대한정형외과학회지 : 제 43 권제 6 호 2008 J Korean Orthop Assoc 2008; 43: 760-765 전자기장네비게이션과고식적방법을이용한슬관절전치환술의방사선학적결과와비교 원예연ㆍ최문권ㆍ이두형ㆍ박태호ㆍ허준혁ㆍ신동선 아주대학교의과대학정형외과학교실 Comparison of the Radiologic Results of Total Knee Arthroplasty using Electromagnetic Navigation with the Conventional Technique Ye-Yeon Won, M.D., Wen-Quan Cui, M.D., Doo-Hyung Lee, M.D., Tai-Hu Piao, M.D., June-Huyck Hur, M.D., and Dong-Sun Shin, M.D. Department of Orthopaedic Surgery, Ajou University School of Medicine, Suwon, Korea Purpose: We wanted to examine the accuracy of the lower limb alignment and implant positioning that was obtained with using the electromagnetic (EM) navigation technique. Materials and Methods: We examined 64 patients who underwent 100 TKAs with using EM navigation technique from July 2006 to February 2007. Sixty-two patients who underwent 100 TKAs with using the conventional technique between August 2005 and July 2006 were used as controls. We assessed the mechanical axis and the α, β, γ and δ angles in the postoperative radiograph of each patient and we compared them among the two groups. Results: The patients in the EM navigation group achieved better accuracy than did the conventional group in terms of the postoperative mean mechanical axis (1.2 o vs. 2.3 o ). Less variations in the coronal femoral component and the tibial component angle were observed in the navigation group (femur: 89.3 o vs. 88.7 o ; tibia: 89.6 o vs. 89.3 o, respectively), although the difference in the coronal tibial component angle was not significant. Conclusion: The use of EM navigation technique in TKA does not always guarantee the precise alignment of the mechanical axis in all planes, as compared to using the conventional technique. Yet it is useful for obtaining better coronal alignment of the femoral component. Key Words: Knee, Osteoarthritis, Total knee arthroplasty, Electromagnetic navigation technique 서론하지의부정정렬과치환물의부적절한위치는삽입물에대한편측부하를가져와서삽입물의불안정성과해리를초래하여치환술실패의주요한요인으로작용한다. 따라서정확한하지의정렬과적절한치환물의위치는슬관절전치환술의임상적경과와장기예후를결정하는중요한요소중하나이다 1). 적절한역학적축의범위에대해서는아직까지많은논란이있지만대부분의연구에서는 통신저자 : 원예연경기도수원시영통구원천동산 5 아주대학교의과대학정형외과교실 TEL: 031-219-5220 ㆍ FAX: 031-219-5229 E-mail: thrtkr@ajou.ac.kr 내반 3 도에서외반 3 도까지를허용범위로보고있다 2,3). 고식적인수술방법에서는하지의부정정렬의빈도가 5-30% 정도로발생한다고보고되었다 4-6). 이에따라보다더정확한하지의정렬과적절한치환물의위치를얻기위해네비게이션시스템등의새로운수술기법이개발되었다 7-11). 이전의연구들에서흔히사용된네비게이션은적외선을이용한광학시스템을사용하였는데광학시스템에서사용된전송자 (transmitter) 는크기가커서 Address reprint requests to Ye-Yeon Won, M.D. Department of Orthopedic Surgery, Ajou University School of Medicine, San 5, Wonchun-dong, Youngtong-gu, Suwon 443-749, Korea Tel: +82.31-219-5220, Fax: +82.31-219-5229 E-mail: thrtkr@ajou.ac.kr 760
