じると、関節唇、軟骨、軟骨下骨に損傷が生じ、最終的には変形性股関節となる。
  1. pistol-grip deformityとmildなOAを有する43人のAP単純骨盤X線像が10年後に再撮影され、OAの進行は1/3にのみみられた。側面像のX線は撮影されていない。
  1. cam lesionの寛骨臼縁への刺激が繰り返し生じると、軟骨のdelamination、erosion、軟骨表面の亀裂や軟骨のflapが生じる。
  1. FAI患者の早期のOAのリスクとなるスポーツ活動、遺伝的関与、重労働、傷害の既往について前向きに検討した結果、OAの家族歴が20%に、重労働が 10%にみられた。またスポーツ活動のないものが30%にみられた。唯一変えることのできない要因はOAの遺伝的要因であった。
  1. X線正面像におけるcam変形は変形性股関節症の発生の危険因子になることが報告されている[19][20][21]
  1. X線正面像上のCE角を用いて評価したpincer変形は、股関節症の発生の危険因子ではないと報告されている[20][22]。一方でCE角を用いてpincer変形を評価した論文ではpincer変形と股関節症の発生が有意に関連することが報告されている[23][24]。Pincer変形の定義が多様であり、また報告により結果がおt子なるため、pincer変形をコカs熱証のp発生の危険因子と結論付けることはできない。
 
問診・診察のポイント  
  1. いつから痛みが始まったか、何をしていたときに発症したか、スポーツや職業の種類、また発症の際の股関節の姿位を確認する。

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文献 

S R Myers, H Eijer, R Ganz
Anterior femoroacetabular impingement after periacetabular osteotomy.
Clin Orthop Relat Res. 1999 Jun;(363):93-9.
Abstract/Text As experience with the Bernese periacetabular osteotomy has grown, an unexpected observation in a group of patients has alerted the authors to the risk of a secondary impingement syndrome that may occur some time after the periacetabular osteotomy. This possibly may explain residual pain and limited range of motion in a larger group of patients. The impingement is produced by abutment of the femoral head or head to neck junction on the anterior rim of the properly aligned acetabulum. The symptoms are those of restricted flexion, and limited or absent internal rotation in flexion, with variable groin pain. Magnetic resonance imaging studies may reveal acetabular labral disease and adjacent cartilage damage associated with the impingement. Lack of anterior or anterolateral offset between the femoral neck and head results in neck to rim contact when the hip is flexed and/or internally rotated. Before the periacetabular osteotomy this is compensated by the lack of anterior acetabular coverage, but after proper correction the mismatch becomes apparent. The authors recently have devised a routine during the periacetabular osteotomy procedure whereby after the acetabular fragment is corrected into the desired position, the joint is opened, visually inspected, and palpated for impingement with the hip flexed and internally rotated. When necessary, a resection osteoplasty of the femoral neck to head junction is performed to improve the head and neck offset and reduce the anterior contact. This, in the short term, has provided satisfactory prevention of postoperative impingement.

PMID 10379309
Martin Beck, Michael Leunig, Javad Parvizi, Vincent Boutier, Daniel Wyss, Reinhold Ganz
Anterior femoroacetabular impingement: part II. Midterm results of surgical treatment.
Clin Orthop Relat Res. 2004 Jan;(418):67-73.
Abstract/Text Femoroacetabular impingement has been shown to cause labral and chondral lesions and leads to osteoarthrosis of the hip. With the elimination of the pathogenic cause we hope to prevent or delay additional degeneration of the hip. Fourteen men and five women with a mean age of 36 years (range, 21-52 years) were treated with a surgical dislocation and offset creation of the hip. The followup averaged 4.7 years (range, 4-5.2 years). Using the Merle d'Aubigné hip score, 13 hips were rated excellent to good, with the pain score improving from 2.9 points to 5.1 points at the latest followup. There was no avascular necrosis of the femoral head. Five of the 19 patients, two with Grade 2 osteoarthrosis, two with Grade 1 osteoarthrosis but severe acetabular cartilage damage, and one with untreated ossified labrum had subsequent total hip arthroplasty (THA). In the stable hips without subluxation of the head into the acetabular cartilage defect, no additional joint space narrowing occurred. Surgical dislocation with correction of femoroacetabular impingement yields good results in patients with early degenerative changes not exceeding Grade 1 osteoarthrosis. This procedure is not suitable for patients with advanced degenerative changes and extensive articular cartilage damage.

PMID 15043095
Reinhold Ganz, Javad Parvizi, Martin Beck, Michael Leunig, Hubert Nötzli, Klaus A Siebenrock
Femoroacetabular impingement: a cause for osteoarthritis of the hip.
Clin Orthop Relat Res. 2003 Dec;(417):112-20. doi: 10.1097/01.blo.0000096804.78689.c2.
Abstract/Text A multitude of factors including biochemical, genetic, and acquired abnormalities may contribute to osteoarthritis of the hip. Although the pathomechanism of degenerative process affecting the dysplastic hip is well understood, the exact pathogenesis for idiopathic osteoarthritis has not been established. Based on clinical experience, with more than 600 surgical dislocations of the hip, allowing in situ inspection of the damage pattern and the dynamic proof of its origin, we propose femoroacetabular impingement as a mechanism for the development of early osteoarthritis for most nondysplastic hips. The concept focuses more on motion than on axial loading of the hip. Distinct clinical, radiographic, and intraoperative parameters can be used to confirm the diagnosis of this entity with timely delivery of treatment. Surgical treatment of femoroacetabular impingement focuses on improving the clearance for hip motion and alleviation of femoral abutment against the acetabular rim. It is proposed that early surgical intervention for treatment of femoroacetabular impingement, besides providing relief of symptoms, may decelerate the progression of the degenerative process for this group of young patients.

PMID 14646708
R H Fitzgerald
Acetabular labrum tears. Diagnosis and treatment.
Clin Orthop Relat Res. 1995 Feb;(311):60-8.
Abstract/Text An acetabular labrum tear was diagnosed and treated in 56 hips in 55 patients. Mechanical hip pain after a relatively minor injury with an associated click characterized the history. The tear of the labrum was shown with arthrography in 88% of the patients. Overall, 89% of the patients were improved by the diagnosis and treatment of an acetabular labrum tear: all 7 patients treated nonsurgically and 42 of 46 patients treated surgically. In recent years, it has been possible to arthroscopically confirm the diagnosis and treat some of these patients.

PMID 7634592
J W Thomas Byrd, Kay S Jones
Arthroscopic management of femoroacetabular impingement in athletes.
Am J Sports Med. 2011 Jul;39 Suppl:7S-13S. doi: 10.1177/0363546511404144.
Abstract/Text BACKGROUND: Hip pathology is a significant source of pain and dysfunction among athletic individuals and femoroacetabular impingement is often a causative factor. Arthroscopic intervention has been proposed to address the joint damage and underlying impingement.
HYPOTHESIS: Arthroscopy may be effective in the management of symptomatic femoroacetabular impingement in athletes.
STUDY DESIGN: Case series, Level of evidence, 4.
METHODS: All patients undergoing hip arthroscopy at 1 institution were prospectively assessed with a modified Harris hip score obtained preoperatively and postoperatively at 3, 12, 24, 60, and 120 months. This report consists of a cohort of 200 patients identified who underwent arthroscopic management of femoroacetabular impingement, participated in athletic activities, and had achieved minimum 1-year follow up.
RESULTS: There was 100% follow-up at an average of 19 months (range, 12-60 months). A total of 116 athletes had achieved 2-year follow-up. For the entire cohort, the average age was 28.6 years (range, 11-60 years) with 148 males and 52 females. There were 159 cam, 31 combined, and 10 pincer lesions. There were 23 professional, 56 intercollegiate, 24 high school, and 97 recreational athletes. The male:female ratio was 2.8:1 among cam lesions and 1:1 among pincer lesions. The median preoperative score was 72 with a postoperative score of 96 and the median improvement was 20.5 points, which was statistically significant (P < .001). Ninety-five percent of professional athletes and 85% of intercollegiate athletes were able to return to their previous level of competition. There were 5 transient neurapraxias (all resolved) and 1 minor heterotopic ossification. One athlete (0.5%) underwent conversion to total hip arthroplasty and 4 (2%) underwent repeat arthroscopy. For the group with minimum 2-year follow up, the median improvement was 21 points with a postoperative score of 96.
CONCLUSION: The data substantiate successful outcomes in the arthroscopic management of femoroacetabular impingement with few complications and most athletes were able to resume activities.

PMID 21709026
A Nogier, N Bonin, O May, J-E Gedouin, L Bellaiche, T Boyer, M Lequesne, French Arthroscopy Society
Descriptive epidemiology of mechanical hip pathology in adults under 50 years of age. Prospective series of 292 cases: Clinical and radiological aspects and physiopathological review.
Orthop Traumatol Surg Res. 2010 Dec;96(8 Suppl):S53-8. doi: 10.1016/j.otsr.2010.09.005. Epub 2010 Oct 28.
Abstract/Text Two hundred and ninety-two patients, aged between 16 and 50 years and presenting with mechanical hip pathology, were included in a prospective multicenter study. The descriptive study concerned the clinical examination and analysis of three X-ray views (AP pelvic, Lequesne false profile and lateral axial view). The series comprised 62% males, mean age 35 years, with 53% right side and 22% bilateral involvement. Initial trauma was reported in 19% of cases, and direct familial history of hip pathology in 20%. Seventy percent of the patients played sports, 30% were high-level athletes, and 17% played combat sports. The physical impingement sign was present in 18% to 65% of cases depending on the variant studied. On imaging (n=241), 62% of hips showed osteoarthritis, with 25% at the evolved stage. In the series, as a whole, there was a 35% rate of dysplasia, 63% of impingement and 5% of normal X-ray results. The radiologic impingement aspects were 58% cam-type, 19% pincer-type and 23% mixed. Twenty-two percent of dysplasia cases showed signs of associated impingement. Pain experienced exclusively in flexion/internal rotation/adduction on examination showed little sensitivity (20%) but considerable specificity (86%) for the main diagnosis of impingement. The links between impingement and dysplasia are discussed, and an integrative schema of all risk factors is put forward.

