Comparative Measurements of Anterior Tibial Translation Using the KT-1000 Knee Arthrometer With the Leg in Neutral, Internal Rotation, and External Rotation

1994 ◽  
Vol 19 (6) ◽  
pp. 331-334 ◽  
Author(s):  
Ira Fiebert ◽  
Jill Gresley ◽  
Stephanie Hoffman ◽  
Kevin Kunkel
Keyword(s):  
Internal Rotation ◽  
External Rotation ◽  
Anterior Tibial Translation ◽  
Anterior Tibial ◽  
Kt 1000 ◽  
Tibial Translation

Effect of Meniscocapsular and Meniscotibial Lesions in ACL-Deficient and ACL-Reconstructed Knees: A Biomechanical Study

2018 ◽  
Vol 46 (10) ◽  
pp. 2422-2431 ◽  
Author(s):  
Nicholas N. DePhillipo ◽  
Gilbert Moatshe ◽  
Alex Brady ◽  
Jorge Chahla ◽  
Zachary S. Aman ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Medial Meniscus ◽  
Pivot Shift ◽  
External Rotation ◽  
Posterior Horn ◽  
Pivot Shift Test ◽  
Anterior Tibial Translation ◽  
Anterior Tibial ◽  
Tibial Translation ◽  
Acl Deficient

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.

scholarly journals Clinical and radiological results after Internal Brace suture versus the all-inside reconstruction technique in anterior cruciate ligament tears 12 to 18 months after index surgery

2020 ◽  
Author(s):  
Georg Mattiassich ◽  
Reinhold Ortmaier ◽  
Harald Kindermann ◽  
Jürgen Barthofer ◽  
Imre Vasvary ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Anterior Tibial Translation ◽  
German Version ◽  
Anterior Tibial ◽  
Kt 1000 ◽  
Internal Brace ◽  
Anterior Cruciate ◽  
Tibial Translation

Abstract Background Anterior cruciate ligament (ACL) injury can lead to reduced function, meniscal lesions, and early joint degeneration. Preservation of a torn ACL using the Internal Brace technique might re-establish normal knee kinematics, avoid donor-site morbidity due to tendon harvesting, and potentially maintain proprioception of the knee. Methods Fifty subjects were recruited for this study between December 2015 and October 2016. Two groups of individuals who sustained a unilateral ACL rupture were included: those who underwent surgery with preservation of the injured ACL (Internal Brace technique; IB) and those who underwent ACL reconstruction using a hamstring tendon graft (all-inside technique; AI). Subjective self-administered scores were used: the German version of the IKDC Subjective Knee Form (International Knee Documentation Committee), the German version of the WOMAC (Western Ontario and McMaster Universities Arthritis Index), SF-36 (short form), the German version of the KOOS (Knee Osteoarthritis Outcome Score), and the German version of themodified Lysholm Score by Lysholm and Gillquist. Anterior tibial translation was assessed using the KT-1000 Arthrometer (KT-1000 Knee Ligament Arthrometer, MEDmetric Corp., San Diego, CA, USA). Magnetic resonance evaluation was performed in all cases. Results Twenty-three subjects (46 %) were men, and the mean age was 34.7 years. The objective IKDC scores were “normal” in 15 and 14 patients, “nearly normal” in 11 and 7 patients, and “abnormal” in 1 and 2 patients, in the IB and AI groups, respectively. KT-1000 assessment showed a sideto-side difference of more than 3 mm on maximum manual testing in 11 (44 %) and 6 subjects (28.6 %) in the IB and AI groups, respectively. In the postoperative MRI, 20 (74 %) and 22 subjects (96 %) in the IB and AI groups had an intact ACL. Anterior tibial translation was significantly higher in the IB group compared with the AI group in the manual maximum test. Conclusions Preservation of the native ACL with the Internal Brace primary repair technique can achieve comparable results to ACL reconstruction using Hamstring autografts over a short term. Clinically relevant limitations such as a higher incidence of pathologic laxity, with patients more prone to pivot-shift phenomenon were observed during the study period.

scholarly journals Adult patients with ACL tears have greater tibial internal rotation in MRI compared to adolescent patients

2022 ◽  
Vol 17 (1) ◽  
Author(s):  
Chih-Kai Hong ◽  
Yu-Ju Lin ◽  
Ting-An Cheng ◽  
Chih-Hsun Chang ◽  
Kai-Lan Hsu ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Intraclass Correlation ◽  
Adult Patients ◽  
Anterior Tibial Translation ◽  
Adult Group ◽  
Adolescent Group ◽  
Tibial Internal Rotation ◽  
Anterior Tibial ◽  
Adolescent Patients ◽  
Tibial Translation

