Clinical Article The Korean Journal of Sports Medicine 2014;32(1):14-19 http://dx.doi.org/10.5763/kjsm.2014.32.1.14 전방십자인대재건술시이식건의봉합을이용한기둥고정에서적절한요소 : 봉합사수, 매듭수, 봉합방법, 봉합수 - 돼지건을이용한실험적연구 - 가천대학교의학전문대학원정형외과학교실 1, 가천대학교의학전문대학원 2, 솔고바이오메디칼의공학연구소 3 심재앙 1 ㆍ최석원 2 ㆍ전창수 3 ㆍ김원석 1 ㆍ이용석 1 ㆍ이범구 1 Optimal Parameters for Sutures Tied to a Post during Anterior Cruciate Ligament Reconstruction: Thread Numbers, Knot Numbers, Suture Techniques and Stitch Numbers - An Experimental Laboratory Study Using Porcine Tendon - Jae Ang Sim 1, Suk Won Choi 2, Chang Soo Chon 3, Won Seok Kim 1, Yong Seuk Lee 1, Beom Koo Lee 1 1 Department of Orthopaedics, Gil Hospital, Gachon University, Incheon, 2 Gachon Medical School, Gachon University, Incheon, 3 Solco Biomedical Institute, Solco Biomedical, Pyeongtaek, Korea We evaluated the conditions required for sutures tied to a post for tibial fixation during anterior cruciate ligament (ACL) reconstruction. Harvested porcine tendon was used as a graft material and nonabsorbable suture was used for sutures. Samples were tested for ultimate tensile load and elongation according to thread numbers, knot numbers, suture techniques and stitch numbers. As thread numbers were increased, ultimate tensile load was increased and elongation was decreased. However, more than 4 strands of threads provided the sufficient ultimate tensile load more than 454 N of normal ACL for daily activities. As knot numbers were increased, ultimate tensile load was increased, but elongation was decreased. In terms of failure mode, unraveling occurred 100% in 3 and 4 knots, 81.2% in 5 knots, 54.5% in 6 knots, and 0% in 7 knots. Suture techniques and stitch numbers didn t significantly affect the ultimate tensile load and the elongation. For sutures tied to a post for tibial fixation in ACL reconstruction, more than 4 threads, more than 7 knots, and more than 4 stitches provide adequate ultimate tensile load and elongation. Keywords: Knee, Anterior cruciate ligament reconstruction, Tibial fixation Received: November 22, 2013 Revised: January 7, 2014 Accepted: January 23, 2014 Correspondence: Beom Koo Lee Department of Orthopaedics, Gil Hospital, Gachon University of Medicine and Science, 21 Namdong-daero, 774beon-gil, Namdong-gu, Incheon 405-760, Korea Tel: +82-32-460-3384, Fax: +82-32-468-5437, E-mail: bklee@gilhospital.com Copyright 2014 The Korean Society of Sports Medicine CC This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 14 대한스포츠의학회지