Copyright © 2010 Elsevier Masson SAS. All rights reserved.
PMID 21035417
M Beck, M Kalhor, M Leunig, R Ganz
Hip morphology influences the pattern of damage to the acetabular cartilage: femoroacetabular impingement as a cause of early osteoarthritis of the hip.
J Bone Joint Surg Br. 2005 Jul;87(7):1012-8. doi: 10.1302/0301-620X.87B7.15203.
Abstract/Text Recently, femoroacetabular impingement has been recognised as a cause of early osteoarthritis. There are two mechanisms of impingement: 1) cam impingement caused by a non-spherical head and 2) pincer impingement caused by excessive acetabular cover. We hypothesised that both mechanisms result in different patterns of articular damage. Of 302 analysed hips only 26 had an isolated cam and 16 an isolated pincer impingement. Cam impingement caused damage to the anterosuperior acetabular cartilage with separation between the labrum and cartilage. During flexion, the cartilage was sheared off the bone by the non-spherical femoral head while the labrum remained untouched. In pincer impingement, the cartilage damage was located circumferentially and included only a narrow strip. During movement the labrum is crushed between the acetabular rim and the femoral neck causing degeneration and ossification. Both cam and pincer impingement lead to osteoarthritis of the hip. Labral damage indicates ongoing impingement and rarely occurs alone.

PMID 15972923
V M Ilizaliturri, J M Nossa-Barrera, E Acosta-Rodriguez, J Camacho-Galindo
Arthroscopic treatment of femoroacetabular impingement secondary to paediatric hip disorders.
J Bone Joint Surg Br. 2007 Aug;89(8):1025-30. doi: 10.1302/0301-620X.89B8.19152.
Abstract/Text Open reduction of the prominence at the femoral head-neck junction in femoroacetabular impingement has become an established treatment for this condition. We report our experience of arthroscopically-assisted treatment of femoroacetabular impingement secondary to paediatric hip disease in 14 hips in 13 consecutive patients (seven women, six men) with a mean age of 30.6 years (24 to 39) at the time of surgery. The mean follow-up was 2.5 years (2 to 4). Radiologically, 13 hips had successful restoration of the normal geometry and only one had a residual deformity. The mean increase in the Western Ontario McMasters Osteoarthritis Index for the series at the last follow-up was 9.6 points (4 to 14). No patient developed avascular necrosis or sustained a fracture of the femoral neck or any other complication. These findings suggest that femoroacetabular impingement associated with paediatric hip disease can be treated safely by arthroscopic techniques.

PMID 17785739
Eijer H, et al.: Cross table lateral radiograph for screening of anterior femoral head -neck offset in patients with femoro-acetabular impingement. Hip Int 2001;11:37-41.
H P Nötzli, T F Wyss, C H Stoecklin, M R Schmid, K Treiber, J Hodler
The contour of the femoral head-neck junction as a predictor for the risk of anterior impingement.
J Bone Joint Surg Br. 2002 May;84(4):556-60.
Abstract/Text Impingement by prominence at the femoral head-neck junction on the anterior acetabular rim may cause early osteoarthritis. Our aim was to develop a simple method to describe concavity at this junction, and then to test it by its ability to distinguish quantitatively a group of patients with clinical evidence of impingement from asymptomatic individuals who had normal hips on examination. MR scans of 39 patients with groin pain, decreased internal rotation and a positive impingement test were compared with those of 35 asymptomatic control subjects. The waist of the femoral head-neck junction was identified on tilted axial MR scans passing through the centre of the head. The anterior margin of the waist of the femoral neck was defined and measured by an angle (alpha). In addition, the width of the femoral head-neck junction was measured at two sites. Repeated measurements showed good reproducibility among four observers. The angle alpha averaged 74.0 degrees for the patients and 42.0 degrees for the control group (p < 0.001). Significant differences were also found between the patient and control groups for the scaled width of the femoral neck at both sites. Using standardised MRI, the symptomatic hips of patients who have impingement have significantly less concavity at the femoral head-neck junction than do normal hips. This test may be of value in patients with loss of internal rotation for which a cause is not found.

PMID 12043778
Marc J Philippon, Allston J Stubbs, Mara L Schenker, R Brian Maxwell, Reinhold Ganz, Michael Leunig
Arthroscopic management of femoroacetabular impingement: osteoplasty technique and literature review.
Am J Sports Med. 2007 Sep;35(9):1571-80. doi: 10.1177/0363546507300258. Epub 2007 Apr 9.
Abstract/Text Morphological and spatial abnormalities of the proximal femur and acetabulum have been recently recognized as causes of femoroacetabular impingement. During joint motion in hips with femoroacetabular impingement, abnormal bony contact occurs, and soft tissue structures (chondral and labral) often fail. Femoroacetabular impingement has been reported to be a contributor to early-onset joint degeneration. Ganz et al have described good midterm success with an open surgical dislocation approach to reconstruct normal joint clearance. The purpose of this report is to discuss relevant literature and describe an arthroscopic approach to treat femoroacetabular impingement. This approach has particular relevance in high-demand patients, particularly in athletes seeking to return to high-level sport.

PMID 17420508
Fabian Kalberer, Rafael J Sierra, Sanjeev S Madan, Reinhold Ganz, Michael Leunig
Ischial spine projection into the pelvis : a new sign for acetabular retroversion.
Clin Orthop Relat Res. 2008 Mar;466(3):677-83. doi: 10.1007/s11999-007-0058-6. Epub 2008 Feb 10.
Abstract/Text Femoroacetabular impingement may occur in patients with so-called acetabular retroversion, which is seen as the crossover sign on standard radiographs. We noticed when a crossover sign was present the ischial spine commonly projected into the pelvic cavity on an anteroposterior pelvic radiograph. To confirm this finding, we reviewed the anteroposterior pelvic radiographs of 1010 patients. Nonstandardized radiographs were excluded, leaving 149 radiographs (298 hips) for analysis. The crossover sign and the prominence of the ischial spine into the pelvis were recorded and measured. Interobserver and intraobserver variabilities were assessed. The presence of a prominent ischial spine projecting into the pelvis as diagnostic of acetabular retroversion had a sensitivity of 91% (95% confidence interval, 0.85%-0.95%), a specificity of 98% (0.94%-1.00%), a positive predictive value of 98% (0.94%-1.00%), and a negative predictive value of 92% (0.87%-0.96%). Greater prominence of the ischial spine was associated with a longer acetabular roof to crossover sign distance. The high correlation between the prominence of the ischial spine and the crossover sign shows retroversion is not just a periacetabular phenomenon. The affected inferior hemipelvis is retroverted entirely. Retroversion is not caused by a hypoplastic posterior wall or a prominence of the anterior wall only and this finding may influence management of acetabular disorders.

PMID 18264856
L B Laborie, T G Lehmann, I Ø Engesæter, F Sera, L B Engesæter, K Rosendahl
The alpha angle in cam-type femoroacetabular impingement: new reference intervals based on 2038 healthy young adults.
Bone Joint J. 2014 Apr;96-B(4):449-54. doi: 10.1302/0301-620X.96B4.32194.
Abstract/Text We report on gender-specific reference intervals of the alpha angle and its association with other qualitative cam-type findings in femoroacetabular impingement at the hip, according to a population-based cohort of 2038 19-year-olds, 1186 of which were women (58%). The alpha angle was measured on standardised frog-leg lateral and anteroposterior (AP) views using digital measurement software, and qualitative cam-type findings were assessed subjectively on both views by independent observers. In all, 2005 participants (837 men, 1168 women, mean age 18.6 years (17.2 to 20.1) were included in the analysis. For the frog-leg view, the mean alpha angle (right hip) was 47° (26 to 79) in men and 42° (29 to 76) in women, with 97.5 percentiles of 68° and 56°, respectively. For the AP view, the mean values were 62° (40 to 105) and 52° (36 to 103) for men and women, respectively, with 97.5 percentiles of 93° and 94°. Associations between higher alpha angles and all qualitative cam-type findings were seen for both genders on both views. The reference intervals presented for the alpha angle in this cross-sectional study are wide, especially for the AP view, with higher mean values for men than women on both views.

PMID 24692609
Doris E Wenger, Kurtis R Kendell, Mark R Miner, Robert T Trousdale
Acetabular labral tears rarely occur in the absence of bony abnormalities.
Clin Orthop Relat Res. 2004 Sep;(426):145-50.
Abstract/Text We evaluated the percentage of patients with acetabular labral tears who have a structural hip abnormality detectable by conventional radiography. Records from our institution from 1996 through 2002 were reviewed to identify all patients with labral tears. Patients were excluded who had classic hip dysplasia, advanced osteoarthritis, or a history of pelvic or femoral osteotomy. The hip radiographs were evaluated for abnormalities of Tönnis angle, center-edge angle of Wiberg, acetabular version, femoral neck-shaft angle, congruency between the femoral head and acetabulum, anterior femoral head-neck offset, and presence of femoral head osteophytes. Twenty-seven of the 31 patients (87%) had at least one abnormal finding and 35% had more than one abnormality. Ten patients had a retroverted acetabulum, 16 had coxa valga, 11 had an abnormal femoral head-neck offset, and 14 had osteophytes on the femoral head. Four of 31 patients (13%) had no identifiable structural abnormalities. To our knowledge, this is the first study to document that the majority of patients with labral tears have a structural hip abnormality detectable with conventional radiographs. Familiarity with these structural abnormalities is important for early detection and accurate diagnosis, and may impact optimal treatment planning and prognosis.

