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臨界髖關(guān)節(jié)發(fā)育不良Borderline DDH (3)：股骨骨骺髖臼頂指數(shù)(FEAR)臨界髖關(guān)節(jié)發(fā)育不良BorderlineDDH(3)：股骨骨骺髖臼頂指數(shù)（TheFemoro-EpiphysealAcetabularRoof(FEAR)index）：一個預(yù)測髖關(guān)節(jié)穩(wěn)定性具有很高價值的功能參數(shù)作者：MichaelWyatt,JanWeidner,DominikPfluger,MartinBeck.作者單位:ClinicforOrthopaedicandTraumaSurgery,LuzernerKantonsspital,Spitalstrasse4,6004,Lucerne,Switzerland.michaelcharleswyatt@icloud.com.譯者：陶可（北京大學(xué)人民醫(yī)院骨關(guān)節(jié)科）摘要TheFemoro-EpiphysealAcetabularRoof(FEAR)index:股骨骨骺髖臼頂指數(shù)FEAR指數(shù)是最近描述的一個預(yù)測髖關(guān)節(jié)穩(wěn)定性具有很高價值的參數(shù)。它是由髖臼頂與股骨生長板中央1/3處之間的夾角。其依據(jù)是：在生長過程中，股骨的骨骺生長板會垂直于髖關(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。Pauwels和Maquet等提出理論，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等人的證實，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°(角開口向內(nèi))，則認(rèn)為髖關(guān)節(jié)穩(wěn)定。統(tǒng)計分析表明，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）。摘要背景：在放射學(xué)臨界髖關(guān)節(jié)發(fā)育不良中，骨性不穩(wěn)定性很難定義。因此，可靠的放射學(xué)工具（可幫助決策）——具體來說，可能與不穩(wěn)定性相關(guān)的工具——對這類患者非常有幫助。問題/目的：(1)比較一種新的放射學(xué)測量方法，我們稱之為股骨-骨骺髖臼頂(FEAR)指數(shù)，與側(cè)中心邊緣角(LCEA)和髖臼指數(shù)(AI)，以了解觀察者內(nèi)和觀察者間的可靠性；(2)將AI、頸干角、LCEA、髂關(guān)節(jié)囊體積、股骨前傾和FEAR指數(shù)與穩(wěn)定和不穩(wěn)定臨界髖關(guān)節(jié)發(fā)育不良接受的手術(shù)治療相關(guān)聯(lián)；以及(3)評估FEAR指數(shù)是否與臨界髖關(guān)節(jié)發(fā)育不良的臨床不穩(wěn)定性相關(guān)。方法：我們使用兩名盲法獨立觀察員在10張無癥狀對照的標(biāo)準(zhǔn)化X線片中定義和驗證了FEAR指數(shù)。計算了評分者間和評分者內(nèi)系數(shù)，并輔以Bland-Altman圖。我們將其可靠性與LCEA和AI進(jìn)行了比較。我們進(jìn)行了一項病例對照研究，使用39例經(jīng)手術(shù)治療的有癥狀的臨界放射學(xué)髖關(guān)節(jié)發(fā)育不良和20例年齡匹配的無癥狀髖關(guān)節(jié)對照者的標(biāo)準(zhǔn)化X線片（比例為2:1），后者是因與髖關(guān)節(jié)無關(guān)的創(chuàng)傷而到我們機構(gòu)就診的患者，但在2016年1月1日至2016年3月1日期間進(jìn)行了標(biāo)準(zhǔn)化骨盆X線片檢查。使用單變量Wilcoxon雙樣本檢驗評估患者的人口統(tǒng)計數(shù)據(jù)。各研究組的平均年齡沒有差異（總體：31.5±11.8歲[95%CI,27.7-35.4歲]；穩(wěn)定臨界DDH組：平均32.1±13.3歲[95%CI,25.5-38.7歲]；不穩(wěn)定臨界DDH組：平均31.1±10.7歲[95%CI,26.2-35.9歲]；p=0.96）。接受的治療是髖臼周圍截骨術(shù)（如果髖關(guān)節(jié)不穩(wěn)定），或者對于股骨髖臼撞擊患者，接受開放式或關(guān)節(jié)鏡下股骨髖臼撞擊手術(shù)。首先使用Wilcoxon雙樣本檢驗（雙側(cè)）評估所接受的治療類別與變量AI、頸干角、LCEA、髂關(guān)節(jié)囊體積、股骨前傾和FEAR指數(shù)之間的關(guān)聯(lián)，然后進(jìn)行逐步多元邏輯回歸分析，以確定組合環(huán)境中的潛在相關(guān)變量。計算了敏感性、特異性和受試者工作曲線。主要終點是FEAR指數(shù)與不穩(wěn)定性之間的關(guān)聯(lián)，我們將其定義為股骨頭移位（在常規(guī)X線片上已經(jīng)可見）或在AP外展視圖上重新集中、Shenton線斷裂或MR關(guān)節(jié)造影時在后下關(guān)節(jié)間隙出現(xiàn)新月形釓積聚。結(jié)果：FEAR指數(shù)顯示出出色的觀察者內(nèi)和觀察者間可靠性，優(yōu)于AI和LCEA。與不穩(wěn)定臨界DDH組（平均值，13.3±15.2；95%CI，6.2-20.4）相比，穩(wěn)定臨界DDH組的FEAR指數(shù)較低（平均值，-2.1±8.4；95%CI，-6.3至2.0）（p<0.001），并且與所接受的治療的相關(guān)性最高。FEAR指數(shù)小于5°時，將髖關(guān)節(jié)正確分為穩(wěn)定和不穩(wěn)定的概率分別為79%（敏感性78%；特異性80%）。