Is an Anterolateral Ligament Reconstruction Required in ACL-Reconstructed Knees With Associated Injury to the Anterolateral Structures? A Robotic Analysis of Rotational Knee Stability

2017 ◽  
Vol 45 (5) ◽  
pp. 1018-1027 ◽  
Author(s):  
Frank R. Noyes ◽  
Lauren E. Huser ◽  
Darin Jurgensmeier ◽  
James Walsh ◽  
Martin S. Levy

Background: The effect of an anterolateral ligament (ALL) reconstruction on rotational knee stability and corresponding anterior cruciate ligament (ACL) graft forces using multiple knee loading conditions including the pivot-shift phenomenon has not been determined. Purpose: First, to determine the rotational stability and ACL graft forces provided by an anatomic bone–patellar tendon–bone ACL reconstruction in the ACL-deficient knee alone and with an associated ALL/iliotibial band (ITB) injury. Second, to determine the added rotational stabilizing effect and reduction in ACL graft forces provided by an ALL reconstruction. Study Design: Controlled laboratory study. Methods: A 6 degrees of freedom robotic simulator was used to test 7 fresh-frozen cadaveric specimens during 5 testing conditions: intact, ACL-sectioned, ACL-reconstructed, ALL/ITB-sectioned, and ALL-reconstructed. Lateral and medial tibiofemoral compartment translations and internal tibial rotations were measured under Lachman test conditions, 5-N·m internal rotation, and 2 pivot-shift simulations. Statistical equivalence within 2 mm and 2° was defined as P < .05. Results: Single-graft ACL reconstruction restored central tibial translation under Lachman testing and internal rotation under 5-N·m internal rotation torque ( P < .05). A modest increase in internal rotation under 5-N·m internal rotation torque occurred after ALL/ITB sectioning of 5.1° (95% CI, 3.6° to 6.7°) and 6.7° (95% CI, 4.3° to 9.1°) at 60° and 90° of flexion, respectively ( P = .99). Lateral compartment translation increases in the pivot-shift tests were <2 mm. ALL reconstruction restored internal rotation within 0.5° (95% CI, –1.9° to 2.9°) and 0.7° (95% CI, –2.0° to 3.4°) of the ACL-reconstructed state at 60° and 90° of flexion, respectively ( P < .05). The ALL procedure reduced ACL graft forces, at most, 75 N in the pivot-shift tests and 81 N in the internal rotation tests. Conclusion: Although the ALL reconstruction corrected the small abnormal changes in the internal rotation limit at high flexion angles, the procedure had no effect in limiting tibiofemoral compartment translations in the pivot-shift test and produced only modest decreases in ACL graft forces. Accordingly, the recommendation to perform an ALL reconstruction to correct pivot-shift abnormalities is questioned. Clinical Relevance: The small changes in rotational stability after ALL/ITB sectioning would not seem to warrant the routine addition of an ALL reconstruction in primary ACL injuries. Clinical exceptions may exist, as in grossly unstable grade 3 pivot-shift knees and revision knees. However, the concern exists of overconstraining normal tibial rotations.

2018 ◽  
Vol 46 (4) ◽  
pp. 839-845 ◽  
Author(s):  
Mark D. Porter ◽  
Bruce Shadbolt ◽  
Samantha Pomroy