PMID 15346066
D Allen, P E Beaulé, O Ramadan, S Doucette
Prevalence of associated deformities and hip pain in patients with cam-type femoroacetabular impingement.
J Bone Joint Surg Br. 2009 May;91(5):589-94. doi: 10.1302/0301-620X.91B5.22028.
Abstract/Text Femoroacetabular impingement is a cause of hip pain in adults and is potentially a precursor of osteoarthritis. Our aim in this study was to determine the prevalence of bilateral deformity in patients with symptomatic cam-type femoroacetabular impingement as well as the presence of associated acetabular abnormalities and hip pain. We included all patients aged 55 years or less seen by the senior author for hip pain, with at least one anteroposterior and lateral pelvic radiograph available. All patients with dysplasia and/or arthritis were excluded. A total of 113 patients with a symptomatic cam-impingement deformity of at least one hip was evaluated. There were 82 men and 31 women with a mean age of 37.9 years (16 to 55). Bilateral cam-type deformity was present in 88 patients (77.8%) while only 23 of those (26.1%) had bilateral hip pain. Painful hips had a statistically significant higher mean alpha angle than asymptomatic hips (69.9 degrees vs 63.1 degrees , p < 0.001). Hips with an alpha angle of more than 60 degrees had an odds ratio of being painful of 2.59 (95% confidence interval 1.32 to 5.08, p = 0.006) compared with those with an alpha angle of less than 60 degrees . Of the 201 hips with a cam-impingement deformity 42% (84) also had a pincer deformity. Most patients with cam-type femoroacetabular impingement had bilateral deformities and there was an associated acetabular deformity in 84 of 201 patients (42%). This information is important in order to define the natural history of these deformities, and to determine treatment.

PMID 19407290
K A Siebenrock, R Schoeniger, R Ganz
Anterior femoro-acetabular impingement due to acetabular retroversion. Treatment with periacetabular osteotomy.
J Bone Joint Surg Am. 2003 Feb;85-A(2):278-86.
Abstract/Text BACKGROUND: This study was performed to evaluate whether symptomatic anterior femoro-acetabular impingement due to acetabular retroversion can be treated effectively with a periacetabular osteotomy.
METHODS: The diagnosis of femoro-acetabular impingement was based on clinical symptoms, a positive anterior impingement test, and findings of acetabular rim lesions on magnetic resonance imaging. The radiographic diagnosis of acetabular retroversion was based on the cross-over and posterior wall signs. Twenty-nine hips in twenty-two patients (average age, twenty-three years) underwent a periacetabular osteotomy. An arthrotomy was performed in twenty-six hips in order to visualize intra-articular lesions and, in selected cases, to improve a low femoral head-neck offset. The range of motion of the hip was measured, clinical evaluation was performed with use of the score described by Merle d'Aubigné and Postel, and the anterior center-edge angle of Lequesne and de Sèze was measured on radiographs preoperatively and at the time of the latest follow-up.
RESULTS: The duration of follow-up averaged thirty months (range, twenty-four to forty-nine months). The anterior center-edge angle of Lequesne and de Sèze decreased significantly from a preoperative average of 36 degrees (range, 26 degrees to 52 degrees ) to a postoperative average of 28 degrees (range, 16 degrees to 46 degrees ) (p = 0.002). There was a significant increase in the average range of internal rotation (10 degrees, p = 0.006), flexion (7 degrees, p = 0.014), and adduction (8 degrees, p = 0.017). The average Merle d'Aubigné score increased from 14.0 points (range, 12 to 16 points) preoperatively to 16.9 points (range, 15 to 18 points) postoperatively (p < 0.001), and the result was good or excellent for twenty-six hips. Three hips underwent subsequent surgery: one, because of early postoperative loss of reduction; one, for correction of posteroinferior impingement; and one, because of recurrent signs of anterior impingement.
CONCLUSION: Periacetabular osteotomy is an effective way to reorient the acetabulum in young adults with symptomatic anterior femoro-acetabular impingement due to acetabular retroversion

PMID 12571306
N V Bardakos, R N Villar
Predictors of progression of osteoarthritis in femoroacetabular impingement: a radiological study with a minimum of ten years follow-up.
J Bone Joint Surg Br. 2009 Feb;91(2):162-9. doi: 10.1302/0301-620X.91B2.21137.
Abstract/Text Although the association between femoroacetabular impingement and osteoarthritis is established, it is not yet clear which hips have the greatest likelihood to progress rapidly to end-stage disease. We investigated the effect of several radiological parameters, each indicative of a structural aspect of the hip joint, on the progression of osteoarthritis. Pairs of plain anteroposterior pelvic radiographs, taken at least ten years apart, of 43 patients (43 hips) with a pistol-grip deformity of the femur and mild (Tönnis grade 1) or moderate (Tönnis grade 2) osteoarthritis were reviewed. Of the 43 hips, 28 showed evidence of progression of osteoarthritis. There was no significant difference in the prevalence of progression between hips with initial Tönnis grade 1 or grade 2 osteoarthritis (p = 0.31). Comparison of the hips with and without progression of arthritis revealed a significant difference in the mean medial proximal femoral angle (81 degrees vs 87 degrees, p = 0.004) and the presence of the posterior wall sign (39% vs 7%, p = 0.02) only. A logistic regression model was constructed to predict the influence of these two variables in the development of osteoarthritis. Mild to moderate osteoarthritis in hips with a pistol-grip deformity will not progress rapidly in all patients. In one-third, progression will take more than ten years to manifest, if ever. The individual geometry of the proximal femur and acetabulum partly influences this phenomenon. A hip with cam impingement is not always destined for end-stage arthritic degeneration.

PMID 19190047
J-E Gedouin, O May, N Bonin, A Nogier, T Boyer, H Sadri, R-N Villar, F Laude, French Arthroscopy Society
Assessment of arthroscopic management of femoroacetabular impingement. A prospective multicenter study.
Orthop Traumatol Surg Res. 2010 Dec;96(8 Suppl):S59-67. doi: 10.1016/j.otsr.2010.08.002. Epub 2010 Oct 28.
Abstract/Text INTRODUCTION: Surgical treatment of femoroacetabular impingement can be performed under arthroscopic control, to limit associated morbidity. Encouraged by recent good reports, arthroscopy is replacing alternative techniques for this indication.
HYPOTHESIS: Arthroscopy enables femoroacetabular impingement to be corrected with a low rate of associated morbidity.
AIM OF STUDY: To assess the indications for and quality of the technique and its impact on preliminary results and complications. To investigate preoperative prognostic factors.
PATIENT AND METHODS: One hundred and eleven hips in 110 patients (78 male, 32 female; mean age, 31 years) were operated on under arthroscopic control for femoroacetabular impingement, by six senior surgeons. Sixty-five patients showed no radiographic sign of osteoarthritis, and 36 showed grade-1 early osteoarthritis on the Tönnis scale.
RESULTS: Mean WOMAC score rose from 60.3 preoperatively to 83 (p<0.001) at a mean 10 months' FU (range, 6-18 mo). Seventy-seven percent of patients were satisfied or very satisfied with their result. Patients with early osteoarthritis had significantly lower WOMAC and satisfaction scores than those free of osteoarthritis. Operative crossover to open surgery occurred in only one case. Five patients (4%) had revision: total hip replacement or resurfacing. There were seven complications (6%): three cases of heterotopic ossification, one of crural palsy, one of pudendal palsy, one of labium majus necrosis, and one non-displacement stress fracture of the femoral head/neck junction (managed by non-weight-bearing). There was no palsy of the territory of the lateral cutaneous nerve of the thigh.
DISCUSSION: Results confirmed the efficacy and low associated morbidity of arthroscopy in the management of femoroacetabular impingement. Short-term functional results matched those of the literature. Planning and assessment seem not yet to be fully standardized. Preoperative osteoarthritis on X-ray was associated with poorer functional results. This attitude does not seem to be indicated for hips showing evolved osteoarthritis (>grade 1).

Copyright © 2010 Elsevier Masson SAS. All rights reserved.
PMID 21035415
Rintje Agricola, Marinus P Heijboer, Sita M A Bierma-Zeinstra, Jan A N Verhaar, Harrie Weinans, Jan H Waarsing
Cam impingement causes osteoarthritis of the hip: a nationwide prospective cohort study (CHECK).
Ann Rheum Dis. 2013 Jun;72(6):918-23. doi: 10.1136/annrheumdis-2012-201643. Epub 2012 Jun 23.
Abstract/Text OBJECTIVE: To determine the association between cam impingement, which is hip incongruity by a non-spherical femoral head and development of osteoarthritis.
METHODS: A nationwide prospective cohort study of 1002 early symptomatic osteoarthritis patients (CHECK), of which standardised anteroposterior pelvic radiographs were obtained at baseline and at 2 and 5 years follow-up. Asphericity of the femoral head was measured by the α angle. Clinically, decreased internal hip rotation (≤20°) is suggestive of cam impingement. The strength of association between those parameters at baseline and development of incident osteoarthritis (K&L grade  2) or end-stage osteoarthritis (K&L grades 3, 4, or total hip replacement) within 5 years was expressed in OR using generalised estimating equations.
RESULTS: At baseline, 76% of the included hips had no radiographic signs of osteoarthritis and 24% doubtful osteoarthritis. Within 5 years, 2.76% developed end-stage osteoarthritis. A moderate (α angle>60°) and severe (α angle>83°) cam-type deformity resulted in adjusted OR of 3.67 (95% CI 1.68 to 8.01) and 9.66 (95% CI 4.72 to 19.78), respectively, for end-stage osteoarthritis. The combination of severe cam-type deformity and decreased internal rotation at baseline resulted in an even more pronounced adjusted OR, and in a positive predictive value of 52.6% for end-stage osteoarthritis. For incident osteoarthritis, only a moderate cam-type deformity was predictive OR=2.42 (95% CI 1.15 to 5.06).
CONCLUSIONS: Individuals with both severe cam-type deformity and reduced internal rotation are strongly predisposed to fast progression to end-stage osteoarthritis. As cam impingement might be a modifiable risk factor, early recognition of this condition is important.