結(jié)論：LCEA為25°或更小且FEAR指數(shù)小于5°的疼痛髖關(guān)節(jié)很可能是穩(wěn)定的，在這種情況下，診斷重點可能更有效地集中在股骨髖臼撞擊上，因為股骨髖臼撞擊是患者疼痛的潛在原因，而不是髖關(guān)節(jié)不穩(wěn)定。?討論臨界發(fā)育不良是一種放射學(xué)定義，由LCEA量化[19]。不幸的是，這種放射學(xué)發(fā)現(xiàn)并不能說明髖關(guān)節(jié)的臨床穩(wěn)定性。其他因素也會導(dǎo)致不穩(wěn)定；這些因素包括前傾、髖臼頂傾角和頸干角。雖然將臨界髖關(guān)節(jié)分類為穩(wěn)定或不穩(wěn)定對于成功治療這些髖關(guān)節(jié)是必要的，但在實踐中很難做到這一點，可能會導(dǎo)致治療不當(dāng)。特別是，如果錯誤地推測問題是FAI而不是不穩(wěn)定，并進(jìn)行髖關(guān)節(jié)鏡檢查來治療，這可能會導(dǎo)致不穩(wěn)定癥狀持續(xù)存在。必須解決的問題不是髖關(guān)節(jié)是發(fā)育不良還是臨界發(fā)育不良，而是髖關(guān)節(jié)是穩(wěn)定還是不穩(wěn)定。因此，關(guān)鍵是準(zhǔn)確地將髖關(guān)節(jié)歸類為其中一種，然后進(jìn)行相應(yīng)的治療。傳統(tǒng)上，LCEA用于將髖關(guān)節(jié)分為正常、邊緣或發(fā)育不良。然而，LCEA并不總是能預(yù)測髖關(guān)節(jié)的穩(wěn)定性。為了幫助決策，我們提出了一種新的放射學(xué)參數(shù)，該參數(shù)可以在標(biāo)準(zhǔn)化AP骨盆X線片上可靠地測量。本研究的目的是評估這個FEAR指數(shù)，看看它是否與臨界不穩(wěn)定髖關(guān)節(jié)的病理行為有關(guān)。這項研究是有限的，因為納入的患者數(shù)量很少，無法進(jìn)行精確的患者匹配。更詳盡的參數(shù)匹配，如全身韌帶松弛的跡象、BMI和肌肉調(diào)節(jié)將是有利的。此外，回顧性研究使我們能夠顯示關(guān)聯(lián)，但不能做出預(yù)測。因此，有必要進(jìn)行未來的前瞻性研究，以顯示FEAR指數(shù)是否預(yù)測進(jìn)行性不穩(wěn)定。我們還通過各種參數(shù)來定義不穩(wěn)定性，包括MR關(guān)節(jié)造影上后下方釓的聚集、股骨頭的旋轉(zhuǎn)中心重新定位或Shenton線的斷裂，而不是純粹基于放射學(xué)；這導(dǎo)致了對不穩(wěn)定性的功能性定義。我們嘗試通過讓兩名對患者所接受的治療不知情的人員進(jìn)行測量來解決評估者偏見的問題。我們的研究結(jié)果表明，我們的新指數(shù)表現(xiàn)出極好的觀察者間和觀察者內(nèi)信度，優(yōu)于LCEA和AI。這種優(yōu)越性可能是因為難以定義髖臼底部的邊緣，正如所提到的[16]。已發(fā)表了幾項研究專門關(guān)注臨界髖關(guān)節(jié)發(fā)育不良的手術(shù)治療結(jié)果，其中一項研究顯示邊緣性髖關(guān)節(jié)的失敗率高于具有足夠髖臼覆蓋的髖關(guān)節(jié)[10]，另一項研究顯示結(jié)果基本一致[15]。目前髖關(guān)節(jié)的穩(wěn)定性通過LCEA進(jìn)行評估。意識到LCEA的局限性，有人嘗試使用臨界髖關(guān)節(jié)的其他參數(shù)作為髖關(guān)節(jié)不穩(wěn)定的替代指標(biāo)，例如盂唇大小或髂關(guān)節(jié)囊體積，已知這兩個結(jié)構(gòu)在髖關(guān)節(jié)發(fā)育不良時通常會肥大[1,8,11]。引入FEAR指數(shù)是評估髖關(guān)節(jié)功能穩(wěn)定性的新嘗試，其基于生長板在生長過程中垂直于關(guān)節(jié)反作用力的生物力學(xué)概念[5,6,8,9]。在對照組和穩(wěn)定臨界DDH組中，F(xiàn)EAR指數(shù)具有向內(nèi)張開的角度，即向內(nèi)指向的向量，表示向內(nèi)指向的關(guān)節(jié)反作用力和穩(wěn)定性。在發(fā)育不良組(13°)中，角度向外側(cè)張開，表示關(guān)節(jié)反作用力有利于關(guān)節(jié)的橫向移位和不穩(wěn)定。我們的研究不支持髂關(guān)節(jié)囊體積作為邊緣發(fā)育不良髖關(guān)節(jié)的鑒別因素。這與Babst等人的研究相反[1]。這可能歸因于患者的選擇。Babst等[1]將髖關(guān)節(jié)發(fā)育不良與鉗狀FAI髖關(guān)節(jié)進(jìn)行了比較，我們將不穩(wěn)定髖關(guān)節(jié)與穩(wěn)定性臨界髖關(guān)節(jié)進(jìn)行了比較，解剖學(xué)差異很小。我們建議進(jìn)一步研究以檢驗這一點，因為我們的研究表明髂關(guān)節(jié)囊體積與股骨前傾之間存在相關(guān)性。FEAR指數(shù)的統(tǒng)計建模表明，這可能成為識別可能表現(xiàn)為穩(wěn)定的臨界髖關(guān)節(jié)的有用工具。這可能有利于識別適合髖關(guān)節(jié)鏡檢查的髖關(guān)節(jié)。79%的髖關(guān)節(jié)被正確識別為穩(wěn)定的臨界髖關(guān)節(jié)，靈敏度為80%，特異性為78%，F(xiàn)EAR指數(shù)似乎適合識別穩(wěn)定的髖關(guān)節(jié)。FEAR指數(shù)識別不穩(wěn)定的能力不太令人鼓舞，這可能反映了其他因素，例如韌帶松弛與決策過程有關(guān)。有趣的是，有癥狀的FAI患者中，關(guān)節(jié)過度活動更為普遍[10,14]。我們認(rèn)為FEAR指數(shù)可能適用于包括標(biāo)準(zhǔn)射線照相在內(nèi)的全面臨床和放射學(xué)檢查，最好將MR關(guān)節(jié)造影術(shù)作為標(biāo)準(zhǔn)的第一步。