심재앙외. 전방십자인대재건술시이식건의봉합을이용한기둥고정에서적절한요소 서론전방십자인대재건술시전방슬관절동통과공여부의이완이적고, 여러가닥으로표면적이넓어혈관재형성에유리하며, 신전기전의손상이적다는장점이있어슬근건의사용빈도가최근에점차증가되고있다. 슬근건의고정방법은크게피질골고정 (cortical fixation), 피질골과해면골고정 (corticocancellous fixation), 터널입구고정 (aperture fixation) 등으로나눌수있으며, 경골부의고정에는봉합을이용한기둥고정 (sutures tied to a post), 나사와스파이크와셔 (spiked washer), 스태플 (staple) 등의피질골고정방법과간섭나사 (interference screw) 등을이용한터널입구고정방법등이이용될수있다. 경골부의고정중간섭나사의경우비교적술식이간단하고강한고정력을얻을수있으나삽입방향등에따라고정력에차이가날수있으며간섭나사의나사선 (thread) 에의해연부조직이식건인슬근건이손상당할수있다 1-6). 나사와스파이크와셔의경우비교적술식이간단하고강한고정력을가질수있으나압력에의한괴사 (pressure necrosis) 나혈관손상가능성등이일어날수있다 7,8). 스태플의경우에도비교적술식이간단하나강한고정력을주기어렵고, 이식건의미끄러짐도크다는단점이있다 9,10). 봉합을이용한기둥고정의경우봉합사에의한신연이일어날수있고, 고정력이충분치못하여간섭나사등의보강술식이요할수있다 9,10). 봉합을이용한기둥고정이이식건의충분한고정력을제공할수있다면슬근건의손상을피하면서미끄러짐을방지할수있는좋은고정방법으로생각된다. 이에저자들은전방십자인대재건술의이식건경골부고정에서봉합을이용한기둥고정시고정력에영향을줄수있는봉합사의수, 매듭 (knot) 수, 봉합방법, 봉합수에따른생역학을연구하여성공적인이식건의봉합을이용한기둥고정을위한적절한요소를알아보고자하였다. 수구별없이약 6개월된 100 kg 전후의돼지를사용하였다. 실험당일도살된돼지의족부신전건을채취하였다. 봉합사는전방십자인대재건술시주로이용하는비흡수성봉합사인 No. 5 ethibond (Ethicon, Somerville, NJ, USA) 를이용하였다. 2. 실험기구인장실험을위한검사기는 858 table top system (MTS Systems Corporation, Eden Prairie, MN, USA) 을이용하였으며, 현수장치는봉합사나이식건이손상받지않도록원통형의현수장치를제작하였으며, 다른한쪽은실험방법에따라같은현수장치또는물림장치 (gripper) 에고정하였다 (Fig. 1). 모든실험방법에서최대인장부하 (ultimate tensile load) 와신연 (elongation) 을측정하였고, 인장속도는 50 mm/min, 최대인장거리는실험재료의 2배의거리인봉합사실험의경우 10 cm, 이식건과봉합사실험의경우 12 cm로하였다. 3. 실험방법 1) 봉합사의수 No. 5 Ethibond를각각 2 가닥 (strands), 4 가닥, 6 가닥, 8 가닥으로하고그길이는 5 cm로동일하게하여길이등에의한오차 (bias) 가없게하였다. 한쪽끝은현수장치에걸고, 다른한쪽끝은물림장치에연결하였다. 최대인장부하와신연정도를측정하였다. 각각의가닥에대하여 20예를시행하였다. 2) 매듭수매듭은오차를줄이기위해한명의술자가동일한술기로시행하였으며최대강도로매듭을형성하였다. 봉합사의수에따른신연정도와마찬가지로봉합사길이는 5 cm로동일하게하였다. 매듭의수는 3개, 4개, 5개, 6개, 7개로하였으며, 현수장치에걸어최대인장부하와신연정도를측정하였으며 연구방법 1. 실험재료 이식건은사람의전방십자인대재건술시주로이용하는반건양건, 박건과그크기가유사한돼지 (porcine) 의제3 또는제4 족지신전건을이용하였다. 실험에사용할돼지는암, Fig. 1. Suture techniques. 제 32 권제 1 호 2014 15
