摘要
前言:
　　後十字韌帶為膝關節中最強壯的一條韌帶，最主要的功能是限制脛骨的向後位移來維持膝關節的穩定度，大多數的受傷發生歸因於脛骨近端承受向後指向的力，然而目前對於後十字韌帶斷裂患者的治療方式仍然是一個充滿爭議的話題，目前較具共識的治療策略是對於等級一與二之病患採取保守性治療，等級三之病患則採取手術重建治療。
研究目的:
　　本研究目的為探討後十字韌帶受傷之患者在進行重建後十字手術後之病患與尚未接受手術並且求助於骨科欲進行手術之病患之間的差異，透過各項物理性檢查、肌力與下肢（髖、膝、踝關節）之生物力學參數，瞭解兩者之間的代償機制與適應策略有何不同，並對於是否需要進行手術與手術方式之討論提供更全面性的評估。
研究方法：
　　本實驗受試者是由高雄醫學大學骨科門診中篩選僅有單獨後十字韌帶受傷，經MRI 確認是後十字韌帶完全斷裂，無合併其他傷害，並且接受利用腿後肌重建後十字韌帶手術後滿一年以上之10位病患為術後組，與接受保守性復健治療後仍然感覺疼痛以及不穩定感並影響日常生活，求助於骨科欲接受開刀之12位治療者為適應不良組，以及健康的10位控制組，進行膝關節功能量表、物理檢查、肌力與利用動作分析系統觀察功能性動作(步態、上下階、全蹲、落地跳與垂直跳)之生物力學分析。統計方法使用單因子變異數分析及配對t檢定分析，並設p<0.05達統計上顯著差異。
結果:
　　術後組與控制組之Lysholm量表分數顯著高於適應不良組。適應不良組的脛骨向後位移量顯著大於術後組與控制組。肌力的部分，術後組在三種角速度下的伸直肌群肌力都顯著大於適應不良組，但術後組在60〫/s時的屈曲肌群肌力顯著小於控制組。步態測試中術後組在著地初期、負荷期與著地中期時的膝關節屈曲角度顯著小於適應不良組與控制組，動力學方面適應不良組在負荷期時，患肢的膝關節力矩顯著小於健肢。上階動作中前導腳離地以及支撐腳離地這兩個瞬間，關節角度以及關節力矩三組之間皆無顯著差異。下階動作中支撐腳著地瞬間的膝關節屈曲角度，適應不良組顯著小於控制組。全蹲動作中，術後組與控制組之膝關節最大屈曲角度與伸直力矩皆顯著大於適應不良組。落地跳測試中在落地瞬間時，三組之間的關節角度與關節力矩都沒有顯著差異，但適應不良組的最大地面反作用力顯著小於術後組與控制組。在垂直跳測試中，在垂直跳著地瞬間適應不良組的膝關節力矩為屈曲力矩並顯著大於術後組與控制組則的伸直力矩。

討論與結論：
　　由功能性動作的結果中可以發現後十字韌帶受傷的患者會有利用股四頭肌向心收縮使膝關節較伸直的適應策略，以及在術後組與適應不良組之間肌力與脛骨位移的差異，導致適應不良組會有將受力轉移至髖關節與踝關節的適應策略，術後組則較能由兩腳平均受力。故加強髖關節伸肌、膝關節伸肌與踝關節蹠屈肌群對於術後患者是個重要的復健目標，只要藉由後十字韌帶重建後恢復良好的膝蓋穩定度搭配良好的肌力就可以恢復良好的膝關節功能與受傷前的運動水平。

Biomechanical Analysis of Patients After Posterior Cruciate Ligament Reconstruction

Author: Chang, Kai-Hao
Advisor: Wang, Rong-Tyai
Department of Engineering Science, National Cheng Kung University

