Robotically Simulated Clinical Pivot Shift: A Better Tool for Analyzing ACL Reconstructions?

Author(s):  
R. W. Colbrunn ◽  
J. E. Dumpe ◽  
T. F. Bonner ◽  
J. D. Kolmodin ◽  
W. K. Barsoum ◽  
...  

A pivot shift is a useful exam for evaluating anterior cruciate ligament (ACL) reconstruction surgery. A positive result is a perceived “clunk” and is quantified by the kinematics that occur during the tibial reduction phase. In vitro evaluation of ACL reconstruction techniques includes robotic testing of cadaveric knees where the applied loads represent estimated in situ loads. Early understanding of the mechanism of the pivot shift has resulted in a simplified representation where static “rotary loads” (10Nm valgus torque, 5Nm internal tibial torque) are applied at a few discrete flexion angles, and changes in anterior tibial translation (ATT) are compared [1]. Building upon this work, and with advances in technology, we are now able to create a robotic test that is more like the clinical exam. Our hypothesis was that kinematics produced during the robotically simulated pivot shift would be similar to the clinical pivot shift but would be significantly different from the rotary loads method. The ability for a test to produce larger kinematic differences between native and deficient states may suggest a more robust methodology by which to evaluate the efficacy of ACL reconstructions.

2001 ◽  
Vol 29 (6) ◽  
pp. 771-776 ◽  
Author(s):  
Jürgen Höher ◽  
Akihiro Kanamori ◽  
Jennifer Zeminski ◽  
Freddie H. Fu ◽  
Savio L-Y. Woo

Ten cadaveric knees (donor ages, 36 to 66 years) were tested at full extension, 15°, 30°, and 90° of flexion under a 134-N anterior tibial load. In each knee, the kinematics as well as in situ force in the graft were compared when the graft was fixed with the tibia in four different positions: full knee extension while the surgeon applied a posterior tibial load (Position 1), 30° of flexion with the tibia at the neutral position of the intact knee (Position 2), 30° of flexion with a 67-N posterior tibial load (Position 3), and 30° of flexion with a 134-N posterior tibial load (Position 4). For Positions 1 and 2, the anterior tibial translation and the in situ forces were up to 60% greater and 36% smaller, respectively, than that of the intact knee. For Position 3, knee kinematics and in situ forces were closest to those observed in the intact knee. For Position 4, anterior tibial translation was significantly decreased by up to 2 mm and the in situ force increased up to 31 N. These results suggest that the position of the tibia during graft fixation is an important consideration for the biomechanical performance of an anterior cruciate ligament-reconstructed knee.


2019 ◽  
Vol 48 (1) ◽  
pp. 109-116 ◽  
Author(s):  
Robert N. Kent ◽  
Carl W. Imhauser ◽  
Ran Thein ◽  
Niv Marom ◽  
Thomas L. Wickiewicz ◽  
...  

Background: Patients with high-grade preoperative side-to-side differences in anterior laxity as assessed via the Lachman test after unilateral anterior cruciate ligament (ACL) rupture are at heightened risk of early ACL graft failure. Biomechanical factors that predict preoperative side-to-side differences in anterior laxity are poorly understood. Purpose: To assess, in a cadaveric model, whether the increase in anterior laxity caused by sectioning the ACL (a surrogate for preoperative side-to-side differences in anterior laxity) during a simulated Lachman test is associated with two biomechanical factors: (1) the tibial translation at which the secondary anterior stabilizers, including the remaining ligaments and the menisci, begin to carry force, or engage, relative to that of the ACL or (2) the forces carried by the ACL and secondary stabilizers at the peak applied anterior load. Study Design: Controlled laboratory study. Methods: Seventeen fresh-frozen human cadaveric knees underwent Lachman tests simulated through a robotic manipulator with the ACL intact and sectioned. The net forces carried by the ACL and secondary soft tissue stabilizers (the medial meniscus and all remaining ligaments, measured as a whole) were characterized as a function of anterior tibial translation. The engagement points of the ACL (with the ACL intact) and each secondary stabilizer (with the ACL sectioned) were defined as the anterior translation at which they began to carry force, or engaged, during a simulated Lachman test. Then, the relative engagement point of each secondary stabilizer was defined as the difference between the engagement point of each secondary stabilizer and that of the ACL. Linear regressions were performed to test each association ( P < .05). Results: The increase in anterior laxity caused by ACL sectioning was associated with increased relative engagement points of both the secondary ligaments (β = 0.87; P < .001; R2 = 0.75) and the medial meniscus (β = 0.66; P < .001; R2 = 0.58). Smaller changes in anterior laxity were also associated with increased in situ medial meniscal force at the peak applied load when the ACL was intact (β = −0.06; P < .001; R2 = 0.53). Conclusion: The secondary ligaments and the medial meniscus require greater anterior tibial translation to engage (ie, begin to carry force) relative to the ACL in knees with greater changes in anterior laxity after ACL sectioning. Moreover, with the ACL intact, the medial meniscus carries more force in knees with smaller changes in anterior laxity after ACL sectioning. Clinical Relevance: Relative tissue engagement is a new biomechanical measure to characterize in situ function of the ligaments and menisci. This measure may aid in developing more personalized surgical approaches to reduce high rates of ACL graft revision in patients with high-grade laxity.


