Mechanisms and Management of Knee Anterior Cruciate Ligament Injury; A Review

Document Type : SCOPING REVIEW

Authors

1 School of Medicine, Orthopedic Department, Golestan University of Medical Sciences, Gorgan, Iran - School of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran

2 School of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran

3 Health Research Center, Life Style Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran- Department of Epidemiology and Biostatistics, Faculty of Health, Baqiyatallah University, Tehran, Iran

4 School of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran- Department of Orthopedics, School of Medicine, Ayatollah Taleghani Hospital, Shahid Beheshti University of Medical Sciences, , Tehran, Iran

10.22038/abjs.2024.77176.3569

Abstract

Objectives: This study aimed to clarify the debate on anterior cruciate ligament (ACL) injury management and the selection of patients for surgical or nonsurgical treatment.
Methods: A retrospective, citation-based approach was employed to search for English literature that assessed management options and mechanisms for ACL injuries.
Results: A variety of mechanical and neurocognitive mechanisms are involved in ACL injuries that could be used to develop practical prevention strategies. More precise preoperative clinical, and paraclinical assessments, as well as clarification of available treatment options for patients, would lead to individualized decisions on injury management, and thus to objective and subjective satisfaction. Prioritization of attentive physical therapy rehabilitation plans will also improve treatment outcomes.
Conclusion: A better understanding of the ACL injury/patient characteristics will help to achieve optimal treatment outcomes for each individual and develop targeted and practical prevention strategies.
        Level of evidence: II