Abstract Purpose To compare the anterior translation and internal rotation of tibia on magnetic resonance imaging (MRI) between adult and adolescent patients with anterior cruciate ligament (ACL) tears. Methods Patients who underwent isolated ACL reconstruction from January 2013 to May 2021 were retrospectively reviewed. The exclusion criteria included incomplete data, poor image quality, a prior ACL surgery, and concomitant fractures or other ligament injuries. The enrolled patients were divided into two groups based on their ages: an adult group (age > 19 years) and an adolescent group (15 to 19 years of age). Anterior tibial translation and femorotibial rotation were measured on MRI. A Student’s t-test was used for the statistical analysis comparing the adult and adolescent groups. Results A total of 365 patients (279 adults and 86 adolescents) were enrolled in the present study. The anterior tibial translation in the adult group (4.8 ± 4.4 mm) and the adolescent group (5.0 ± 4.2 mm) was not significantly different (p = 0.740). On the other hand, the tibial internal rotation in the adult group (5.6 ± 5.0 degree) was significantly greater compared to the adolescent group (4.2 ± 5.6 degree) (p = 0.030). The intraclass correlation coefficients (ICC) of the measured data from two independent observers showed excellent reliability (0.964 and 0.961 for anterior tibial translation and tibial internal rotation, respectively). Conclusion The adult patients with ACL tears exhibited significant greater tibial internal rotation compared to the adolescent patients, whereas the magnitude of the anterior tibial translation was similar in both groups. Care should be taken if clinicians plan to establish the cutoff point values for diagnosis of ACL tears using the femorotibial internal rotation angle.

Clinical and radiological results after Internal Brace ® suture versus the all-inside reconstruction technique in anterior cruciate ligament tears 12 to 18 months after index surgery.

2020 ◽  
Author(s):  
Georg Mattiassich ◽  
Reinhold Ortmaier ◽  
Harald Kindermann ◽  
Jürgen Barthofer ◽  
Imre Vasvary ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Anterior Tibial Translation ◽  
German Version ◽  
Anterior Tibial ◽  
Kt 1000 ◽  
Internal Brace ◽  
Anterior Cruciate ◽  
Tibial Translation

Abstract Background Anterior cruciate ligament (ACL) injury can lead to reduced function, meniscal lesions, and early joint degeneration. Preservation of a torn ACL using the Internal Brace® technique might re-establish normal knee kinematics, avoid donor-site morbidity due to tendon harvesting, and potentially maintain proprioception of the knee. Methods Fifty subjects were recruited for this study between December 2015 and October 2016. Two groups of individuals who sustained unilateral ACL rupture were included: those who underwent surgery with preservation of the injured ACL (Internal Brace® technique; IB) and those who underwent ACL reconstruction using a hamstring tendon graft (all-inside technique; AI). Subjective self-administered scores were used: the German Version of the IKDC Subjective Knee Form (International Knee Documentation Committee), the German Version of the WOMAC (Western Ontario and McMaster Universities Arthritis Index), SF-36 (short form), the German Version of the KOOS (Knee Osteoarthritis Outcome Score), and the German Version of the modified Lysholm-score by Lysholm and Gillquist. Anterior tibial translation was assessed using the KT-1000 arthrometer® (KT-1000 Knee Ligament Arthrometer, MEDmetric Corp., San Diego, CA, USA). Magnetic resonance evaluation was performed in all cases. Results Twenty-three subjects (46%) were men, and the mean age was 34.7 years. The objective IKDC scores were “normal” in 15 and 14 patients, “nearly normal” in 11 and 7 patients, and “abnormal” in 1 and 2 patients, in the IB and AI groups, respectively. KT-1000 assessment showed a side-to-side difference of more than 3 mm on maximum manual testing in 11 (44%) and 6 subjects (28.6%) in the IB and AI groups, respectively. In the postoperative MRI, 20 (74%) and 22 subjects (96%) in the IB and AI groups showed an intact ACL. Anterior tibial translation was significantly higher in the IB group compared to the AI group in the manual maximum test. Conclusions Preservation of the native ACL with the Internal Brace ® primary repair technique can achieve comparable results to ACL reconstruction using Hamstring autografts over a short term. Clinically relevant limitations such as a higher incidence of pathologic laxity, with patients more prone to pivot shift phenomenon were observed during the study period.