Author(s):  
Georg Mattiassich ◽  
Reinhold Ortmaier ◽  
Harald Kindermann ◽  
Jürgen Barthofer ◽  
Imre Vasvary ◽  
...  

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.


2020 ◽  
Author(s):  
Georg Mattiassich ◽  
Reinhold Ortmaier ◽  
Harald Kindermann ◽  
Jürgen Barthofer ◽  
Imre Vasvary ◽  
...  

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.


2019 ◽  
Vol 47 (9) ◽  
pp. 2077-2085 ◽  
Author(s):  
Robert Magnussen ◽  
Emily K. Reinke ◽  
Laura J. Huston ◽  
Jack T. Andrish ◽  
Charles L. Cox ◽  
...  

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.


2000 ◽  
Author(s):  
Jennifer Zeminski ◽  
Akihiro Kanamori ◽  
Masayoshi Yagi ◽  
Richard E. Debski ◽  
Freddie H. Fu ◽  
...  

Abstract A successful reconstruction of the anterior cruciate ligament (ACL) after its injury should restore the kinematics of the intact knee, as well as reproduce the in-situ force in this ligament. While ACL reconstruction has been successful to limit anterior tibial translation under anterior loads applied to the tibia (1, 2), the same cannot be said about more complex loading conditions that include valgus and internal tibial torques.


2017 ◽  
Vol 45 (5) ◽  
pp. 1049-1058 ◽  
Author(s):  
Takuya Naraoka ◽  
Yuka Kimura ◽  
Eiichi Tsuda ◽  
Yuji Yamamoto ◽  
Yasuyuki Ishibashi

Background: Remnant-preserved anterior cruciate ligament (ACL) reconstruction was introduced to improve clinical outcomes and biological healing. However, the effects of remnant preservation and the influence of the delay from injury until reconstruction on the outcomes of this technique are still uncertain. Purpose/Hypothesis: The purposes of this study were to evaluate whether remnant preservation improved the clinical outcomes and graft incorporation of ACL reconstruction and to examine the influence of the delay between ACL injury and reconstruction on the usefulness of remnant preservation. We hypothesized that remnant preservation improves clinical results and accelerates graft incorporation and that its effect is dependent on the delay between ACL injury and reconstruction. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 151 consecutive patients who underwent double-bundle ACL reconstruction using a semitendinosus graft were enrolled in this study: 74 knees underwent ACL reconstruction without a remnant (or the remnant was <25% of the intra-articular portion of the graft; NR group), while 77 knees underwent ACL reconstruction with remnant preservation (RP group). These were divided into 4 subgroups based on the time from injury to surgery: phase 1 was <3 weeks (n = 24), phase 2 was 3 to less than 8 weeks (n = 70), phase 3 was 8 to 20 weeks (n = 32), and phase 4 was >20 weeks (n = 25). Clinical measurements, including KT-1000 arthrometer side-to-side anterior tibial translation measurements, were assessed at 3, 6, 12, and 24 months after reconstruction. Magnetic resonance imaging evaluations of graft maturation and graft-tunnel integration of the anteromedial and posterolateral bundles were assessed at 3, 6, and 12 months after reconstruction. Results: There was no difference in side-to-side anterior tibial translation between the NR and RP groups. There was also no difference in graft maturation between the 2 groups. Furthermore, the time from ACL injury until reconstruction did not affect graft maturation, except in the case of very long delays before reconstruction (phase 4). Graft-tunnel integration was significantly increased in both groups in a time-dependent manner. However, there was no difference between the NR and RP groups. Conclusion: Remnant preservation did not improve knee stability at 2 years after ACL reconstruction. Furthermore, remnant preservation did not accelerate graft incorporation, especially during the acute and subacute injury phases.


2009 ◽  
Vol 37 (8) ◽  
pp. 1522-1530 ◽  
Author(s):  
Max Ekdahl ◽  
Masahiro Nozaki ◽  
Mario Ferretti ◽  
Andrew Tsai ◽  
Patrick Smolinski ◽  
...  

Background Misplacement of the bone tunnels is one of the main causes of graft failure of anterior cruciate ligament surgery. Hypothesis Anatomic tunnel placement in anterior cruciate ligament surgery reconstruction will lead to improved outcomes, including biological ingrowth and biomechanical properties, when compared with nonanatomic tunnel placement. Study Design Controlled laboratory study. Methods Anterior cruciate ligament surgery reconstructions were performed on 3 different groups of goats (1 anatomic tunnel placement group and 2 different nonanatomic tunnel placement groups, with 10 goats in each group). For each group of 10 knees, 3 knees were used for histologic evaluation (bone tunnel enlargement, number of osteoclasts at the bone tendon interface, and revascularization of the graft) and 7 knees were used for biomechanical testing (anterior tibial translation, in situ force, cross-sectional area, and ultimate failure load). Animals were sacrificed at 12 weeks after surgery. Results The anatomic tunnel placement group showed less tunnel enlargement on the tibial side, fewer osteoclasts on both the tibial and femoral sides, and more vascularity in the femoral side when compared with the 2 nonanatomic reconstruction groups. Biomechanically, the anatomic tunnel placement group demonstrated less anterior tibial translation and greater in situ force than both nonanatomic tunnel placement groups. Conclusion Anatomic tunnel placement leads to superior biological healing and biomechanical properties compared with nonanatomic placement at 12 weeks after anterior cruciate ligament surgery reconstruction in a goat model. Clinical Relevance The findings of this study demonstrate the importance of anatomic tunnel placement in anterior cruciate ligament surgery reconstruction.


2021 ◽  
Vol 9 (4) ◽  
pp. 232596712199806
Author(s):  
Michèle N.J. Keizer ◽  
Egbert Otten ◽  
Chantal M.I. Beijersbergen ◽  
Reinoud W. Brouwer ◽  
Juha M. Hijmans

Background: At 1 year after anterior cruciate ligament reconstruction (ACLR), two-thirds of patients manage to return to sports (copers), whereas one-third of patients do not return to sports (noncopers). Copers and noncopers have different muscle activation patterns, and noncopers may not be able to control dynamic anterior tibial translation (ATTd) as well as copers. Purpose/Hypothesis: To investigate whether (1) there is a positive correlation between passive ATT (ATTp; ie, general joint laxity) and ATTd during jump landing, (2) whether ATTd is moderated by muscle activating patterns, and (3) whether there is a difference in moderating ATTd between copers and noncopers. We hypothesized that patients who have undergone ACLR compensate for ATTd by developing muscle strategies that are more effective in copers compared with noncopers. Study Design: Controlled laboratory study. Methods: A total of 40 patients who underwent unilateral ACLR performed 10 single-leg hops for distance with both legs. Lower body kinematic and kinetic data were measured using a motion-capture system, and ATTd was determined with an embedded method. Muscle activity was measured using electromyographic signals. Bilateral ATTp was measured using a KT-1000 arthrometer. In addition, the Beighton score was obtained. Results: There was no significant correlation between ATTp and ATTd in copers; however, there was a positive correlation between ATTp and ATTd in the operated knee of noncopers. There was a positive correlation between the Beighton score and ATTp as well as between the Beighton score and ATTd in both copers and noncopers in the operated knee. Copers showed a negative correlation between ATTd and gastrocnemius activity in their operated leg during landing. Noncopers showed a positive correlation between ATTd and knee flexion moment in their operated knee during landing. Conclusion: Copers used increased gastrocnemius activity to reduce ATTd, whereas noncopers moderated ATTd by generating a smaller knee flexion moment. Clinical Relevance: This study showed that copers used different landing techniques than noncopers. Patients who returned to sports after ACLR had sufficient plantar flexor activation to limit ATTd.


Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 419
Author(s):  
Chien-Kuo Wang ◽  
Liang-Ching Lin ◽  
Yung-Nien Sun ◽  
Cheng-Shih Lai ◽  
Chia-Hui Chen ◽  
...  

We sought to design a computer-assisted system measuring the anterior tibial translation in stress radiography, evaluate its diagnostic performance for an anterior cruciate ligament (ACL) tear, and assess factors affecting the diagnostic accuracy. Retrospective research for patients with both knee stress radiography and magnetic resonance imaging (MRI) at our institution was performed. A complete ACL rupture was confirmed on an MRI. The anterior tibial translations with four different methods were measured in 249 patients by the designed algorithm. The diagnostic accuracy of each method in patients with all successful measurements was evaluated. Univariate logistic regression analysis for factors affecting diagnostic accuracy of method four was performed. In the inclusive 249 patients, 177 patients (129 with completely torn ACLs) were available for analysis. Mean anterior tibial translations were significantly increased in the patients with a completely torn ACL by all four methods, with diagnostic accuracies ranging from 66.7% to 75.1%. The diagnostic accuracy of method four was negatively associated with the time interval between stress radiography and MRI as well as force-joint distance on stress view, and not significantly associated with age, gender, flexion angle, intercondylar distance, and force-joint angle. A computer-assisted system measuring the anterior tibial translation in stress radiography showed acceptable diagnostic performance of complete ACL injury. A shorter time interval between stress radiography and MRI as well as shorter force-joint distance were associated with higher diagnostic accuracy.


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