전자기장네비게이션과고식적방법을이용한슬관절전치환술의방사선학적결과와비교 761 양면피질나사못의사용이필요하고이는드릴구멍을통한피로골절을유발할수있고 12,13) 또한전송자를부착하기위해추가적피부절개가필요한단점이있었다. 전자기장신호를이용하는네비게이션방법은수술장에서금속기구에의해신호가간섭을받을수있다는단점에도불구하고작은전송자를사용할수있는장점이부각되어새로소개되었다 7). 저자들은전자기장네비게이션을이용한슬관절전치환술이고식적인수술방법에비해보다더정확한하지정렬과적절한치환물의위치를얻을수있다고가정하고본연구를시작하였다. 대상및방법 2006년 7월에서 2007년 2월까지한술자에의해서연속적으로시행된전자기장네비게이션을이용한슬관절전치환술 100예와 2005년 8월에서 2006년 7월까지고식적인방법을이용하여한술자에의해서연속적으로시행된슬관절전치환술 100예를후향적으로모집하여비교분석하였다. 네비게이션을이용한군의성별은남자가 7명, 여자가 57명이었으며평균연령은 66.9 세 (57-79) 였다. 고식적인방법을이용한군의성별은남자가 2 명, 여자가 60명이었으며평균연령은 69.4 세 (55-78) 였다. 진단은모든예에서퇴행성관절염이었으며두군간의연령, 성별, 관절염의등급 (Kellgren-Lawrence grading system) 14) 의유의한차이는없었다 (Table 1). 네비게이션에서지원하지않는경우 ( 하지변형이심한류마티스관절염환자에게서구속형삽입물을사용하여수술하였던 2예 ) 는대상에서제외하였다. 전자기장네비게이션은 AxiEM navigation 2.0 ver (Medtronic, Co, USA) 를사용하였고삽입물은전자기장네비게이션군에서 LPS-flex PS Nexgen (Zimmer, Table 1. Demographics of Patients Navigation group Conventional group p-value Number of patients 64 62 Number of cases 100 100 Sex (M:F) 7:57 2:60 0.093 Age 66.9±7.6 69.4±6.3 0.427 Grade of arthritis* 0.440 Grade 3 14 18 Grade 4 86 82 *Graded by Kellgren-Lawrence 21. Warsaw, IN, USA) 를사용하였고고식적인방법을이용한군에서는 PFC Sigma (DuPuy Inc, Warsaw, IN, USA) 를사용하였다. 전자기장네비게이션을이용한수술에서는슬개내측도달법을사용하였고추가적인피부절개없이약 1 cm 2 크기의두개의전송자를원위대퇴골의내측슬개상낭과내측경골고평부직하방의전내측피질골에두개의단면피질나사못을이용하여고정하였다. 전송자를연결하는선은접착테이프를이용하여피부에고정하였다. 고관절의회전중심을인식한후전방피질골, 내측및외측외상과, 대퇴골중심, Whiteside line, 내측및외측대퇴골후과를지침자를통해입력한후다음으로경골중심, 내측및외측경골과, 경골결절, 원위경골내과및외과를입력하였다. Freehand technique 을이용하여골절제를시행하였다. 나머지술기는광학네비게이션방법과같았다 12,15). 수술전및수술후 3개월에대퇴골두에서족근관절까지포함하는기립장하지전후면방사선사진과앙와위측면사진을이용하여방사선학적평가를시행하였다. 기립장하지전후면방사선사진에서대퇴골의기계적축과경골의기계적축이이루는기계적축의편향, 대퇴골의기계적축과대퇴삽입물관절면이이루는내측각인대퇴삽입물내외반각 (α각 ), 경골의기계적축과경골삽입물의관절면이이루는내측각인경골삽입물내외반각 (β각) 을측정하였고, 앙와위측면사진에서대퇴골의해부학적축과대퇴골원위절단면의수직선이이루는대퇴삽입물굴곡각 (γ각) 및비골골간의해부학적축과경골삽입물의관절면이이루는경골후방경사각 (δ각) 을측정하였다 (Fig. 1). 기계적축의편향각도는내반을 (+), 외반은 (-) 로정하고값이절대값이 3이내인경우는만족한결과로절대값이 3보다큰경우는불만족한결과로나누었다. γ각은대퇴골의해부학적축에대해대퇴삽입물이굴곡되어삽입된경우를 (+), 신전되어삽입된경우를 (-) 로정하였다. α각, β각, γ각은각각의이상적인값 (α각 : 90도, β각 : 90도, γ각 : 0도 ) 에서절대값이 3이내인경우는만족한결과로절대값이 3보다큰경우는불만족한결과로나누었다 24). SPSS 11.0 (SPSS Inc, Chicago, IL, USA) 를이용하여통계학적분석을시행하였고두군간의비교를위해 Student's t-test와 Chi-square test 를이용하였다. p 값이 0.05 이하인경우유의하다고판단하였다.
