Review Article http://dx.doi.org/10.5371/jkhs.2011.23.3.169 The Causes and Treatment of Dislocations after Total Hip Arthroplasty Kwang Young So, MD, Young Yool Chung, MD Department of Orthopedic Surgery, Kwangju Christian Hospital, Gwangju, Korea A dislocation after total hip arthroplasty is a serious complication that is related to the component position and poor patient compliance. Therefore, the attendants and surgeons need to be aware of the risk factors for dislocations and take steps to prevent them. In addition, the surgeon should insert the components within the safe zone. The patients should also be informed of possibility of dislocations after total hip arthroplasty. Dislocations can be treated conservatively but a recurrent dislocation requires surgery. The causes of recurrent dislocations must be evaluated before surgery to achieve a high success rate. Key Words: Total hip arthroplasty, Dislocation, Complication 서 론 탈구의발생요인 인공고관절의목적은통증없는안정된관절을얻는데있다. 그런데탈구는인공관절치환술후발생할수있는심각한합병증중하나이다. 탈구는수술후처음 3 개월에가장많이발생하며 1,2), 발생률은적게는 0.3% 에서많게는 9.2% 에이른다 3-5). 인공고관절치환술이시작된이후로탈구에대해많은연구가있었지만아직완전하게는해결되지못하고있다. 탈구는여러가지인자가관련되어있으므로고관절의해부학과인공관절치환술에대해종합적으로이해하여야탈구의원인을진단할수있고치료의방향을정할수있다. 무엇보다도중요한것은탈구의원인에대해잘이해하여탈구가발생하지않도록최선을다하는것이최상의치료방법이다. Submitted: May 14, 2011 1st revision: July 4, 2011 2nd revision: July 13, 2011 3rd revision: September 15, 2011 Final acceptance: September 28, 2011 Address reprint request to Young Yool Chung, MD Department of Orthopaedic Surgery, Kwangju Christian Hospital, 264 Yanglim-dong, Nam-gu, Gwangju 503-715, Korea TEL: +82-62-650-5064 FAX: +82-62-650-5066 E-mail: paedic@chol.com Copyright c 2011 by Korean Hip Society 1. 수술전요인 (Preoperative Factors) 탈구의발생을감소시키기위해선수술전에탈구의위험요인을미리아는것이중요하다. 고관절골절후인공관절전치환술은탈구의발생을증가시킨다. 퇴행성관절염으로인공고관절전치환술후탈구율이 3.7% 인반면대퇴골경부골절후탈구율은 14% 이었다 6-8). 재치환술의탈구율은일차인공고관절전치환술의 2 배로보고되고있다 5,9). 그러므로수술전고관절부위의수술과거력 ( 절골술, 골절의관혈적정복술, 인공관절치환술 ) 을알아보는것도중요하다. 또남성에비해여성에서탈구율이높게보고되고있다 1). 탈구를일으킬수있는기타원인들로신경근육성질환, 정신질환, 치매, 알코올중독등이있으므로수술전자세한병력청취가중요하다 10,11). 오랜세월동안골성강직상태였던환자는수술전외전근의상태를확인하여야하며, 비구이형성증환자에서는수술전비구의형태와전염각을확인해야한다. 강직성척추염환자에서요추의전만각의소실여부를확인하여비구컵이과도한전염각으로삽입되지않도록주의한다. 2. 수술과관련된요인 (Intraoperative Factors) 1) 수술도달법 (Surgical approach) 수술자가어떤수술도달법을사용하여수술을시행하 169