JA Sim, et al. Optimal Parameters for Sutures Tied to a Post 실패요인이풀림에의한것인지혹은끊김에의한것인지를확인하였다. 3개의매듭의경우 19예, 4개의매듭과 5개의매듭의경우각각 16예, 6개의매듭의경우 11예, 7개의매듭의경우 16예를시행하였다. 3) 봉합방법이식건의봉합방법은단순봉합 (simple suture), 맞물림봉합 (interlocking suture), Krackow 봉합방법 11) 을이용하였다 (Fig. 1). 단순봉합의경우한쪽의봉합부위가반대편봉합부위와겹치지않게일렬로봉합하였고, 교차봉합의경우한쪽의봉합부위가반대편봉합부위와겹치도록봉합하였다. 봉합은 No. 5 Ethibond를이용하여모든봉합방법에서동일하게양측에 6번을봉합하였다. 돼지신전건의봉합부위길이는 1 cm, 비봉합부위의길이는 2 cm로하였으며, 봉합사의길이는 3 cm로동일하게하였다. 오차를줄이기위해한명의술자가시행하였으며, 최대인장부하와신연정도를측정하였다. 단순봉합의경우 14예, 맞물림봉합의경우 13예, Krackow 봉합의경우 14예를시행하였다. 4) 봉합수봉합수에따른신연정도측정은맞물림봉합방법으로시행하였으며각각 4번, 5번, 6번, 7번의봉합을시행하여각각의최대인장부하와신연정도를측정하였다 (Fig. 2). 돼지신전건의봉합부위길이는 1 cm, 비봉합부위의길이는 2 cm로하였으며, 봉합사의길이는 3 cm로동일하게하였고, 오차를줄이기위해한명의술자가동일한술기로시행하였다. 4번봉합과 5번봉합의경우각각 14예, 6번봉합의경우 13예, 7번봉합의경우 14예를시행하였다. 4. 통계방법통계학적분석은 SPSS ver. 12 (SPSS Inc., Chicago, IL, USA) 를이용하여 Kruskal-Wallis 검사를이용하여결과를비교하였고 (P K ), Mann-Whitney 검사를이용하여각군간의결과를비교하였다 (P M ). 유의수준이 0.05 이하일때통계적으로의의가있는것으로판정하였다. 결과 1. 봉합사의수에따른최대인장부하및봉합사신연정도최대인장부하는봉합사의수가늘어날수록증가되었다 (P K <0.001). 봉합사의신연정도도봉합사의수가늘어날수록증가되었다 (P K <0.001). 최대인장부하의경우각군간비교에서봉합사가닥이늘어날수록유의하게증가되었다 (P M24, P M26, P M28, P M46, P M48 and P M68 <0.001) (Fig. 3). 봉합사의신연정도도각군간비교에서봉합사가닥이늘어날수록유의하게감소되었으나 2 가닥의경우와 4 가닥의경우는유의한차이가없었다 (P M24 =0.425, P M26, P M28, P M46, and P M48, P M68 <0.001) (Fig. 4). 봉합사의수가 4 가닥의경우부터는최대인장부하가 569.5±26.2 N으로일상생활에서활동할때필요한 454 N 정도 Fig. 2. Stitch numbers. Fig. 3. Ultimate tensile load according to thread numbers, knot numbers, suture technique, and stitch numbers. *Significant difference compared to second column of the respective group; Significant difference compared to second column of the respective group; Significant difference compared to third column of the respective group. 16 대한스포츠의학회지
심재앙외. 전방십자인대재건술시이식건의봉합을이용한기둥고정에서적절한요소 의정상전방십자인대의부하보다는높았다. 2. 매듭수에따른최대인장부하, 봉합사신연정도및실패요인실패요인은 3개의매듭군과 4개의매듭군의경우모두풀림이일어났으며, 5개의매듭군에서는 81.2% 에서풀림이일어났으며, 6개의매듭군에서는 54.5% 에서풀림이일어났고, 7개의매듭군에서는모두풀림이일어나지않고끊김이일어났다 (Table 1). 최대인장부하는매듭수가늘어날수록증가되었다 (P K <0.001). 각군간비교에서 3개와 4개의매듭군사이, 5개, 6개, 7개의매듭군사이의경우유의한차이를보이진않았다 (P M34 =0.243, P M56 =0.251, P M67 =0.342, P M57 =0.423). 하지만전자 의두군과후자의세군간의각각의비교는유의한차이를보였다 (P M35, P M36, P M37 and P M46 <0.001, P M45 =0.015, P M46 =0.011, P M47 =0.003) (Fig. 3). 봉합사의신연정도는매듭의수가늘어날수록감소되었다 (P K <0.001). 실패요인이풀림인경우에는최대인장거리가 10 cm이므로신연정도를 50 mm로계산하였다. 각군간의비교에서 3개의매듭군과 4개의매듭군은모두풀림이일어났으므로신연정도가동일하였고, 3개또는 4개의매듭군과 5개매듭군은유의한차이가없었으나 (P M35 =0.086), 6개또는 7개매듭군과는유의한차이가있었다 (P M36 =0.003, P M37 <0.001). 5개매듭군과 6개매듭군은유의한차이가없었으나 (P M56 =0.234), 7개매듭군과는유의한차이가있었다 (P M57 <0.001). 6개매듭군과 7개매듭군도유의한차이가있었다 (P M67 =0.003) (Fig. 4). 