MR關(guān)節(jié)造影術(shù)在檢測髖關(guān)節(jié)不穩(wěn)定方面優(yōu)于MRI，因為可以觀察到新月征。必須尋找不穩(wěn)定的跡象，例如標(biāo)準(zhǔn)X線片上的股骨頭移位和MR關(guān)節(jié)造影上的新月征。如果存在，則必須通過髖臼周圍截骨術(shù)來穩(wěn)定髖關(guān)節(jié)。如果仍不確定髖關(guān)節(jié)是否穩(wěn)定，可以使用FEAR指數(shù)來評估穩(wěn)定性的可能性。我們發(fā)現(xiàn)，如果患者出現(xiàn)髖關(guān)節(jié)疼痛和臨界發(fā)育不良（定義為LCEA20°至25°），F(xiàn)EAR指數(shù)小于5°表示髖關(guān)節(jié)穩(wěn)定的可能性為80%，如果FEAR指數(shù)增加1°，發(fā)生撞擊的幾率會降低24%。在這種情況下，F(xiàn)AI似乎比發(fā)育不良更有可能；然而，在確定FAI診斷之前，應(yīng)考慮并排除其他原因。如有指征，應(yīng)相應(yīng)選擇手術(shù)治療。需要進(jìn)一步研究以前瞻性驗證FEAR指數(shù)。?Fig.1A–COurmeasurements,usingthepicturearchivingandcommunicationsystem(PACS)measurementdevice,of(A)theFEARindex;(B)LCEA;and(C)AIareshown.StandardizedAPpelvicradiographsof10asymptomaticcontrolpatientstreatedforunrelatedtraumaatourinstitutionduringJanuary2016wereselectedforthemeasurements.Nopatientshadpriorhipproblems.UsingthedigitalmeasurementtoolsontheMerlinpicturearchivingandcommunicationsystem(PACS)(Ph?nixMerlinSoftware5.0;Ph?nixPACSGmbH,Freiburg,Germany),twoindependentreviewers(MCWandJW)measuredtheFEARindex,LCEA,andAI,whichwedefinedastheangleofthesourcilversusthehorizontal(Fig.1).圖1A–C?我們使用圖片存檔和通信系統(tǒng)(PACS)測量設(shè)備測量了(A)FEAR指數(shù)；(B)LCEA；和(C)AI。選擇了2016年1月在我們機構(gòu)接受無關(guān)創(chuàng)傷治療的10名無癥狀對照患者的標(biāo)準(zhǔn)化AP骨盆X線片進(jìn)行測量。沒有患者之前有髖關(guān)節(jié)問題。使用Merlin圖片存檔和通信系統(tǒng)(PACS)上的數(shù)字測量工具（Ph?nixMerlinSoftware5.0；Ph?nixPACSGmbH，德國弗萊堡），兩名獨立審查員（MCW和JW）測量了FEAR指數(shù)、LCEA和AI（我們將其定義為髖臼眉弓與水平線之間的夾角）（圖1）。Fig.2A–BBland-AltmanplotsareshownfortheFEARindexforthe(A)firstand(B)secondmeasurements.Theinter-andintraobserverreliabilitywasfairtogoodfortheLCEA,whereastheAIwasexcellentforbothyetinferiortotheFEARindex.TheFEARindexdidnotvarysubstantiallybetweenassessorsforeachreplication(Fig.2).圖2A–B?顯示了(A)第一次和(B)第二次測量的FEAR指數(shù)的Bland-Altman圖。對于LCEA來說，觀察者間和觀察者內(nèi)信度為中等至良好，而AI對兩者而言都非常好，但不如FEAR指數(shù)。評估者之間的FEAR指數(shù)在每次重復(fù)中沒有顯著差異（圖2）。Fig.3AboxplotoftheFEARindexversustreatmentgroupisshown.Therewasnodifferenceinmeanage(overall:31.5±11.8years[95%CI,27.7–35.4years];stableborderlinegroup:mean,32.1±13.3years[95%CI,25.5–38.7years];unstableborderlinegroup:mean,31.1±10.7years[95%CI,26.2–35.9years])betweenstudygroups..TheFEARindexwashigheramongthegroupswithFAIandunstabletreatmentcomparedwiththeasymptomaticcontrolgroup(mean?2.1±8.4and13.3±15.2respectivelyversus?7.7±7.1forcontrols;p<0.001)(Fig.3).圖3?顯示了FEAR指數(shù)與治療組的箱線圖。各研究組間平均年齡無差異（總體：31.5±11.8歲[95%CI,27.7–35.4歲]；穩(wěn)定臨界DDH組：平均32.1±13.3歲[95%CI,25.5–38.7歲]；不穩(wěn)定臨界DDH組：平均31.1±10.7歲[95%CI,26.2–35.9歲]）。FAI組和不穩(wěn)定治療組的FEAR指數(shù)高于無癥狀對照組（平均-2.1±8.4和13.3±15.2，對照組為-7.7±7.1；p<0.001）（圖3）。