는지에따라인공고관절전치환술후인공관절탈구의발생률이다르게보고되고있다 12,13). 후외방도달법은많은수술자에게익숙한도달법이다. 그러나탈구의발생률은다른도달법과비교하여높게보고되고있다. 저자들의연구에서도전외방도달법을사용한경우탈구율이 1% 이었으나후외방도달법을이용한인공고관절전치환술후에탈구율은 5.6% 로증가하였다 14,15). Woo 와 Morrey 5) 의연구에의하면후외방도달법으로수술한경우후방탈구율이 5.8% 인반면전외방도달법을사용한경우탈구율이 2.3% 였다고하였다. 최근후방관절낭을견고히봉합하고단외회전건을대전자에봉합하여후방탈구율을감소시킬수있다는보고가있다 16,17). Kwon 등 18) 의연구에의하면후외방도달법을사용한경우연부조직을재봉합하면전외방, 외측도달법의탈구율과비슷하다고하였다. 그러나신경근육질환으로고관절의굴곡, 내전구축을가진환자나치매가있는환자에서후외방도달법을시행할경우후방탈구율이높기때문에전외방도달법을사용하는것이탈구를예방하는데좋을것으로생각된다. 2) 삽입물의위치 (Position of components) 인공고관절전치환술에서인공치환물의삽입위치는매우중요하다. 비구컵의삽입각도가경사각은 40± 10, 전염각은 15±10 가되도록한다. Lewinnek 등 2) 은비구컵의각도가안전범위내에있으면탈구율은 1.5% 이나안전범위를벗어난경우탈구율은 6.1% 로증가하였다고한다. 그러므로비구컵을안전범위내에삽입하는것이탈구율을줄이는데무엇보다중요하다 2,19). 환자를측와위상태로놓고수술을시행하는경우수술대에골반의고정상태와골반과어깨의넓이에따른골반의기울기에따라서비구컵의삽입각도가변할수있다. 비구컵을삽입하기전골반의위치를확인하고, 시험컵 (trial cup) 을이용하여비구와의위치도살펴보아야한다. 비구이형성증환자는수술전에컴퓨터단층촬영을하여비구의모양과전염각을측정하여수술시비구컵의삽입각도에실수를줄일수있다. 탈구를예방하기위해서는비구컵의삽입각도뿐아니라대퇴골치환물의전염각도중요하다. 대퇴골치환물의전염각은보통 10~20 를권유한다. Malik 등 20) 은비구컵과대퇴골치환물의전염각을합한통합전염각 (combined anteversion) 의중요성을언급하며대퇴골치환물의전염각에따라비구컵의전염각의조절이필요하다고하였다. 3) 연부조직의긴장도 (Tension of soft tissue) 고관절주위의연부조직긴장도는인공고관절전치환술후관절의안정성에매우중요하다. 연부조직의긴장도감소는관절의불안정을가져와탈구의위험을증가시킨다 4). 대퇴골두의중심과대전자부사이의거리인대퇴 오프셋 (femoral offset) 의감소는대전자에부착하는근육들의긴장도를줄이고 lever arm 의길이도감소시키고대퇴골과비구의충돌까지유발될수있어탈구의원인이된다. 그러므로수술전에방사선사진에서고관절의중심과 femoral offset 를측정하여연부조직의긴장도도회복하고하지길이도유지해야한다 5). 4) 충돌 (Impingement) 탈구의또다른원인으로대퇴골과비구주위의돌출된뼈나시멘트에의한충돌이있다. 인공관절을삽입후고관절의모든방향으로운동을시켜충돌이발생하는지확인하여충돌이발생하는구조물을제거하여탈구를예방한다. 대퇴골치환물의경부와비구컵의충돌에대해서도확인하여야한다. 큰대퇴골두를사용하면대퇴골두경부비율이증가되어관절운동을증가시키며충돌로인한탈구를예방할수있다 21). 인공고관절치환술후발생하는탈구를예방하기위해폴리에틸렌라이너의일부가융기 (elevated liner) 된것을사용하였다. 그러나융기된부분과대퇴골치환물사이에충돌로오히려탈구가발생하며이부위에서라이너의마모로골용해가발생할수있으므로신중하게선택해야한다 22,23). 따라서, 융기된폴리에틸렌라이너의사용은재치환술에국한하여사용하는것이바람직하겠다. 3. 수술후요인 (Postoperative Factors) 대부분의탈구는수술후 3 개월이내에발생하기때문에수술후재활기간동안환자가탈구예방프로그램에얼마나잘순응하는지도중요하다. 수술후과도한굴곡, 내전, 내회전을하지않도록교육을시켜야한다. 특히고령의환자에서는보호자의교육이매우중요하다. 퇴원후집에서앉는자세, 화장실사용, 목욕탕이용에대해그림을이용하여교육하는것이필요하다. 치매환자처럼교육으로탈구를예방할수없는경우에는외전보조기의착용도하나의방법이라고생각된다. 1. 도수정복 탈구의치료 환자가비정상적인자세에서갑자기고관절부위에심한통증과관절운동의제한이발생하면탈구를의심하여방사선검사가필요하다. 방사선검사에서탈구가확인되면마취하에서방사선투과기를이용하여도수정복을시도한다. 도수정복시무리한힘을가하여골절이발생하지않도록주의한다. 탈구의약 2/3 는도수정복이가능하나정복되지않는경우에는수술적정복을필요로한다. 170
Kwang Young So et al.: The Causes and Treatment of Dislocations after Total Hip Arthroplasty 도수정복후대퇴골두가비구컵내에정확한위치에놓여있는지확인하여야한다. 도수정복후외전보조기를이용하여하지를 20 외전시키고굴곡은 60 미만으로제한해야한다. 외전보조기는보통 6 주에서 3 개월착용을권유한다 24,25). 그러나외전보조기의착용이재탈구를예방하는데효과가없다는보고도있다 26). 2. 수술적치료 인공고관절전치환술후발생하는탈구는대부분도수정복이가능하지만도수정복이안되거나탈구가재발되는경우는탈구의원인을조사하여수술적방법으로원인을교정하여주어야한다. 재발성탈구를수술적방법으로치료하는방법은탈구의원인에따라여러방법이있다. 1) 대전자윈위전위술 (Trochanteric advancement) 인공치환물의위치에이상이없으며연부조직긴장도가불충분하다고의심될때는대전자원위전위술을시행할수있다. Morrey 12) 는약 70% 에서효과가있다고보고하였고, Ekelund 6) 는 21 예의재발성탈구환자에서대전자윈위전위술을시행하여 19 예에서성공을얻었다고하였다. 2) 큰대퇴골두사용 Beaule 등 27) 은재발성탈구환자에서 36 mm 이상의큰대퇴골두를사용하여탈구를성공적으로치료하였고최근의보고에의하면큰골두를이용하면속박형비구컵 (constrained acetabular cup) 을사용하지않아도탈구를치료할수있다고하였다 28,29). 3) 속박형비구컵 (Constrained acetabular cup) Callaghan 30,31) 은 constrained tripolar cup 을이용하여인공고관절치환술후불안정이나탈구를성공적으로치료하였다한다. 그러나 Harman 등 32) 은속박형라이너를사용한환자에서 4~29% 의재탈구가발생하였다고하였다. 속박형비구컵은불안정성이심한환자에게제한하여사용할수있는수술적치료방법으로생각된다 33). 저자들은고령환자의재발성탈구에서속박형비구컵을제한하여사용하고있다. 4) 재치환술 (Revision) 비구컵의위치가잘못된경우에서탈구가반복되면비구컵의재치환이필요하다. Daly 와 Morrey 1) 는비구컵의삽입위치이상으로탈구를보인환자에서비구컵재치환술로 70% 에서성공적인치료를하였다. 비구컵의전염각과경사각이정상에서심하게벗어나지않은경우에는융기된라이너로교체하거나연부조직의긴장도를증 가시키기위해인공골두를교체하여대퇴길이를증가시키는것도하나의방법이라고생각된다. 결 인공고관절전치환술후발생하는탈구는환자와의사에게괴로움과분쟁을가져다주는심각한합병증이다. 수술자는술전에탈구의위험요인을파악하고수술중에는치환물을정확한위치로삽입해야하며수술을마치기전에충돌의유무와불안정에대해검사를해야한다. 수술후에는환자와보호자에게탈구예방법과재활에대해반복적인교육이반드시필요하다. 수술후발생하는탈구는도수정복후보존적치료를시행하지만재발성탈구는원인을분석하여수술적으로교정해야한다. 현재까지어떤방법도완전하게탈구를해결하지못하고있으므로예방이무엇보다중요하다고생각된다. 론 REFFERENCES 01. Daly PJ, Morrey BF. Operative correction of an unstable total hip arthroplasty. J Bone Joint Surg Am. 1992;74: 1334-43. 02. Lewinnek GE, Lewis JL, Tarr R, Compere CL, Zimmerman JR. Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am. 1978;60:217-20. 03. Ali Khan MA, Brakenbury PH, Reynolds IS. Dislocation following total hip replacement. J Bone Joint Surg Br. 1981;63-B:214-8. 04. Fackler CD, Poss R. Dislocation in total hip arthroplasties. Clin Orthop Relat Res. 1980;151:169-78. 05. Woo RY, Morrey BF. Dislocations after total hip arthroplasty. J Bone Joint Surg Am. 1982;64:1295-306. 06. Ekelund A, Rydell N, Nilsson OS. Total hip arthroplasy in patients 80 years of age and older. Clin Orthop Relat Res. 1992;281:101-6. 07. Iorio R, Healy WL, Lemos DW, Appleby D, Lucchesi CA, Saleh KJ. Displaced femoral neck fractures in the elderly: outcomes and cost effectiveness. Clin Orthop Relat Res. 2001;383:229-42. 08. Lee BP, Berry DJ, Harmsen WS, Sim FH. Total hip arthroplasty for the treatment of an acute fracture of the femoral neck: long-term results. J Bone Joint Surg Am. 1998;80:70-5. 09. Alberton GM, High WA, Morrey BF. Dislocation after revision total hip arthroplasty: an analysis of risk factors and treatment options. J Bone Joint Surg Am. 2002;84- A:1788-92. 10. Hedlundh U, Fredin H. Patient characteristics in dislocations after primary total hip arthroplasty. 60 patients compared with a control group. Acta Orthop Scand. 1995;66:225-8. 11. Woolson ST, Rahimtoola ZO. Risk factors for dislocation 171
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Kwang Young So et al.: The Causes and Treatment of Dislocations after Total Hip Arthroplasty 국문초록 인공고관절치환술후발생한탈구의원인과치료 소광영 정영율 광주기독병원정형외과 인공고관절전치환술후발생하는탈구는빈도는높지않으나감염, 해리와함께삼대심각한합병증의하나이다. 탈구는수술과관련이있거나환자의비협조에의해대부분발생한다. 그러므로수술자는수술중치환물이안정각도내에고정되도록주의를해야하며, 수술후에는환자와보호자의교육을철저히하여탈구를예방하여야한다. 인공고관절전치환술후발생하는탈구는대부분도수정복후보존적치료를시행하나재발성탈구에서는수술적치료를고려하여야한다. 탈구의원인을정확하게진단하고수술적방법을선택함으로써높은성공률을얻을수있다. 색인단어 : 인공고관절치환술, 탈구, 합병증 173