PMID 22730371
G E R Thomas, A J R Palmer, R N Batra, A Kiran, D Hart, T Spector, M K Javaid, A Judge, D W Murray, A J Carr, N K Arden, S Glyn-Jones
Subclinical deformities of the hip are significant predictors of radiographic osteoarthritis and joint replacement in women. A 20 year longitudinal cohort study.
Osteoarthritis Cartilage. 2014 Oct;22(10):1504-10. doi: 10.1016/j.joca.2014.06.038. Epub 2014 Jul 15.
Abstract/Text OBJECTIVE: Femoroacetabular Impingement (FAI) and Acetabular Dysplasia are common deformities, which have been implicated as a major cause of hip osteoarthritis (OA). We examined whether these subtle deformities of the hip are associated with the development of radiographic OA and total hip replacement (THR) in women.
DESIGN: A population-based, longitudinal cohort of 1003 women underwent pelvis radiographs at years 2 and 20. Alpha Angle, Triangular Index Height, Lateral Centre Edge (LCE) angle and Extrusion Index were measured. An alpha angle of greater than 65° was defined as Cam-type FAI. Radiographic OA and the presence of a THR were then determined at 20 years.
RESULTS: Cam-type FAI was significantly associated with the development of radiographic OA. Each degree increase in alpha angle above 65° was associated with an increase in risk of 5% (Odds Ratio (OR) 1.05 [95% confidence interval (CI) 1.01-1.09]) for radiographic OA and 4% (OR 1.04 [95% CI 1.00-1.08]) for THR. For Acetabular Dysplasia, each degree reduction in LCE angle below 28° was associated with an increase in risk of 13.0% (OR 0.87 [95% CI 0.78-0.96]) for radiographic OA and 18% (OR 0.82 [95% CI 0.75-0.89]) for THR.
CONCLUSIONS: This study demonstrates that Cam-type FAI and mild Acetabular Dysplasia are predictive of subsequent OA and THR in a large female population cohort. These are independent of age, BMI and joint space and significantly improve current predictive models of hip OA development.

Copyright © 2014. Published by Elsevier Ltd.
PMID 25047637
Alex S Nicholls, Amit Kiran, Thomas C B Pollard, Deborah J Hart, Charlotte P A Arden, Tim Spector, H S Gill, David W Murray, Andrew J Carr, Nigel K Arden
The association between hip morphology parameters and nineteen-year risk of end-stage osteoarthritis of the hip: a nested case-control study.
Arthritis Rheum. 2011 Nov;63(11):3392-400. doi: 10.1002/art.30523.
Abstract/Text OBJECTIVE: Subtle deformities of the hip joint are implicated in the etiology of osteoarthritis (OA) of the hip. Parameters that quantify these deformities may aid understanding of these associations. We undertook this study to examine relationships between such parameters and the 19-year risk of total hip arthroplasty (THA) for end-stage OA.
METHODS: A new software program designed for measuring morphologic parameters around the hip was developed and validated in a reliability study. THA was the outcome measure for end-stage OA. A nested case-control study was used with individuals from a cohort of 1,003 women who were recruited at year 1 in 1989 and followed up to year 20 (the Chingford Study). All hips with THA by year 20 and 243 randomly selected control hips were studied. Pelvis radiographs obtained at year 2 were analyzed for variations in hip morphology. Measurements were compared between the THA case group and the control group.
RESULTS: Patients with THA had a higher prevalence of cam deformity than did their respective controls (median alpha angle 62.4° versus 45.8° [P = 0.001]; mean modified triangular index height 28.5 mm versus 26.9 mm [P = 0.001]) as well as a higher prevalence of acetabular dysplasia (mean lateral center edge angle 29.5° versus 34.3° [P = 0.001]; median extrusion index 0.25 versus 0.185 [P = 0.009]). Logistic regression analyses clustering by subject and adjusting for radiographic hip OA at year 2 showed that these morphologic parameters were still significantly associated with THA by year 20. The alpha angle and lateral center edge angle predicted the risk of THA independently when included in the same model.
CONCLUSION: This investigation describes measurements that predict the risk of THA for end-stage OA by year 20, independently of the presence of radiographic hip OA at year 2. These measurements can be made on an anteroposterior pelvis radiograph, which is an inexpensive and commonly used clinical method of investigation.

Copyright © 2011 by the American College of Rheumatology.
PMID 21739424
R Agricola, M P Heijboer, R H Roze, M Reijman, S M A Bierma-Zeinstra, J A N Verhaar, H Weinans, J H Waarsing
Pincer deformity does not lead to osteoarthritis of the hip whereas acetabular dysplasia does: acetabular coverage and development of osteoarthritis in a nationwide prospective cohort study (CHECK).
Osteoarthritis Cartilage. 2013 Oct;21(10):1514-21. doi: 10.1016/j.joca.2013.07.004. Epub 2013 Jul 9.
Abstract/Text OBJECTIVE: Determining the relation between acetabular coverage, especially overcoverage which may lead to pincer impingement, and development of osteoarthritis (OA) of the hip.
DESIGN: From a prospective cohort study of 1,002 individuals with symptoms of early OA (Cohort Hip and Cohort Knee, CHECK), 720 participants were included. Standardized anteroposterior pelvic radiographs and false profile lateral radiographs were obtained at baseline and 5 years follow-up. Acetabular undercoverage (mild dysplasia) and overcoverage (pincer deformity) were measured by a centre edge angle of <25° and >40° respectively in both radiographic views. The strength of association between those parameters at baseline and development of incident OA (Kellgren and Lawrence (K&L) grade >2 or total hip replacement), or joint space narrowing within 5 years was expressed in odds ratio (OR) adjusted for K&L grade, age, body mass index (BMI), and sex using generalized estimating equations.
RESULTS: At baseline, 76% of the included hips had no signs of radiographic OA (K&L = 0) whereas 24% had doubtful OA (K&L = 1). Within 5 years, 7.0% developed incident OA. Acetabular dysplasia was significantly associated with development of incident OA with ORs between 2.62 (95% confidence interval (CI) 1.44-4.77) and 5.45 (95% CI 2.40-12.34), dependent on the radiographic view. A pincer deformity was not associated with any outcome measure, except for a significantly protective effect on incident OA when a pincer deformity was present in both radiographic views OR 0.34 (95% CI 0.13-0.87).
CONCLUSION: Acetabular dysplasia was significantly associated with development of OA. However, a pincer deformity was not associated with OA, and might even have a protective effect on its development, which questions the supposed detrimental effect of pincer impingement.

Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
PMID 23850552
Kasper Kjaerulf Gosvig, Steffen Jacobsen, Stig Sonne-Holm, Henrik Palm, Anders Troelsen
Prevalence of malformations of the hip joint and their relationship to sex, groin pain, and risk of osteoarthritis: a population-based survey.
J Bone Joint Surg Am. 2010 May;92(5):1162-9. doi: 10.2106/JBJS.H.01674.
Abstract/Text BACKGROUND: Although the clinical consequences of femoroacetabular impingement have been well described, little is known about the prevalence of the anatomical malformations associated with this condition in the general population, the natural history of the condition, and the risk estimates for the development of osteoarthritis.
METHODS: The study material was derived from a cross-sectional population-based radiographic and questionnaire database of 4151 individuals from the Copenhagen Osteoarthritis Substudy cohort between 1991 and 1994. The subjects were primarily white, and all were from the county of Østerbro, Copenhagen, Denmark. The inclusion criteria for this study were met by 1332 men and 2288 women. On the basis of radiographic criteria, the hips were categorized as being without malformations or as having an abnormality consisting of a deep acetabular socket, a pistol grip deformity, or a combination of a deep acetabular socket and a pistol grip deformity. Hip osteoarthritis was defined radiographically as a minimum joint-space width of RESULTS: The male and female prevalences of hip joint malformations in the 3620 study subjects were 4.3% and 3.6%, respectively, for acetabular dysplasia; 15.2% and 19.4% for a deep acetabular socket; 19.6% and 5.2% for a pistol grip deformity; and 2.9% and 0.9% for a combination of a deep acetabular socket and pistol grip deformity. The male and female prevalences of a normal acetabular roof were 80.5% and 77.0%. We found no significantly increased prevalence of groin pain in subjects whose radiographs showed these hip joint malformations (all p > 0.13). A deep acetabular socket was a significant risk factor for the development of osteoarthritis (risk ratio, 2.4), as was a pistol grip deformity (risk ratio, 2.2). Acetabular dysplasia and the subject's sex were not found to be significant risk factors for the development of hip osteoarthritis (p = 0.053 and p = 0.063, respectively). The prevalence of hip osteoarthritis was 9.5% in men and 11.2% in women. The prevalence of concomitant malformations was 71.0% in men with hip osteoarthritis and 36.6% in women with hip osteoarthritis.
CONCLUSIONS: In our study population, a deep acetabular socket and a pistol grip deformity were common radiographic findings and were associated with an increased risk of hip osteoarthritis. The high prevalence of osteoarthritis in association with malformations of the hip joint suggests that an increased focus on early identification of malformations should be considered.