762 원예연ㆍ최문권ㆍ이두형외 3 인 Fig. 1. (A) Anteroposterior radiograph showing the mechanical axis angle (MAA), the medial inclination angle of the femoral component with the mechanical axis of the femur (α angle), and the medial inclination angle of the tibial component with the mechanical axis of the tibia (β angle). (B) Lateral radiograph showing the angle of the femoral component with the anatomical axis of the femur (γ angle), and the angle of the tibial component with the anatomical axis of the tibia (δ angle). 결과술전에기계적축편향각도의평균은전자기장네비게이션군에서 8.1±6.7 o 였고고식적인방법을이용한군에서 8.7±7.0 o 로양군간의차이가없었다 (p>0.05). 술후에기계적축편향각도의평균은전자기장네비게이션군에서 1.2±1.9 o 였고고식적인방법을이용한군에서 2.3±2.3 o 이었다 (p=0.002). 전자기장네비게이션군에서술후에기계적축편향각도의최대값은 5.5 o 였고만족한결과의비율은 86% 였다. 반면에고식적인방법을이용한군에서술후에기계적축편향각도의최대값은 12.2 o 였고만족한결과의비율은 79% 였다. α각의평균값은전자기장네비게이션군에서 89.3±1.6 o 이었고고식적인방법을이용한군에서 88.7±2.6 o 이었다 (p =0.034). β각의평균값은각각 89.6±1.5 o 와 89.3± 2.1 o 로각군간의유의한차이는없었다 (p=1.35). γ각의평균값은각각 -0.9±2.4 o 와 -0.6±3.4 o 로각군간의유의한차이는없었다 (p=0.075). δ각의평균값은각각 87.2±2.0 o 와 86.0±1.9 o 로각군간의유의한차이는없었다 (p=0.98)(table 2). Table 2. Radiologic Measurments Such as Mechanical Axis Angle, Alpha (α) Angle, Beta (β) Angle, Gamma (γ) Angle and Delta (δ) Angle in Navigation and Conventional Group Navigation Conventional p-value group group Preoperative MAA* 8.1±6.7 8.7±7.0 0.979 Postoperative MAA 1.2±1.9 2.3±2.3 0.002 Outlier (> 3 o ) incidence 14% 21% Postoperative α angle 89.3±1.6 88.7±2.6 0.034 Outlier (> 3 o ) incidence 8% 23% Postoperative β angle 89.6±1.5 89.3±2.1 1.35 Outlier (> 3 o ) incidence 6% 13% Postoperative γ angle 0.9±2.4 0.6±3.4 0.075 Outlier (> 3 o ) incidence 23% 33% Postoperative δ angle 87.2±2.0 86.0±1.9 0.98 *MAA, mechanical axis angle. 전자기장네비게이션을사용하면서발생한수술주위의합병증이나문제점은다음과같았다. 3예에서전송자의해리 (loosening) 가있었고, 1예에서전송자날개의파손이있었다 (Fig. 2). 전송자의해리가있었던 3예에서는고식적인방법으로전환해서수술을하였고전송자날개의파손이있었던 1예에서는전송자를교체한후수술을
전자기장네비게이션과고식적방법을이용한슬관절전치환술의방사선학적결과와비교 763 Fig. 2. The broken transmitter during the operative procedure. (A) The line of the transmitter was torn because it was impinged in the foot positioner. (B) The wing of the transmitter was broken during fixation. 하였다. 수술중전송자의해리가있어서고식적인방법으로전환해수술을마친 3예는본연구대상에는포함시키지않았다. 드릴구멍을통한피로골절, 심부감염, 관절강직, 심폐기능합병증등은발생하지않았다. 고찰많은연구에서네비게이션시스템이기존의고식적인수술방법보다하지기계적축의정렬과적절한치환물의위치를더향상시킬수있다고보고하였다 11,12,15-18). Jenny 등은 555예의슬관절전치환술을분석한연구에서네비게이션수술군이고식적인수술군보다만족스러운기계적축의정렬을얻을수있다고하였다 19). Matziolis 등의연구에서도네비게이션을사용하여 32예중 31예에서만족스러운하지기계적축의정렬을얻을수있다고보고하였다 8). 