Keywords

Main Subjects

References

  1. Risberg MA, Lewek M, Snyder-Mackler L. A systematic review of evidence for anterior cruciate ligament rehabilitation: how much and what type? Physical Therapy in Sport. 2004; 5(3):125-145. doi:10.1016/j.ptsp.2004.02.003.
  2. MacLeod TD, Snyder-Mackler L, Buchanan TS. Differences in neuromuscular control and quadriceps morphology between potential copers and noncopers following anterior cruciate ligament injury. J Orthop Sports Phys Ther. 2014; 44(2):76-84. doi:10.2519/jospt.2014.4876.
  3. Duthon V, Barea C, Abrassart S, Fasel J, Fritschy D, Ménétrey J. Anatomy of the anterior cruciate ligament. Knee Surg Sports Traumatol Arthrosc. 2006; 14:204-213. doi:10.1007/s00167-005-0679-9.
  4. Grindem H, Wellsandt E, Failla M, Snyder-Mackler L, Risberg MA. Anterior cruciate ligament Injury—who succeeds without reconstructive surgery? The Delaware-Oslo ACL cohort study. Orthop J Sports Med. 2018; 6(5):2325967118774255. doi:10.1177/2325967118774255.
  5. Mowbray MAS, Ireland J. Personal and narrative review of the current management of the injured anterior cruciate ligament of the knee in the UK with reference to surgical treatment versus rehabilitation. BMJ Open Sport Exerc Med. 2022; 8(3):e001410. doi: 10.1136/bmjsem-2022-001410.
  6. Filbay SR, Grindem H. Evidence-based recommendations for the management of anterior cruciate ligament (ACL) rupture. Best Pract Res Clin Rheumatol. 2019; 33(1):33-47. doi:10.1016/j.berh.2019.01.018.
  7. Lucarno S, Zago M, Buckthorpe M, et al. Systematic video analysis of anterior cruciate ligament injuries in professional female soccer players. Am J Sports Med. 2021; 49(7):1794-1802. doi: 10.1177/03635465211008169.
  8. Della Villa F, Buckthorpe M, Grassi A, et al. Systematic video analysis of ACL injuries in professional male football (soccer): injury mechanisms, situational patterns and biomechanics study on 134 consecutive cases. Br J Sports Med. 2020; 54(23):1423-1432. doi: 10.1136/bjsports-2019-101247.
  9. Wetters N, Weber AE, Wuerz TH, Schub DL, Mandelbaum BR. Mechanism of injury and risk factors for anterior cruciate ligament injury. Operative Techniques in Sports Medicine. 2016; 24(1):2-6.
  10. Shimokochi Y, Shultz SJ. Mechanisms of noncontact anterior cruciate ligament injury. J Athl Train. 2008; 43(4):396-408. doi: 10.4085/1062-6050-43.4.396.
  11. Schick S, Cantrell CK, Young B, et al. The mechanism of anterior cruciate ligament injuries in the National Football League: a systematic video review. Cureus. 2023; 15(1):e34291. doi: 10.7759/cureus.34291.
  12. Dix C, Arundale A, Silvers-Granelli H, Marmon A, Zarzycki R, Snyder-Mackler L. Biomechanical measures during two sport-specific tasks differentiate between soccer players who go on to anterior cruciate ligament injury and those who do not: a prospective cohort analysis. Int J Sports Phys Ther. 2020; 15(6):928. doi: 10.26603/ijspt20200928.
  13. Musahl V, Karlsson J. Anterior cruciate ligament tear. N Engl J Med. 2019; 380(24):2341-2348. doi: 10.1056/NEJMcp1805931.
  14. Gokeler A, Benjaminse A, Della Villa F, Tosarelli F, Verhagen E, Baumeister J. Anterior cruciate ligament injury mechanisms through a neurocognition lens: implications for injury screening. BMJ Open Sport Exerc Med. 2021; 7(2):e001091. doi:10.1136/bmjsem-2021-001091.
  15. Rodriguez K, Soni M, Joshi PK, et al. Anterior cruciate ligament injury: conservative versus surgical treatment. Cureus. 2021; 13(12).doi:10.7759/cureus.20206.
  16. Rigg JD, Perera NKP, Toohey LA, Cooke J, Hughes D. Anterior cruciate ligament injury occurrence, return to sport and subsequent injury in the Australian High Performance Sports System: A 5-year retrospective analysis. Physical Therapy in Sport. 2023; 64:140-146.
  17. Ahn J, Choi B, Lee YS, Lee KW, Lee JW, Lee BK. The mechanism and cause of anterior cruciate ligament tear in the Korean military environment. Knee Surg Relat Res. 2019; 31:1-5. doi:10.1186/s43019-019-0015-1.
  18. Schram B, Orr R, Pope R. A profile of knee injuries suffered by Australian army reserve soldiers. Int J Environ Res Public Health. 2019; 16(1):12. doi:10.3390/ijerph16010012.
  19. Hosseininejad S-M, Emami Meybodi MK, Raei M, Rahimnia A. Prevalence and mechanisms of anterior cruciate ligament tears in military personnel: A cross-sectional study in Iran. PLoS One. 2024; 19(6):e0303326. doi: 10.1371/journal.pone.0303326.
  20. Schick S, Cantrell CK, Young B, et al. The mechanism of anterior cruciate ligament injuries in the National Football League: a systematic video review. Cureus. 2023; 15(1).doi:10.7759/cureus.34291.
  21. Haddara R, Harandi VJ, Lee PVS. Anterior cruciate ligament agonist and antagonist muscle force differences between males and females during perturbed walking. J Biomech. 2020; 110:109971. doi:10.1016/j.jbiomech.2020.109971.
  22. Wall SJ, Rose DM, Sutter EG, Belkoff SM, Boden BP. The role of axial compressive and quadriceps forces in noncontact anterior cruciate ligament injury: a cadaveric study. Am J Sports Med. 2012; 40(3):568-573. doi:10.1177/0363546511430204.
  23. Boden BP, Sheehan FT. Mechanism of non‐contact ACL injury: OREF Clinical Research Award 2021. J Orthop Res. 2022; 40(3):531-540. doi:10.1002/jor.25257.
  24. Faude O, Junge A, Kindermann W, Dvorak J. Risk factors for injuries in elite female soccer players. Br J Sports Med. 2006; 40(9):785-790. doi:10.1136/bjsm.2006.027540.
  25. Delincé P, Ghafil D. Anterior cruciate ligament tears: conservative or surgical treatment? A critical review of the literature. Knee Surg Sports Traumatol Arthrosc. 2012; 20:48-61. doi:10.1007/s00167-011-1614-x.
  26. Myer GD, Ford KR, Hewett TE. Rationale and clinical techniques for anterior cruciate ligament injury prevention among female athletes. J Athl Train. 2004; 39(4):352.
  27. Myer GD, Ford KR, Foss KDB, Liu C, Nick TG, Hewett TE. The relationship of hamstrings and quadriceps strength to anterior cruciate ligament injury in female athletes. Clin J Sport Med. 2009; 19(1):3-8. doi: 10.1097/JSM.0b013e318190bddb.
  28. Wojtys EM, Brower AM. Anterior cruciate ligament injuries in the prepubescent and adolescent athlete: clinical and research considerations. J Athl Train. 2010; 45(5):509-512. doi: 10.4085/1062-6050-45.5.509.
  29. Tuca M, Valderrama I, Eriksson K, Tapasvi S. Current trends in anterior cruciate ligament surgery. A worldwide benchmark study. J ISAKOS. 2023; 8(1):2-10. doi:10.1016/j.jisako.2022.08.009.
  30. Buerba RA, Boden SA, Lesniak B. Graft selection in contemporary anterior cruciate ligament reconstruction. JAAOS Global Research & Reviews. 2021; 5(10) doi:10.1016/j.eats.2023.02.022.
  31. Snaebjörnsson T, Hamrin-Senorski E, Svantesson E, et al. Graft diameter and graft type as predictors of anterior cruciate ligament revision: a cohort study including 18,425 patients from the Swedish and Norwegian National Knee Ligament Registries. J Bone Joint Surg Am. 2019; 101(20):1812-1820. doi:10.2106/JBJS.18.01467.
  32. Todor A. Graft Choice in Anterior Cruciate Ligament Reconstruction.in: Arthroscopic Surgery - New Perspectives. 1th ed. Stetson WB,eds. IntechOpen ;2024.
  33. Saueressig T, Braun T, Steglich N, et al. Primary surgery versus primary rehabilitation for treating anterior cruciate ligament injuries: a living systematic review and meta-analysis. Br J Sports Med. 2022; 56(21):1241-1251. doi:10.1136/bjsports-2021-105359.
  34. Cheung EC, DiLallo M, Feeley BT, Lansdown DA. Osteoarthritis and ACL Reconstruction-Myths and Risks. Curr Rev Musculoskelet Med. 2020; 13:115-122. doi:10.1007/s12178-019-09596-w.
  35. Etoundi AC, Semasinghe CL, Agrawal S, Dobner A, Jafari A. Bio-inspired knee joint: trends in the hardware systems development. Front Robot AI. 2021; 8:613574. doi:10.3389/frobt.2021.613574.
  36. Guenoun D, Vaccaro J, Le Corroller T, et al. A dynamic study of the anterior cruciate ligament of the knee using an open MRI. Surg Radiol Anat. 2017; 39(3):307-314. doi: 10.1007/s00276-016-1730-x.
  37. Pauzenberger L, Syré S, Schurz M. “Ligamentization” in hamstring tendon grafts after anterior cruciate ligament reconstruction: a systematic review of the literature and a glimpse into the future. Arthroscopy.2013; 29(10):1712-1721. doi:10.1016/j.arthro.2013.05.009.