Background: Iliotibial band (ITB) tenodesis improves stability and functional outcomes when added to anterior cruciate ligament (ACL) reconstruction. Its precise indications are unknown. Persistence of the pivot shift after revision ACL reconstruction may be one indication. Hypothesis: The addition of ITB tenodesis for a persistent pivot shift after revision ACL reconstruction will improve stability and activity levels. Study Design: Cohort study; Level of evidence, 2. Methods: Adults with recurrent ACL ruptures underwent revision ACL reconstruction, followed by a pivot-shift test before the surgery ended. If the pivot shift was grade 0 or 1, no further surgery was performed (group 1). If it was grade 2 or 3, ITB tenodesis was performed (group 2). The pivot-shift test was performed, graded, and measured using computer navigation before revision ACL reconstruction and after revision ACL reconstruction with and without ITB tenodesis. Tegner activity scores were obtained 2 years after surgery. Groups were compared with regard to anterior translation and internal rotation during the pivot shift as well as Tegner activity scores ( P < .05). Results: There were 20 patients in group 1 and 18 in group 2. The mean anterior translation improved in group 1, from 17.7 ± 3.5 mm to 6.6 ± 1.9 mm, and group 2, from 18.5 ± 3.3 mm to 6.1 ± 1.2 mm, after revision ACL reconstruction ( P < .001), with no difference between the groups ( P = .15). After ITB tenodesis, the reduction in anterior translation in group 2 (5.3 ± 1.5 mm) became greater than that in group 1 (6.6 ± 1.9 mm) ( P = .03). In both groups after revision ACL reconstruction, there was a reduction in internal rotation (group 1: 24.2° ± 4.0° to 10.3° ± 1.1°; group 2: 25.4° ± 3.7° to 14.6° ± 2.8°; P < .001), but this change was less in group 2 ( P = .02). After ITB tenodesis, internal rotation in group 2 (8.3° ± 2.6°) became less than that in group 1 (10.3° ± 1.1°) ( P = .02). The mean Tegner activity scores in group 1 were 8.1 ± 1.1 before surgery and 7.4 ± 0.9 after surgery, while in group 2 they were 7.0 ± 1.3 and 7.2 ± 0.4, respectively, and not significantly different ( P = .29). Conclusion: ITB tenodesis improved laxity, although it did not affect activity levels, when there was a persistent pivot shift after revision ACL reconstruction. Clinical Relevance: An indication to perform ITB tenodesis is the persistence of a grade ≥2 pivot shift after revision ACL reconstruction.


2017 ◽  
Vol 46 (3) ◽  
pp. 607-616 ◽  
Author(s):  
Andrew G. Geeslin ◽  
Gilbert Moatshe ◽  
Jorge Chahla ◽  
Bradley M. Kruckeberg ◽  
Kyle J. Muckenhirn ◽  
...  

Background: Persistent clinical instability after anterior cruciate ligament (ACL) reconstruction may be associated with injury to the anterolateral structures and has led to renewed interest in anterolateral extra-articular procedures. The influence of these procedures on knee kinematics is controversial. Purpose/Hypothesis: The purpose was to investigate the biomechanical properties of anatomic anterolateral ligament (ALL) reconstruction and a modified Lemaire procedure (lateral extra-articular tenodesis [LET]) in combination with ACL reconstruction as compared with isolated ACL reconstruction in the setting of deficient anterolateral structures (ALL and Kaplan fibers). It was hypothesized that both techniques would reduce tibial internal rotation when combined with ACL reconstruction in the setting of anterolateral structure deficiency. Study Design: Controlled laboratory study. Methods: A 6 degrees of freedom robotic system was used to assess tibial internal rotation, a simulated pivot-shift test, and anterior tibial translation in 10 paired fresh-frozen cadaveric knees. The following states were tested: intact; sectioned ACL, ALL, and Kaplan fibers; ACL reconstruction; and an anterolateral extra-articular procedure (various configurations of ALL reconstruction and LET). Knees within a pair were randomly assigned to either ALL reconstruction or LET with a graft tension of 20 N and a randomly assigned fixation angle (30° or 70°). ALL reconstruction was then repeated and secured with a graft tension of 40 N. Results: In the setting of deficient anterolateral structures, ACL reconstruction was associated with significantly increased residual laxity for tibial internal rotation (up to 4°) and anterior translation (up to 2 mm) laxity as compared with the intact state. The addition of ALL reconstruction or LET after ACL reconstruction significantly reduced tibial internal rotation in most testing scenarios to values lower than the intact state (ie, overconstraint). Significantly greater reduction in laxity with internal rotation and pivot-shift testing was found with the LET procedure than ALL reconstruction when compared with the intact state. Combined with ACL reconstruction alone, both extra-articular procedures restored anterior tibial translation to values not significantly different from the intact state with most testing scenarios (usually within 1 mm). Conclusion: Residual laxity was identified after isolated ACL reconstruction in the setting of ALL and Kaplan fiber deficiency, and the combination of ACL reconstruction in this setting with either ALL reconstruction or the modified Lemaire LET procedure resulted in significant reductions in tibiofemoral motion at most knee flexion angles, although overconstraint was also identified. ALL reconstruction and LET restored anterior tibial translation to intact values with most testing states. Clinical Relevance: ALL reconstruction and lateral extra-articular tenodesis have been described in combination with intra-articular ACL reconstruction to address rotational laxity. This study demonstrated that both procedures resulted in significant reductions of tibial internal rotation versus the intact state independent of graft tension or fixation angle, although anterior tibial translation was generally restored to intact values. The influence of overconstraint with anterolateral knee reconstruction procedures has not been fully evaluated in the clinical setting and warrants continued evaluation based on the findings of this biomechanical study.