본연구의결과에서술후기계적축의편향각의절대값이 3도를넘지않는경우가고식적인수술군에서는 79% 인반면전자기장네비게이션수술군에서는 86% 였다. 위결과는전자기장네비게이션을이용하여수술한첫 100예의결과로시간적으로마지막 20예만따로분석한결과에서는만족스러운기계적축의정렬을얻은경우가 95% 였다. 이러한결과는네비게이션을사용하는수술에서초기에필요한학습시간이지난후에는수술의정확도가보다더좋아짐을말해준다고할수있다. 대부분의연구가적외선을사용하는광학네비게이션을사용하여보고하였지만이러한시스템은전송자가크기때문에추가적인피부절개및박리가필요하고전송자를고정하기위한드릴구멍이크다는단점이있었다 23). 또이로인해창상감염이나드릴구멍을통한피로골절이증가할수있다는문제점이있었다 13,15). 전자기장네 비게이션은이러한광학네비게이션의단점을극복하기위해새로개발된방법으로처음에는주로신경외과나이비인후과영역에서사용되었다 20,21). 정형외과영역에서사용되는금속삽입물이안정적인전자기장신호에장애가되어정형외과영역에서전자기장네비게이션을사용하는데어려움이있었으나 'Dynamic reference frame' 이라알려진작은전송자의개발로인해이러한문제가해결이되었다 22). 전자기장네비게이션의장점은전송자의크기가작기때문에추가적인피부절개없이기존의수술장내에서전송자를고정할수있고신호를감지하기위한공간확보가필요없다는점이다 7). 철이나알루미늄같은금속에의해전자기장신호가왜곡될수있지만티타늄기구를사용하는슬관절전치환술에서발생하는오류는 1 mm 또는 1도내로보고되고있다 22). 전자기장네비게이션을이용해서수술을시행한지 18개월이지났지만아직드릴구멍을통한피로골절, 창상감염, 심폐기능합병증등은없었다. 하지만전송자의해리나파열같은사고가 5예발생하였다. 1예에서전송자를연결하는선이발고정대에걸려파열된경우가있었고 1예에서전송자날개를고정하기위해먼저고정한나사못이있는상태에서두번째나사못을무리하게삽입하다가전송자날개가파열된경우가있었다. 3예에서경골의골수강내로돌출된전송자고정용나사못과경골부품의골수강내주대가충돌하여전송자의해리가발생하였다. 이러한전송자의파열은 100예중중반기이후부터는없었다. 반면골다공증이심한환자의경우발생한전송자의해리는 100예중반기이후에도발생하였다. 저자는큰피치의나사를사용함으로써이러한문제가발생하는것을줄일수있다고생각한다. 본연구는각각다른시기에시행된예를후향적으로모집하여비교군과대조군을설정하
764 원예연ㆍ최문권ㆍ이두형외 3 인 였고각군간에사용한삽입물이다르다는한계가있다. 하지만삽입물이달라도본연구에서측정한술후기계적축의각도나 α, β, γ각의이상적인값 ( 기계적축의각도 : 0도, α각 : 90도, β각 : 90도, γ각 : 0도 ) 에는영향을미치지않기때문에위값들의비교가의의가있다고생각한다. 하지만 δ각의경우삽입물의디자인이나술자의의도에따라이상적인값이달라질수있기때문에 δ각의비교는큰의의가있다고보기힘들다. 또본연구의목적은술후의방사선학적결과만을비교하는것이었기때문에술후관절운동범위, 슬관절동통, 걷기, 계단오르기, 대퇴사두근근력, 슬관절의굴곡변형및불안정성등의임상적결과를각군간에비교해보지못한점이제한점이라고생각한다. 따라서이를위한추가적연구가필요할것으로생각된다. 결론전자기장네비게이션을이용한슬관절전치환술이고식적인수술방법보다모든방향에서더나은하지기계적축의정렬을얻을수는없으나관상면에서는더좋은대퇴삽입물의위치를얻을수있도록도와줄수있다고생각된다. 참고문헌 1. Knutson K, Lindstrand A, Lidgren L: Survival of knee arthroplasties. A nation-wide multicentre investigation of 8000 cases. J Bone Joint Surg Br, 68: 795-803, 1986. 2. Riebel GD, Werner FW, Ayers DC, Bromka J, Murray DG: Early failure of the femoral component in unicompartmental knee arthroplasty. J Arthroplasty, 10: 615-621, 1995. 3. Ritter MA, Faris PM, Keating EM, Meding JB: Postoperative alignment of total knee replacement. Its effect on survival. Clin Orthop Relat Res, 299: 153-156, 1994. 4. Ranawat CS, Flynn WF Jr, Saddler S, Hansraj KK, Maynard MJ: Long-term results of the total condylar knee arthroplasty. A 15-year survivorship study. Clin Orthop Relat Res, 286: 94-102, 1993. 