PMID 20439662
C Y Chung, M S Park, K M Lee, S H Lee, T K Kim, K W Kim, J H Park, J J Lee
Hip osteoarthritis and risk factors in elderly Korean population.
Osteoarthritis Cartilage. 2010 Mar;18(3):312-6. doi: 10.1016/j.joca.2009.11.004. Epub 2009 Nov 10.
Abstract/Text OBJECTIVE: To investigate the prevalence of hip osteoarthritis (OA) in a community-based elderly Korean population and to identify its risk factors.
DESIGN: Radiographs of hip and knee were evaluated in 288 men and 386 women (age>or=65 years) that participated in the Korean Longitudinal Study on Health and Aging (KLoSHA). Minimum joint space widths (JSW), center-edge angles (CEA), and neck-shaft angles were measured on hip radiographs, and tibio-femoral angles on knee radiographs. Hip OA was defined as minimum JSW of or=40 degrees) and deformities of femoral neck and knee joint. Multivariate analysis with generalized estimating equation (GEE) model was performed to exclude confounding factors.
RESULTS: When hip OA was defined as JSWor=70 years) was identified as a significant risk factors with an odds ratio (OR) of 10.0. However, when hip OA was defined as a JSW of or=70 years), female, large CEA (>or=40 degrees), and acetabular dysplasia (CEA<20 degrees) were identified as significant risk factors with ORs of 2.1, 2.1, 2.3, and 10.2, respectively.
CONCLUSIONS: The prevalence of hip OA in elderly Korean was 2.1% (JSWor=70 years), female, large CEA (>or=40 degrees), and acetabular dysplasia (CEA<20 degrees) appeared to be significant risk factors of hip OA.

Copyright 2009 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
PMID 19914196
M P Reiman, A P Goode, C E Cook, P Hölmich, K Thorborg
Diagnostic accuracy of clinical tests for the diagnosis of hip femoroacetabular impingement/labral tear: a systematic review with meta-analysis.
Br J Sports Med. 2015 Jun;49(12):811. doi: 10.1136/bjsports-2014-094302. Epub 2014 Dec 16.
Abstract/Text BACKGROUND: Surgery for hip femoroacetabular impingement/acetabular labral tear (FAI/ALT) is exponentially increasing despite lacking investigation of the accuracy of various diagnostic measures. Useful clinical utility of these measures is necessary to support diagnostic imaging and subsequent surgical decision-making.
OBJECTIVE: Summarise/evaluate the current diagnostic accuracy of various clinical tests germane to hip FAI/ALT pathology.
METHODS: A computer-assisted literature search of MEDLINE, CINAHL and EMBASE databases using keywords related to diagnostic accuracy of the hip joint, as well as the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for the search and reporting phases of the study. Quality assessment of bias and applicability was conducted using the Quality of Diagnostic Accuracy Studies-2 (QUADAS-2). Random effects models were used to summarise sensitivities (SN), specificities (SP), diagnostic odds ratio (DOR) and respective confidence intervals (CI).
RESULTS: The employed search strategy revealed 21 potential articles, with one demonstrating high quality. Nine articles qualified for meta-analysis. The meta-analysis demonstrated that flexion-adduction-internal rotation (pooled SN ranging from 0.94 (95% CI 0.90 to 0.97) to 0.99 (95% CI 0.98 to 1.00); DOR 5.71 (95% CI 0.84 to 38.86) to 7.82 (95% CI 1.06 to 57.84)) and flexion-internal rotation (pooled SN 0.96 (95% CI 0.81 to 0.99); DOR 8.36 (95% CI 0.41 to 171.3) tests possess only screening accuracy.
CONCLUSIONS: Few hip physical examination tests for diagnosing FAI/ALT have been investigated in enough studies of substantial quality to direct clinical decision-making. Further high-quality studies across a wider spectrum of hip pathology patients are recommended to discern the confirmed clinical utility of these tests.
TRIALS REGISTRATION NUMBER: PROSPERO Registration # CRD42014010144.

Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
PMID 25515771
Jeffrey J Nepple, Heidi Prather, Robert T Trousdale, John C Clohisy, Paul E Beaulé, Siôn Glyn-Jones, Young-Jo Kim
Clinical diagnosis of femoroacetabular impingement.
J Am Acad Orthop Surg. 2013;21 Suppl 1:S16-9. doi: 10.5435/JAAOS-21-07-S16.
Abstract/Text The diagnosis of femoroacetabular impingement (FAI) syndrome is made based on a combination of clinical symptoms, physical examination findings, and imaging studies. A detailed assessment of each of these components is important to differentiate FAI from other intra- and extra-articular hip disorders. Clinical and physical examination findings must be viewed collectively because no single pathognomonic finding exists for FAI. Nevertheless, common components of the history and physical examination do suggest a diagnosis of FAI.

PMID 23818186
RobRoy L Martin, James J Irrgang, Jon K Sekiya
The diagnostic accuracy of a clinical examination in determining intra-articular hip pain for potential hip arthroscopy candidates.
Arthroscopy. 2008 Sep;24(9):1013-8. doi: 10.1016/j.arthro.2008.04.075. Epub 2008 Jun 16.
Abstract/Text PURPOSE: One purpose of this study was to determine whether signs and symptoms could identify when a majority of the hip pain was originating from intra-articular sources in potential arthroscopic surgery candidates. The second purpose was to quantify pain reduction after an anesthetic intra-articular injection in those with potential labral pathology.
METHODS: Subjects with hip pain being evaluated by an orthopaedic surgeon specializing in hip arthroscopy were prospectively enrolled in the study. Clinical examination results were recorded. Sensitivity, specificity, and likelihood ratios were calculated to determine their accuracy in identifying those who would have greater than 50% pain relief from those with 50% pain relief or less.
RESULTS: We enrolled 105 subjects in this study. An anesthetic intra-articular injection was performed in 49 potential candidates for arthroscopic surgery (47%). The mean age in these 49 subjects was 42 years (SD, 15 years; range, 18 to 68 years), with 25 men (51%) and 24 women (49%). According to magnetic resonance imaging (MRI) arthrogram, 18 individuals had a definite labral tear, 29 had a possible tear, and 2 had no labral tears. In those with definite tears or possible tears, 39% (n = 7) and 45% (n = 13), respectively, did not achieve a greater than 50% reduction of pain. Groin pain, clicking, pinching pain with sitting, lateral thigh pain, flexion abduction external rotation test, flexion-internal rotation-adduction test, and trochanteric tenderness were not useful in identifying those with greater than 50% pain relief from those with 50% relief or less.
CONCLUSIONS: The symptoms and signs investigated in this study did not accurately or consistently identify subjects with primary intra-articular pain sources. Furthermore, candidates for hip arthroscopy with a labral tear identified on MRI arthrogram had varied responses to anesthetic intra-articular injection. Therefore all labral tears identified on MRI arthrogram may not be a major contributor to patients' pain complaints, and medical personnel should look for other causes of pain.
LEVEL OF EVIDENCE: Level III, diagnostic study of nonconsecutive patients (without consistently applied gold standard).

PMID 18760208
Marsha Tijssen, Robert van Cingel, Linn Willemsen, Enrico de Visser
Diagnostics of femoroacetabular impingement and labral pathology of the hip: a systematic review of the accuracy and validity of physical tests.
Arthroscopy. 2012 Jun;28(6):860-71. doi: 10.1016/j.arthro.2011.12.004. Epub 2012 Feb 24.
Abstract/Text PURPOSE: Femoroacetabular impingement (FAI) and labral pathology have been recognized as causative factors for hip pain. The clinical diagnosis is now based on MRI-A (magnetic resonance imaging-arthrogram) because the physical diagnostic tests available are diverse and information on diagnostic accuracy and validity is lacking. The purpose of this systematic review was to identify the diagnostic accuracy and validity of physical tests that are used to assess FAI and labral pathology of the hip joint.
METHODS: We performed a computerized literature search using PubMed, Medline, Web of Science, PEDro, the Cochrane Library, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) (through EBSCO). Studies describing tests and diagnostic accuracy studies were included. All included studies were assessed by the Levels of Evidence for Primary Research Questions list. All diagnostic accuracy studies were assessed by the QUADAS (Quality Assessment of Diagnostic Accuracy Studies) score.
RESULTS: We included 21 studies in which 18 different tests were described. For 11 of these tests, diagnostic accuracy figures were presented. Sensitivity was examined for all tests. Other diagnostic accuracy figures were often lacking, and when available, these were low. All articles describing tests had Level IV or V evidence. All diagnostic accuracy studies, except 1, had Level II or III evidence. Three articles had a good QUADAS score.
CONCLUSIONS: In previous studies a wide range of physical diagnostic tests have been described. Little is known about the diagnostic accuracy and validity of these tests, and if available, these figures were low. The quality of the studies investigating these tests is too low to provide a conclusive recommendation for the clinician. Thus, currently, no physical tests are available that can reliably confirm or discard the diagnoses of FAI and/or labral pathology of the hip in clinical practice.
LEVEL OF EVIDENCE: Level III, systematic review of Level III studies.