Dynamic Restraints of the Medial Side of the Knee: The Semimembranosus Corner Revisited

2019 ◽  
Vol 47 (4) ◽  
pp. 863-869 ◽  
Author(s):  
Christoph Kittl ◽  
Deborah K. Becker ◽  
Michael J. Raschke ◽  
Marcus Müller ◽  
Guido Wierer ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Medial Collateral Ligament ◽  
External Rotation ◽  
Optical Tracking ◽  
Anterior Tibial Translation ◽  
Collateral Ligament ◽  
Posterior Oblique Ligament ◽  
Medial Knee ◽  
Medial Side ◽  
Tibial Translation

Background: Little is known about the dynamic restraints of the semimembranosus muscle (SM). Purpose and Hypothesis: The goal of the present study was to elucidate the role of (1) passive and (2) active restraints to medial-side instability and to analyze (3) the corresponding tightening of the posteromedial structures by loading the SM. It was hypothesized that points 1 to 3 will significantly restrain medial knee instability. This will aid in understanding the synergistic effect of the semimembranosus corner. Study Design: Controlled laboratory study. Methods: Nine knees were tested in a 6 degrees of freedom robotic setup and an optical tracking system. External rotation (ER; 4 N·m), internal rotation (4 N·m), anteromedial rotation (4-N·m ER and 89-N anterior tibial translation), and valgus rotation (8 N·m) were applied at 0°, 30°, 60°, and 90°, with and without an SM load of 75 N. Sequential cutting of the medial collateral ligament and posterior oblique ligament was then performed. At the intact state of the knee and after each cut, the aforementioned simulated laxity tests were performed. Results: The medial collateral ligament was found to be the main passive stabilizer to ER and anteromedial rotation, resulting in 9.3° ± 6.8° ( P < .05), 8.1° ± 3.6° ( P < .05), and 7.6° ± 4.2° ( P < .05) at 30°, 60°, and 90°, respectively. Conversely, after the posterior oblique ligament was cut, internal rotation instability increased significantly at early flexion angles (9.3° ± 3.2° at 0° and 5.2° ± 1.1 at 30°). Loading the SM had an overall effect on restraining ER ( P < .001) and anteromedial rotation ( P < .001). This increased with flexion angle and sectioning of the medial structures and resulted in a pooled 2.8° ± 1.7° (not significant), 5.4° ± 2° ( P < .01), 7.5° ± 2.8° ( P < .001), and 8.3° ± 4.4° ( P < .001) at 0°, 30°, 60°, and 90° when compared with the unloaded state. Conclusion: The SM was found to be a main active restraint to ER and anteromedial rotation, especially at higher flexion angles and in absence of the main passive medial restraints. The calculated tensioning effect was small in all flexion angles for all simulated laxity tests. Clinical Relevance: A complete semimembranosus avulsion may indicate severe medial knee injury, and refixation should be considered in multiligament injury.

Anterolateral Knee Extra-articular Stabilizers: A Robotic Sectioning Study of the Anterolateral Ligament and Distal Iliotibial Band Kaplan Fibers

2018 ◽  
Vol 46 (6) ◽  
pp. 1352-1361 ◽  
Author(s):  
Andrew G. Geeslin ◽  
Jorge Chahla ◽  
Gilbert Moatshe ◽  
Kyle J. Muckenhirn ◽  
Bradley M. Kruckeberg ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Pivot Shift ◽  
Iliotibial Band ◽  
Anterior Tibial Translation ◽  
Tibial Internal Rotation ◽  
Anterior Tibial ◽  
Robotic Testing ◽  
Tibial Translation ◽  
Acl Deficient ◽  
Deficient Knee

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.

scholarly journals Anterior and Rotational Knee Laxity Does Not Affect Patient-Reported Knee Function 2 Years After Anterior Cruciate Ligament Reconstruction

2019 ◽  
Vol 47 (9) ◽  
pp. 2077-2085 ◽  
Author(s):  
Robert Magnussen ◽  
Emily K. Reinke ◽  
Laura J. Huston ◽  
Jack T. Andrish ◽  
Charles L. Cox ◽  
...  
Keyword(s):  
Acl Reconstruction ◽  
Pivot Shift ◽  
Cruciate Ligament ◽  
Knee Laxity ◽  
Anterior Tibial Translation ◽  
Patient Reported ◽  
Anterior Tibial ◽  
Kt 1000 ◽  
Tibial Translation ◽  
Rotational Knee Laxity