실패요인이끊김인 24예를비교하면최대인장부하는유의한차이를보이지않았고 (P K =0.162), 신연정도도유의한차이를보이지않았다 (P K =0.586). 최대인장부하의경우 3개의군간유의한차이를보이지않았으며 (P M56 =0.143, P M67 =0.660, P M57 =0.085) (Table 1), 신연정도도 3개의군간유의한차이를보이지않았다 (P M56 =0.393, P M67 =0.431, P M57 =0.723) (Table 1). 3. 봉합방법에따른따른최대인장부하및이식건과봉합사신연정도 Fig. 4. Enlongation according to thread numbers, knot numbers, suture technique, and stitch numbers. *Significant difference compared to first column of the respective group; Significant difference compared to second column of the respective group; Significant difference compared to third column of the respective group; Significant difference compared to fourth column of the respective group. 세가지봉합방법에따른최대인장부하는유의한차이가없었다 (P K =0.842). 각군간최대인장부하도유의한차이를보이지않았다 (P MSC =0.756, P MCK =1.000, P MKS =0.541) (Fig. 3). 신연정도도유의한차이가없었으며 (P K =0.834), 각군간비교에서도유의한차이를보이지않았다 (P MSC =1.000, P MCK =0.562, P MKS =0.839) (Fig. 4). Table 1. Failure mode according to knot numbers Variables All specimens Failure mode Snapped knots only UTL (N) Elongation (mm) (unraveling/snapped) UTL (N) Elongation (mm) 3 Knots 117.1±90.6 50.0±0.0 19/0 - - 4 Knots 142.9±95.0 50.0±0.0 16/0 - - 5 Knots 232.6±67.3 42.4±16.3 13/3 279.5±1.1 9.5±0.5 6 Knots 246.4±71.8 31.9±20.8 6/5 261.7±18.5 10.1±0.7 7 Knots 262.9±13.9 9.8±0.8 0/16 262.9±13.9 9.8±0.8 UTL: ultimate tensile load. 제 32 권제 1 호 2014 17
JA Sim, et al. Optimal Parameters for Sutures Tied to a Post 4. 봉합수에따른최대인장부하및이식건과봉합사신연정도봉합수에따른최대인장부하는유의한차이가없었다 (P K =0.286). 각군간최대인장부하도유의한차이를보이지않았다 (P M45 =0.077, P M56 =0.375, P M67 =0.830) (Fig. 3). 신연정도도유의한차이가없었으며 (P K =0.825), 각군간비교에서도유의한차이를보이지않았다 (P M45 =0.886, P M56 =0.352, P M67 = 0.610) (Fig. 4). 고찰최근에전방십자인대재건술시공여부의이완이적고, 혈관재형성에유리함등으로인해슬근건의사용이점차증가되고있다. 하지만양쪽에골을포함하고있어간섭나사로골간 (bone to bone) 강한고정력을얻을수있는슬개건과달리슬근건은연부조직이기때문에강한고정을얻기어렵다. 특히경골부에서는대퇴부에서이용될수있는비교적고정력이강한피질골고정기구나피질골- 해면골고정기구를이용할수없기때문에고정기기가제한되어있고, 고정력도대퇴부에비해약하다. 흔히사용되는경골부고정방법은봉합을이용한기둥고정, 나사와스파이크와셔, 스태플, 간섭나사등이있다. 간섭나사는터널입구고정방법으로피질골고정에비해미끄러짐등이적을수있다. 하지만, 나사의삽입방향이터널의방향과일치하지않은경우가 46% 에서 84% 까지일어날수있고이러한경우고정력이현격히감소할수있으며 1,2), 나사선에의해슬근건이손상당할가능성이있을수있고 3,5,6), 간섭나사의고정부위에서이식건의치유 (healing) 를방해할수있다 4). 최근에는슬근건과같은연부조직이식건을위해나사의깊이를감소시키고나사의끝을부드럽게하거나간섭나사와이식건사이에막 (sheath) 을삽입하여연부조직이식건의손상을줄이는간섭나사가개발되었으나, 간섭나사의고정역학자체가쐐기효과를이용하였기때문에생물학적 (biological) 으로나생역학적 (biomechanical) 으로연부조직이식건의손상을피할수는없고이러한손상은추후조기재활운동에영향을줄수있다 3-6). 