Fig.4Athree-dimensionalscattergraphshowstheLCEA,AI,andFEARindex.Inaddition,theFEARindexyieldedthegreatestdistinctionwithrespecttotreatmentstatus(impingementborderlinegroupmean?2.1±8.4versusunstableborderlinegroupmean13.3±15.2;p<0.001)comparedwiththeLCEA(impingementborderlinegroup20±3.1versusunstableborderlinegroupmean13.7±8.3;p<0.001)andAI(impingementborderlinegroup13.6±3.6versusunstableborderlinegroupmean19.2±6.8;p=0.006),respectively(Fig.4).Iliocapsularisvolume,neck-shaftangle,andfemoralantetorsiondidnotdiscriminatebetweentreatmentgroups.However,inourstudy,iliocapsularisvolumehadapositiveassociationwithfemoralantetorsion,thatis,alargeriliocapsularisvolumewasassociatedwithgreaterantetorsion.圖4?三維散點圖顯示LCEA、AI和FEAR指數(shù)。此外，與LCEA（撞擊臨界DDH組20±3.1對比不穩(wěn)定臨界DDH組平均值13.7±8.3；p<0.001）和AI（撞擊臨界DDH組13.6±3.6對比不穩(wěn)定臨界DDH組平均值19.2±6.8；p=0.006）相比，F(xiàn)EAR指數(shù)在治療狀態(tài)方面產(chǎn)生了最大的區(qū)別（撞擊臨界DDH組平均值-2.1±8.4對比不穩(wěn)定臨界DDH組平均值13.3±15.2；p<0.001）（圖4）。髂關(guān)節(jié)囊體積、頸干角和股骨前傾在治療組之間沒有區(qū)別。然而，在我們的研究中，髂關(guān)節(jié)囊體積與股骨前傾呈正相關(guān)，也就是說，髂關(guān)節(jié)囊體積越大，前傾越大。Fig.5TheROCforFEARindexmodelisshown(areaunderthecurve=0.8944).Thisisshowngraphically(Fig.5).ThevalueofareaunderthecurveinthisROCcurvebeingclosetotheupperleftcornerindicatesthattheFEARindexhasaveryhighassociationwithinstability.圖5?顯示了FEAR指數(shù)模型的ROC（曲線下面積=0.8944）。這以圖形方式顯示（圖5）。此ROC曲線中曲線下面積的值接近左上角，表明FEAR指數(shù)與不穩(wěn)定性有非常高的關(guān)聯(lián)性。?DiscussionBorderlinedysplasticisaradiographicdefinitionthatisquantifiedbytheLCEA[19].Unfortunatelythisradiographicfindingdoesnotgiveanyindicationregardingtheclinicalstabilityofthehip.Additionalfactorscontributetoinstability;theseincludeantetorsion,acetabularroofinclination,andneckshaftangle.Althoughthecategorizationofborderlinehipsasstableorunstableisnecessaryforsuccessfultreatmentofthesehips,thiscanbedifficulttodoinpracticeandmayleadtoincorrecttreatment.Inparticular,ifonemistakenlysurmisestheproblemisFAIratherthaninstabilityandperformshiparthroscopytotreatit,thislikelywillresultinpersistentsymptomsfrominstability.Thequestionthathastobeaddressedisnotwhetherahipisdysplasticorborderlinedysplastic,butwhetherthehipisstableorunstable.Thekeythereforeistoclassifythehipaccuratelyasoneortheotherandthentreatitaccordingly.Traditionally,theLCEAwasusedtocategorizehipsasnormal,borderline,ordysplastic.However,theLCEAdoesnotalwayspredictstabilityofthehip.Toaiddecision-making,wehaveproposedanewradiographicparameterthatcanbemeasuredreliablyonstandardizedAPpelvicradiographs.ThepurposeofthisstudywastoevaluatethisFEARindextoseewhetheritisassociatedwithpathologicbehaviorintheborderline-unstablehip.Thestudyislimitedbecausewiththesmallnumberofpatientsincluded,precisepatientmatchingcouldnotbeperformed.More-exhaustivematchingforparameterslikesignsofgeneralizedligamentouslaxity,BMI,andmuscularconditioningwouldbeadvantageous.Furthermore,aretrospectivestudyallowsustoshowassociationsbutnottomakepredictions.ThereforefutureprospectivestudiestoshowwhethertheFEARindexpredictsprogressiveinstabilityarewarranted.Wealsodefinedinstabilitybyvariousparameters,includingpoolingofgadoliniumposteroinferiorlyonMRarthrography,recenteringofthefemoralheadorabreakinShenton’slineandratherthanonapurelyradiographicbasis;thisresultsinafunctionaldefinitionofinstability.Weattemptedtoaddresstheissueofassessorbiasbyhavingtwoindividualsblindedtothetreatmentspatientsreceivedperformthemeasurements.Thefindingsfromourstudyshowthatournewindexshowsexcellentinter-andintraobserverreliabilityandwassuperiortotheLCEAandAI.Thissuperioritymaybebecauseofdifficultyindefiningtheedgeoftheacetabularsourcilashasbeenalludedto[16].?Acoupleofstudieshavebeenpublishedlookingspecificallyattheresultsofsurgicaltreatmentofborderlinedysplastichips,withonestudyshowinghigherratesoffailureintheborderlinehipsthaninthosewithadequateacetabularcover[10],andtheotherstudyshowingcomparableoutcomes[15].CurrentlystabilityofthehipisassessedwiththeLCEA.RealizingthelimitationsoftheLCEA,therehavebeenattemptstouseotherparametersinborderlinehipsassurrogatemarkersforhipinstability,suchasthesizeofthelabrumorthevolumeoftheiliocapsularis,bothstructuresknownoftentobehypertrophicinhipdysplasia[1,8,11].IntroducingtheFEARindexisanewattempttoassessfunctionalstabilityofthehip,basedonthebiomechanicalconceptthatthegrowthplateorientsitselfperpendicularlytothejointreactingforcesduringgrowth[5,6,8,9].Inthecontrolgroupandthestableborderlinegroup,theFEARindexhadamediallyopenangle,thatis,amediallydirectedvector,indicatingmedial-directedjoint-reactionforcesandstability.Inthedysplasticgroup(13°),theangleopenedlaterally,indicatingjoint-reactionforcesfavoringlateralmigrationandinstabilityofthejoint.Ourstudydidnotsupporttheiliocapsularisvolumeasadiscriminatorinborderlinedysplastichips.ThisiscontrarytothestudybyBabstetal.[1].Thisprobablyisattributabletopatientselection.Babstetal.[1]compareddysplastichipswithhipswithpincerFAIandwecomparedunstablewithstableborderlinehips,theanatomicdifferencebeingonlyminimal.Werecommendfurtherresearchtoexaminethis,becauseourstudyshowedacorrelationbetweeniliocapsularisvolumewithfemoralantetorsion.StatisticalmodelingoftheFEARindexsuggeststhatthiscouldbecomeausefultoolinidentifyingborderlinehipsthatlikelywillbehaveasstable.Thiscouldproveadvantageousinidentifyinghipsthatwouldbeappropriateforhiparthroscopy.With79%correctlyidentifiedasstableborderlinehipswithasensitivityof80%andspecificityof78%,theFEARindexseemssuitabletoidentifystablehips.TheabilityoftheFEARindextoidentifyinstabilitywaslessencouragingandthismayreflectotherfactorssuchasligamentouslaxitybeingpertinentinthedecision-makingprocess.Interestingly,hypermobilityhasbeennotedtobemoreprevalentinsymptomaticpatientswithFAI[10,14].WebelievetheFEARindexmightbeappliedinthecontextofathoroughclinicalandradiographicworkupincludingstandardradiographs,andpreferablyMRarthrographyremainsthestandardfirststep.MRarthrographyissuperiortoMRIfordetectionofhipinstabilitybecausethecrescentsigncanbeobserved.Signsofinstability,likemigrationofthefemoralheadonstandardradiographsandthecrescentsignonMRarthrography,havetobelookedfor.Ifpresent,thehiphastobestabilizedwithaperiacetabularosteotomy.Ifoneisstillundecidedwhetherthehipisstable,theFEARindexcanbeusedtoassessthelikelihoodofstability.Wefoundthatifapatientpresentswithhippainandborderlinedysplasia(definedasaLCEA20°to25°),aFEARindexlessthan5°indicatesan80%probabilitythatthehipisstable,andiftheFEARindexincreasesby1°,theoddsofhavingimpingementdecreasesby24%.Inthatsituation,FAIseemsmorelikelythandysplasia;however,othercausesshouldbeconsideredandexcludedbeforedeterminingadiagnosisofFAI.Surgicaltreatment,ifindicated,shouldbeselectedaccordingly.FurtherstudiesareneededtovalidatetheFEARindexprospectively.?TheFemoro-EpiphysealAcetabularRoof(FEAR)Index:ANewMeasurementAssociatedWithInstabilityinBorderlineHipDysplasia?AbstractBackground:Thedefinitionofosseousinstabilityinradiographicborderlinedysplastichipsisdifficult.Areliableradiographictoolthataidsdecision-making-specifically,atoolthatmightbeassociatedwithinstability-thereforewouldbeveryhelpfulforthisgroupofpatients.Questions/purposes:(1)Tocompareanewradiographicmeasurement,whichwecalltheFemoro-EpiphysealAcetabularRoof(FEAR)index,withthelateralcenter-edgeangle(LCEA)andacetabularindex(AI),withrespecttointra-andinterobserverreliability;(2)tocorrelateAI,neck-shaftangle,LCEA,iliocapsularisvolume,femoralantetorsion,andFEARindexwiththesurgicaltreatmentreceivedinstableandunstableborderlinedysplastichips;and(3)toassesswhethertheFEARindexisassociatedclinicalinstabilityinborderlinedysplastichips.Methods:WedefinedandvalidatedtheFEARindexin10standardizedradiographsofasymptomaticcontrolsusingtwoblindedindependentobservers.Interraterandintraratercoefficientswerecalculated,supplementedbyBland-Altmanplots.WecompareditsreliabilitywithLCEAandAI.Weperformedacase-controlstudyusingstandardizedradiographsof39surgicallytreatedsymptomaticborderlineradiographicallydysplastichipsand20age-matchedcontrolswithasymptomatichips(a2:1ratio),thelatterwerepatientsattendingourinstitutionfortraumaunrelatedtotheirhipsbutwhohadstandardizedpelvicradiographsbetweenJanuary1,2016andMarch1,2016.PatientdemographicswereassessedusingunivariateWilcoxontwo-sampletests.Therewasnodifferenceinmeanage(overall:31.5±11.8years[95%CI,27.7-35.4years];stableborderlinegroup:mean,32.1±13.3years[95%CI,25.5-38.7years];unstableborderlinegroup:mean,31.1±10.7years[95%CI,26.2-35.9years];p=0.96)amongstudygroups.Treatmentreceivedwaseitheraperiacetabularosteotomy(ifthehipwasunstable)or,forpatientswithfemoroacetabularimpingement,eitheranopenorarthroscopicfemoroacetabularimpingementprocedure.TheassociationofreceivedtreatmentcategorieswiththevariablesAI,neck-shaftangle,LCEA,iliocapsularisvolume,femoralantetorsion,andFEARindexwereevaluatedfirstusingWilcoxontwo-sampletests(two-sided)followedbystepwisemultiplelogisticregressionanalysistoidentifythepotentialassociatedvariablesinacombinedsetting.Sensitivity,specificity,andreceiveroperatorcurveswerecalculated.TheprimaryendpointwastheassociationbetweentheFEARindexandinstability,whichwedefinedasmigrationofthefemoralheadeitheralreadyvisibleonconventionalradiographsorrecenteringoftheheadonAPabductionviews,abreakofShenton'sline,ortheappearanceofacrescent-shapedaccumulationofgadoliniumintheposteroinferiorjointspaceatMRarthrography.Results:TheFEARindexshowedexcellentintra-andinterobserverreliability,superiortotheAIandLCEA.TheFEARindexwaslowerinthestableborderlinegroup(mean,-2.1±8.4;95%CI,-6.3to2.0)comparedwiththeunstableborderlinegroup(mean,13.3±15.2;95%CI,6.2-20.4)(p<0.001)andhadthehighestassociationwithtreatmentreceived.AFEARindexlessthan5°hada79%probabilityofcorrectlyassigninghipsasstableandunstable,respectively(sensitivity78%;specificity80%).Conclusions:ApainfulhipwithaLCEAof25°orlessandFEARindexlessthan5°islikelytobestable,andinsuchasituation,thediagnosticfocusmightmoreproductivelybedirectedtowardfemoroacetabularimpingementasapotentialcauseofapatient'spain,ratherthaninstability.文獻(xiàn)出處：MichaelWyatt,JanWeidner,DominikPfluger,MartinBeck.TheFemoro-EpiphysealAcetabularRoof(FEAR)Index:ANewMeasurementAssociatedWithInstabilityinBorderlineHipDysplasia?ComparativeStudy,ClinOrthopRelatRes.2017Mar;475(3):861-869.doi:10.1007/s11999-016-5137-0.