5. Song EK, Seon JK, Chung JY, Cho SG, Kong IK: Comparison of results of total knee arthroplasty performed using a navigation system and the conventional technique. J Korean Orthop Assoc, 41: 1002-1007, 2006. 6. Voss F, Sheinkop MB, Galante JO, Barden RM, Rosenberg AG: Miller-Galante unicompartmental knee arthroplasty at 2- to 5-year follow-up evaluations. J Arthroplasty, 10: 764-771, 1995. 7. Alan RK, Shin MS, Tria AJ Jr: Initial experience with electromagnetic navigation in total knee arthroplasty: a radiographic comparative study. J Knee Surg, 20: 152-157, 2007. 8. Matziolis G, Krocker D, Weiss U, Tohtz S, Perka C: A prospective, randomized study of computer-assisted and conventional total knee arthroplasty. Three-dimensional evaluation of implant alignment and rotation. J Bone Joint Surg Am, 89: 236-243, 2007. 9. Ranawat CS: History of total knee replacement. J South Orthop Assoc, 11: 218-226, 2002. 10. Seon JK, Song EK, Yoon TR, Bae BH, Kim CY: The radiographic comparative study of the unicompartmental knee arthroplasty: Manual versus navigation system. J Korean Orthop Assoc, 41: 140-147, 2006. 11. Stulberg SD, Yaffe MA, Koo SS: Computer-assisted surgery versus manual total knee arthroplasty: a case-controlled study. J Bone Joint Surg Am, 88(Suppl 4): S47-S54, 2006. 12. Haaker RG, Stockheim M, Kamp M, Proff G, Breitenfelder J, Ottersbach A: Computer-assisted navigation increases precision of component placement in total knee arthroplasty. Clin Orthop Relat Res, 483: 152-159, 2005. 13. Ossendorf C, Fuchs B, Koch P: Femoral stress fracture after computer navigated total knee arthroplasty. Knee, 13: 397-399, 2006. 14. Kellgren JH, Lawrence JS: Radiological assessment of osteoarthrosis. Ann Rheum Dis, 16: 494-502, 1957. 15. Bäathis H, Perlick L, Tingart M, Lüring C, Zurakowski D, Grifka J: Alignment in total knee arthroplasty. A comparison of computer-assisted surgery with the conventional technique. J Bone Joint Surg Br, 86: 682-687, 2004. 16. Jenny JY, Boeri C: Unicompartmental knee prosthesis implantation with a non-image based navigation system: rationale, technique, case-control comparative study with a conventional instrumented implantation. Knee Surg Sports Traumatol Arthrosc, 11: 40-45, 2003. 17. Mielke RK, Clemens U, Jens JH, Kershally S: Navigation
