슬관절전치환술시경골후방경사각감소가슬개골높이에미치는영향 한양대학교의과대학구리병원정형외과학교실 김종헌 Effect of the Decrease in Tibial Posterior Slope on the Patellar Height after Total Knee Arthroplasty Jongheon Kim, M.D. Department of Orthopedic Surgery, Guri Hospital, Hanyang University College of Medicine, Guri, Korea Purpose: To evaluate the effect of the decrease in posterior slope of the tibia on the patellar height after TKA. Materials and Methods: One hundred and fifty three cases of TKA (CR type: 43, PS type: 110) were evaluated to measure the posterior slope of the tibia and the patellarheight on lateral radiographs of the knee before and after surgery. Then, we analyzed a correlation between two measurements. Results: The decrease in tibial posterior slope and patellar height was average 6.6 degrees and 1.4mm, there was a weak correlation (r= 0.293, p=0.000), as more decrease in tibial slope, less decrease in patellar height. Comparing CR group with PS group, the decrease of posterior slope of tibia and patella height was average 3.5 vs 7.8 degrees (p=0.000) and 2.2 and 1.2 mm (p=0.146) respectively. There were also correlations (r= 0.438, p=0.003 vs r= 0.228, p=0.017) between two decreases. Conclusion: It is considered that the decrease in tibial posterior slope is one of elements influencing in patellar height, and through preoperative radiological examination, estimation of expected decrease in tibial posterior slope is helpful in preserving patellar height in TKA. Key Words: Patellar height, Posterior slope of the tibia, Total knee arthroplasty 서 슬관절의굴곡-신전과정에서슬개골높이에따라슬개대퇴관절의역학이달라져, 고위슬개골은슬개골연골연화증, 슬개건과대퇴사두건염, 슬개대퇴관절의불안정을초래할수있으며, 저위슬개골은관절운동의제한, 슬개대퇴관절염등을초래할수있다. 슬관절전치환술에서슬 론 통신저자 : 김종헌 471-701, 경기도구리시교문동 246-1 한양대학교구리병원정형외과 TEL: 031-560-2313, FAX: 031-557-8781 E-mail: jhkim111@hanyang.ac.kr 개골높이는슬개골이수술후상부로이동할수록 HSS 점수, 관절운동범위가증가하고슬관절동통은감소하여술후결과에영향을준다고잘알려져있다 6,8,19). 슬개골높이의측정기준은슬개건의부착부위를포함하는경골결절과, 대퇴경골관절선의위치를포함하는경골고평부로크게구별하여, 측정의재현율과정확도에대한보고들이있으며 9,15), 대퇴골활차구안의슬개골의위치가슬개대퇴관절의생역학을결정하게되며, 체중부하시대퇴경골간관절선의위치가직접적으로대퇴골과및활차구의위치를결정하므로, 슬개골높이의변화는대퇴경골간관절선을기준으로측정하는것을추천하고있다. 슬관절전치환술시경골후방경사각의감소는대퇴경골간관절 149
150 선의변화를가져온다. 저자는슬관절전치환술시대퇴경골간관절선의변화를초래하는경골후방경사각의감소가슬개골높이에미치는영향을알아보고자본연구를시행하였다. 대상및방법 2003 년 2월부터 2005 년 3월까지본교실에서슬관절전치환술을시행받은환자중방사선계측에적합했던 99 명, 153 슬관절을대상으로후향적분석을하였다. 환자들의수술당시평균연령은 51세에서 77세까지로평균 65세였고여자는 87명, 135 슬관절이었으며남자는 12명, 18슬관절이었다. 선행질환은전예에서퇴행성관절염이었다. 총 153 예중후방십자인대보존형은 43예, 후방십자인대대치형 110 예였다. 사용된치환물의종류로는 NexGen system (Zimmer, Warsaw, IN) 100슬관절, P.F.C system (Depuy, Warsaw, IN) 27슬관절, Scorpio system (Osteonics, Stryker, NJ) 26슬관절이었다. 수술은 1인술자에의해행해졌으며, 내측슬개골도달법을이용하여, 기본적인슬관절전치환술의술식을따랐다. 