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嬰幼兒髖關(guān)節(jié)彩超如何看？一、正常髖關(guān)節(jié)（I型）的特點(diǎn)及治療特點(diǎn)：Ⅰ型髖關(guān)節(jié)發(fā)育正常，其中又分Ia型和Ib型。Ia型β角小于55度，Ib型β角在55-77度，兩者α角都大于60度。髖臼角30°，α角60°，β角55°。髖臼對(duì)股骨頭有良好的覆蓋，骨頂外緣銳利成角（Ⅰa型）或輕度變鈍（Ⅰb型），臼頂軟骨狹窄呈三角形1。治療：對(duì)于Ⅰ型髖關(guān)節(jié)，通常不需要特殊治療，只需定期進(jìn)行復(fù)查，觀察髖關(guān)節(jié)的發(fā)育情況。因?yàn)檫@是正常的髖關(guān)節(jié)發(fā)育狀態(tài)，在日常的生長發(fā)育過程中，正常的活動(dòng)和生活不會(huì)對(duì)其產(chǎn)生不良影響。但家長也需要關(guān)注孩子的一些日常行為，例如孩子的活動(dòng)是否自如等，若發(fā)現(xiàn)異常情況應(yīng)及時(shí)就醫(yī)進(jìn)一步檢查。二、髖關(guān)節(jié)發(fā)育稍差（Ⅱ型）的特點(diǎn)與治療特點(diǎn)：Ⅱ型髖關(guān)節(jié)發(fā)育稍差，分為Ⅱa、Ⅱb、Ⅱc、Ⅱd四個(gè)亞型。Ⅱa型指出生12周以內(nèi)嬰兒，α角為50°-59°，β角小于55度；Ⅱb型指12周以上嬰兒髖，α角50°-59°，β角55°；Ⅱc型α角43°-49°，β角小于77度；Ⅱd型α角同Ⅱc型，β角大于77度。髖臼角在30°-43°之間，α角55°-60°，β角55°。該型髖的骨性髖臼外上緣缺少鈣化，骨頂輪廓發(fā)育缺陷的部分由軟骨頂增寬充填，覆蓋在股骨頭上25。治療：對(duì)于Ⅱ型髖關(guān)節(jié)，尤其是Ⅱa和Ⅱb型，因?yàn)樘幱隗y關(guān)節(jié)發(fā)育的臨界狀態(tài)或者骨化延遲狀態(tài)，在早期通常采取觀察和定期復(fù)查的策略。如果沒有進(jìn)一步的惡化或者有好轉(zhuǎn)的趨勢，可以繼續(xù)觀察。而對(duì)于Ⅱc和Ⅱd型髖臼發(fā)育不良的情況，可采用軟式支具矯治，如Pavlik吊帶等。通過支具將髖關(guān)節(jié)保持在合適的位置，促進(jìn)髖臼的正常發(fā)育。在使用支具期間，需要定期進(jìn)行超聲檢查來評(píng)估治療效果，并且要注意支具的佩戴是否合適，避免對(duì)孩子的皮膚等造成損傷。三、髖關(guān)節(jié)發(fā)育不良（Ⅲ型）的特點(diǎn)與治療特點(diǎn)：Ⅲ型髖關(guān)節(jié)發(fā)育不良，分為Ⅲa和Ⅲb型。Ⅲ型髖關(guān)節(jié)髖臼角43°-55°，α角40°-55°，β角55°-77°。兩類髖中股骨頭均向上外方脫位，Ⅲa軟骨頂為無回聲結(jié)構(gòu)，是透明軟骨成分，Ⅲb的軟骨頂可見有程度不同回聲，說明透明軟骨可能發(fā)生了纖維化或變性改變。在單一冠狀聲像上，脫位的股骨頭和髖臼不能同時(shí)完整顯現(xiàn)，參考測量點(diǎn)難以辨認(rèn)5。治療：對(duì)于Ⅲ型髖關(guān)節(jié)發(fā)育不良，早期（6-7個(gè)月以下）可采用保守治療，如使用Pavlik吊帶、支具等。從經(jīng)驗(yàn)和文獻(xiàn)的報(bào)道來說，這種保守治療對(duì)于這個(gè)年齡段的孩子成功率可以達(dá)到90%以上。在使用支具或吊帶期間，需要密切關(guān)注孩子髖關(guān)節(jié)的復(fù)位情況，定期進(jìn)行超聲檢查。如果保守治療不成功，可以改用麻醉下石膏復(fù)位。經(jīng)過復(fù)位的關(guān)節(jié)對(duì)髖臼的刺激，局部發(fā)育就會(huì)逐步的改善。同時(shí)，在治療過程中，還需要關(guān)注孩子下肢的血液循環(huán)、神經(jīng)功能等情況，避免因治療導(dǎo)致其他并發(fā)癥的出現(xiàn)。四、髖關(guān)節(jié)脫位（Ⅳ型）的特點(diǎn)與治療特點(diǎn)：Ⅳ型髖關(guān)節(jié)脫位，髖臼角55°，α角40°，β角77°。此型髖的聲學(xué)特點(diǎn)是股骨頭脫位，表面只有薄層關(guān)節(jié)囊覆蓋，髖臼唇盂和軟骨頂也向原始髖臼的內(nèi)下方移位。在B超下α角甚至測量不出，屬于髖關(guān)節(jié)高位脫位的情況212。治療：對(duì)于Ⅳ型髖關(guān)節(jié)脫位，因?yàn)槊撐磺闆r較為嚴(yán)重，一般需要積極治療。對(duì)于6-7個(gè)月以下的嬰兒，如果保守治療（如Pavlik吊帶等）效果不佳，可考慮麻醉下石膏復(fù)位。而對(duì)于年齡較大的孩子（7-18個(gè)月），可能需要進(jìn)行麻醉下閉合復(fù)位或者切開復(fù)位，然后用石膏固定。在復(fù)位過程中，要確保股骨頭準(zhǔn)確復(fù)位到髖臼內(nèi)，并且要關(guān)注復(fù)位后髖關(guān)節(jié)的穩(wěn)定性。在術(shù)后，需要長期的康復(fù)隨訪，觀察髖關(guān)節(jié)的發(fā)育情況以及孩子的下肢功能恢復(fù)情況，預(yù)防股骨頭壞死、髖關(guān)節(jié)僵硬等并發(fā)癥的發(fā)生。五、髖關(guān)節(jié)半脫位（Ⅴ型）的特點(diǎn)與治療特點(diǎn)：Ⅴ型髖關(guān)節(jié)半脫位，髖臼角55°，α角40°，β角77°-90°。髖關(guān)節(jié)處于半脫位狀態(tài)，股骨頭部分脫離髖臼，關(guān)節(jié)的穩(wěn)定性受到影響，髖臼對(duì)股骨頭的覆蓋不完全，這會(huì)影響髖關(guān)節(jié)的正常發(fā)育和功能1。治療：對(duì)于Ⅴ型髖關(guān)節(jié)半脫位的治療與Ⅲ型髖關(guān)節(jié)發(fā)育不良類似。在早期可嘗試保守治療，如使用Pavlik吊帶或支具，并且定期復(fù)查超聲，觀察髖關(guān)節(jié)復(fù)位情況。如果保守治療失敗，根據(jù)孩子的年齡可選擇麻醉下石膏復(fù)位（6-7個(gè)月以下）或者其他更復(fù)雜的復(fù)位手術(shù)（年齡較大時(shí)）。在整個(gè)治療過程中，同樣要關(guān)注髖關(guān)節(jié)的功能恢復(fù)和發(fā)育情況，避免出現(xiàn)并發(fā)癥。
臨界髖關(guān)節(jié)發(fā)育不良Borderline DDH (2)：疼痛性臨界髖關(guān)節(jié)發(fā)育不良的治療臨界髖關(guān)節(jié)發(fā)育不良BorderlineDDH(2)：疼痛性臨界髖關(guān)節(jié)發(fā)育不良的治療作者：MichaelCWyatt,MartinBeck.作者單位:KlinikfürOrthop?dieundUnfallchirurgieLuzernerKantonsspital6004Luzern,Switzerland.譯者：陶可（北京大學(xué)人民醫(yī)院骨關(guān)節(jié)科）摘要在過去的幾十年里，影像技術(shù)的改進(jìn)和手術(shù)技術(shù)的進(jìn)步使得保髖手術(shù)得到了快速發(fā)展。然而，疼痛性臨界髖關(guān)節(jié)發(fā)育不良的治療仍然存在爭議。在這篇評(píng)論中，我們將確定相關(guān)問題并描述患者評(píng)估和治療方案。我們將提供自己的建議，并確定未來的研究領(lǐng)域。簡介在過去的幾十年里，髖關(guān)節(jié)生物力學(xué)知識(shí)的提高和手術(shù)技術(shù)的進(jìn)步使得保髖手術(shù)得到了快速發(fā)展。保髖手術(shù)適應(yīng)范圍廣泛，從髖臼淺且不穩(wěn)定的髖關(guān)節(jié)到髖臼深且患有股骨髖臼撞擊(FAI)的髖關(guān)節(jié)。雖然人們普遍認(rèn)為，不穩(wěn)定髖關(guān)節(jié)發(fā)育不良的最佳治療方法是重新定位髖臼以增加覆蓋范圍，但人們同樣認(rèn)為，必須減小過度覆蓋的髖臼臨界以消除撞擊。所有這些髖關(guān)節(jié)都可能存在凸輪畸形，需要在手術(shù)矯正時(shí)加以解決[1]。在最極端的情況下，所需的治療是顯而易見的。然而，有一個(gè)過渡區(qū)，很難區(qū)分不穩(wěn)定性和股骨髖臼撞擊(FAI)。過去，這些髖關(guān)節(jié)被稱為“臨界”髖關(guān)節(jié)。通常，這包括外側(cè)中心臨界(LCE)角度在20°到25°之間的髖關(guān)節(jié)[2]。然而，“臨界”一詞是有問題的，因?yàn)樗且粋€(gè)放射學(xué)定義，只涉及描述髖關(guān)節(jié)穩(wěn)定性的幾個(gè)重要參數(shù)之一。髖臼頂傾斜角、前后覆蓋和股骨前傾是應(yīng)納入髖關(guān)節(jié)穩(wěn)定性分析的其他因素。髖關(guān)節(jié)發(fā)育不良與髖關(guān)節(jié)骨關(guān)節(jié)炎之間的關(guān)聯(lián)已經(jīng)確定[3,4]，有不穩(wěn)定跡象的髖關(guān)節(jié)發(fā)育不良退化速度更快[5]。臨界髖關(guān)節(jié)可能不穩(wěn)定、撞擊或兩者兼而有之。臨界髖關(guān)節(jié)發(fā)育不良的穩(wěn)定性很難確定，并且容易受個(gè)人主觀影響，骨科界普遍傾向于低估不穩(wěn)定性，從而導(dǎo)致不適當(dāng)?shù)闹委煛Ｗ罱难芯勘砻?，?duì)患有臨界發(fā)育不良(LCEA?