Author(s):  
Ryan P. Roach ◽  
David P. Beason ◽  
Jonathan S. Slowik ◽  
A. Ryves Moore ◽  
Ajay C. Lall ◽  
...  

AbstractInjuries to the anterolateral ligament (ALL) of the knee are commonly associated with anterior cruciate ligament (ACL) ruptures. Biomechanical studies have demonstrated conflicting results with regard to the role of the ALL in limiting tibial internal rotation. Clinically, residual pivot shift following ACL reconstruction has been reported to occur up to 25% and has been correlated with poor outcomes. As such, surgical techniques have been developed to enhance rotational stability. Recent biomechanical studies have demonstrated restoration of internal rotational control following ALL reconstruction. The purpose of our study was to understand the biomechanical effects of ACL reconstruction with an ALL internal brace augmentation. We hypothesized that (1) sectioning of the ALL while preserving other lateral extra-articular structures would lead to significant internal rotation laxity and gap formation and (2) ALL repair with internal brace augmentation would lead to reduction in internal rotation instability and gap formation. In total, 10 fresh-frozen cadaveric knees were thawed and biomechanically tested in internal rotation for 10 cycles of normal physiologic torque in the intact, ACL-deficient, ACL/ALL-deficient, ACL-reconstructed, and ALL-repaired conditions. Each condition was tested at 30, 60, and 90 degrees of flexion. Following the final ALL-repaired condition, specimens were additionally subjected to a final internal rotation to failure at 1 degree at the last-tested degree of flexion. Kinematic measurements of angle and linear gap between the femur and tibia were calculated in addition to torsional stiffness and failure torque. As hypothesized, ALL repair with internal brace augmentation significantly reduced internal rotation angular motion and gap formation at flexion angles greater than 30 degrees. Additionally, ALL sectioning produced nonsignificant increases in internal rotation laxity and gap formation compared with ACL-deficient and ACL-reconstructed states, which did not support our other hypothesis.


2018 ◽  
Vol 46 (10) ◽  
pp. 2422-2431 ◽  
Author(s):  
Nicholas N. DePhillipo ◽  
Gilbert Moatshe ◽  
Alex Brady ◽  
Jorge Chahla ◽  
Zachary S. Aman ◽  
...  

Background: Ramp lesions were initially defined as a tear of the peripheral attachment of the posterior horn of the medial meniscus at the meniscocapsular junction. The separate biomechanical roles of the meniscocapsular and meniscotibial attachments of the posterior medial meniscus have not been fully delineated. Purpose: To evaluate the biomechanical effects of meniscocapsular and meniscotibial lesions of the posterior medial meniscus in anterior cruciate ligament (ACL)–deficient and ACL-reconstructed knees and the effect of repair of ramp lesions. Study Design: Controlled laboratory study. Methods: Twelve matched pairs of human cadaveric knees were evaluated with a 6 degrees of freedom robotic system. All knees were subjected to an 88-N anterior tibial load, internal and external rotation torques of 5 N·m, and a simulated pivot-shift test of 10-N valgus force coupled with 5-N·m internal rotation. The paired knees were randomized to the cutting of either the meniscocapsular or the meniscotibial attachments after ACL reconstruction (ACLR). Eight comparisons of interest were chosen before data analysis was conducted. Data from the intact state were compared with data from the subsequent states. The following states were tested: intact (n = 24), ACL deficient (n = 24), ACL deficient with a meniscocapsular lesion (n = 12), ACL deficient with a meniscotibial lesion (n = 12), ACL deficient with both meniscocapsular and meniscotibial lesions (n = 24), ACLR with both meniscocapsular and meniscotibial lesions (n = 16), and ACLR with repair of both meniscocapsular and meniscotibial lesions (n = 16). All states were compared with the previous states. For the repair and reconstruction states, only the specimens that underwent repair were compared with their intact and sectioned states, thus excluding the specimens that did not undergo repair. Results: Cutting the meniscocapsular and meniscotibial attachments of the posterior horn of the medial meniscus significantly increased anterior tibial translation in ACL-deficient knees at 30° ( P ≤ .020) and 90° ( P < .005). Cutting both the meniscocapsular and meniscotibial attachments increased tibial internal (all P > .004) and external (all P < .001) rotation at all flexion angles in ACL-reconstructed knees. Reconstruction of the ACL in the presence of meniscocapsular and meniscotibial tears restored anterior tibial translation ( P > .053) but did not restore internal rotation ( P < .002), external rotation ( P < .002), and the pivot shift ( P < .05). To restore the pivot shift, an ACLR and a concurrent repair of the meniscocapsular and meniscotibial lesions were both necessary. Repairing the meniscocapsular and meniscotibial lesions after ACLR did not restore internal rotation and external rotation at angles >30°. Conclusion: Meniscocapsular and meniscotibial lesions of the posterior horn of the medial meniscus increased knee anterior tibial translation, internal and external rotation, and the pivot shift in ACL-deficient knees. The pivot shift was not restored with an isolated ACLR but was restored when performed concomitantly with a meniscocapsular and meniscotibial repair. However, the effect of this change was minimal; although statistical significance was found, the overall clinical significance remains unclear. The ramp lesion repair used in this study failed to restore internal rotation and external rotation at higher knee flexion angles. Further studies should examine improved meniscus repair techniques for root tears combined with ACLRs. Clinical Relevance: Meniscal ramp lesions should be repaired at the time of ACLR to avoid continued knee instability (anterior tibial translation) and to eliminate the pivot-shift phenomenon.


2020 ◽  
Vol 8 (5) ◽  
pp. 232596712091767 ◽  
Author(s):  
Kazuhisa Hatayama ◽  
Masanori Terauchi ◽  
Kenichi Saito ◽  
Ryota Takase ◽  
Hiroshi Higuchi

Background: Although the biomechanical importance of the ramp lesion in the anterior cruciate ligament (ACL)–deficient knee has been demonstrated, there is no clear consensus on the appropriate treatment for ramp lesions during ACL reconstruction. Purpose: To compare the postoperative outcomes for ramp lesions between patients treated with all-inside repair through the posteromedial portal and those whose ramp lesions were left in situ without repair during ACL reconstruction. We also determined whether ramp lesion healing status affected postoperative knee stability. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 57 patients who underwent anatomic double-bundle ACL reconstruction between August 2011 and December 2017 had attendant ramp lesions. Of these, 25 ramp lesions that were considered stable were left in situ without repair (Nonrepaired group), and 25 ramp lesions, including 21 stable and 4 unstable lesions, were treated using all-inside repair through the posteromedial portal (Repaired group). We evaluated the side-to-side difference (SSD) in anterior tibial translation on stress radiographs and rotational stability by using the pivot-shift test 2 years after surgery, and healing status of the ramp lesions was evaluated on 3.0-T magnetic resonance imaging (MRI) scans 1 year after surgery. Results: The mean SSDs in anterior translation were 2.4 ± 1.6 mm for the Nonrepaired group and 1.9 ± 1.6 mm for the Repaired group, with no significant differences. The positive ratios on the pivot-shift test were not significantly different between groups. Healing rates of ramp lesions on MRI scans showed a significant difference between the Nonrepaired group (60%) and the Repaired group (100%) ( P = .001). The mean SSDs for knees in which the ramp lesion had healed as shown on MRI scans and those in which it had not healed were 1.9 ± 1.6 mm and 3.2 ± 1.1 mm, respectively, which was a significant difference ( P = .02). Conclusion: Healing rates of ramp lesions were significantly better in the Repaired group than in the Nonrepaired group, although postoperative knee stability was not significantly different between groups. Anterior laxity in the knees in which the ramp lesion was unhealed was significantly greater compared with the knees in which the ramp lesion healed. All-inside repair through the posteromedial portal was a reliable surgical procedure to heal ramp lesions.