Background: While a primary goal of anterior cruciate ligament (ACL) reconstruction is to reduce pathologically increased anterior and rotational knee laxity, the relationship between knee laxity after ACL reconstruction and patient-reported knee function remains unclear. Hypothesis: There would be no significant correlation between the degree of residual anterior and rotational knee laxity and patient-reported outcomes (PROs) 2 years after primary ACL reconstruction. Study Design: Cross-sectional study; Level of evidence, 3. Methods: From a prospective multicenter nested cohort of patients, 433 patients younger than 36 years of age injured in sports with no history of concomitant ligament surgery, revision ACL surgery, or surgery of the contralateral knee were identified and evaluated at a minimum 2 years after primary ACL reconstruction. Each patient underwent Lachman and pivot-shift evaluation as well as a KT-1000 arthrometer assessment along with Knee injury and Osteoarthritis Outcome Score and subjective International Knee Documentation Committee (IKDC) scores. A proportional odds logistic regression model was used to predict each 2-year PRO score, controlling for preoperative score, age, sex, body mass index, smoking, Marx activity score, education, subsequent surgery, meniscal and cartilage status, graft type, and range of motion asymmetry. Measures of knee laxity were independently added to each model to determine correlation with PROs. Results: Side-to-side manual Lachman differences were IKDC A in 246 (57%) patients, IKDC B in 183 (42%) patients, and IKDC C in 4 (<1%) patients. Pivot-shift was classified as IKDC A in 209 (48%) patients, IKDC B in 183 (42%) patients, and IKDC C in 11 (2.5%) patients. The mean side-to-side KT-1000 difference was 2.0 ± 2.6 mm. No significant correlations were noted between pivot-shift or anterior tibial translation as assessed by Lachman or KT-1000 and any PRO. All predicted differences in PROs based on IKDC A versus B pivot-shift and anterior tibial translation were less than 4 points. Conclusion: Neither the presence of IKDC A versus B pivot-shift nor increased anterior tibial translation of up to 6 mm is associated with clinically relevant decreases in PROs 2 years after ACL reconstruction.

scholarly journals The Effect of Medial Tibial Slope on Anterior Tibial Translation and Short-Term ACL Reconstruction Outcome

2018 ◽  
Vol 04 (03) ◽  
pp. e160-e163 ◽  
Author(s):  
Steffen Sauer ◽  
Mark Clatworthy
Keyword(s):  
Acl Reconstruction ◽  
Tibial Slope ◽  
Anterior Tibial Translation ◽  
Short Term ◽  
Anterior Tibial ◽  
Kt 1000 ◽  
Tibial Translation ◽  
Medial Tibial Slope ◽  
Acl Deficient

Background Increased tibial slope has been shown to be associated with higher anterior cruciate ligament (ACL) reconstruction failure rate. Little is known about the correlation of tibial slope and anterior tibial translation in ACL deficient and reconstructed knees as well as the correlation of tibial slope and ACL reconstruction outcome. Purpose/Hypothesis The purpose of this study was to investigate the correlation of tibial slope with anterior tibial translation and ACL reconstruction outcome. It is hypothesized that increased medial tibial slope is associated with increased anterior tibial translation in the ACL deficient knee. Medial tibial slope is neither expected to affect anterior tibial translation in the ACL reconstructed knee nor short-term ACL reconstruction outcome. Materials and Methods A cohort of 104 patients with unilateral isolated ACL deficiency undergoing hamstring ACL reconstruction by a single surgeon between 2002 and 2004 was followed up prospectively. Preoperative data were collected including patient demographics, time to surgery, subjective and objective International Knee Documentation Committee (IKDC) outcome scores, as well as manual maximum anterior tibial translation measured with the KT-1000 measuring instrument. Medial tibial slope was assessed on long lateral X-rays using the method described by Dejour and Bonnin (1994). Intraoperative data were collected including meniscal integrity; postoperative data were collected at 1-year follow-up including manual maximum anterior tibial translation (KT-1000 measured), and subjective and objective IKDC scores. Results A significant positive correlation was seen between medial tibial slope in ACL deficient knees and KT-1000–measured anterior tibial translation (r = 0.24; p = 0.003). The positive relationship increased when meniscal integrity was factored in (r = 0.33; p < 0.001). No significant correlation was seen between medial or lateral meniscal integrity and KT-1000–measured anterior tibial translation (r = −18; p = 0.06). No significant correlation was seen between KT-1000–measured anterior tibial translation and time to surgery. One year postoperatively, 82 patients were assessed, while 26 patients were lost to follow-up; no significant correlation was found between increased medial tibial slope and poor ACL reconstruction outcome measured by post-ACL reconstruction anterior tibial translation (KT-1000) or subjective and objective IKDC scores. Conclusion Increased medial tibial slope is associated with increased (KT-1000 measured) anterior tibial translation in ACL deficient knees. No significant correlation is found between increased medial tibial slope and poor short-term ACL reconstruction outcome.

Anterolateral Knee Extra-articular Stabilizers: A Robotic Study Comparing Anterolateral Ligament Reconstruction and Modified Lemaire Lateral Extra-articular Tenodesis

2017 ◽  
Vol 46 (3) ◽  
pp. 607-616 ◽  
Author(s):  
Andrew G. Geeslin ◽  
Gilbert Moatshe ◽  
Jorge Chahla ◽  
Bradley M. Kruckeberg ◽  
Kyle J. Muckenhirn ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Acl Reconstruction ◽  
Pivot Shift ◽  
Anterolateral Ligament ◽  
Anterior Tibial Translation ◽  
Intact State ◽  
Graft Tension ◽  
Tibial Internal Rotation ◽  
Anterior Tibial ◽  
Tibial Translation

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.

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