전자기장네비게이션과고식적방법을이용한슬관절전치환술의방사선학적결과와비교 765 in knee endoprosthesis implantation-preliminary experiences and prospective comparative study with conventional implantation technique. Z Orthop Ihre Grenzgeb, 139: 109-116, 2001. 18. Sparmann M, Wolke B, Czupalla H, Banzer D, Zink A: Positioning of total knee arthroplasty with and without navigation support. A prospective, randomized study. J Bone Joint Surg Br, 85: 830-835, 2003. 19. Jenny JY, Mielke RK, Kohler S, et al: Total knee prosthesis implantation with a non image based navigation system: a multicentric analysis. Procs 70 th Annual Meeting AAOS, American Academy of Orthopaedic Surgeons, 96, 2003. 20. Fried MP, Kleefield J, Gopal H, Reardon E, Ho BT, Kuhn FA: Image-guided endoscopic surgery: results of accuracy and performance in a multicenter clinical study using an electromagnetic tracking system. Laryngoscope, 107: 594-601, 1997. 21. Manwaring KH, Manwaring ML, Moss SD: Magnetic field guided endoscopic dissection through a burr hole may avoid more invasive craniotomies. A preliminary report. Acta Neurochir, 61(Suppl): S34-S39, 1994. 22. Lionberger DR: The attraction of electromagnetic computerassisted navigation in orthopaedic surgery. In: Stiehl, ed. Navigation and MIS in orthopedic surgery. 1st ed. New York, Springer: 44-53, 2007. 23. Tria AJ Jr: The evolving role of navigation in minimally invasive total knee arthroplasty. Am J Orthop, 35(Suppl 7), S18-S22, 2006. 24. Song EK, Seon JK, Chung JY, Cho SG, Kong IK: Comparison of results of total knee arthroplasty performed using a navigation system and the conventional technique. J Korean Orthop Assoc, 41: 1002-1007, 2006. = 국문초록 = 목적 : 전자기장네비게이션을이용한슬관절전치환술에서하지정렬의정확성과치환물위치의적절함을평가하고자한다. 대상및방법 : 2006 년 7 월에서 2007 년 2 월까지한술자에의해서시행된전자기장네비게이션을이용한슬관절전치환술 100 예와 2005 년 8 월에서 2006 년 7 월까지고식적인방법을이용하여한술자에의해서연속적으로시행된슬관절전치환술 100 예를후향적으로모집하여비교분석하였다. 결과 : 술후에기계적축편향각도의평균은전자기장네비게이션군에서 1.2±1.9 o 였고고식적인방법을이용한군에서 2.3±2.3 o 이었다 (p=0.002). α 각의평균값은전자기장네비게이션군에서 89.3±1.6 o 이었고고식적인방법을이용한군에서 88.7±2.6 o 이었다 (p=0.034). β 각의평균값은각각 89.6±1.5 o 와 89.3±2.1 o 로각군간의유의한차이는없었다 (p=1.35). γ 각의평균값은각각 0.9±2.4 o 와 0.6±3.4 o 각군간의유의한차이는없었다 (p=0.075). δ 각의평균값은각각 87.2±2.0 o 와 86.0±1.9 o 로각군간의유의한차이는없었다 (p =0.98). 결론 : 전자기장네비게이션을이용한슬관절전치환술이고식적인수술방법보다모든방향에서더나은하지기계적축의정렬을얻을수는없으나관상면에서는더좋은대퇴삽입물의위치를얻을수있도록도와줄수있다고생각된다. 색인단어 : 슬관절, 퇴행성관절염, 슬관절전치환술, 전자기장네비게이션