SUMMARY

Twenty-two isolated PCL injured patients and ten normal subjects were recruited in this study. Post-op group are ten patients who underwent single-bundle PCL reconstructive surgery by hamstring graft. Non-copers are twelve patients who complain about knee pain and knee instability after non-operative treatment. The extensor strength of post-op group was similar to control group, and even bigger than control group. But the flexor strength at 60∘/s of non-copers and post-op group is significant smaller than control group. Based on the result, found that the average extensor strength of post-op group recovery to a good level, but the average flexor strength is relatively weak. The reason is that the patients of post-op group underwent the PCL reconstruction by hamstrings autograft. From the comparison of the relative contributions of each joint to the support moment at loading response, it is obviously that the non-copers transferred the load from knee to ankle. In the analysis of descending stairs, due to the knee instability in non-coper group, they have to reduce the knee flexion angle by concentric contraction of quadriceps in order to make a more stable landing. From the result of jump and landing, the patients in non-coper group with deficient PCL knee had to avoid excessive ground reaction force when touching the ground.Consequently, a rehabilitation program can be designed to strengthen the Quadriceps, flexors of ankle and hip in order to help patients with PCL deficiency.

Key words: PCL, PCL reconstruction by hamstrings, kinematics, kinetics, muscle strength.

 
INTRODUCTION

The posterior cruciate ligament (PCL) is the strongest ligament in the knee and is approximately twice as strong as the anterior cruciate ligament. The PCL plays an integral role in knee joint stability. It is the primary restraint to posterior translocation of the proximal tibia and is a secondary restraint to varus, valgus, and external rotation forces. Current clinical treatment strategies must take into account the degree of laxity, which can be divided into three grades based on the results of a posterior drawer test. Grade I and II injuries represent partial tears of the PCL, whereas grade III tears represent complete tears and suspicion of associated injuries should be increased. Grade I and II PCL injuries with conservative treatment has been shown to have consistently good functional results, but a large percentage progress to have instability and arthritis. Surgical reconstruction is suggested for use in grade III and combined PCL injuries. The treatment of PCL injury remains controversial. It is necessary to conduct an analysis of the kinematics and kinetics of the lower limbs of these patients to gain a better understanding of the clinical performance of patients with isolated PCL injuries, to serve as reference for evaluating the clinical prognosis and establishing treatment strategies. The purpose of this study is to investigate the difference of kinematics parameters, kinetics parameters and muscle strength among three groups. And the difference of kinematics parameters, kinetics parameters and muscle strength between non-involved side and involved side were also be investigated.

METHOD

Twenty-two isolated PCL injured patients and ten normal subjects were recruited in this study. Post-op group are ten patients who underwent single-bundle PCL reconstructive surgery by hamstring graft more than a year ago. Non-copers are twelve patients who complain about knee pain and knee instability after non-operative treatment. The experiment is divided into six parts, respectively laxity examination, range of motion test, thigh circumference, strength test, proprioception test, functional motion analysis. The biodex Biodex System3 Pro (Biodex Medical System, New York,USA) was used to measure the isokinetic muscle strength and proprioception test. The Qualysis motion capture system (Qualisys, Swenden) was used to collect the biomechanical data during functional tasks. There are 6 infrared cameras with 200 Hz of capture freduency. Two force plates (Type 9286 and 9286AA, Kistler Instrument Corp., Winterthur,Switzerland) recorded the GRFs of the two feet with 1000 Hz of capture frequency.

RESULTS & DISCUSSION

In comparison of average Lysholm score, non-copers were 63.75 belong to scale of poor and post-op group were 89.63 belong to scale of good. In the comparison of muscle strength, it can be seen that the extensor strength of post-op group was similar to control group, and even bigger than control group. But the flexor strength at 60∘/s of non-copers and post-op group is significant smaller than control group. Based on the result, found that the average extensor strength of post-op group recovery to a good level, but the average flexor strength is relatively weak. The reason is that the patients of post-op group underwent the PCL reconstruction by hamstrings autograft, caused flexor strength weak.

In the analysis of gait, the knee flexion angle of post-op group is significant smaller than rest of two group at initial contact, loading response and mid-stance. We inferred that the patients in post-op group had better extensor strength, and they used the concentric contraction of quadriceps to keep the knee stable. From the comparison of the relative contributions of each joint to the support moment at loading response, the knee contribution of involved side (45.9%) is smaller than non-involved side (49.37%), but the ankle contributions of involved side (24.6%) is greater than non-involved (19%). It is obviously that the non-copers transferred the load from knee to ankle at loading response.

In the analysis of descending stairs, the knee flexion angle of non-copers was significant smaller than control group at instant of toe contact. And the same situation also can be seen between non-involved and involved side, the knee flexion angle of non-involved side was significant smaller than involved side at instant of toe contact. It is because the knee instability in non-coper group, they have to reduce the knee flexion angle by concentric contraction of quadriceps in order to make a more stable landing.

In this study, the maximum knee flexion angle of non-copers is significant smaller than post-op and control group in squatting. We concluded that the lower the squatting, the moment of body weight acted on knee higher. Subjects in post-op and control group had good extensor strength so that they could be lower in squatting, but not collapsed because they could not support the body weight. From the result of jump and landing, it can be seen that the maximum ground reaction force of non-copers is significant smaller than post-op and control group. The same situation occurred between non-involved and involved side in non-copers, the maximum ground reaction force of involved side is significant smaller than non-involved side. Obviously, the patients in non-coper group with deficient PCL knee had to avoid excessive ground reaction force when touching the ground.

CONCLUSION
It can be seen that the patients after posterior cruciate ligament reconstruction could recovery to the good level. In this study, the patients after PCL reconstruction would have better extensor strength but relatively poor flexor strength, due to the patients underwent the single-bundle PCL reconstruction by hamstrings autograft. From the comparison of the relative contributions of each joint to the support moment of non-copers can be seen that the non-copers transferred the loading from knee to hip and ankle. Consequently, a rehabilitation program can be designed to strengthen the Quadriceps, flexors of ankle and hip in order to help patients with PCL deficiency.

[1] Girgis FG, Marshall JL, Monajem A. The cruciate ligaments of the knee joint. Anatomical, functional and experimental analysis. Clin Orthop Relat Res; 106: 216–231. 1975.
[2] Sheps DM, Otto D, Fernhout M. The anatomic characteristics of the tibial insertion of the posterior cruciate ligament. Arthroscopy; 21:820–825. 2005.
[3]Fanelli GC. Posterior cruciate ligament injuries in trauma patients. Arthroscopy; 9:291-4. 1993.
[4] Race A, Amis AA. The mechanical properties of the two bundles of the human posterior cruciate ligament. J Biomech 27:13–24. 1994.
[5] Fox RJ, Harner CD, Sakane M, Carlin GJ, Woo SL. Determination of the in situ forces in the human posterior cruciate ligament using robotic technology. A cadaveric study. Am J Sports Med; 26:395-401. 1998.
[6] Fanelli GC, Beck JD, and Edson CJ. Current concepts review: the posterior cruciate ligament. The journal of knee surgery; 23: 61-72. 2010.
[7] McAllister DR, Petrigliano FA. Diagnosis and treatment of posterior cruciate ligament injuries. Curr Sports Med Rep; 6:293–299. 2007.
[8] Margheritini F, Mariani PP. Diagnostic evaluation of posterior cruciate ligament injuries. Knee Surg Sports Traumatol Arthrosc; 11:282–288. 2003.
[9] Harner, C.D., et al. The human posterior cruciate ligament complex: an interdisciplinary study. Ligament morphology and biomechanical evaluation. Am J Sports Med; 23: 736-45. 1995.
[10] Castle, T.H., Jr., F.R. Noyes, and E.S. Grood. Posterior tibial subluxation of the posterior cruciate-deficient knee. Clin Orthop Relat Res; 284:193-202. 1992.
[11] Gollehon, D., P. Torzilli, and R. Warren. The role of the posterolateral and cruciate ligaments in the stability of the human knee. A biomechanical study. J Bone Joint Surg Am; 69:233-242. 1987.
[12] Covey DC, Sapega AA, Riffenburgh RH. The effects of sequential sectioning of defined posterior cruciate ligament fiber regions on translational knee motion. Am J Sports Med; 36:480–486. 2008.
[13] Janousek, A.T., et al. Posterior cruciate ligament injuries of the knee joint. Sports Med; 28:429-41. 1999.
[14] Dejour H, Walch G, Peyrot J, et al. The natural history of rupture of the posterior cruciate ligament. Fr J Orthop Surg; 2:112–120. 1988.
[15] Parolie, J.M. and J.A. Bergfeld. Long-term results of nonoperative treatment of isolated posterior cruciate ligament injuries in the athlete. Am J Sports Med; 14:35-8. 1986.
[16] Dejour, H., et al. The natural history of rupture of the posterior cruciate ligament. Rev Chir Orthop Reparatrice Appar Mot; 74:35-43. 1988.
[17] Schulz MS, Russe K, Weiler A, Eichhorn HJ, Strobel MJ. Epidemiology of posterior cruciate ligament injuries. Arch Orthop Trauma Surg; 123:186–191. 2003.
[18] Janousek, A.T., et al. Posterior cruciate ligament injuries of the knee joint.Sports Med; 28: 429-41. 1999.
[19] Chen CH, Chen WJ, Shih CH. Arthroscopic reconstruction of the posterior cruciate ligament with quadruple hamstring tendon graft: a double fixation method. J Trauma; 52:938–945. 2002.
[20] Cain EL Jr, Clancy WG Jr. Posterior cruciate ligament reconstruction: two-bundle technique. J Knee Surg; 15:108–113. 2002.
[21] Nyland J, Hester P, Caborn DN. Double-bundle posterior cruciate ligament reconstruction with allograft tissue: 2-year postoperative outcomes. Knee Surg Sports Traumatol Arthrosc; 10:274–279. 2002.
[22] Wang CJ, Chen HS, Huang TW. Outcome of arthroscopic single bundle reconstruction for complete posterior cruciate ligament tear. Injury; 34:747–751. 2003.
[23] Hatayama K, Higuchi H, Kimura M, Kobayashi Y,Asagumo H, Takagishi K. A comparison of arthroscopic single- and double-bundle posterior cruciate ligament reconstruction: review of 20 cases. Am J Orthop; 35:568–571. 2006.
[24] Chen CH, Chen WJ, Shih CH. Arthroscopic reconstruction of the　posterior cruciate ligament: a comparison of quadriceps tendon　autograft and quadruple hamstring tendon graft. Arthroscopy; 18:603–12. 2002.
[25] Gollehon, D., P. Torzilli, and R. Warren. The role of the posterolateral and cruciate ligaments in the stability of the human knee. A biomechanical study. J Bone Joint Surg Am; 69: 233-242. 1987.
[26] Shelbourne, K.D., T.J. Davis, and D.V. Patel, The natural history of acute,isolated, nonoperatively treated posterior cruciate ligament injuries. A prospective study. Am J Sports Med; 27:276-83. 1999.
[27] Grassmayr, M.J., et al. Posterior cruciate ligament deficiency: biomechanical and biological consequences and the outcomes of conservative treatment. A systematic review. J Sci Med Sport; 11:433-43. 2008.
[28] Li, G., et al. Biomechanical consequences of PCL deficiency in the knee under simulated muscle loads—an in vitro experimental study. Journal of Orthopaedic Research; 20:887-892. 2002.
[29] Pearsall, A.W. and J.M. Hollis. The Effect of Posterior Cruciate Ligament Injury and Reconstruction on Meniscal Strain. The American Journal of Sports Medicine; 32:1675-1680. 2004.
[30] Kumagai, M., et al. Posterior cruciate ligament rupture alters in vitro knee kinematics. Clin Orthop Relat Res; 395:241-8. 2002.
[31] Ogata, K., et al. Pathomechanics of posterior sag of the tibia in posterior cruciate deficient knees. The American Journal of Sports Medicine; 16: 630-636. 1988.
[32] Kaneda, Y., et al. Experimental Study on External Tibial Rotation of the Knee. The American Journal of Sports Medicine; 25: 796-800. 1997.
[33] Gupte, C.M., et al. The meniscofemoral ligaments: secondary restraints to the posterior drawer. Analysis of anteroposterior and rotary laxity in the intact and posterior-cruciate-deficient knee. J Bone Joint Surg Br; 85: 765-73. 2003.
[34] Tibone, J.E., et al. Functional analysis of untreated and reconstructed posterior cruciate ligament injuries. Am J Sports Med; 16: 217-23. 1988.
[35] TORG, J.S., et al. Natural History of the Posterior Cruciate Ligament-Deficient Knee. Clinical Orthopaedics and Related Research; 246: 208-216. 1989.
[36] Shirakura, K., K. Kato, and E. Udagawa. Characteristics of the isokinetic performance of patients with injured cruciate ligaments. The American Journal of Sports Medicine; 20: 754-760. 1992.