>?20°)的患者進(jìn)行關(guān)節(jié)鏡髖關(guān)節(jié)手術(shù)（包括盂唇修復(fù)和關(guān)節(jié)囊折疊縫合術(shù)）可能會(huì)在短期內(nèi)帶來適當(dāng)?shù)母纳芠3,4]。然而，有證據(jù)表明，之前錯(cuò)誤的髖關(guān)節(jié)鏡檢查會(huì)對(duì)此類髖關(guān)節(jié)的治療結(jié)果產(chǎn)生負(fù)面影響[6]。因此，疼痛性臨界髖關(guān)節(jié)發(fā)育不良的治療仍然是一個(gè)極具爭議的問題。臨界性髖關(guān)節(jié)發(fā)育不良在患有髖關(guān)節(jié)疼痛的年輕人中很常見，在選定的患者群中報(bào)告的患病率為37.6%[7]。在臨界髖關(guān)節(jié)發(fā)育不良中，可能與其他不穩(wěn)定原因（如韌帶松弛癥）有顯著重疊[8]。然而，根本問題是難以正確分類潛在的病理生物力學(xué)。定義第一個(gè)問題在于定義。在前后位骨盆X線片[9](LCEA)上測量的Wiberg外側(cè)中心邊緣角傳統(tǒng)上用于將髖關(guān)節(jié)分類為正常(LCEA?>25°)、發(fā)育不良(LCEA?<20°)或臨界(LCEA20–25°)，盡管這些定義值在文獻(xiàn)中差異很大[3,10]。然而，使用外側(cè)中心邊緣角(LCEA)存在兩個(gè)問題。首先是測量方法。為了測量外側(cè)中心邊緣角(LCEA)，首先通過與股骨頭輪廓相符的圓來定義股骨頭的中心。角度的第一個(gè)分支垂直穿過旋轉(zhuǎn)中心。第二個(gè)分支由股骨頭的中心和股骨最外側(cè)點(diǎn)定義（圖1a）。重要的是不要使用髖臼的最外側(cè)點(diǎn)（圖1b），因?yàn)檫@不符合Wiberg的定義，并且會(huì)給出錯(cuò)誤的高值(外側(cè)中心邊緣角(LCEA)偏大)[11]。Fig.1.(a)CorrectmeasurementoftheLCEAusingtheedgeofthesourcil,indicatingmoderatedysplasia.(b)IncorrectmeasurementoftheLCEAinthesamehip.Usingthisvaluewouldfalselyclassifythishipasborderline.圖1(a)使用髖臼臨界正確測量外側(cè)中心邊緣角(LCEA)，表明中度髖關(guān)節(jié)發(fā)育不良。(b)同一髖關(guān)節(jié)的外側(cè)中心邊緣角(LCEA)測量不正確。使用此值會(huì)錯(cuò)誤地將此髖關(guān)節(jié)歸類為臨界。其次，實(shí)際術(shù)語“臨界髖關(guān)節(jié)發(fā)育不良”是由Wiberg本人首次提出的，包括外側(cè)中心邊緣角(LCEA)在20°和25°之間的髖關(guān)節(jié)[2]。外側(cè)中心邊緣角(LCEA)是一種放射學(xué)測量，本身無法預(yù)測臨界髖關(guān)節(jié)發(fā)育不良的穩(wěn)定性，也無法完全描述股骨頭覆蓋范圍。因此，外側(cè)中心邊緣角(LCEA)無法指導(dǎo)手術(shù)決策[12–14]。部分原因是外側(cè)中心邊緣角(LCEA)本身無法涵蓋發(fā)育不良的精確位置，并且忽略了前后股骨頭覆蓋范圍。此外，髖臼指數(shù)(AI)和股骨前傾等其他參數(shù)也與髖關(guān)節(jié)穩(wěn)定性密切相關(guān)。如果外側(cè)中心邊緣角(LCEA)減少，AI可能正常，在這種情況下很難評(píng)估髖關(guān)節(jié)的穩(wěn)定性[15]。另一方面，股骨前傾過度可能會(huì)加劇髖關(guān)節(jié)前部不穩(wěn)定[16]。根本問題是什么？對(duì)于疼痛的臨界髖關(guān)節(jié)發(fā)育不良，很難僅通過二維射線測量將病理機(jī)制表征為撞擊（穩(wěn)定）或發(fā)育不良（不穩(wěn)定），尤其是僅由髖臼功能決定而不考慮股骨的測量。髖關(guān)節(jié)穩(wěn)定性的功能表征對(duì)于指導(dǎo)手術(shù)決策至關(guān)重要。不穩(wěn)定髖關(guān)節(jié)從邏輯上可以從髖臼重新定向截骨術(shù)中受益，而穩(wěn)定髖關(guān)節(jié)可以從撞擊手術(shù)（如股骨凸輪骨成形術(shù)）中受益。那么關(guān)于髖關(guān)節(jié)內(nèi)病理學(xué)的了解有多少？應(yīng)該如何評(píng)估這些患者？有哪些治療方案？手術(shù)結(jié)果如何？這組患者的潛在隱患是什么？未來的發(fā)展方向是什么？在這篇敘述性綜述文章中，我們旨在解決這些問題，并闡明這組具有挑戰(zhàn)性的患者的處理方法。髖關(guān)節(jié)發(fā)育不良和臨界髖關(guān)節(jié)不穩(wěn)定的潛在病理是什么？髖關(guān)節(jié)發(fā)育不良患者的關(guān)節(jié)接觸壓力異常增高，股骨頭（軟骨損傷，導(dǎo)致軟骨下）骨質(zhì)相對(duì)暴露。髖臼通常較淺且前傾，盂唇經(jīng)常有代償性增大，但同時(shí)伴有髖臼后傾的情況也很高[17]。股骨通常呈外翻，前傾度高[10]。這些異常的解剖特征會(huì)導(dǎo)致病理性髖關(guān)節(jié)生物力學(xué)，表現(xiàn)為盂唇撕裂、軟骨損傷和髖關(guān)節(jié)不穩(wěn)定，這些很容易被誤解為撞擊。由于骨穩(wěn)定性受損，軟組織穩(wěn)定器（即纖維軟骨盂唇和髖關(guān)節(jié)囊）的重要性就凸顯出來[18]。一旦軟組織約束失效，髖關(guān)節(jié)就會(huì)變得不穩(wěn)定。然而，我們必須明白，主要的潛在病理是缺乏骨性穩(wěn)定性，這會(huì)導(dǎo)致髖關(guān)節(jié)失效，而不是軟組織穩(wěn)定性失效。半脫位髖關(guān)節(jié)發(fā)育不良的自然病史預(yù)后非常差，并且必然會(huì)導(dǎo)致關(guān)節(jié)退化[5]。惡化速度與半脫位嚴(yán)重程度和患者年齡直接相關(guān)，通常在癥狀出現(xiàn)后約10年，就會(huì)出現(xiàn)嚴(yán)重的退行性變化[19]。在沒有半脫位的情況下，自然病史很難預(yù)測退化速度。臨界髖關(guān)節(jié)發(fā)育不良也是如此。最近的一項(xiàng)研究強(qiáng)調(diào)了髖臼覆蓋的重要性。在一項(xiàng)為期20年的大型女性隊(duì)列研究中，研究顯示，如果外側(cè)中心邊緣角(LCE)低于28°，則每降低一度，放射學(xué)OA風(fēng)險(xiǎn)就會(huì)增加13%[20]。因此，除了短期緩解癥狀外，還必須考慮長期可能的發(fā)展。臨床表現(xiàn)臨界髖關(guān)節(jié)發(fā)育不良的臨床表現(xiàn)與其他年輕活躍成人髖關(guān)節(jié)疾?。ㄈ鏔AI綜合征[21]）非常相似，因此，徹底的病史、體格檢查和放射學(xué)評(píng)估對(duì)于正確診斷這些患者至關(guān)重要。病史重點(diǎn)記錄病史。臨界髖關(guān)節(jié)發(fā)育不良患者的主要癥狀是疼痛。這通常發(fā)生在腹股溝和髖關(guān)節(jié)外側(cè)，但也可能發(fā)生在臀部(臀后區(qū))。有必要記錄完整的疼痛病史。尋找特定的不穩(wěn)定和“避免疼痛”癥狀，這可能表明已經(jīng)達(dá)到因缺乏骨性穩(wěn)定性而需要的軟組織代償?shù)臉O限。咔嗒聲和卡住的癥狀也很常見。此外，還會(huì)詢問患者是否有任何跡象表明患者已經(jīng)患上髖關(guān)節(jié)炎，例如夜間疼痛。癥狀應(yīng)結(jié)合患者的功能限制和已經(jīng)接受的醫(yī)療護(hù)理，包括物理治療、藥物、其他意見和手術(shù)。檢查隨后應(yīng)進(jìn)行髖關(guān)節(jié)的合理臨床檢查，包括恐懼試驗(yàn)和撞擊測試。患者通常會(huì)表現(xiàn)出“膝內(nèi)翻”步態(tài)，同時(shí)伴有髖關(guān)節(jié)內(nèi)收肌力矩增加和髖關(guān)節(jié)內(nèi)旋增加，這與股骨前傾增加一致。為了功能性地增加前覆蓋，可能存在前凸過度。應(yīng)確定大轉(zhuǎn)子處有無壓痛[22]。務(wù)必記住檢查患者的旋轉(zhuǎn)輪廓、進(jìn)行神經(jīng)血管檢查以及檢查全身關(guān)節(jié)松弛的跡象，并使用Beighton評(píng)分對(duì)此進(jìn)行量化。具體關(guān)鍵目標(biāo)包括排除(i)晚期退化過程的存在，例如表現(xiàn)為固定屈曲畸形和運(yùn)動(dòng)范圍減少，以及(ii)其他病理，例如腰椎病或L5神經(jīng)根病引起的疼痛。調(diào)查診斷成像應(yīng)從骨盆的標(biāo)準(zhǔn)化AP平片和股骨頸側(cè)位片（穿桌側(cè)位、Dunn位、假斜位）[23]開始。仔細(xì)檢查這些圖像以測量LCEA、AI、擠壓指數(shù)、股骨頸干角和FEAR指數(shù)（見下文）。應(yīng)確定骨關(guān)節(jié)炎的Tonnis等級(jí)以及是否存在凸輪形態(tài)。應(yīng)仔細(xì)檢查不穩(wěn)定的直接跡象，這些跡象包括股骨頭移位，可通過與髂坐線的距離增加、Shenton線斷裂和AP視圖上股骨頭重新定位來識(shí)別，髖關(guān)節(jié)處于外展?fàn)顟B(tài)，使用MR關(guān)節(jié)造影時(shí)后關(guān)節(jié)間隙中有釓，這表明股骨頭向前移位，因此不穩(wěn)定。