  38. Claes S, Verdonk P, Forsyth R, Bellemans J. The “ligamentization” process in anterior cruciate ligament reconstruction: what happens to the human graft? A systematic review of the literature. Am J Sports Med. 2011; 39(11):2476-2483. doi:10.1177/0363546511402662.
  39. Scheffler SU, Unterhauser FN, Weiler A. Graft remodeling and ligamentization after cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2008; 16:834-842. doi:10.1007/s00167-008-0560-8.
  40. Howell SM, Clark JA, Blasier RD. Serial magnetic resonance imaging of hamstring anterior cruciate ligament autografts during the first year of implantation: a preliminary study. Am J Sports Med. 1991; 19(1):42-47. doi:10.1177/036354659101900107.
  41. Liu S, Li H, Tao H, Sun Y, Chen S, Chen J. A randomized clinical trial to evaluate attached hamstring anterior cruciate ligament graft maturity with magnetic resonance imaging. Am J Sports Med. 2018; 46(5):1143-1149. doi:10.1177/0363546517752918.
  42. Murray MM, Kalish LA, Fleming BC, et al. Bridge-enhanced anterior cruciate ligament repair: two-year results of a first-in-human study. Orthop J Sports Med. 2019; 7(3):2325967118824356. doi:10.1177/2325967118824356.
  43. Bedi A, Maak T, Musahl V, et al. Effect of tibial tunnel position on stability of the knee after anterior cruciate ligament reconstruction: is the tibial tunnel position most important? The Am J Sports Med. 2011; 39(2):366-373. doi:10.1177/0363546510388157.
  44. Samitier G, Marcano AI, Alentorn-Geli E, Cugat R, Farmer KW, Moser MW. Failure of anterior cruciate ligament reconstruction. Arch Bone Jt Surg. 2015; 3(4):220.
  45. Rahnemai-Azar AA, Sabzevari S, Irarrázaval S, Chao T, Fu FH. Anatomical individualized ACL reconstruction. Arch Bone Jt Surg. 2016; 4(4):291.
  46. Śmigielski R, Zdanowicz U, Drwięga M, Ciszek B, Ciszkowska-Łysoń B, Siebold R. Ribbon like appearance of the midsubstance fibres of the anterior cruciate ligament close to its femoral insertion site: a cadaveric study including 111 knees. Knee Surg Sports Traumatol Arthrosc. 2015; 23:3143-3150. doi:10.1007/s00167-014-3146-7.
  47. Rayan F, Nanjayan SK, Quah C, Ramoutar D, Konan S, Haddad FS. Review of evolution of tunnel position in anterior cruciate ligament reconstruction. World J Orthop. 2015; 6(2):252. doi:10.5312/wjo.v6.i2.252.
  48. Meynard P, Pelet H, Angelliaume A, et al. ACL reconstruction with lateral extra-articular tenodesis using a continuous graft: 10-year outcomes of 50 cases. Orthop Traumatol Surg Res. 2020; 106(5):929-935. doi:10.1016/j.otsr.2020.04.007.
  49. Sonnery-Cottet B, Barbosa NC, Vieira TD, Saithna A. Clinical outcomes of extra-articular tenodesis/anterolateral reconstruction in the ACL injured knee. Knee Surg Sports Traumatol Arthrosc. 2018; 26:596-604. doi:10.1007/s00167-017-4596-5.
  50. Topliss C, Webb J. An audit of tunnel position in anterior cruciate ligament reconstruction. Knee. 2001; 8(1):59-63. doi:10.1016/s0968-0160(01)00067-9.
  51. Andrade R, Pereira R, van Cingel R, Staal JB, Espregueira-Mendes J. How should clinicians rehabilitate patients after ACL reconstruction? A systematic review of clinical practice guidelines (CPGs) with a focus on quality appraisal (AGREE II). Br J Sports Med. 2020; 54(9):512-519. doi:10.1136/bjsports-2018-100310.
  52. Jenkins SM, Guzman A, Gardner BB, et al. Rehabilitation after anterior cruciate ligament injury: Review of current literature and recommendations. Curr Rev Musculoskelet Med. 2022; 15(3):170-179. doi:10.1007/s12178-022-09752-9.
  53. Culvenor AG, Girdwood MA, Juhl CB, et al. Rehabilitation after anterior cruciate ligament and meniscal injuries: a best-evidence synthesis of systematic reviews for the OPTIKNEE consensus. Br J Sports Med. 2022; 56(24):1445-1453. doi:10.1136/bjsports-2022-105495.
  54. Petersen W, Häner M, Guenther D, et al. Management after acute injury of the anterior cruciate ligament (ACL), part 2: management of the ACL-injured patient. Knee Surg Sports Traumatol Arthrosc. 2023; 31(5):1675-1689. doi:10.1007/s00167-022-07260-4.