2018 ◽  
Vol 6 (12) ◽  
pp. 232596711881106 ◽  
Author(s):  
Joseph S. Tramer ◽  
Mohsin S. Fidai ◽  
Omar Kadri ◽  
Toufic R. Jildeh ◽  
Zamaan Hooda ◽  
...  

Background: A proposed mechanism for recurrent instability following anterior cruciate ligament (ACL) reconstruction is failure of the anterolateral ligament (ALL). Presently, there are a number of approaches to treating ALL pathology. Purpose: To determine practice patterns among orthopaedic surgeons regarding ALL during ACL reconstruction. Study Design: Cross-sectional study. Methods: An online 7-question survey was sent to all physicians registered with the American Orthopaedic Society for Sports Medicine between June and July 2017. Results were analyzed with the survey website. Results: Overall, 225 of 3467 surgeons responded to the survey, 86 of whom performed ALL reconstruction and completed each question in the survey. Eighty-six (38.2%) surgeons who responded to the questionnaire stated that they perform ALL reconstruction/lateral extra-articular tenodesis in conjunction with ACL reconstruction. The most common indications for ALL reconstruction were grade III pivot-shift test (46.0%) on physical examination and revision ACL reconstruction (46.0%). The most common technique used to perform ALL reconstruction was hamstring autograft (48.2%). The majority of participating surgeons (87.5%) stated that they do not make any alterations to their postoperative rehabilitation protocol after they perform ALL reconstruction. In addition, most surgeons responding to the survey (91.3%) anticipated either an increase in or the same number of ALL procedures performed in the coming year. Conclusion: The majority of surgeons who responded to the survey did not routinely reconstruct the ALL. Revision procedures and grade III pivot shift were the most cited indications for performing lateral augmentation. Anatomic reconstruction with hamstring was the most commonly used procedure, although there was no consensus among surgeons responding to the survey. Understanding the ALL and its contribution to knee stability is essential. For a community of physicians, it is useful to discover how fellow sports orthopaedic surgeons address ALL pathology to integrate effective and efficient treatment strategies into practice.


2019 ◽  
Vol 28 (7) ◽  
pp. 2139-2146 ◽  
Author(s):  
Tomas Söderman ◽  
Marie-Louise Wretling ◽  
Mari Hänni ◽  
Christina Mikkelsen ◽  
Robert J. Johnson ◽  
...  

Abstract Purpose The aim was to assess the results of anterior cruciate ligament (ACL) reconstruction regarding graft failure, knee laxity, and osteoarthritis (OA) from a longterm perspective. It was hypothesized that intact ACL graft reduces the risk for increased OA development. Methods The cohort comprised 60 patients with a median follow-up 31 (range 28–33) years after ACL reconstruction. They were evaluated with magnetic resonance imaging, radiography, KT-1000 arthrometer and the pivot shift test. Results Out of the 60 patients, 30 (50%) showed an intact ACL graft and 30 (50%) a ruptured or absent ACL graft. Patients with ruptured ACL grafts had more medial tibiofemoral compartment OA than those with an intact ACL graft (p = 0.0003). OA was asymmetric in patients with ruptured ACL grafts with more OA in the medial than in the lateral tibiofemoral compartment (p = 0.013) and the patellofemoral compartment (p = 0.002). The distribution of OA between compartments was similar in patients with an intact ACL graft. KT-1000 values of anterior knee laxity were higher in patients with ruptured compared to those with intact ACL grafts (p = 0.012). Side-to-side comparisons of anterior knee laxity showed higher KT-1000 values in patients with ruptured ACL graft (p = 0.0003) and similar results in those with intact graft (p = 0.09). The pivot shift grade was higher in the group with a ruptured ACL graft (p < 0.0001). Conclusions Median 31 (range 28–33) years after ACL reconstruction, 50% of the patients showed an intact ACL graft and no side-to-side difference regarding anterior knee laxity. Patients with ruptured ACL grafts had more OA of the medial tibiofemoral compartment than those with intact ACL grafts. Level of evidence Retrospective cohort study, Level III.