나사와스파이크와셔는피질골고정방법으로비교적술식이간단하고강한고정력을가질수있다 9,10,12,13). 하지만고정방향과이식건의방향이거의직각을이루어이식건의미끄러짐이일어날수있고, 피질골부위가파손되는경우이식건의이완이일어날수있다 9). 스파이크와셔는일반적인와셔에비해이식건의압력에의한괴사가거의없다고보고하고있으나 8), 스파이크와셔의고정역학이압박 (compression) 이므로이를완전히배제하기는어려울것으로생각된다. 또한고정부위의스파이크로인하여이식건의파열등이일어날수있고, 나사고정을위한천공으로인하여슬와동, 정맥의이분부위 (bifurcation) 와전경골정맥을손상시킬수있다 7). 스태플도피질골고정방법으로비교적술식이간단하나, 강한고정력을주기어렵고, 이식건의미끄러짐도크다 9,10). 또한고정부위의스파이크로인하여이식건의파열등이일어날수있다. 봉합을이용한기둥고정은피질골고정방법으로봉합사에의한신연이일어날수있고, 고정력이약할수있으나 9,10), 봉합사가충분한고정력을제공한다면고정뱡향과이식건이일치하여미끄러짐이일어나지않고쐐기효과등으로인한연부조직이식건의손상등도피할수있다. 본연구에서는봉합사의수에따른실험에서최대인장부하는봉합사의개수에비례하여증가되었다. 이는봉합을이용한기둥고정시인대의강도를고려하여필요한강도로봉합사의개수를결정할수있으리라생각된다. 정상전방십자인대의경우걸을때 169 N, 계단을내려갈때 445 N, 일상생활에서활동할때 454 N 정도의인장부하가필요한것으로알려져있다 14-16). 이를고려할때 569.5 N의최대인장부하를갖는 4가닥즉 2개의 No. 5 ethibond를사용한다면다른추가적인고정없이도충분한강도를얻을수있으리라생각된다. 다만봉합사의개수가많아진다면좀더강한고정력을제공할수있고신연정도를감소시킬수있으나봉합사의수가많아질수록이식건의봉합부위가두꺼워지게되어봉합부위가아닌이식건부위에서터널과이식건간부조화 (mismatching) 가일어날수있다. 다른방법으로는최대인장부하가크고신연이적게일어나는봉합사를사용한다면봉합부위가두꺼워짐을방지할수있어적은개수의봉합사를가지고도터널과이식건간부조화를방지할수있으리라생각된다. 매듭의경우일단풀림이일어나게되면최대인장부하는현격하게감소하게되고, 신연정도는증가하게되므로이는이식건의이완 (loosening) 으로이어질수있으므로주의를요할것으로생각된다. 매듭수의경우 5개의매듭을만든경우약 80% 정도에서풀림이일어나고, 6개의매듭을만든경우에도약 65% 정도풀림이일어났다. 하지만 7개의매듭을만든경우에는풀림이일어나지않아봉합을이용한기둥고정시최소한 7개이상의매듭을만들어야풀림에의한이식건의이완이일어나지않을것으로기대된다. 봉합방법에서는 Krackow 봉합방법 11) 이 18 대한스포츠의학회지
심재앙외. 전방십자인대재건술시이식건의봉합을이용한기둥고정에서적절한요소 최대인장부하나신연정도면에서좀더좋은결과를보였으나단순봉합, 맞물림봉합방법간의유의한차이는없어봉합방법간에는차이가없었다. 봉합수의경우봉합수가증가될수록최대인장부하는약간증가하고, 신연정도는약간감소하는경향을보이긴하였으나유의한차이를보이진않아 4번이상의봉합경우에는이식건의이완을방지할수있을것으로생각된다. 인간사체의건을이용하지못하고돼지의건을이용한점, 단순히이식건만을가지고실험을시행하여완벽하게인대재건술상태를복원하지못한점, 인대재건술상태에서반복적인주기성인장검사를하지못한점등이본연구의한계점으로생각된다. 전방십자인대재건술의이식건경골부고정에서 No. 5 ethibond 봉합을이용한기둥고정시 2개이상의봉합사, 7회이상의매듭, 4번이상의봉합을시행한다면일상생활에서활동할때필요한 454 N 정도의정상전방십자인대의부하보다는높은충분한최대인장부하와신연정도를제공할수있으리라생각된다. References 1. Krackow KA, Thomas SC, Jones LC. A new stitch for ligament-tendon fixation. Brief note. J Bone Joint Surg Am 1986;68:764-6. 2. Fanelli GC, Desai GM, Cummings PD, Hanks GA, Kalanak A. Divergent alignment of the femoral interference screw in single incision endoscopic reconstruction of the anterior cruciate ligament. Contemp Orthop 1994;28:21-5. 3. Pierz K, Baltz M, Fulkerson J. The effect of Kurosaka screw divergence on the holding strength of bone-tendon-bone grafts. Am J Sports Med 1995;23:332-5. 