  55. Noyes FR, Mooar P, Matthews D, Butler D. The symptomatic anterior cruciate-deficient knee. Part I: the long-term functional disability in athletically active individuals. J Bone Joint Surg Am. 1983; 65(2):154-162. doi:10.2106/00004623-198365020-00003.
  56. Button K, van Deursen R, Price P. Classification of functional recovery of anterior cruciate ligament copers, non-copers, and adapters. Br J Sports Med. 2006; 40(10):853-859. doi:10.1136/bjsm.2006.028258.
  57. Group MK. 10 Year Outcomes and Risk Factors after ACL Reconstruction: A MOON Longitudinal Prospective Cohort Study. Am J Sports Med. 2018; 46(4):815. doi:10.1177/0363546517749850.
  58. Costa GG, Perelli S, Grassi A, Russo A, Zaffagnini S, Monllau JC. Minimizing the risk of graft failure after anterior cruciate ligament reconstruction in athletes. A narrative review of the current evidence. Journal of Experimental Orthopaedics. 2022; 9(1):26. doi:Minimizing the risk of graft failure after anterior cruciate ligament reconstruction in athletes. A narrative review of the current evidence. J Exp Orthop.2022; 9(1):26. doi: 10.1186/s40634-022-00461-3.
  59. DeFazio MW, Curry EJ, Gustin MJ, et al. Return to sport after ACL reconstruction with a BTB versus hamstring tendon autograft: a systematic review and meta-analysis. Orthop J Sports Med. 2020; 8(12):2325967120964919. doi:10.1177/2325967120964919.
  60. Blom AW, Donovan RL, Beswick AD, Whitehouse MR, Kunutsor SK. Common elective orthopaedic procedures and their clinical effectiveness: umbrella review of level 1 evidence. BMJ. 2021:374:n1511.doi:10.1136/bmj.n1511.
  61. McGinty JB, Burkhart SS, eds. Operative arthroscopy. 3st ed. Lippincott Williams & Wilkins; 2003.
  62. Giummarra M, Vocale L, King M. Efficacy of non-surgical management and functional outcomes of partial ACL tears. A systematic review of randomised trials. BMC Musculoskelet Disord. 2022; 23(1):332. doi:10.1186/s12891-022-05278-w.
  63. Chellamuthu G, Muthu S, Damodaran UK, Rangabashyam R. “Only 50% of randomized trials have high level of confidence in arthroscopy and sports medicine”—a spin-based assessment. Knee Surg Sports Traumatol Arthrosc. 2021; 29(9):2789-2798. doi:10.1007/s00167-021-06614-8.
  64. Webster KE. Return to sport and reinjury rates in elite female athletes after anterior cruciate ligament rupture. Sports Med. 2021; 51(4):653-660. doi:10.1007/s40279-020-01404-7.
  65. Sanders TL, Maradit Kremers H, Bryan AJ, et al. Incidence of anterior cruciate ligament tears and reconstruction: a 21-year population-based study. Am J Sports Med. 2016; 44(6):1502-1507. doi:10.1177/0363546516629944.
  66. Ball S, Haddad FS. The impact of an acute knee clinic. Ann R Coll Surg Engl. 2010; 92(8):685-688. doi:10.1308/003588410X12771863936684.
  67. Clifford C, Ayre C, Edwards L, Guy S, Jones A. Acute knee clinics are effective in reducing delay to diagnosis following anterior cruciate ligament injury. Knee. 2021; 30:267-274. doi:10.1016/j.knee.2021.04.007.
  68. Joseph AM, Collins CL, Henke NM, Yard EE, Fields SK, Comstock RD. A multisport epidemiologic comparison of anterior cruciate ligament injuries in high school athletics. J Athl Train. 2013; 48(6):810-817. doi:10.4085/1062-6050-48.6.03.
  69. Webster KE, Feller JA. A research update on the state of play for return to sport after anterior cruciate ligament reconstruction. J Orthop Traumatol. 2019; 20(1):1-7. doi:10.1186/s10195-018-0516-9.
  70. Mostafaee N, Negahban H, Shaterzadeh Yazdi MJ, Goharpey S, Mehravar M, Pirayeh N. Responsiveness of a Persian version of Knee Injury and Osteoarthritis Outcome Score and Tegner activity scale in athletes with anterior cruciate ligament reconstruction following physiotherapy treatment. Physiother Theory Pract. 2020; 36(9):1019-1026. doi:10.1080/09593985.2018.1548672.
  71. Randsborg P-H, Adamec D, Cepeda NA, Ling DI. Two-year Recall bias after ACL reconstruction is affected by clinical result. JB JS Open Access. 2021; 6(1) doi:10.2106/JBJS.OA.20.00164.