2019 ◽  
Vol 7 (5_suppl3) ◽  
pp. 2325967119S0020
Author(s):  
Thomas Neri ◽  
Antoine Lamotte ◽  
Tommaso Bonanzinga ◽  
Frederic Farizon ◽  
Remi Philippot

Objectives: The objective of this study was to compare the use of a laximeter and a triaxial accelerometer, for Anterolateral ligament injury diagnosis of in ACL deficient knee. We hypothesized that a triaxial accelerometer was more effective than a laximeter. Methods: A total of 11 cadaver knees were studied according to a new conservative dissection protocol without damage to the lateral structures. A GnRB® laximeter (Genourob, France) was used to determine anterior tibial translation (AP) of the tibia. Simultaneously, a KiRA® triaxial accelerometer (Kinetic Rapid Assessment) (OrthoKey, Italy) was used to determine two parameters: the AP translation and the Pivot Shift (PS). For each knee, 5 conditions were successively applied: intact knee (intact), knee with ALL (ALLsec) isolated section, knee with ALL and ACL section (ALL + ACLsec). Results: For the laximeter, the ACL and ALL sections led to a significant AP translation increase: + 2.1 mm for the ACL section, and + 0.9 mm for the ALL section. This difference was significant regardless of the level of force applied (p <0.05). For the triaxial accelerometer, the ACL and the ALL sections led to a significant AP translation increase: + 2.8 mm for ACL, and + 1.5 mm for ALL section. In contrast, for the PS, the increase was more consistent. There was a multiplier factor between the ACLsec condition and the ACL + ALLsec condition comparable to that between the intact condition and the ACLsec condition (P> 0.05). Conclusion: Whatever the device, the AP translation difference induced by the ALL injury, of the order of mm, remains too small to make the diagnosis of an ALL injury. The evaluation of the AP translation is therefore not a relevant to diagnostic an ALL injury. With greater increase, the evaluation of the rotatory laxity, through the PS test, is more relevant. In current practice, there is no clinical interest to use a laximeter or accelerometer on AP translation assessment to diagnosis an ALL injury in a deficient ACL knee. On the other hand, the use of a triaxial accelerometer to quantify the lateral tibial plateau acceleration in the pivot shift test appears to be relevant for detecting an ALL injury on a deficient ACL knee. These findings help provide clinical guidelines for more effective objective measures to diagnose ALL injury, and determine the most effective management for each patient.


2021 ◽  
pp. 036354652110417
Author(s):  
Tomomasa Nakamura ◽  
Brandon D. Marshall ◽  
Taylor M. Price ◽  
Yongtao Mao ◽  
Monica A. Linde ◽  
...  

Background: A lateral meniscal (LM) disorder is one factor that causes rotational laxity after anterior cruciate ligament (ACL) reconstruction (ACLR). There are different types of irreparable meniscal disorders, one of which is a massive meniscal defect. Hypothesis/Purpose: The purpose of this study was to evaluate the kinematic effects of arthroscopic centralization on an irreparable LM defect. The hypothesis was that arthroscopic centralization for an irreparable LM defect with concomitant ACLR would improve knee rotational stability. Study Design: Controlled laboratory study. Methods: A total of 14 fresh-frozen human cadaveric knees were tested in 4 states: (1) intact ACL and intact lateral meniscus, (2) reconstructed ACL and intact lateral meniscus, (3) reconstructed ACL and lateral meniscus defect, and (4) reconstructed ACL and centralized lateral meniscus. Anatomic ACLR was performed using an 8 mm–diameter hamstring tendon graft. An LM defect (20% of the anteroposterior length) was created arthroscopically, and arthroscopic centralization was performed. Kinematics were analyzed using a 6 degrees of freedom robotic system under 4 knee loads: (1) an 89.0-N anterior tibial load, (2) a 5.0-N·m external rotation tibial torque, (3) a 5.0-N·m internal rotation tibial torque, and (4) a simulated pivot-shift load with a combined 7.0-N·m valgus and 5.0-N·m internal rotation tibial torque. Results: LM centralization reduced anterior tibial translation similar to that of the ACLR intact LM state under anterior tibial loading (~2 mm at 30° of flexion) and showed 40% to 100% of tibial displacement in the 4 knee states under simulated pivot-shift loading. The procedure overconstrained the knee under internal rotation tibial torque and simulated pivot-shift loading. Conclusion: Arthroscopic centralization reduced knee laxity after ACLR for a massive LM defect in a cadaveric model. Clinical Relevance: In cases involving irreparable LM injuries during ACLR, consideration should be given to arthroscopic centralization for reducing knee laxity. However, the procedure may overconstrain the knee in certain motions.