Copyright © 2012 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.
PMID 22365268
S J Ferguson, J T Bryant, R Ganz, K Ito
The influence of the acetabular labrum on hip joint cartilage consolidation: a poroelastic finite element model.
J Biomech. 2000 Aug;33(8):953-60.
Abstract/Text The goal of this study was to investigate the influence of the acetabular labrum on the consolidation, and hence the solid matrix strains and stresses, of the cartilage layers of the hip joint. A plane-strain finite element model was developed, which represented a coronal slice through the acetabular and femoral cartilage layers and the acetabular labrum. Elements with poroelastic properties were used to account for the biphasic solid/fluid nature of the cartilage and labrum. The response of the joint over an extended period of loading (10,000s) was examined to simulate the nominal compressive load that the joint is subjected to throughout the day. The model demonstrated that the labrum adds an important resistance in the flow path of the fluid being expressed from the cartilage layers of the joint. Cartilage layer consolidation was up to 40% quicker in the absence of the labrum. Following removal of the labrum from the model, the solid-on-solid contact stresses between the femoral and acetabular cartilage layers were greatly increased (up to 92% higher), which would increase the friction between the joint surfaces. In the absence of the labrum, the centre of contact shifted towards the acetabular rim. Subsurface strains and stresses were much higher without the labrum, which could contribute to fatigue damage of the cartilage layers. Finally, the labrum provided some structural resistance to lateral motion of the femoral head within the acetabulum, enhancing joint stability and preserving joint congruity.

PMID 10828325
Christopher M Larson, M Russell Giveans, Rebecca M Stone
Arthroscopic debridement versus refixation of the acetabular labrum associated with femoroacetabular impingement: mean 3.5-year follow-up.
Am J Sports Med. 2012 May;40(5):1015-21. doi: 10.1177/0363546511434578. Epub 2012 Feb 3.
Abstract/Text BACKGROUND: The acetabular labrum provides a sealing function and a degree of hip joint stability. Limited, short-term follow-up studies suggest that labral refixation/preservation leads to superior outcomes compared with labral debridement/excision.
PURPOSE: To compare the results of labral refixation versus focal labral excision/debridement in a cohort of patients who underwent arthroscopic correction of femoroacetabular impingement (FAI).
STUDY DESIGN: Cohort study; Level of evidence, 3.
METHODS: We reported on patients who underwent labral debridement/focal labral excision during a period before the development of labral repair techniques. Patients with labral tears thought to be repairable with our current arthroscopic technique were compared with a cohort of patients who underwent labral refixation. To better match the 2 groups, only patients with labral pincer- or combined-type FAI were included. In the first 44 hips, the labrum was focally excised/debrided (group 1); in the next 50 hips, the labrum was refixed (group 2). Outcomes were measured with the modified Harris Hip Score (HHS), Short Form 12 (SF-12), and a visual analog scale (VAS) for pain preoperatively and postoperatively. Preoperative and postoperative radiographs were obtained to evaluate bony resection.
RESULTS: The mean age was 32 years in group 1 and 28 years in group 2 with a mean follow-up of 42 months (range, 24-72 months). Preoperative mean subjective outcome scores were not significantly different between groups. At a mean 3.5 years' follow-up, subjective outcomes were significantly improved (P < .01) for both groups compared with preoperative scores. The HHS (P = .001), SF-12 (P = .041), and VAS pain scores (P = .004) were all significantly better for the refixation group compared with the debridement group at the most recent follow-up. At a mean 3.5 years' follow-up, good to excellent results were noted in 68% of the focal excision/debridement group and 92% of the refixation group (P = .004).
CONCLUSION: Although other factors may have influenced these results, labral refixation compared with an earlier cohort of focal labral excision/debridement resulted in better HHS, SF-12, and VAS pain outcomes and a greater percentage of good to excellent results at a mean 3.5-year follow-up.

PMID 22307078
J-E Gédouin, D Duperron, F Langlais, H Thomazeau
Update to femoroacetabular impingement arthroscopic management.
Orthop Traumatol Surg Res. 2010 May;96(3):222-7. doi: 10.1016/j.otsr.2009.12.002. Epub 2010 Apr 10.
Abstract/Text INTRODUCTION: Arthroscopic treatment of femoroacetabular impingement (FAI) is recommended since it is a minimally invasive procedure allowing full access to the hip joint.
HYPOTHESIS: Arthroscopic treatment can alleviate FAI without use of a perineal support.
GOALS OF THE STUDY: To describe an early experience of hip arthroscopy in the treatment of FAI using two types of hip distraction without perineal support; to assess morbidity of FAI release under arthroscopic control and its early clinical and radiological outcome.
PATIENTS AND METHODS: In the first 32 cases, the procedure used an invasive distractor and started with the central compartment. In the last six cases, it started with the peripheral compartment using a dedicated traction table with a contralateral buttock support. Inclusion criteria were: positive impingement test and radiological evidence of FAI. Thirty-eight consecutive patients with mean age 36 years (range 24-64) underwent arthroscopic treatment for FAI. Clinical outcome used WOMAC and Postel Merle d'Aubigné (PMA) scores. Radiological development of osteoarthritis (OA) was graded according to Tönnis score.
RESULTS: At mean final follow-up of 1.3 years (range 0.5-3), there were no complications of either type of traction technique used. Mean WOMAC score increased from 55 to 75 points and PMA from 14.6 to 16.7 points. The subjective overall satisfaction rate was 79%. Radiological OA changes appeared in two hips, were unchanged in 33, and deteriorated in three.
DISCUSSION: Invasive distraction device has been effective but appeared complex and costly. The procedure is now performed without it and begins at the peripheral compartment by the capsulotomy, which allows secondary distraction using a contralateral buttock. Preoperative OA seems to be a negative prognostic factor for clinical outcome.
CONCLUSIONS: Arthroscopic treatment of FAI is a safe technique which can be achieved without perineal complications. Limited anterior-superior capsulectomy and cephalic bone resection represent the first operative step, allowing acetabular trimming, labral reattachment and FAI relief. It is effective in terms of early clinical results.
LEVEL OF EVIDENCE: Level IV: retrospective study.

Copyright 2010 Elsevier Masson SAS. All rights reserved.
PMID 20488139
Frédéric Laude, Elhadi Sariali, Alexis Nogier
Femoroacetabular impingement treatment using arthroscopy and anterior approach.
Clin Orthop Relat Res. 2009 Mar;467(3):747-52. doi: 10.1007/s11999-008-0656-y. Epub 2008 Dec 16.
Abstract/Text Femoroacetabular impingement (FAI) has been identified as a common cause of hip pain in young adults. However, treatment is not well standardized. We retrospectively reviewed 97 patients (100 hips) who underwent osteochondroplasty of the femoral head-neck for FAI using a mini-open anterior Hueter approach with arthroscopic assistance. The mean age of the patients was 33.4 years. The labrum was refixed in 40 hips, partially excised in 39 cases, completely excised in 14 cases, and left intact in seven. Six patients were lost to followup, leaving 91 (94 hips) with a minimum followup of 28.6 months (mean, 58.3 months; range, 28.6-104.4 months). We assessed patients clinically using the nonarthritic hip score (NAHS). One patient had a femoral neck fracture 3 weeks postoperatively. At the last followup, the mean NAHS score increased by 29.1 points (54.8 +/- 12 preoperatively to 83.9 +/- 16 points at last followup). Eleven hips developed osteoarthritis and subsequently had total hip arthroplasty. The best results were obtained in patients younger than 40 years old with a 0 Tönnis grade. Refixation of the labrum did not correlate with a higher NAHS score (87 +/- 11 with refixation versus 82 +/- 19 points without) at the last followup. The technique for FAI treatment allowed direct visualization of the anterior femoral head-neck junction while avoiding surgical dislocation, had a low complication rate, and improved functional scores.

PMID 19089524
Vincent Y Ng, Naveen Arora, Thomas M Best, Xueliang Pan, Thomas J Ellis
Efficacy of surgery for femoroacetabular impingement: a systematic review.
Am J Sports Med. 2010 Nov;38(11):2337-45. doi: 10.1177/0363546510365530. Epub 2010 May 20.
Abstract/Text BACKGROUND: Recent case studies on the surgical treatment of femoroacetabular impingement (FAI) have introduced a large amount of clinical data. However, there has been no clear consensus on its efficacy.
HYPOTHESIS: The current literature can be clarified to address 4 questions: (1) Does treatment for FAI succeed in improving symptoms? (2) In which subset of patients should treatment for FAI be avoided? (3) Is labral refixation superior to simple resection? (4) Does treatment for FAI alter the natural progression of osteoarthritis in this group of typically young patients?
STUDY DESIGN: Systematic review.
METHODS: Twenty-three reports of case studies on the surgical treatment of FAI were identified and a systematic review was conducted. Data from each study were collected to answer each of the 4 focus questions.
RESULTS: This review of 970 cases included 1 level II evidence trial, 2 level III studies, and 20 level IV studies. Based on patient outcome scores and effect size, all studies demonstrated improvement of patient symptoms. Up to 30% of patients will eventually require total hip arthroplasty; those patients with Outerbridge grade III or IV cartilage damage seen intraoperatively or with preoperative radiographs showing greater than Tonnis grade I osteoarthritis will have worse outcomes with treatment for FAI. Only 2 studies directly compared labral refixation with labral debridement. Several studies reported postoperative osteoarthritis findings; only a minority of these patients had progression of their osteoarthritis.
CONCLUSION: Surgical treatment for FAI reliably improves patient symptoms in the majority of patients without advanced osteoarthritis or chondral damage. Early evidence supports labral refixation. It is too soon to predict whether progression of osteoarthritis is delayed.
CLINICAL RELEVANCE: These results may be used to help predict the outcome of surgical treatment of FAI in different patient populations and to assess the need for labral refixation.