FEAR指數(shù)與不穩(wěn)定性有很高的相關(guān)性（見下文）。必須精確測量和記錄各種參數(shù)。有必要使用三維計(jì)算機(jī)斷層掃描(CT)進(jìn)行橫斷面成像，以獲得有關(guān)骨解剖結(jié)構(gòu)和發(fā)育不良位置的精確信息，包括髖關(guān)節(jié)周圍囊腫的存在和位置[24-26]。此外，CT還應(yīng)包括股骨前傾的評(píng)估，如果前傾過大，可能會(huì)加劇髖關(guān)節(jié)前部不穩(wěn)定。磁共振成像(MR-關(guān)節(jié)造影)應(yīng)遵循專門的髖關(guān)節(jié)檢查方案，包括徑向圖像采集或重建和關(guān)節(jié)內(nèi)造影劑應(yīng)用[27]，以檢查關(guān)節(jié)內(nèi)結(jié)構(gòu)和盂唇和關(guān)節(jié)軟骨的病理?？梢詤^(qū)分引起類似癥狀的其他原因，例如缺血性壞死、轉(zhuǎn)子滑囊炎或臀肌病變。其他測量包括盂唇大小[13,28]和髂關(guān)節(jié)囊體積[29]。對(duì)于這些患者，我們還提倡進(jìn)行非牽引性MR關(guān)節(jié)造影檢查，以檢查是否存在釓積聚，即所謂的“新月征”，這是軸向視圖上不穩(wěn)定的細(xì)微征兆[30]。這些測量值的價(jià)值是什么？在平片上，那些直接表明不穩(wěn)定的測量值是股骨頭移位，與髂坐線的距離增加，Shenton線斷裂，髖關(guān)節(jié)外展時(shí)AP視圖上股骨頭重新定位，以及FEAR指數(shù)。在MR關(guān)節(jié)造影中，后下關(guān)節(jié)間隙中釓的存在表明股骨頭移位，因此不穩(wěn)定。AI、NSA、AT、高髂囊體積和盂唇體積可能存在增加，但不能預(yù)測不穩(wěn)定性[30]（表1）。表1.用于評(píng)估髖關(guān)節(jié)不穩(wěn)定性的各種參數(shù)概述TheFemoro-EpiphysealAcetabularRoof(FEAR)index:股骨骨骺髖臼頂指數(shù)Thefemoralneck-shaftangle(NSA):頸干角FEAR指數(shù)是最近描述的參數(shù)，似乎對(duì)預(yù)測髖關(guān)節(jié)穩(wěn)定性具有很高的價(jià)值[27]。它是由髖臼頂與股骨生長板中央1/3處之間的角度形成的（圖2）。其依據(jù)是：在生長過程中，股骨的骨骺生長板會(huì)垂直于髖關(guān)節(jié)的關(guān)節(jié)反作用力。股骨頸的生長和方向受股骨頸下生長板的控制[31]。Pauwels和Maquet[32]提出理論，合力作用于骨骺軟骨的中心，在生長過程中，根據(jù)Heuter-Volkman原理，骨骺板會(huì)垂直于關(guān)節(jié)反作用力。Pauwels和Maquet的理論后來得到了Carter等人[33]的證實(shí)，他們通過二維有限元分析研究了髖關(guān)節(jié)負(fù)荷的影響。閉合的骨骺板的角度表示跨股骨近端骨骺[34]的力的平衡，也表示跨關(guān)節(jié)力在過去的作用方式。因此，它是一個(gè)功能參數(shù)，反映了髖關(guān)節(jié)在生長過程中長期的關(guān)節(jié)反作用力。如果FEAR<0°，則認(rèn)為髖關(guān)節(jié)穩(wěn)定。統(tǒng)計(jì)分析表明，5°的臨界值預(yù)測穩(wěn)定性的概率為80°。最近的研究表明，2°的臨界值預(yù)測穩(wěn)定性的概率為90%（Batailler等人，正在準(zhǔn)備發(fā)表中）。使用FEAR指數(shù)的案例如圖3a和b所示。Fig.2.TheFEARindex.Theangleismeasuredbetweenalineconnectingthemostmedialandlateralpointofthesourcilandalineconnectingthemedialandlateralendofthestraightpart(usuallycentralthird)ofthephysealscarofthefemoralhead.AnegativeFEARindex,withtheangleopeningmediallyasshowninFig.3a,indicatesastablehip.圖2.?FEAR指數(shù)。測量連接股骨最內(nèi)側(cè)和外側(cè)點(diǎn)的線與連接股骨頭骨骺直線部分（通常為中央三分之一）內(nèi)側(cè)和外側(cè)端的線之間的角度。如圖3a所示，角度向內(nèi)側(cè)打開的陰性FEAR指數(shù)，表示髖關(guān)節(jié)穩(wěn)定。Fig.3.(a)CaseexamplesusingtheFEARindex.17-year-oldmale,LCEA20°,FEAR0°.Hipdeemedthereforestableandpatientmanagedwithhiparthroscopy.(b)CaseexamplesusingtheFEARindex.17-year-oldfemale,LCEA20°,FEAR8°.HipdeemedthereforeunstableandpatientmanagedwithPAO.圖3.(a)使用FEAR指數(shù)的病例。17歲男性，LCEA20°，F(xiàn)EAR0°。因此髖關(guān)節(jié)穩(wěn)定，患者接受髖關(guān)節(jié)鏡治療。(b)使用FEAR指數(shù)的病例。17歲女性，LCEA20°，F(xiàn)EAR8°。因此髖關(guān)節(jié)不穩(wěn)定，患者接受PAO截骨治療。有哪些治療方案？治療取決于髖關(guān)節(jié)的穩(wěn)定性。疼痛性臨界髖關(guān)節(jié)發(fā)育不良的治療方案包括非手術(shù)治療、解決關(guān)節(jié)內(nèi)撞擊的手術(shù)治療（通過髖關(guān)節(jié)鏡或髖關(guān)節(jié)外科脫位進(jìn)行的FAI手術(shù)）和解決不穩(wěn)定性的手術(shù)治療（采用PAO和/或股骨截骨術(shù)的重新定位截骨術(shù)）（見圖2）。非手術(shù)治療包括患者教育、活動(dòng)調(diào)整、簡單的止痛藥、非甾體抗炎藥和髖關(guān)節(jié)腔內(nèi)注射藥物[35]。有針對(duì)性的物理治療可以改善肌肉調(diào)節(jié)、疼痛和本體感受控制。以下段落將討論包括關(guān)節(jié)鏡和/或截骨術(shù)的臨界髖關(guān)節(jié)發(fā)育不良的手術(shù)治療方案。這組患者接受髖關(guān)節(jié)鏡檢查的結(jié)果如何？隨著髖關(guān)節(jié)鏡技術(shù)的最新發(fā)展，許多外科醫(yī)生正在使用它來治療臨界髖關(guān)節(jié)發(fā)育不良，尤其是因?yàn)槿藗冋J(rèn)為髖臼周圍截骨術(shù)等替代技術(shù)的風(fēng)險(xiǎn)更高，術(shù)后恢復(fù)時(shí)間更長。臨界髖關(guān)節(jié)發(fā)育不良的髖關(guān)節(jié)鏡檢查還可以讓外科醫(yī)生處理髖關(guān)節(jié)內(nèi)病變，如盂唇撕裂或股骨凸輪畸形[3,12,36]。如果考慮使用PAO來解決骨穩(wěn)定性不足的問題，那么關(guān)節(jié)鏡檢查不僅可以讓外科醫(yī)生了解髖關(guān)節(jié)的關(guān)節(jié)內(nèi)狀態(tài)，還可以了解患者在隨后進(jìn)行更大規(guī)模手術(shù)時(shí)的表現(xiàn)[37]。然而，關(guān)于臨界髖關(guān)節(jié)發(fā)育不良的髖關(guān)節(jié)鏡檢查的已發(fā)表文獻(xiàn)很少，而且短期隨訪也存在局限性。在Jo等的系統(tǒng)綜述中，確定了13項(xiàng)關(guān)于髖關(guān)節(jié)發(fā)育不良的關(guān)節(jié)鏡檢查的研究[10]。這些研究各不相同，所有研究都是病例系列。僅有6項(xiàng)研究報(bào)告了主觀和/或客觀結(jié)果。關(guān)節(jié)鏡檢查的手術(shù)指征不明確，患者事先接受過多種非手術(shù)治療。此外，臨界髖關(guān)節(jié)發(fā)育不良的確切定義各不相同，只有兩項(xiàng)研究使用了Byrd和Jones的定義[36]。三項(xiàng)研究報(bào)告了髖關(guān)節(jié)鏡作為輔助工具，三項(xiàng)研究報(bào)告了髖關(guān)節(jié)鏡作為獨(dú)立治療。盂唇撕裂的總患病率為77.3%，主要位于髖臼緣的前部或前上部。髖臼軟骨病變比股骨病變更常見（59-75.2%比11-32%），并且位于盂唇病變的鄰近。僅有兩項(xiàng)研究檢查了臨界髖關(guān)節(jié)發(fā)育不良病例（LCEA20-25°）的關(guān)節(jié)鏡檢查結(jié)果，其中只有一項(xiàng)描述了患者報(bào)告的結(jié)果測量。后者是Byrd和Jones[36]的前瞻性臨床病例系列，其中66%的髖關(guān)節(jié)（32髖）患有臨界髖關(guān)節(jié)發(fā)育不良。關(guān)節(jié)鏡檢查后，平均改良Harris髖關(guān)節(jié)評(píng)分從50（差）改善到77（一般）。作者得出結(jié)論，髖關(guān)節(jié)鏡治療可能解決髖關(guān)節(jié)內(nèi)病理而不是發(fā)育不良的放射學(xué)證據(jù)的結(jié)果。