2018 ◽  
Vol 46 (6) ◽  
pp. 1352-1361 ◽  
Author(s):  
Andrew G. Geeslin ◽  
Jorge Chahla ◽  
Gilbert Moatshe ◽  
Kyle J. Muckenhirn ◽  
Bradley M. Kruckeberg ◽  
...  

Background: The individual kinematic roles of the anterolateral ligament (ALL) and the distal iliotibial band Kaplan fibers in the setting of anterior cruciate ligament (ACL) deficiency require further clarification. This will improve understanding of their potential contribution to residual anterolateral rotational laxity after ACL reconstruction and may influence selection of an anterolateral extra-articular reconstruction technique, which is currently a matter of debate. Hypothesis/Purpose: To compare the role of the ALL and the Kaplan fibers in stabilizing the knee against tibial internal rotation, anterior tibial translation, and the pivot shift in ACL-deficient knees. We hypothesized that the Kaplan fibers would provide greater tibial internal rotation restraint than the ALL in ACL-deficient knees and that both structures would provide restraint against internal rotation during a simulated pivot-shift test. Study Design: Controlled laboratory study. Methods: Ten paired fresh-frozen cadaveric knees (n = 20) were used to investigate the effect of sectioning the ALL and the Kaplan fibers in ACL-deficient knees with a 6 degrees of freedom robotic testing system. After ACL sectioning, sectioning was randomly performed for the ALL and the Kaplan fibers. An established robotic testing protocol was utilized to assess knee kinematics when the specimens were subjected to a 5-N·m internal rotation torque (0°-90° at 15° increments), a simulated pivot shift with 10-N·m valgus and 5-N·m internal rotation torque (15° and 30°), and an 88-N anterior tibial load (30° and 90°). Results: Sectioning of the ACL led to significantly increased tibial internal rotation (from 0° to 90°) and anterior tibial translation (30° and 90°) as compared with the intact state. Significantly increased internal rotation occurred with further sectioning of the ALL (15°-90°) and Kaplan fibers (15°, 60°-90°). At higher flexion angles (60°-90°), sectioning the Kaplan fibers led to significantly greater internal rotation when compared with ALL sectioning. On simulated pivot-shift testing, ALL sectioning led to significantly increased internal rotation and anterior translation at 15° and 30°; sectioning of the Kaplan fibers led to significantly increased tibial internal rotation at 15° and 30° and anterior translation at 15°. No significant difference was found when anterior tibial translation was compared between the ACL/ALL- and ACL/Kaplan fiber–deficient states on simulated pivot-shift testing or isolated anterior tibial load. Conclusion: The ALL and Kaplan fibers restrain internal rotation in the ACL-deficient knee. Sectioning the Kaplan fibers led to greater tibial internal rotation at higher flexion angles (60°-90°) as compared with ALL sectioning. Additionally, the ALL and Kaplan fibers contribute to restraint of the pivot shift and anterior tibial translation in the ACL-deficient knee. Clinical Relevance: This study reports that the ALL and distal iliotibial band Kaplan fibers restrain anterior tibial translation, internal rotation, and pivot shift in the ACL-deficient knee. Furthermore, sectioning the Kaplan fibers led to significantly greater tibial internal rotation when compared with ALL sectioning at high flexion angles. These results demonstrate increased rotational knee laxity with combined ACL and anterolateral extra-articular knee injuries and may allow surgeons to optimize the care of patients with this injury pattern.


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