수술전후의경골후방경사각의감소과슬개골높이의감소를측정하여두측정값간의상관관계를분석하고, 후방십자인대보존군과대치군의비교를하였다. 수술전후의경골후방경사각의측정은 Brazier 등 3) 이제시한 6가 지방법중경골의후방피질을기준으로하여 (Fig. 1) 술전수치 (Preop. Slope) 에서술후수치 (Postop. Slope) 를뺀값을후방경사각의감소 (dslope) 로정의하였다. 슬개골높이의측정은대퇴경골간관절선을기준으로하는 Blackburne-Peel ratio 2) 를응용하여, 수술전후의일치성을고려하여, 슬개골관절면대신슬개골의하첨부를기준으로대퇴경골간관절선으로부터수직거리를슬개골높이 (Patella Bone Height, PBH) 로측정하였다 (Fig. 2). 슬관절측면사진은앙아위에서 30도굴곡상태에서촬영되었으며, 측정치는방사선촬영의확대비율에따라차이가나므로이를보정하기위하여, 슬개골길이의수술전후의비를구하여측정치를보정하였다. 슬개골의길이는골극을제외한슬개골의상단에서하단까지측정하였다. 슬개골높이감소 (dpbh) 는술전슬개골높이 (preop. PBH) 에서확대비율로보정한술후의슬개골높이 (C-postop. PBH) 를뺀값으로하였다. 통계처리는 SPSS for windows 12.0 을사용하였으며, 방사선계측치간의상관관계를분석하는데는 Pearson correlation analysis 를술전, 술후값들의차이의유의성을검정하는경우는 paired t-test 방법을사용하였다. 결과경골후방경사각은술전평균 8.9 도, 술후평균 2.3도로평균 6.6도의감소를, 슬개골높이는술전평균 12.7 mm, 술후평균 11.3 mm로, 평균 1.4 mm 의감소를보였으며 (Table 1, 2), 후방경사각의감소가많을수록슬개골높 Fig. 1. The picture shows various methods of determining posterior slope of tibia (PTC: Posterior tibial cortex). Fig. 2. Radiologic measurements of PBH.
김종헌 : 슬관절전치환술시경골후방경사각감소가슬개골높이에미치는영향 151 이의감소가적은약한음의상관관계를보였다 (r= 0.293, p=0.000)(fig. 3). 후방십자인대보존군과대치군의비교에서각각후방경사각은각각술전평균 6.5 도, 9.8도, 술후평균 3.0도, 2.0도로, 평균 3.5도, 7.8도의감 Table 1. Radiological Measurements of Tibial Slope ( o ) Preop. S* Postop. S ds 소를보였고 (p=0.000), 슬개골높이는술전평균 14.0 mm, 12.2 mm에서술후평균 11.8 mm, 11.0 mm로평균 2.2 mm, 1.2 mm의감소를보였다 (p=0.146)(table 1, 2). 두군모두에서역시후방경사각의감소가많을수록슬개골높이의감소가적은음의상관관계를보였으며, 그경향은후방십자인대보존군이대치군보다강하였다 (r= 0.431, p=0.003 vs r= 0.240, p=0.017)(fig. 4A, B). CR (n=43) 6.5 (0 19) 3.0 (0 8) 3.5 ( 5 18) PS (n=110) 9.8 (0 22) 2.0 (0 9) 7.8 ( 3 18) Total (n=153) 8.9 (0 22) 2.3 (0 9) 6.6 ( 5 18) (p=0.000) *preoperative slope angle of tibia, postoperative slope angle of tibia, differnce of between preop. S and postop. S Table 2. Radiological Measurements of Patellar Height (mm) Preop. C-postop. PBHJ* PBHJ dpbhj CR (n=43) 14.0 (5 24) 11.8 (5 29) 2.2 ( 9 11) PS (n=110) 12.2 (1 24) 11.0 (0 22) 1.2 (9 13) Total (n=153) 12.7 (1 24) 11.3 (0 29) 1.4 ( 9 13) (p=0.146) *preoperative patellar height from femorotibial articular line, corrected postoperatve patellar height from femorotibial articular line, difference between preop. PBHJ and C-postop. PBHJ Fig. 3. The graph shows the correlation between decrease of posterior slope and difference of patella height from articular line (Pearson correlation coefficient r= 0.293, p=0.000). Fig. 4. The graph shows the correlation between decrease of posterior slope and difference of patella height from articular line in both group, respectively. (A) CR group (Pearson correlation coefficient r= 0.431, p=0.003). (B) PS group (Pearson correlation coefficient r= 0.240, p=0.017).