4. Zantop T, Weimann A, Schmidtko R, Herbort M, Raschke MJ, Petersen W. Graft laceration and pullout strength of soft-tissue anterior cruciate ligament reconstruction: in vitro study comparing titanium, poly-d,l-lactide, and poly-d,llactide-tricalcium phosphate screws. Arthroscopy 2006;22: 1204-10. 5. Park DK, Fogel HA, Bhatia S, et al. Tibial fixation of anterior cruciate ligament allograft tendons: comparison of 1-, 2-, and 4-stranded constructs. Am J Sports Med 2009;37: 1531-8. 6. Weiler A, Windhagen HJ, Raschke MJ, Laumeyer A, Hoffmann RF. Biodegradable interference screw fixation exhibits pull-out force and stiffness similar to titanium screws. Am J Sports Med 1998;26:119-26. 7. Giurea M, Zorilla P, Amis AA, Aichroth P. Comparative pull-out and cyclic-loading strength tests of anchorage of hamstring tendon grafts in anterior cruciate ligament reconstruction. Am J Sports Med 1999;27:621-5. 8. Magen HE, Howell SM, Hull ML. Structural properties of six tibial fixation methods for anterior cruciate ligament soft tissue grafts. Am J Sports Med 1999;27:35-43. 9. Post WR, King SS. Neurovascular risk of bicortical tibial drilling for screw and spiked washer fixation of soft-tissue anterior cruciate ligament graft. Arthroscopy 2001;17:244-7. 10. Kousa P, Jarvinen TL, Vihavainen M, Kannus P, Jarvinen M. The fixation strength of six hamstring tendon graft fixation devices in anterior cruciate ligament reconstruction. Part II: tibial site. Am J Sports Med 2003;31:182-8. 11. Muller W. The knee: form, function, and ligament reconstruction. Berlin Springer-Verlag; 1983. 12. Coleridge SD, Amis AA. A comparison of five tibial-fixation systems in hamstring-graft anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc 2004;12: 391-7. 13. Brand J Jr, Weiler A, Caborn DN, Brown CH Jr, Johnson DL. Graft fixation in cruciate ligament reconstruction. Am J Sports Med 2000;28:761-74. 14. Noyes FR, Butler DL, Grood ES, Zernicke RF, Hefzy MS. Biomechanical analysis of human ligament grafts used in knee-ligament repairs and reconstructions. J Bone Joint Surg Am 1984;66:344-52. 15. Morrison JB. Function of the knee joint in various activities. Biomed Eng 1969;4:573-80. 16. Morrison JB. The mechanics of the knee joint in relation to normal walking. J Biomech 1970;3:51-61. 제 32 권제 1 호 2014 19