 

  1. Zadro JR, Pappas E. Time for a different approach to anterior cruciate ligament injuries: educate and create realistic expectations. Sports Med. 2019; 49:357-363. doi:10.1007/s40279-018-0995-0.
  2. Ardern CL, Österberg A, Sonesson S, Gauffin H, Webster KE, Kvist J. Satisfaction with knee function after primary anterior cruciate ligament reconstruction is associated with self-efficacy, quality of life, and returning to the preinjury physical activity. Arthroscopy. 2016; 32(8):1631-1638. e3. doi:10.1016/j.arthro.2016.01.035.
  3. Kocher MS, Steadman JR, Briggs KK, Sterett WI, Hawkins RJ. Relationships between objective assessment of ligament stability and subjective assessment of symptoms and function after anterior cruciate ligament reconstruction. Am J Sports Med. 2004;32(3):629-634. doi:10.1177/0363546503261722.
  4. Bergerson E, Persson K, Svantesson E, et al. Superior outcome of early ACL reconstruction versus initial non-reconstructive treatment with late crossover to surgery: a study from the Swedish National Knee Ligament Registry. Am J Sports Med. 2022; 50(4):896-903. doi:10.1177/03635465211069995.
  5. Davies L, Cook J, Leal J, et al. Comparison of the clinical and cost effectiveness of two management strategies (rehabilitation versus surgical reconstruction) for non-acute anterior cruciate ligament (ACL) injury: study protocol for the ACL SNNAP randomised controlled trial. Trials. 2020; 21:1-16. doi:10.1186/s13063-020-04298-y.
  6. Tashman S, Zandiyeh P, Irrgang JJ, et al. Anatomic single-and double-bundle ACL reconstruction both restore dynamic knee function: a randomized clinical trial—part II: knee kinematics. Knee Surg Sports Traumatol Arthrosc. 2021; 29:2676-2683. doi:10.1007/s00167-021-06479-x.
  7. Kato Y, Ingham SJ, Kramer S, Smolinski P, Saito A, Fu FH. Effect of tunnel position for anatomic single-bundle ACL reconstruction on knee biomechanics in a porcine model. Knee Surg Sports Traumatol Arthrosc. 2010; 18:2-10. doi:10.1007/s00167-009-0916-8.
  8. Mascarenhas R, Cvetanovich GL, Sayegh ET, et al. Does double-bundle anterior cruciate ligament reconstruction improve postoperative knee stability compared with single-bundle techniques? A systematic review of overlapping meta-analyses. Arthroscopy.2015; 31(6):1185-1196. doi:10.1016/j.arthro.2014.11.014.
  9. Boyer J, Meislin RJ. Double-bundle versus single-bundle ACL reconstruction. Bull NYU Hosp Jt Dis. 2010; 68(2):119-26.
  10. Pioger C, Saithna A, Rayes J, et al. Influence of preoperative tunnel widening on the outcomes of a single stage–only approach to every revision anterior cruciate ligament reconstruction: an analysis of 409 consecutive patients from the SANTI study group. Am J Sports Med. 2021; 49(6):1431-1440. doi:10.1177/0363546521996389.
  11. Johnson DH, Maffulli N, King JB, Shelbourne KD. Anterior cruciate ligament reconstruction: a cynical view from the British Isles on the indications for surgery. Arthroscopy. 2003; 19(2):203-209. doi:10.1053/jars.2003.50031.
  12. Frobell RB, Roos EM, Roos HP, Ranstam J, Lohmander LS. A randomized trial of treatment for acute anterior cruciate ligament tears. N Engl J Med. 2010; 363(4):331-342. doi:10.1056/NEJMoa0907797.
  13. Reijman M, Eggerding V, van Es E, et al. Early surgical reconstruction versus rehabilitation with elective delayed reconstruction for patients with anterior cruciate ligament rupture: COMPARE randomised controlled trial. BMJ. 2021:372:n375.doi:10.1136/bmj.n375.
  14. Fleming JD, Ritzmann R, Centner C. Effect of an anterior cruciate ligament rupture on knee proprioception within 2 Years after conservative and operative treatment: A systematic review with meta-analysis. Sports Med. 2022; 52(5):1091-1102. doi:10.1007/s40279-021-01600-z.

 

 

 

 

 

The Archives of Bone and Joint Surgery
Volume 13, Issue 5
May 2025
Pages 249-257

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History

  • Receive Date: 01 January 2024
  • Revise Date: 03 September 2024
  • Accept Date: 08 September 2024

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