152 고찰퇴행성관절염에서시행되는경골근위부절골술후경골후방경사각의변화에따른슬개골높이의변화에대한보고는잘알려져있으며 13), Brouwer 등 4) 은경골근위부절골술후폐쇄성및개방성모두에서경골후방경사가변화하면슬개골의높이가달라질수있으므로후방경사각의선택에신중을기해야한다고하였다. 슬관절전치환술에서의경골후방경사각의측정기준 3,11,14,18) 및크기 5) 와증감에따른관절운동범위 12), 경골치환물에대한부하 1,10), 후방십자인대의긴장 16,17) 및생역학 7) 등에대한영향등이보고되어있으며, 슬관절전치환술후대퇴경골관절선과슬개골간의관계에대하여, Figgie 등 6) 은술후대퇴경골간관절선으로부터슬개골관절높이가증가할수록, 즉슬개골이수술후상부로이동할수록 HSS 점수, 관절운동범위가증가하고, 슬관절동통은감소한다고보고한바있으며, Goldberg 등 8) 은인공슬개골의하단부가관절선에서 1 내지 3 cm 범위에있을때좋은술후결과를얻었다고하였다. 슬관절전치환술후슬개골높이에대하여, Grelsamer 9) 는원인과방사선학적소견에따라진성저위슬개골과가성저위슬개골을구별하여치료하여야한다고하면서, 대퇴경골관절선의상승이가성저위슬개골의원인이된다고하였으며, Rogers 등 15) 은수술전후의슬개골높이측정의재현율과정확도의평가를통하여, 슬개건의부착부위를기준으로하는 Insall-Salvati 와 modified Insall-Savati 방법보다, 대퇴경골관절선을기준으로하는 Blackburne-Peel 과 Caton-Deschamps 방법이관찰자간의오차가적다고하였고, 고찰을통하여슬개-대퇴관절의생역학은대퇴골활차구안에슬개골의위치에연관되어있어슬개- 대퇴관절의변화는심각한문제를야기하며, 체중부하에따른대퇴골과의위치즉, 활차구의위치는대퇴경골관절선의위치에직접적으로연관되있어, 잠재적문제점을시사하는슬개골높이의변화는대퇴경골관절선을기준으로측정하는것이합당하다고하였다. 저자들은본연구에서대퇴경골관절선을기준으로슬개골높이를측정하여, 수술후경골후방경사각의감소가클수록슬개골높이의감소가작다는사실을확인할수있었다. 후방경사각의감소에따르는경골고평부의전방부위의골절제가대퇴경골간관절선의하향을초래 하여슬개골과의거리에영향을주는것으로생각하며, 후방경사각의감소가더많았던 (p=0.000) 후방십자인대대치형에서보존형보다상관관계가더적은것은대치형술식에서시행되는후방십자인대절제에따르는굴곡, 신전간격의변화등이대퇴경골간관절선에영향을주었으리라생각한다. 본연구에서고려하지않은폴리에틸렌삽입물의두께및경사도, 추가적인원위대퇴골의절제, 수술전후의슬개건의길이변화등의슬개골높이에영향을줄수있는다른요소들과함께향후추가적인연구가필요하리라생각한다. 결 슬관절전치환술시경골후방경사각의감소는술후슬개골높이에영향을주는요소중하나가될수있어, 술전방사선학적검사에서예상할수있는술후후방경사각감소에대한평가가술후슬개골높이를유지하는데도움이되리라생각한다. 론 REFERENCES 1. Bai B, Baez J, Testa N, Kummer FJ: Effect of posterior cut angle on tibial component loading. J Arthroplasty, 15: 916-920, 2000. 2. Blackburne JS, Peel TE: A new method of measuring patellar height. J Bone Joint Surg Br, 59: 241-242, 1977. 3. Brazier J, Migaud H,Gougeon F, Cotton A, Fontaine C, Duquennoy A: Evaluation of methods for radiographic measurement of the tibial slope. A study of 83 healthy knees. Rev Chir Orthop Reparatrice Appar Mot, 82: 195-200, 1996. 4. Brouwer RW, Bierma-Zeinstra SM, van Koeveringe AJ, Verhaar JA: Patellar height and the inclination of the tibial plateau after high tibial osteotomy. The open versus the closed-wedge technique. J Bone Joint Surg Br, 87: 1227-1232, 2005. 5. Chiu KY, Zhang SD, Zhang GH: Posterior slope of tibial plateau in Chinese. J Arthroplasty, 15: 224-227, 2000. 6. Figgie HE 3rd, Goldberg VM, Heiple KG, Moller HS 3rd, Gordon NH: The influence of tibial-patellofemoral location on function of the knee in patients
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