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。在這篇評論中，我們將確定相關(guān)問題并描述患者評估和治療方案。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，因為它是一個放射學(xué)定義，只涉及描述髖關(guān)節(jié)穩(wěn)定性的幾個重要參數(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?。最近的研究表明，對患有臨界發(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，之前錯誤的髖關(guān)節(jié)鏡檢查會對此類髖關(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。角度的第一個分支垂直穿過旋轉(zhuǎn)中心。第二個分支由股骨頭的中心和股骨最外側(cè)點定義（圖1a）。重要的是不要使用髖臼的最外側(cè)點（圖1b），因為這不符合Wiberg的定義，并且會給出錯誤的高值(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。使用此值會錯誤地將此髖關(guān)節(jié)歸類為臨界。其次，實際術(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加劇髖關(guān)節(jié)前部不穩(wěn)定[16]。根本問題是什么？對于疼痛的臨界髖關(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。最近的一項研究強調(diào)了髖臼覆蓋的重要性。在一項為期20年的大型女性隊列研究中，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)險就會增加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)評估對于正確診斷這些患者至關(guān)重要。病史重點記錄病史。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，包括恐懼試驗和撞擊測試?；颊咄ǔ憩F(xiàn)出“膝內(nèi)翻”步態(tài)，同時伴有髖關(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評分對此進(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動范圍減少，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別，髖關(guān)節(jié)處于外展?fàn)顟B(tài)，使用MR關(guān)節(jié)造影時后關(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)。有必要使用三維計算機斷層掃描(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)包括股骨前傾的評估，如果前傾過大，可能會加劇髖關(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)，似乎對預(yù)測髖關(guān)節(jié)穩(wěn)定性具有很高的價值[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，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，尤其是因為人們認(rèn)為髖臼周圍截骨術(shù)等替代技術(shù)的風(fēng)險更高，術(shù)后恢復(fù)時間更長。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項研究報告了主觀和/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，只有兩項研究使用了Byrd和Jones的定義[36]。三項研究報告了髖關(guān)節(jié)鏡作為輔助工具，三項研究報告了髖關(guān)節(jié)鏡作為獨立治療。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，其中只有一項描述了患者報告的結(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？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)就會變得不穩(wěn)定?；謴?fù)軟組織穩(wěn)定性可能只會在短時間內(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，對這組患者單獨進(jìn)行髖關(guān)節(jié)鏡檢查應(yīng)謹(jǐn)慎處理。但是，對于那些由于髖關(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)報道術(shù)后20多年效果良好。傳統(tǒng)上，PAO時關(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)時間[45]。最近的一項研究表明，一些可改變的因素，例如較高的體力活動量和較高的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°，這涵蓋了我們對臨界髖關(guān)節(jié)發(fā)育不良的定義。最近的一項多中心前瞻性隊列研究檢查了患者報告的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，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)。如果接受這個概念，治療就會變得相對簡單。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)果的機會，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的領(lǐng)域，以指導(dǎo)進(jìn)一步的研究。將對這些患者進(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評分。此外，還應(yīng)獲得患者報告的結(jié)果測量和恢復(fù)時間，以及包括運動在內(nèi)的活動恢復(fù)時間。?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.