PMID 20489213
L Bellaïche, M Lequesne, J-E Gedouin, F Laude, T Boyer, French Arthroscopy Society
Imaging data in a prospective series of adult hip pain in under-50 year-olds.
Orthop Traumatol Surg Res. 2010 Dec;96(8 Suppl):S44-52. doi: 10.1016/j.otsr.2010.09.008. Epub 2010 Oct 30.
Abstract/Text Two hundred and ninety-two patients under the age of 50 years, presenting with mechanical hip pain, were included in a prospective multicenter study. In 241 cases, imaging assessment included AP standing pelvic X-ray and Lequesne's false profile (LFP) and/or lateral neck (Ducroquet, Dunn or variant) hip X-ray. Cross-sectional arthroscan and/or arthro-MRI images were available in 81 cases. Exploration looked for acetabular and femoral head/neck dysplasia liable to induce cam or pincer anterior femoroacetabular impingement (AFAI), respectively. Labral and chondral lesions arise secondarily to hip osteoarthritis (HOA) and/or AFAI. Two-thirds of patients showed HOA. Only 6% showed a strictly normal aspect on imaging. More than half (52%) of cases had cam AFAI, half of these involving an osteophytic neck, associated in more than 90% of cases with large multifocal bone spurs of the head, neck and acetabula. These cases were considered ambiguous, due to the uncertainty as to the congenital nature of the cervico-cephalic dysmorphy; if they are excluded, only 23% of the series involved cam AFAI. Crossover sign on AP standing pelvic X-ray is the best assessment criterion for acetabular retroversion, the most frequent form of acetabular dysplasia underlying pincer AFAI, and should be explored for. Secondary neck lesions were visible only on lateral neck view in 42% of cases: this view should be included in standard radiologic work-up in under-50 year-olds. The alpha angle can be measured on this type of lateral view and on axial arthroscan and arthro-MR images; more than half of the cases in which it was pathological involved an osteophytic neck and thus a pseudo-cam effect.

Copyright © 2010 Elsevier Masson SAS. All rights reserved.
PMID 21036686
Khaled Emara, Wail Samir, El Hausain Motasem, Khaled Abd El Ghafar
Conservative treatment for mild femoroacetabular impingement.
J Orthop Surg (Hong Kong). 2011 Apr;19(1):41-5. doi: 10.1177/230949901101900109.
Abstract/Text PURPOSE: To report early results of conservative treatments (including modifications in activities of daily living) for mild femoroacetabular impingement.
METHODS: 27 male and 10 female athletic patients aged 23 to 47 years presented with unilateral hip pain secondary to femoroacetabular impingement and an alpha angle of <60 degrees. Patients were instructed to adapt to their safe range of movement and perform activities of daily living with minimal friction. The Harris Hip Score and non-arthritic hip score before and after treatment were compared. Open or arthroscopic hip surgery to remove the impinging bone was indicated when conservative treatment failed.
RESULTS: Patients were followed up for 25 to 28 months. Of the 37 patients, 4 underwent surgical treatment after conservative management failed. For the remaining 33 patients, the mean Harris Hip Score improved significantly from 72 before treatment to 91 at the 24-month follow-up. The mean non-arthritic hip scores improved from 72 to 91, and the mean visual analogue scores for hip pain from 6 to 2. Six of the 33 patients had recurrent hip pain and discomfort but not severe enough for surgical treatment.
CONCLUSION: Conservative treatment did not improve the range of hip movement, despite improvement in function and symptoms. Yet it achieved good early results, as long as the patients could modify activities of daily living to adapt to their hip morphology.

PMID 21519074
Peter D H Wall, Miguel Fernandez, Damian R Griffin, Nadine E Foster
Nonoperative treatment for femoroacetabular impingement: a systematic review of the literature.
PM R. 2013 May;5(5):418-26. doi: 10.1016/j.pmrj.2013.02.005. Epub 2013 Feb 16.
Abstract/Text OBJECTIVE: Femoroacetabular impingement (FAI) has been identified as a common cause of hip pain in young adults. However, it is not known whether an effective nonoperative treatment exists and whether there is any evidence to support such a treatment. The purpose of this review is to establish whether nonoperative treatments exist for FAI in the published literature and whether there is any evidence to support their use. TYPE: A systematic review. LITERACY SURVEY: PubMed, Medline, EMBASE, CINAHL, AMED, and Cochrane Library databases were searched by using the following terms: femoroacetabular impingement, femoro-acetabular impingement, and hip impingement. The search was limited to English only but with no time constraints.
METHODOLOGY: The review was undertaken at 2 academic institutions within the United Kingdom; any article that described or provided evidence that related to a nonoperative treatment for FAI was included. Fifty-three articles met our criteria, of which, 48 were review and/or discussion based.
SYNTHESIS: Five articles summarized primary experiments that described or evaluated nonoperative treatment, of which, 3 reported favorable outcomes. Many review and/or discussion articles (31 [65%]) indicated that a trial of conservative care was appropriate. Activity modification was most frequently recommended (39 [81%]), and nearly half promoted physical therapy as a treatment (23 [48%]).
CONCLUSION: The review literature appears to promote initial nonoperative treatment for FAI. Although the available literature with experimental data is limited, there is a suggestion that physical therapy and activity modification confer some benefit to patients. Nonoperative treatment regimens, particularly physical therapy, need to be evaluated more extensively and rigorously, preferably against operative care, to determine the true clinical effectiveness.

Copyright © 2013 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.
PMID 23419746
Stephen Murphy, Moritz Tannast, Young-Jo Kim, Robert Buly, Michael B Millis
Debridement of the adult hip for femoroacetabular impingement: indications and preliminary clinical results.
Clin Orthop Relat Res. 2004 Dec;(429):178-81.
Abstract/Text Untreated femoro-acetabular impingement is a common cause of osteoarthrosis of the hip. Surgical debridement of the adult hip with femoro-acetabular impingement recently has been advocated with the aim of relieving symptoms and slowing or halting progression of the arthrosis. At surgery, femoral sources of impingement are relieved by debriding the aspheric peripheral portion of the femoral head and the adjacent femoral neck. Acetabular sources of impingement can be relieved by debridement of the anterior rim. The most fundamental questions concerning these procedures relate to the preoperative and postoperative function, postoperative survivorship of these hips and the incidence of osteonecrosis. The current study assesses a group of 23 hips in 23 patients treated by surgical debridement for impingement. Twenty-two patients were treated by full surgical dislocation and one patient was treated by relief of impingement without dislocation. Followup ranged from a minimum of 2 years to 12 years. At most recent evaluation, seven patients had been converted to total hip arthroplasty, one had arthroscopic debridement of a recurrent labral tear, and 15 patients have had no further surgery. No hips developed osteonecrosis. Of the seven patients who had to have their procedure converted to total hip arthroplasty, three of these hips failed early and four patients' hips recovered and functioned well and subsequently deteriorated with total hip arthroplasty done between 6.4 and 9.5 years after debridement. Hips at greatest risk of failure have advanced arthrosis or a combination of impingement and instability preoperatively. The procedure effectively treats hips with impingement and without considerable secondary arthrosis or instability.

PMID 15577484
Frantz Langlais, Jean-Christophe Lambotte, Ronan Lannou, Jean-Emmanuel Gédouin, Nicolas Belot, Hervé Thomazeau, Jean-Michel Frieh, François Gouin, Christophe Hulet, Franck Marin, Henri Migaud, Hassan Sadri, Claude Vielpeau, Dominique Richter
Hip pain from impingement and dysplasia in patients aged 20-50 years. Workup and role for reconstruction.
Joint Bone Spine. 2006 Dec;73(6):614-23. doi: 10.1016/j.jbspin.2006.09.001. Epub 2006 Oct 25.
Abstract/Text In the 20-50-year age group, hip pain usually indicates dysplasia. Chronic mechanical pain is the usual pattern, although acute pain caused by avulsion or degeneration of the labrum may occur. The morphological characteristics of the dysplastic hip should be evaluated, and the link between the dysplasia and the osteoarthritis should be confirmed. Three factors indicate a favorable prognosis: joint space preservation, age younger than 40 years, and correctable femoral and acetabular abnormalities. Reconstruction is highly desirable, as it delays the need for joint replacement by 20 years. After 15 years, good outcomes are seen in 87% of patients after shelf arthroplasty and 85% after femoral varus osteotomy with or without shelf arthroplasty. Chiari acetabular osteotomy can be performed in patients with osteoarthritis but is followed by prolonged limping. Periacetabular osteotomy should be reserved for patients with moderate dysplasia and no evidence of osteoarthritis. Shelf arthroplasty and femoral osteotomy require 5-8 months off work (compared to 5 months after hip replacement surgery) but subsequently permits a far more active lifestyle. Hip replacement, which is required 20 years or more after biologic reconstruction, carries the same prognosis as first-line hip replacement (good results in 80% of patients after 15 years). Acute sharp pain related to anterior hip derangement also occurs in primary femoroacetabular impingement (FAI). The most common pattern is cam impingement, which is due to a decrease in head-neck offset and manifests as pain during flexion and adduction of the hip. Cam impingement can be corrected by anterolateral osteoplasty, which is often performed arthroscopically. Pincer-type impingement is contact between the anterior acetabular rim and the femoral neck due to retroversion of the proximal acetabulum. The imaging study strategy is discussed. Coxometry, computed tomography, and arthrography can be used. Primary FAI, which occurs as a result of geometric abnormalities, should be distinguished from secondary impingement. Causes of secondary impingement include exaggerated lumbar lordosis with pelvic tilt and to hip osteophytosis (sports or posterior hip osteoarthritis). Osteoplasty is rarely appropriate in patients with secondary impingement. The features of acute anterior hip derangement are now better defined. They can be used to guide palliative treatment, which is effective, in the medium term at least. Experience acquired over the last two decades has established the efficacy of surgery for hip dysplasia.

