Influence of the Anterolateral Ligament on Knee Laxity: A Biomechanical Cadaveric Study Measuring Knee Kinematics in 6 Degrees of Freedom Using Dynamic Radiostereometric Analysis

Abstract

Background:An anterior cruciate ligament (ACL) rupture often occurs during rotational trauma to the knee and may be associated with damage to extracapsular knee rotation–stabilizing structures such as the anterolateral ligament (ALL).Purpose:To investigate ex vivo knee laxity in 6 degrees of freedom with and without ALL reconstruction as a supplement to ACL reconstruction.Study Design:Controlled laboratory study.Methods:Cadaveric knees (N = 8) were analyzed using dynamic radiostereometry during a controlled pivotlike dynamic movement simulated by motorized knee flexion (0° to 60°) with 4-N·m internal rotation torque. We tested the cadaveric specimens in 5 successive ligament situations: intact, ACL lesion, ACL + ALL lesion, ACL reconstruction, and ACL + ALL reconstruction. Anatomic single-bundle reconstruction methods were used for both the ACL and the ALL, with a bone-tendon quadriceps autograft and gracilis tendon autograft, respectively. Three-dimensional kinematics and articular surface interactions were used to determine knee laxity.Results:For the entire knee flexion motion, an ACL + ALL lesion increased the mean knee laxity (P < .005) for internal rotation (2.54°), anterior translation (1.68 mm), and varus rotation (0.53°). Augmented ALL reconstruction reduced knee laxity for anterior translation (P = .003) and varus rotation (P = .047) compared with ACL + ALL–deficient knees. Knees with ACL + ALL lesions had more internal rotation (P < .001) and anterior translation (P < .045) at knee flexion angles below 40° and 30°, respectively, compared with healthy knees. Combined ACL + ALL reconstruction did not completely restore native kinematics/laxity at flexion angles below 10° for anterior translation and below 20° for internal rotation (P < .035). ACL + ALL reconstruction was not found to overconstrain the knee joint.Conclusion:Augmented ALL reconstruction with ACL reconstruction in a cadaveric setting reduces internal rotation, varus rotation, and anterior translation knee laxity similar to knee kinematics with intact ligaments, except at knee flexion angles between 0° and 20°.Clinical Relevance:Patients with ACL injuries can potentially achieve better results with augmented ALL reconstruction along with ACL reconstruction than with stand-alone ACL reconstruction. Furthermore, dynamic radiostereometry provides the opportunity to examine clinical patients and compare the recontructed knee with the contralateral knee in 6 degrees of freedom.

Biomechanical Effects of Combined Anterior Cruciate Ligament Reconstruction and Anterolateral Ligament Reconstruction: A Systematic Review and Meta-analysis

“…Schon et al 29 looked at 7 different graft fixation angles from 0 to 90 with 88 N of tension and found that there was no difference in knee kinematics based on fixation angle, but they did note overconstraint at all fixation angles. Geeslin et al 11 also noted overconstraint at differing fixation angles, even with lower graft tensions of 20 N and 40 N, which is in contrast to multiple studies 5,15,16,23,30 that showed no overconstraint at lower fixation tensions. Although the clinical relevance of overconstraint remains to be determined, a way to prevent it may be to perform ALLR at lower fixation angles and tensions.…”

“…Although there have been clinical studies 5 , 7 , 8 , 17 , 29 , 32 that support combined reconstruction, there are biomechanical studies that do and do not recommend a combined approach. 11 , 15 , 16 , 23 , 29 , 30 The purpose of this study was to perform a systematic review and meta-analysis of biomechanical data to evaluate the kinematic changes of a combined ACLR/ALLR compared with isolated ACLR as well as to assess the effects of different fixation techniques.…”

Udružena rekonstrukcija prednjeg križnog i anterolateralnog ligamenta koljena

“…Smatra se da udružena rekonstrukcija ACL-a i ALL-a sprječava pojavu rotacijske nestabilnosti i pridonosi ukupno boljoj stabilnosti koljena 20,21 . Iako su u studiji rađenoj na kadaverima Schon i suradnici upozorili na mogući rizik od prekomjernog ograničenja unutarnje rotacije koljena nakon rekonstrukcije ALL-a, takve su tvrdnje nedavno osporene dokazom da rekonstrukcija ALL-a ne dovodi do prekomjernog opterećenja zgloba koljena 20,22,23 . Značajna razlika u odnosu na tehnike koje su se upotrebljavale 1990-ih godina u današnjoj tehnici rekonstrukcije ACL-a i ALL-a je u pozicioniranju ALL-ova tunela na bedrenoj kosti (slika 3) i fiksaciji ALL-presatka u punoj ekstenziji koljena i neutralnoj rotaciji potkoljenice, što smanjuje mogućnost razvoja komplikacija i neželjenih ishoda 5 .…”

“…Također je pokazano i da je udružena rekonstrukcija ACL-a i ALL-a povezana sa znatno većom vjerojatnošću povratka na istu razinu sportske aktivnosti kao i prije ozljede 24 . Prevelika napetost presatka ALL-a i dalje predstavlja izvor rasprava, ali se pokazalo da rekonstrukcija ALL-a, s položajem fiksacije neposredno proksimalno i straga u odnosu na lateralni epikondil bedrene kosti i zatezanjem u punoj ekstenziji koljena, može vratiti normalnu kinematiku koljena bez dodatnog opterećenja na lateralni odjeljak koljena 23 . Važno je napomenuti da udružena rekonstrukcija ALL-a uz rekonstrukciju ACL-a ne povećava rizik od postoperativnih komplikacija.…”

Assessment of knee kinematics with dynamic radiostereometry: Validation of an automated model‐based method of analysis using bone models

“…Condition-numbers ensured a high-quality MM reference. We used previously validated methods of placing ACS based on bone geometry 24,32. Results from theBM are expressed in clinically relevant terms through inheritance use of ACS.…”