對(duì)臨界髖關(guān)節(jié)發(fā)育不良進(jìn)行髖關(guān)節(jié)鏡檢查有什么危險(xiǎn)？臨界髖關(guān)節(jié)發(fā)育不良患者進(jìn)行關(guān)節(jié)鏡盂唇切除術(shù)和髖臼外側(cè)緣切除術(shù)可導(dǎo)致爆發(fā)性髖關(guān)節(jié)不穩(wěn)定[38]。即使修復(fù)了盂唇，也必須保留髂股韌帶和髖關(guān)節(jié)的其他靜態(tài)穩(wěn)定器，以防止不可逆的后果或?qū)е麦y關(guān)節(jié)不穩(wěn)定[39–41]。沒有確鑿的文獻(xiàn)支持在這些情況下進(jìn)行關(guān)節(jié)囊修復(fù)，但這似乎是一種安全合理的做法[42]。關(guān)節(jié)囊復(fù)位技術(shù)可提高臨界髖關(guān)節(jié)發(fā)育不良的穩(wěn)定性[12]。如果髖關(guān)節(jié)在術(shù)前足夠不穩(wěn)定，那么僅通過髖關(guān)節(jié)鏡治療關(guān)節(jié)內(nèi)病變是不夠的，患者將需要進(jìn)行PAO截骨術(shù)[43,44]。必須記住，髖關(guān)節(jié)的穩(wěn)定性首先取決于髖骨幾何形狀。在輕微不穩(wěn)定（臨界發(fā)育不良）中，穩(wěn)定性可能由次級(jí)軟組織結(jié)構(gòu)來確保。一旦這些結(jié)構(gòu)因微創(chuàng)傷或大創(chuàng)傷而失效，髖關(guān)節(jié)就會(huì)變得不穩(wěn)定?；謴?fù)軟組織穩(wěn)定性可能只會(huì)在短時(shí)間內(nèi)改善髖關(guān)節(jié)穩(wěn)定性，但軟組織很可能再次磨損。因此，必須首先解決潛在的骨病理問題，才能取得良好的長期效果。最近的一份報(bào)告顯示，髖關(guān)節(jié)發(fā)育不良患者在髖關(guān)節(jié)鏡檢查失敗后，PAO的髖關(guān)節(jié)特定功能結(jié)果較差[6]。因此，對(duì)這組患者單獨(dú)進(jìn)行髖關(guān)節(jié)鏡檢查應(yīng)謹(jǐn)慎處理。但是，對(duì)于那些由于髖關(guān)節(jié)狀況不佳（即AI和股骨前傾正常）或高齡（即>40歲）而不適合進(jìn)行PAO的患者，它可能有用。重新定向髖臼周圍截骨術(shù)對(duì)這組患者有何影響？通過髖臼周圍截骨術(shù)進(jìn)行髖臼重新定向已成為髖關(guān)節(jié)發(fā)育不良最常見的治療方法，據(jù)報(bào)道術(shù)后20多年效果良好。傳統(tǒng)上，PAO時(shí)關(guān)節(jié)內(nèi)病變的處理方法是進(jìn)行前關(guān)節(jié)切開術(shù)。然而，隨著PAO微創(chuàng)技術(shù)的發(fā)展，情況已不再如此。微創(chuàng)PAO技術(shù)縮短了術(shù)后恢復(fù)時(shí)間[45]。最近的一項(xiàng)研究表明，一些可改變的因素，例如較高的體力活動(dòng)量和較高的BMI（大于30kg/m2）可導(dǎo)致PAO的發(fā)病年齡下降[46]。此外，患有較重發(fā)育不良程度的患者患PAO的年齡也較早：LCEA是手術(shù)年齡的獨(dú)立預(yù)測因素，即LCEA較低的患者往往需要在較早的年齡接受PAO手術(shù)。但是，輕度和中度發(fā)育不良患者的PAO預(yù)后沒有差異。在本研究中，輕度發(fā)育不良被歸類為15-25°，這涵蓋了我們對(duì)臨界髖關(guān)節(jié)發(fā)育不良的定義。最近的一項(xiàng)多中心前瞻性隊(duì)列研究檢查了患者報(bào)告的PAO結(jié)果指標(biāo)，結(jié)果表明，雖然總體結(jié)果良好，但臨界髖關(guān)節(jié)發(fā)育不良患者和男性的改善程度低于發(fā)育較重的患者[47]。作者討論了小范圍矯正的危險(xiǎn)，這可能導(dǎo)致過度矯正和醫(yī)源性FAI、股骨前傾增加和軟組織松弛。建議和未來方向在臨界髖關(guān)節(jié)中，關(guān)鍵步驟是確定穩(wěn)定性。關(guān)于髖關(guān)節(jié)的穩(wěn)定性，只有兩種情況：髖關(guān)節(jié)穩(wěn)定或不穩(wěn)定。沒有中間狀態(tài)。如果接受這個(gè)概念，治療就會(huì)變得相對(duì)簡單。不穩(wěn)定可能與其他病癥（如FAI或超負(fù)荷/過度使用和軟骨疾?。┫嘟Y(jié)合，需要同時(shí)治療。如果髖關(guān)節(jié)不穩(wěn)定，則需要髖臼重新定位。僅解決磨損的二級(jí)穩(wěn)定器并不能解決潛在的生物力學(xué)問題，最多只能產(chǎn)生令人滿意的短期結(jié)果。在穩(wěn)定的髖關(guān)節(jié)中，可以進(jìn)行開放或關(guān)節(jié)鏡關(guān)節(jié)保留手術(shù)。然而，我們必須記住，低于28°的LCE角度每減少一度，骨關(guān)節(jié)炎的發(fā)病率就會(huì)增加13%[20]。因此，如果有疑問，為了最大限度地提高獲得良好長期結(jié)果的機(jī)會(huì)，我們主張進(jìn)行髖臼重新定向PAO截骨手術(shù)。重要的是要確定我們?nèi)狈χR(shí)的領(lǐng)域，以指導(dǎo)進(jìn)一步的研究。將對(duì)這些患者進(jìn)行長期隨訪研究，比較髖臼重新定向和髖關(guān)節(jié)鏡檢查，理想情況下，將記錄所有成像參數(shù)和Beighton評(píng)分。此外，還應(yīng)獲得患者報(bào)告的結(jié)果測量和恢復(fù)時(shí)間，以及包括運(yùn)動(dòng)在內(nèi)的活動(dòng)恢復(fù)時(shí)間。?TheFEARindexisarecentlydescribedparameterthatseemstohaveahighvaluetopredictstabilityofthehip[27].Itisformedbytheanglebetweentheacetabularroofandthecentralthirdofthefemoralgrowthplate(Fig.2).Itisbasedonthefactthatduringgrowththeepiphysealgrowthplateofthefemurorientsitselfperpendicularlytothejointreactingforcesofthehip.Growthandtheorientationofthefemoralneckareunderthecontrolofthesubcapitalgrowthplate[31].PauwelsandMaquet[32]theorizedthattheresultantforceactsfromthecenteroftheepiphysealcartilageandthatduringgrowth,theepiphysealplateorientsitselfperpendiculartothejointreactionforceinaccordancewiththeHeuter–Volkmanprinciple.PauwelsandMaquet’stheorylaterwasconfirmedbyCarteretal.[33]whostudiedtheinfluenceofhiploadingbybi-dimensionalfiniteelementanalysis.Theangleoftheclosedepiphysealplateindicatesthebalanceofforcesacrosstheproximalfemoralphysis[34]andindicateshowthetransarticularforcesactedinthepast.Therefore,itisafunctionalparameterthatreflectsthejointreactingforcesoveralongperiodoftimeduringgrowthofthehip.IftheFEARis?<0°thehipisconsideredstable.Statisticalanalysishasshownthatacutoffvalueof5°predictsstabilitywith80°probability.Morerecentworkhasshownthatacutoffvalueof2°predictsstabilitywith90%probability(Batailleretal.,inpreparation).CaseexamplesofusingtheFEARindexareshowninFig.3aandb.ThemanagementofthepainfulborderlinedysplastichipAbstractImprovedimagingandtheevolutionofsurgicaltechniqueshavepermittedarapidgrowthinhippreservationsurgeryoverthelastfewdecades.Themanagementofthepainfulborderlinedysplastichiphoweverremainscontroversial.Inthisreview,wewillidentifythepertinentissuesanddescribethepatientassessmentandtreatmentoptions.Wewillprovideourownrecommendationsandalsoidentifyfutureareasforresearch.INTRODUCTIONImprovedknowledgeabouthipbiomechanicsandtheevolutionofsurgicaltechniqueshavepermittedarapidgrowthinhippreservationsurgeryoverthelastfewdecades.Thespectrumcoversawiderangefromhipswithshallowacetabuli,whichareunstable,tohipswithdeepacetabulithataresufferingfromfemoro-acetabularimpingement(FAI).Whilethereisageneralagreementthatthebesttreatmentfortheunstabledysplastichipisareorientationoftheacetabulumtoincreasecover,thereisequalagreementthattherimoftheover-coveringacetabulumhastobereducedtoremoveimpingement.Onallthosehipsacamdeformitymaybepresentthatneedstobeaddressedatthetimeofsurgicalcorrection[1].Atthefarendsofthespectrumtherequisitetreatmentisobvious.However,thereisatransitionzonewhereitisdifficulttodiscriminateinstabilityfromFAI.Inthepastthesehipswerereferredtoas‘borderline’hips.Usually,thisincludedhipswithalateralcenteredge(LCE)anglebetween20°and25°[2].However,theterm‘borderline’isproblematic,becauseitisaradiographicdefinitionandonlyaddressesoneofseveralparametersimportanttodescribehipstability.Acetabularroofobliquity,anteriorandposteriorcoverandfemoralantetorsionareotherfactorsthatshouldbeincludedintoananalysisofhipstability.Theassociationofhipdysplasiawithhiposteoarthritisisestablished[3,4]anddysplastichipswithsignsofinstabilitydegenerateatahigherrate[5].Aborderlinehipcaneitherbeunstable,impingingormaybeboth.Thestabilityoftheborderlineisdifficulttodetermineandsubjecttointerpretationwithageneraltendencyintheorthopaediccommunitytounderestimateinstabilitythatthenleadstoinappropriatetreatment.Recentstudiessuggestthatarthroscopichipsurgerywithlabralrepairandcapsularplicationinpatientswithborderlinedysplasia(LCEA?>?20°)mayresultinappropriateshort-termimprovements[3,4].However,thereisevidencethatawronglydoneprevioushiparthroscopyhasanegativeimpactontheoutcomeonthetreatmentofsuchhips[6].Therefore,themanagementofthepainfulborderlinedysplastichiphoweverremainsanissueofgreatcontroversy.Borderlinehipdysplasiaiscommoninyoungadultswithhippainwithareportedprevalenceof37.6%inselectedpatientcohorts[7].Intheborderlinedysplastichiptheremaybesignificantoverlapwithothercausesofinstabilitysuchasconnectivetissuelaxity[8].However,thefundamentalissueisthedifficultyincorrectlyclassifyingtheunderlyingpatho-biomechanics.DEFINITIONThefirstproblemliesinthedefinition.TheLateralCentreEdgeAngleofWibergasmeasuredonanAntero-posteriorpelvicradiograph[9](LCEA)hastraditionallybeenusedtoclassifyhipsasnormal(LCEA?>25°),dysplastic(LCEA?<20°)orborderline(LCEA20–25°)althoughthesedefiningvaluesvarywidelyintheliterature[3,10].However,theuseoftheLCEAhastwoproblems.Firstlythemethodbywhichitshouldbemeasured.TomeasuretheLCEAthecenterofthefemoralheadisfirstdefinedbyacirclefittingthecontourofthefemoralhead.Thefirstbranchoftheanglerunsperpendicularthroughthecenterofrotation.Thesecondbranchisdefinedbythecenterofthefemoralheadandthemostlateralpointofthesourcil(Fig.1a).Itisimportantnottousethemostlateralpointoftheacetabulum(Fig.1b),becausethisdoesnotfollowthedefinitionofWiberg,andwillgivefalsehighvalues[11].Secondlytheactualterm‘Borderlinehipdysplasia’wasfirstintroducedbyWiberghimself,includinghipswithaLCEAbetween20°and25°[2].LCEAisaradiographicmeasureandpersecannotpredictstabilityintheborderlinedysplastichipnordoesfullydescribefemoralheadcoverage.ThereforetheLCEAcannotdirectsurgicaldecisionmaking[12–14].PartofthereasonisthatLCEAalonedoesnotencompassthepreciselocationofdysplasiaanddisregardsanteriorandposteriorfemoralheadcoverage.Alsootherparameterssuchasacetabularindex(AI)andfemoralantetorsionareveryrelevantforstabilityofthehip.InthepresenceofadecreasedLCEAAImaybenormalinwhichcasethestabilityofthehipisdifficulttoassess[15].Ontheotherhand,excessivefemoralanteversionmaypotentiateanteriorhipinstability[16].WHATISTHEFUNDAMENTALISSUE?Inthepainfulborderlinedysplastichipitisdifficulttocharacterizethepathologicalmechanismasimpingement(stable)ordysplasia(unstable)byatwo-dimensionalradiographicmeasurementalone,especiallyonethatissolelyafunctionoftheacetabulumandtakesnoaccountofthefemur.Thisfunctionalcharacterizationofhipstabilityisofparamountimportancetoguidesurgicaldecision-making.Anunstablehipwouldlogicallybenefitfromacetabularreorientationosteotomywhilstastablehipwouldbenefitfromimpingementsurgerysuchasfemoralcamosteoplasty.Sowhatisknownabouttheintra-articularpathology?Howshouldthesepatientsbeassessed?Whatarethetreatmentoptions?Whatarethesurgicaloutcomes?Whatarethepotentialpitfallswiththisgroupofpatients?Whatarethefuturedirections?Inthisnarrativereviewarticleweaimtoaddressthesequestionsandelucidatethemanagementofthischallenginggroupofpatients.WHATISTHEUNDERLYINGPATHOLOGYOFHIPDYSPLASIAANDUNSTABLEBORDERLINEHIPS?Inhipdysplasia,thereareabnormallyhigharticularcontactpressuresandrelativebonyuncoveringofthefemoralhead.Theacetabulumistypicallyshallowandantevertedwithanoftencompensatoryenlargedlabrum,butthereisalsoahighprevalenceofconcomitantacetabularretroversion[17].Thefemurisclassicallyinvalguswithhighantetorsion[10].Theseabnormalanatomicalfeaturescausepathologicalhipbiomechanicswhichmanifestaslabraltears,chondrallesions,andhipinstability,whichcaneasilybemisinterpretedasimpingement.Astheosseousstabilityiscompromisedtheimportanceofthesofttissuestabilisers,namelythefibrocartilaginouslabrumandthehipcapsule,isaccentuated[18].Oncethesofttissueconstraintsfailthenthehipbecomesunstable.However,onehastounderstandthattheprincipalunderlyingpathologyisthelackofosseousstability,whichleadstofailureofthehipandnotthefailingsofttissuestability.Thenaturalhistoryofthesubluxingdysplastichipisaverypoorprognosisandinvariablyleadstojointdegeneration[5].Therateofdeteriorationisdirectlyrelatedtosubluxationseverityandpatientageandusuallyabout10?yearsafteronsetofsymptomsseveredegenerativechangeshavedeveloped[19].Thenaturalhistoryintheabsenceofsubluxationismoredifficulttopredictconcerningthespeedofdegeneration.Thesameaccountsforborderlinedysplastichips.Arecentstudyhighlightstheimportanceofacetabularcover.Inalargecohortoffemales,followedfor20?years,itwasshownthateachdegreereductioninLCEbelow28°isassociatedwith13%increasedriskofradiographicOA[20].Therefore,besidesshort-termreliefofsymptoms,thelong-termpossibleevolutionhastobekeptinmind.CLINICALPRESENTATIONTheclinicalpresentationofborderlineacetabulardysplasiaisverysimilartothatofotheryoungactiveadulthipdisorders,suchasFAIsyndrome[21]soathoroughhistory,physicalexamination,andradiographicevaluationareessentialtoproperlydiagnosethesepatients.HISTORYAfocusedhistoryistaken.Theprimarysymptominpatientswithborderlinehipdysplasiaispain.Thisistypicallyperceivedingroinandlateralhipbutcanalsobeinthebuttock.Afullpainhistoryiswarranted.Particularsymptomsofinstabilityand‘givingway’aresoughtthatmayindicatethatthelimitsofsofttissuecompensationforalackofosseousstabilityhavebeenreached.Symptomsofclickingandcatchingarealsocommon.Furthermoreanyindicationsthatthepatienthasestablishedhiparthritis,suchasnightpain,areaskedfor.Thesymptomsshouldbeputintothecontextofthepatient’sfunctionallimitationsandmedicalattentionalreadyreceivedincludingphysiotherapy,medications,otheropinionsandsurgery.EXAMINATIONAlogicalclinicalexaminationofthehipshouldfollowincludingapprehensionandimpingementtests.Thepatientwilloftendisplaya‘kneeing-in’gaitinassociationwithanincreasedhipadductormomentandincreasedinternalhiprotationconsistentwithincreasedfemoralantetorsion.Hyperlordosismaybepresentinordertofunctionallyincreaseanteriorcover.Tendernessoverthegreatertrochantershouldbedetermined[22].Itiscrucialtoremembertoexaminethepatient’srotationalprofile,performaneurovascularexaminationandtocheckforsignsofgeneralizedjointlaxityandquantifythisusingBeighton’sscore.Specifickeyaimsincluderefutingthepresenceof(i)anadvanceddegenerativeprocessmanifestforexamplewithfixedflexiondeformityanddecreasedrangeofmotionand(ii)alternativepathologysuchaspainreferredfromlumbarspondylosisorL5radiculopathy.INVESTIGATIONSDiagnosticimagingshouldcommencewithstandardizedplainAPradiographofthepelvisandalateralfemoralneckviews(lateralcrosstable,Dunnview,falseprofileviews)[23].TheseimagesarescrutinizedtomeasuretheLCEA,AI,extrusionindex,femoralneck-shaftangleandFEARindex(seebelow).TheTonnisgradeofosteoarthritisshouldbedeterminedalongwithwhetherthereiscammorphology.Directsignsofinstabilityshouldbescrutinizedforandthesecomprisefemoralheadmigration,recognizedbyanincreaseddistancefromtheilioischialline,abreakinShenton’slineandrecenteringofthefemoralheadonanAPviewwiththehipinabductionandGadoliniumintheposteriorjointspacewhenusingMR-arthrography,thatindicatesanteriormigrationandthusinstabilityofthefemoralhead.TheFEARindexhasahighassociationwithinstability(seebelow).Thevariousparametershavetobemeasuredpreciselyandrecorded.Cross-sectionalimagingwiththree-dimensionalcomputerizedtomography(CT)forpreciseinformationonbonyanatomyandlocationofdysplasiaincludingthepresenceandlocationofperiarticularcystsiswarranted[24–26].FurthermoreCTshouldincludeestimationoffemoralantetorsionwhich,ifhighmaypotentiateanteriorhipinstability.Magneticresonanceimaging(MR-arthrography)shouldfollowadedicatedprotocolfortheexaminationofthehip,includingradialimageacquisitionorreconstructionandintra-articularapplicationofcontrast[27]toexamineforintra-articularstructuresandpathologyofbothlabrumandarticularcartilage.Othercausesforsimilarsymptomssuchasavascularnecrosis,trochantericbursitisorglutealpathologycanbedifferentiated.Additionalmeasurementsincludelabralsize[13,28]andiliocapsularisvolume[29].Inthesepatients,wealsoadvocatenon-tractionMRarthrographytoexamineforaaccumulationofgadoliniumknownasa‘crescentsign’whichisasubtlesignofinstabilityontheaxialview[30].WHATISTHEVALUEOFTHESEMEASUREMENTS?Onplainfilmsthosemeasurementsthataredirectsignsofinstabilityarefemoralheadmigrationwithanincreaseofthedistancefromtheilioischialline,abreakinShenton’slineandrecenteringofthefemoralheadontheAPviewwithhipsinabductionandtheFEARindex.OnMR-arthrographythepresenceofGadoliniuminthepostero-inferiorjointspaceindicatesmigrationofthefemoralheadandthusinstability.TheAI,NSA,AT,highiliocapsularisvolumeandincreasedlabralvolumemaybepresentbutarenotpredictiveofinstability[30](Table1).WHATARETHETREATMENTOPTIONS?Treatmentdependsonthestabilityofthehip.Thetreatmentalternativesforthepainfulborderlinedysplastichipincludenon-operativetreatment,surgicaltreatmenttoaddressintra-articularimpingement(FAIsurgerybyeitherhiparthroscopyorsurgicalhipdislocation)andsurgicaltreatmenttoaddressinstability(reorientationosteotomywithPAOand/orfemoralosteotomy)(seeFig.2).Non-operativemanagementincludespatienteducation,activitymodification,simpleanalgesics,non-steroidalanti-inflammatorymedications,andintra-articularinjections[35].Targetedphysiotherapycanimprovemuscularconditioning,painandproprioceptivecontrol.Thesurgicaltreatmentoptionsfortheborderlinedysplastichipwhichcomprisearthroscopyand/orosteotomywillbediscussedinthefollowingparagraphs.WHATARETHERESULTSOFHIPARTHROSCOPYINTHISGROUPOFPATIENTS?Withtherecentevolutioninhiparthroscopymanysurgeonsareusingthistoaddressborderlinedysplastichips,notleastbecauseofperceivedhigherrisksandlongerpost-operativerecoveryassociatedwithalternativetechniquessuchasperiacetabularosteotomy.Hiparthroscopyinborderlinedysplastichipspermitsthesurgeontoaddressintra-articularpathologysuchasalabraltearorfemoralcamdeformity[3,12,36].IfPAOisbeingconsideredtoaddresstheinadequatebonystabilitythenarthroscopymaygivethesurgeonvaluableinsightsnotonlyintotheintra-articularstatusofthehipbutalsohowthepatientislikelytofarewithamuchlargersubsequentoperation[37].However,thereislittlepublishedliteratureonhiparthroscopyinborderlinedysplastichipsandwhatthereislimitedbyshort-termfollow-up.InthesystematicreviewbyJoetal.,13studieslookingatarthroscopyindysplastichipswereidentified[10].Thestudieswereheterogeneousandallstudieswerecaseseries.Onlysixstudiesreportedonsubjectiveand/orobjectiveoutcomes.Thesurgicalindicationsforarthroscopywereambiguousandpatientshadreceivedvariablenon-operativemanagementapriori.FurthermoretheprecisedefinitionofborderlinehipdysplasiavariedandonlytwostudiesusedthedefinitionofByrdandJones[36].Threestudiesreportedonhiparthroscopyasanadjuvanttoolandthreeasastand-alonetreatment.Labraltearshadanoverallprevalenceof77.3%andtheseweremostlylocatedintheanteriororanterosuperiorportionoftheacetabularrim.Acetabularchondrallesionsweremorecommonthanfemorallesions(59–75.2%versus11–32%)andlocatedadjacenttothatofthelabralpathology.Therewereonlytwostudiesthatexaminedtheoutcomesofarthroscopyinborderlinehipdysplasticcases(LCEA20–25°)ofwhichonlyonedescribedpatientreportedoutcomemeasures.Thelatter,aprospectiveclinicalcaseseriesbyByrdandJones[36],had66%ofhips(32hips)withborderlinedysplasia.ThemeanmodifiedHarrisHipscoreimprovedfrom50(poor)to77(fair)followingarthroscopy.Theauthorsconcludedthatthetreatmentresponseislikelyafunctionofaddressingtheintra-articularpathologyratherthantheradiographicevidenceofdysplasia.WHATARETHEDANGERSWITHDOINGHIPARTHROSCOPYINBORDERLINEDYSPLASTICHIPS?Arthroscopiclabralresectionandremovaloflateralacetabularriminborderlinehipdysplasiacanleadtofulminantjointinstability[38].Evenifthelabrumisrepaireditisimperativetopreservetheiliofemoralligamentandotherstaticstabilizersofthehiptopreventtheirreversibleconsequencesorrenderingthehipunstable[39–41].Thereisnoconclusiveliteraturetosupportcapsularrepairinthesecasesbutthisseemsasafeandsensiblepractice[42].Capsularreductiontechniquestoimprovestabilityhavebeendescribedinborderlinedysplastichips[12].Ifthehipissufficientlyunstablepre-operativelythenaddressingtheintra-articularpathologyalonebyhiparthroscopywillbeinsufficientandthepatientwillrequireaPAO[43,44].Onehastobearinmindthatstabilityofthehipfirstlinedependsontheosseousgeometry.Insubtleinstability(borderlinedysplasia)stabilitymaybesecuredbysecondarysofttissuestructures.Oncethesefailduetomicro-ormacrotraumathehipbecomesunstable.Restoringsofttissuestabilitymayimprovehipstabilityforashortperiodoftimeonly,butitislikelythatthesofttissueswearoutagain.Thereforetheunderlyingosseouspathologyhastobeaddressedfirsttoachievegoodlong-termresults.ArecentreportshowedaninferiorhipspecificfunctionaloutcomeofPAOafterfailedhiparthroscopyinhipdysplasia[6].Hiparthroscopyaloneinthisgroupofpatientsshouldbethereforeapproachedwithcaution.However,itmayhavearoleinthosepatientswhoareeitherunsuitableforPAOeitherbecausetheirhipsareunfavourable(i.e.haveanormalAIandnormalfemoralanteversion)orbecausetheiradvancedage(i.e.>40years).WHATARETHERESULTSOFREORIENTINGPERIACETABULAROSTEOTOMYINTHISGROUPOFPATIENTS?Acetabularreorientationviatheperiacetabularosteotomyhasbecomethemostcommontreatmentforacetabulardysplasiawithgoodoutcomesreportedatover20?yearspostoperatively.Traditionallyintra-articularpathologywasaddressedatthetimeofPAObyperformingananteriorarthrotomy.HoweverwiththedevelopmentofminimallyinvasivetechniquesforPAOthisisnolongernecessarilythecase.LessinvasivePAOtechniqueshavedecreasedthetimetopostoperativerecovery[45].ArecentstudyshowedmodifiablefactorssuchashigherphysicalactivityandhigherBMIgreaterthan30?kg/m2leadtoadecreasedageofpresentationforPAO[46].FurthermorepatientsalsopresentedearlierforPAOwithworsedegreesofdysplasia:theLCEAwasindependentlypredictiveofageatsurgery,i.e.patientswithalowerLCEAtendedtorequirePAOsurgeryatanearlierage.However,therewasnodifferenceinoutcomesfollowingPAObetweenmildandmoderatedysplasia.Inthisstudymilddysplasiawasclassifiedas15–25°whichencompassesourdefinitionofborderlinehipdysplasia.Arecentmulticenterprospectivecohortstudythatexaminedpatient-reportedoutcomemeasuresofPAOshowedthat,althoughoverallresultsweregood,improvementsinborderlinehipdysplasticsandmaleswerelessthaninthosepatientswhohadmoreseveredysplasia[47].TheauthorsdiscussedthiswiththedangerofasmallcorrectionthatmayleadtoovercorrectionandiatrogenicFAI,increasedfemoralantetorsionandsofttissuelaxity.RECOMMENDATIONSANDFUTUREDIRECTIONSInborderlinehipsthecrucialstepistodefinestability.Regardingthestabilityofthehipthereareonlytwoconditions:Thehipiseitherstableorunstable.Thereisnothinginbetween.Ifthisconceptisaccepted,thetreatmentgetscomparablysimple.InstabilitymaybecombinedwithotherpathologieslikeFAIoroverload/overuseandcartilagediseasewhichneedconcomitanttreatment.Ifthehipisunstable,acetabularreorientationisnecessary.Addressingonlywornoutsecondarystabilizersdoesnotsolvetheunderlyingbiomechanicproblemandatbestwillyieldsatisfactoryshorttermresults.Instablehips,openorarthroscopicjointpreservingsurgerymaybeperformed.However,wehavetokeepinmindthateachdegreedecreaseoftheLCEanglebelow28°isassociatedwitha13%increaseofosteoarthrosis[20].Therefore,ifindoubt,inordertomaximizethechanceofgoodlong-termresults,wewouldadvocateforanacetabularreorientationoperation.Itisimportanttoidentifytheareaswherewelackknowledgeinordertoguidefurtherresearch.Longer-termfollow-upstudiescomparingacetabularreorientationandhiparthroscopyinthesepatients,ideallyinwhichallimagingparametersandBeightonscoresarerecordedwouldbeperformed.Inadditionpatient-reportedoutcomemeasuresandtimetorecoveryandresumptionofactivitiesincludingsportshouldbeattained.文獻(xiàn)出處：MichaelCWyatt,MartinBeck.Themanagementofthepainfulborderlinedysplastichip.ReviewJHipPreservSurg.2018Apr5;5(2):105-112.doi:10.1093/jhps/hny012.