PMID 17137820
John C Clohisy, Lauren C St John, Amanda L Schutz
Surgical treatment of femoroacetabular impingement: a systematic review of the literature.
Clin Orthop Relat Res. 2010 Feb;468(2):555-64. doi: 10.1007/s11999-009-1138-6.
Abstract/Text UNLABELLED: The surgical treatment of femoroacetabular impingement has become more common, yet the strength of clinical evidence to support this surgery is debated. We performed a systematic review of the literature to (1) define the level of evidence regarding hip impingement surgery; (2) determine whether the surgery relieves pain and improves function; (3) identify the complications; and (4) identify modifiable causes of failure (conversion to total hip arthroplasty). We searched the literature between 1950 and 2009 for all studies reporting on surgical treatment of femoroacetabular impingement. Studies with clinical outcome data and minimum two year followup were analyzed. Eleven studies met our criteria for inclusion. Nine were Level IV and two were Level III. Mean followup was 3.2 years; range (2-5.2 years). Reduced pain and improvement in hip function were reported in all studies. Conversion to THA was reported in 0% to 26% of cases. Major complications occurred in 0% to 18% of the procedures. Current evidence regarding femoroacetabular impingement surgery is primarily Level IV and suggests the various surgical techniques are associated with pain relief and improved function in 68-96% of patients over short-term followup. Long-term followup is needed to determine survivorship and impact on osteoarthritis progression and natural history.
LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

PMID 19830504
J W Thomas Byrd, Kay S Jones
Arthroscopic management of femoroacetabular impingement: minimum 2-year follow-up.
Arthroscopy. 2011 Oct;27(10):1379-88. doi: 10.1016/j.arthro.2011.05.018. Epub 2011 Aug 20.
Abstract/Text PURPOSE: We report the results of arthroscopic management of femoroacetabular impingement with 2-year follow-up.
METHODS: All patients undergoing hip arthroscopy were prospectively assessed with the modified Harris Hip Score. Arthroscopic correction of femoroacetabular impingement was first performed in 2003. The cohort of this study consists of the first 100 consecutive cases that had achieved 2-year follow-up.
RESULTS: There was 100% follow-up at 2 years. The mean age was 34 years (range, 13 to 76 years), with 67 male and 33 female patients. There were 63 cam, 18 pincer, and 19 combined lesions. Acetabular articular damage was found in 97 cases, femoral damage was present in 23, and there were 92 labral tears. The median improvement was 21.5 points, with 79 good and excellent results. No patient required revision to total hip arthroplasty, but 6 patients underwent a subsequent arthroscopic procedure. There were 3 complications including a transient neurapraxia of the pudendal nerve and a transient neurapraxia of the lateral femoral cutaneous nerve, which resolved uneventfully, and 1 mild case of heterotopic ossification.
CONCLUSIONS: We report favorable outcomes for the arthroscopic management of femoroacetabular impingement in our early experience in the first 100 consecutive cases. The high incidence of significant articular damage observed at the time of arthroscopic intervention is concerning.

Copyright © 2011 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.
PMID 21862276
F Langlais, J-M Frieh, J-E Gédouin, F Gouin, C Hulet, P Abadie, J-C Lambotte, R Lannou, F Marin, D Richter, H Sadri, V Than Trong, C Vielpeau
[Hip dysplasia and misalignment in patients aged 20-50 years].
Rev Chir Orthop Reparatrice Appar Mot. 2006 Jun;92(4 Suppl):1S41-1S81.
Abstract/Text Anterior hip pain in young adult (20 to 50) has two main causes: secondary osteo-arthritis on development dysplasia of the hip, and femoro-acetabular impigement (FAI). This symposium had two parts: the first one analyses long-term results of non-prosthetic surgery (283 osteotomies and shelfs at 15 years FU). The second part concerned the different syndromes with acute anterior hip pain, especially due to FAI and to labral tears.In hip dysplasia, 56 shelf operations, 100 proximal femoral varus osteotomies associated or not with a shelf arthroplasty,and 127 Chiari osteotomies were examined with 10 years minimum follow-up. Only 15% of patients were lost at follow-up before 10 years and average follow-up was 15 years. Results were considered as satisfactory when the Merle d'Aubigne rating was 15/18 or more. The 3 main factors of good prognosis were: a complete correction of both femoral and acetabular dysplasia; age at operation under 40; a moderate arthritis (grade I or II according to De Mourgues and Patte). In single acetabular dysplasia with 3 favorable prognosis factors(no coxa valga, age under 40, arthritis 1 or 2), 85% good results were achieved at 15 years. When patients were over 40 at operation, or in arthritis grade over 2, only 55% of good results were observed. Varus osteotomies, associated or not with shelf arthroplasties, achieved also 85% goods results at 15 years when the 3 favorable prognosis factors were present. Similar good results were also obtained by Chiari osteotomy, but this operation was associated with 12% complications, and more that 25% of lasting limping. Therefore, with 85% good results at 15 years (and often over 20 years), non prosthetic surgery performed at 30-35 years, achieved better functional results than total hip arthroplasty, longer lasting, and not jeopardizing any further possibility of prosthetic surgery.As concerns acute anterior pain of the hip, the clinical and imaging patterns of the different syndromes have been precised: femoro-acetabular impigement by cam (or by pincer), labral tears in hip dysplasia. There were distinguished from the other secondary impigements, for example by acetabular malposition due to pelvis anteflexion or by other hip diseases: overuse arthritis, coxa retrorsa, etc. Several examples of typical syndromes were presented to support the recommended imaging techniques. The results of the speakers with different surgical treatments were reported as well as concerns open surgery than arthroscopic treatment (60 cases).

PMID 16767027
Jack G Skendzel, Marc J Philippon, Karen K Briggs, Peter Goljan
The effect of joint space on midterm outcomes after arthroscopic hip surgery for femoroacetabular impingement.
Am J Sports Med. 2014 May;42(5):1127-33. doi: 10.1177/0363546514526357. Epub 2014 Mar 7.
Abstract/Text BACKGROUND: Excellent short-term results have been reported after hip arthroscopic surgery to address femoroacetabular impingement (FAI). Purpose/
HYPOTHESIS: The purpose of this study was to determine if patients with narrow joint spaces had inferior outcomes at a postoperative minimum of 5 years and if they had a higher conversion rate to total hip arthroplasty (THA). The hypothesis was that patients with ≤2-mm joint spaces would report inferior outcomes and that patients with >2-mm joint spaces would have improved survivorship (no conversion to THA).
STUDY DESIGN: Cohort study; Level of evidence, 3.
METHODS: Between March 2005 and January 2008, prospectively collected data were analyzed for patients older than 18 years of age undergoing hip arthroscopic surgery for FAI. Radiographic measurements of joint space were collected, and hips were grouped as having preserved (>2 mm) or limited (≤2 mm) joint space. Outcome measures included the Western Ontario and McMaster Universities Arthritis Index (WOMAC), modified Harris Hip Score (MHHS), Hip Outcome Score (HOS) for activities of daily living and sports, and Short Form-12 (SF-12).
RESULTS: There were 559 patients included, 466 (83%) of whom were contacted. Fifty-four patients with limited joint spaces (86%) converted to THA, while only 63 patients with preserved joint spaces (16%) converted to THA. The mean survival time for patients with preserved joint spaces was 88 months (95% CI, 85-91 months), and the mean survival time for patients with limited joint spaces was 40.0 months (95% CI, 33.7-46.3 months) (P = .0001). Complete follow-up outcome data were available on 323 patients, none of whom had THA, with a mean follow-up of 73 months. The mean postoperative HOS for activities of daily living and sports were significantly better in patients with preserved joint spaces (82 vs. 62 [P = .012] and 77 vs. 47 [P = .003], respectively) compared with those with limited joint spaces at a mean of 73 months postoperatively (range, 60-97 months).
CONCLUSION: Hip arthroscopic surgery for FAI resulted in significantly better outcomes and activity levels at minimum 5-year follow-up in patients with preserved joint spaces. Hips with limited joint spaces converted to THA earlier than did those with preserved joint spaces.

PMID 24607652
薬剤監修について:
オーダー内の薬剤用量は日本医科大学付属病院 薬剤部 部長 伊勢雄也 以下、渡邉裕次、井ノ口岳洋、梅田将光および日本医科大学多摩永山病院 副薬剤部長 林太祐による疑義照会のプロセスを実施、疑義照会の対象については著者の方による再確認を実施しております。
※薬剤中分類、用法、同効薬、診療報酬は、エルゼビアが独自に作成した薬剤情報であり、 著者により作成された情報ではありません。
尚、用法は添付文書より、同効薬は、薬剤師監修のもとで作成しております。
※同効薬・小児・妊娠および授乳中の注意事項等は、海外の情報も掲載しており、日本の医療事情に適応しない場合があります。
※薬剤情報の(適外/適内/⽤量内/⽤量外/㊜)等の表記は、エルゼビアジャパン編集部によって記載日時にレセプトチェックソフトなどで確認し作成しております。ただし、これらの記載は、実際の保険適応の査定において保険適応及び保険適応外と判断されることを保証するものではありません。また、検査薬、輸液、血液製剤、全身麻酔薬、抗癌剤等の薬剤は保険適応の記載の一部を割愛させていただいています。
(詳細はこちらを参照)
著者のCOI(Conflicts of Interest)開示:
星野裕信 : 特に申告事項無し[2025年]
監修:酒井昭典 : 講演料(旭化成ファーマ(株),帝人ヘルスケア(株))[2025年]

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