[37] MacLean, C.L., et al. Eccentric and concentric isokinetic moment characteristics in the quadriceps and hamstrings of the chronic isolated posterior cruciate ligament injured knee. British Journal of Sports Medicine; 33: 405-408. 1999.
[38] Vanwanseele, B., et al. THE KINEMATIC AND KINETIC RESPONSES OF ATHLETES WITH POSTERIOR CRUCIATE LIGAMENT INJURIES. Journal of Biomechanics; 41: S111. 2008.
[39] Lephart, S. and T. Henry. The physiological basis for open and closed kinetic chain rehabilitation for the upper extremity. J Sport Rehab; 5: 71-87. 1996.
[40] Clark, P., P.B. MacDonald, and K. Sutherland. Analysis of proprioception in the posterior cruciate ligament-deficient knee. Knee Surg Sports Traumatol Arthrosc; 4: 225-7. 1996.
[41] Safran, M.R., et al. Proprioception in the posterior cruciate ligament deficient knee. Knee Surg Sports Traumatol Arthrosc; 7: 310-7. 1999.
[42] 劉玫舫, et al. 慢性後十字韌帶斷裂患者之步態分析–先驅研究報告. 物理治療; 32: 114-122. 2007.
[43] Fontbote, C.A., et al. Neuromuscular and biomechanical adaptations of patients with isolated deficiency of the posterior cruciate ligament. Am J Sports Med; 33: 982-9. 2005.
[44] Tibone, J.E., et al. Functional analysis of untreated and reconstructed posterior cruciate ligament injuries. Am J Sports Med; 16: 217-23. 1988.
[45] Durselen, L., L. Claes, and H. Kiefer. The influence of muscle forces and external loads on cruciate ligament strain. Am J Sports Med; 23: 129-36. 1995.
[46] Li, G., et al. Effect of posterior cruciate ligament deficiency on in vivo translation and rotation of the knee during weightbearing flexion. Am J Sports Med; 36: 474-9. 2008.
[47] Liu, M.F., et al. Lower-limb adaptation during squatting after isolated posterior cruciate ligament injuries. Clin Biomech (Bristol, Avon), 2010.
[48] Iwata, S., et al. Dynamic instability during stair descent in isolated PCL-deficient knees: what affects abnormal posterior translation of the tibia in PCL-deficient knee Knee Surgery, Sports Traumatology, Arthroscopy; 15: 705-711. 2007.
[49] Hooper, D.M., et al. Gait adaptations in patients with chronic posterior instability of the knee. Clinical Biomechanics; 17: 227-233. 2002.
[50] Shelbourne, K.D., T.J. Davis, and D.V. Patel. The natural history of acute, isolated, nonoperatively treated posterior cruciate ligament injuries. A prospective study. Am J Sports Med; 27: 276-83. 1999.
[51] Lien, O.A., et al. Clinical outcome after reconstruction for isolated posterior cruciate ligament injury. Knee Surg Sports Traumatol Arthrosc. 2010.
[52] Cynthia C. Norkin, D.J.W. Measurement of Joint Motion: A guide to Goniometry.3rd ed. 2003.
[53] Winter, D.A. Overall principle of lower limb support during stance phase of gait. Journal of Biomechanics; 13: 923-927. 1980.
[54]范瓉予. 單獨後十字韌帶受傷患者之功能性適應. 高雄醫學大學運動醫學系2011.
[55] Holcomb, W.R., et al. Effect of hamstring-emphasized resistance training on hamstring:quadriceps strength ratios. J Strength Cond Res; 21: 41-7. 2007.
[56] Heiser, T.M., et al. Prophylaxis and management of hamstring muscle injuries in intercollegiate football players. The American Journal of Sports Medicine; 12: 368-370. 1984.
[57] Jonsson, H. and J. Kärrholm. Three-dimensional knee kinematics and stability in patients with a posterior cruciate ligament tear. Journal of Orthopaedic Research; 17: 185-191. 1999.
[58] Markolf, K.L., et al. Effects of Applied Quadriceps and Hamstrings Muscle Loads on Forces in the Anterior and Posterior Cruciate Ligaments. The American Journal of Sports Medicine; 32: 1144-1149. 2004.
[59] Li, G., et al. The importance of quadriceps and hamstring muscle loading on knee kinematics and in-situ forces in the ACL. Journal of Biomechanics; 32: 395-400. 1999.