Where Are We Now?
Although ACL reconstruction has been successfully performed for the last three decades, only about 60% of patients return to their preinjury levels of activity [9]. Young athletes who return to sports too early or have incorrectly placed graft tunnels have an increased risk of reinjury. Recently, researchers have been exploring the biomechanical role of the anterolateral ligament (ALL), a secondary ligament of the knee that plays a role in rotatory stability. The Segond fracture, frequently observed on plain radiographs in an acute ACL injury, is believed to be a sign of ALL involvement as well [3, 6, 7].
In the current study, Kent III and colleagues investigated ALL function and found that not all ACL-deficient knees benefit from an ALL reconstruction. Their study, similar to a study published earlier this year [2], demonstrated that the clinical function of the ALL varies in different knees in relation to the ACL. While Drews and colleagues [2] show that the ALL plays a role in supporting the ACL to a minor degree, the current study indicates that ALL has function in some cadaveric knees, and as such, supports reconstruction in selected cases.
These findings suggest that surgical decisions, such as joint position and tension at which lateral extraarticular grafts are fixed, should be customized for each patient. Based on the current knowledge, extraarticular grafts may only be needed in revision surgeries.
Where Do We Need To Go?
One of the questions that often vexes researchers is how to translate these results into clinical practice. Although training on cadaveric specimens will help surgeons improve their surgical skills, this is not an option for all facilities. Furthermore, as we see wider use of direct repair of ligaments [10], perhaps a Segond fracture repair could improve the stability to the same degree as an ALL reconstruction. If so, ACL ruptures could then be treated more acutely than current practice.
Clearly, more evidence is needed to further our understanding of how the ALL functions. For example, more clinical data prior to surgery and at long-term followup could help us determine whether revision surgeries improve patient-reported outcomes compared to historical controls after the ALL reconstruction is added to the procedure. Gathering this data will take time because ALL reconstruction is not a common procedure among orthopaedic surgeons. But as we build off of studies like the one from Kent and colleagues, we could see a rise in the amount of data gathered in the near future.
How Do We Get There?
In the meantime, we can carefully investigate ALL reconstruction in knee ligament surgery through the use of existing registries like the Multicenter Orthopaedic Outcomes Network (MOON) [4] and Scandinavian (Denmark, Norway, and Sweden) registries [1, 5, 8]. These registries can provide information on how frequently ALL reconstruction is performed, as well as help us determine whether improved patient-reported outcomes are reported after the introduction of the procedure.
Additionally, researchers who cannot use cadaveric specimens should perform a biomechanical study that reproduces both ACL and ALL injuries along with a Segond fracture. A robotic study could reveal whether the same result in knee kinematics can be achieved with direct repair of a Segond fracture as compared to an ALL reconstruction.
Footnotes
This CORR Insights® is a commentary on the article “High Interspecimen Variability in Engagement of the Anterolateral Ligament: An In Vitro Cadaveric Study” by Kent III and colleagues available at: DOI: 10.1007/s11999-017-5375-9.
The author certifies that neither he, nor any members of his immediate family, have any commercial associations (such as consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article.
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research ® editors and board members are on file with the publication and can be viewed on request.
The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR ® or The Association of Bone and Joint Surgeons®.
This CORR Insights® comment refers to the article available at DOI: 10.1007/s11999-017-5375-9.
References
- 1.Danish Knee Arthroplasty Registry. Background. Available at: http://www.kea.au.dk/en/Research/ResearchProgrammes/Background.html. Accessed June 5, 2017.
- 2.Drews BH, Kessler O, Franz W, Durselen L, Freutel M. Function and strain of the anterolateral ligament part I: Biomechanical analysis. Knee Surg Sports Traumatol Arthrosc. 2017;25:1132–1139. doi: 10.1007/s00167-017-4472-3. [DOI] [PubMed] [Google Scholar]
- 3.Inderhaug E, Stephen JM, Williams A, Amis AA. Biomechanical comparison of anterolateral procedures combined with anterior cruciate ligament reconstruction. Am J Sports Med. 2017;45:347–354. doi: 10.1177/0363546516681555. [DOI] [PubMed] [Google Scholar]
- 4.Lynch TS, Parker RD, Patel RM, Andrish JT; MOON Group, Spindler KP, Amendola A, Brophy RH, Dunn WR, Flanigan DC, Huston LJ, Jones MH, Kaeding CC, Marx RG, Matava MJ, McCarty EC, Pedroza AD, Reinke EK, Wolf BR, Wright RW. The impact of the Multicenter Orthopaedic Outcomes Network (MOON) research on anterior cruciate ligament reconstruction and orthopaedic practice. [DOI] [PMC free article] [PubMed]
- 5.Norwegian Arthroplasty Register. Cruciate ligament. Available at: http://nrlweb.ihelse.net/eng/#. Accessed June 5, 2017.
- 6.Sonnery-Cottet B, Daggett M, Fayard JM, Ferretti A, Helito CP, Lind M, Monaco E, de Pádua VBC, Thaunat M, Wilson A, Zaffagnini S, Zijl J, Claes S. Anterolateral ligament expert group consensus paper on the management of internal rotation and instability of the anterior cruciate ligament - deficient knee. J Orthop Traumatol. 2017;18:91–106. doi: 10.1007/s10195-017-0449-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Stuyts B, Van den Eeden E, Victor J. A new reconstructive technique of the anterolateral ligament with iliotibial band-strip. Open Orthop J. 2017;11:321–326. doi: 10.2174/1874325001711010321. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.The Swedish Knee Arthroplasty Register. About. Available at: http://www.myknee.se/en/about. Accessed June 5, 2017.
- 9.Webster KE, Feller JA, Whitehead TS, Myer GD, Merory PB. Return to sport in the younger patient with anterior cruciate ligament reconstruction. Orthop J Sports Med. 2017;5:2325967117703399. doi: 10.1177/2325967117703399. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Wilson WT, Hopper GP, Byrne PA, MacKay GM. Anterior cruciate ligament repair with internal brace ligament augmentation. Surg Technol Int. 2016;29:273–278. [PubMed] [Google Scholar]