ACL-deficient Knee Research Articles

Increased lateral meniscal slope is associated with greater incidence of lateral bone contusions in noncontact ACL injury.

(1) To investigate whether an increased lateral meniscal slope measured on magnetic resonance image (MRI) would be associated with greater risk of bone contusions in noncontact anterior cruciate ligament injury, and (2) to measure the relationship between the occurrence of bone contusions and associated findings observed in ACL deficient knees such as cartilage damage, anterolateral complex injury and concomitant meniscal tears. Patients who underwent ACL reconstruction surgery between 2013 and 2018 were retrospectively reviewed. Sixty-three patients were included in the study group (ACL + bone contusions group), 56 participants were in the control group (isolated ACL group). The presence and severity of bone contusions were determined from preoperative MRIs. The lateral meniscal slope and lateral posterior tibial slope were measured on the MRIs in a blinded fashion. The predictors of lateral bone contusions including age, sex, body mass index, lateral meniscal slope and lateral posterior tibial slope were examined by multivariable logistic regression. Associated findings including concomitant meniscal lesions, intra-articular cartilage damage and anterolateral complex injury, which were also calculated bymultivariable logistic regression. The mean lateral meniscal slope in the study group was 6.5° ± 3.5°, which was significantly larger than that in the control group (3.8° ± 2.7°;P < 0.01). In addition, increased lateral meniscal slope was significantly associated with lateral bone contusions in noncontact ACL injury (Lateral femoral condyle (LFC): AOR 16.5; 95% CI 5.40-50.20; P < 0.01; Lateral tibial plateau (LTP): AOR 31.8; 95% CI 8.68-116.7; P < 0.01). However, lateral posterior tibial slope was not significantly associated with bone contusions. Moreover, the presence of lateral bone contusions was associated with concomitant lateral meniscal tears (OR 12.4; 95% CI 3.30-46.30) and cartilage damage (OR 2.9; 95% CI 1.04-8.18). An increased lateral meniscal slope was associated with increased risk of lateral bone contusions in noncontact ACL injury. In addition, the presence of lateral bone contusions was associated with intra-articular cartilage damage, anterolateral complex injury and concomitant meniscal tears. Hence, additional information was provided for counseling patients who have increased LMS on the greater risk of knee rotational instability and identify patients undergoing ACL reconstruction who may benefit from extra-articular tenodesis. IV.

Comparison of functional outcomes of double-bundle anterior cruciate ligament (ACL) reconstruction with and without use of dedicated zig for femoral and tibial tunnel preparation

Aim: To compare the functional outcomes of double-bundle anterior cruciate ligament (ACL) reconstruction with and without use of dedicated zig for femoral and tibial tunnel preparation.Materials and Methods: Forty patients with ACL deficient knees fulfilling the inclusion criteria were selected and after careful alternate randomization, twenty each underwent ACL reconstruction surgery with and without using dedicated zig for tibial and femoral tunnel preparation respectively. Post operatively patients were followed up regularly with clinical evaluation based on IKDC (International Knee Documentation Committee) and modified Lysholm’s score and knee stability tests viz. anterior drawer, lachman’s and pivot shift tests. Final evaluation was done at 6 months and results were compared between the two techniques.Results: Forty patients ranging from 18 to 42 years, with mean age of 26.4 years in zig group and 24.6 years in freehand group with complete ACL tear included in study. All cases in both groups were males and sports injury being the most common mode of injury in both groups. Post operatively none of patient shows frank laxity in both groups. Average IKDC and modified Lysholm’s score at 6 month were 74.6/92.2 and 73.67/93.9 respectively. No major complication was noted and functional results were comparable between two groups.Conclusions: Functional results with both techniques are good and comparable and choice depends on surgeon’s skills and preference.

Sequential analysis of three-dimensional tibiofemoral relationship through anatomic anterior cruciate ligament reconstruction with gravity-assisted radiographic technique in prone position

Background/objectivesIt is important to restore the tibiofemoral relationship as well as the anterior knee laxity for more successful anterior cruciate ligament (ACL) reconstruction, since a residual abnormality in the tibiofemoral relationship would lead an abnormal stress on the articular cartilages/menisci and consequently increase the risk of osteoarthritis in the future. This study aimed to sequentially clarify the three-dimensional tibiofemoral relationship before and after anatomic anterior cruciate ligament (ACL) reconstruction under an anterior tibial load with a gravity-assisted radiographic technique in the prone position. MethodsFifteen patients with unilateral ACL injury participated in the study. Anatomic triple-bundle ACL reconstruction was performed using semitendinosus tendon autografts. During the computed tomography scans that were performed preoperatively, and those performed at 3 weeks and at 6 months postoperatively, the patients lay in the prone position with the knee flexed at 15°, wherein the calf weight could exert an anterior drawer force on the tibia due to gravity. Three-dimensional the tibial position relative to the femur were evaluated for each time point, followed by calculation of side-to-side differences in the parameters between the ACL-deficient/ACL-reconstructed knees and the contralateral intact knees. Seven healthy volunteers were enrolled in the control group and the side-to-side differences (right minus left) in these parameters were calculated. ResultsThe tibia in the ACL-deficient knee was located anteriorly by 3.5 ± 1.1 mm and rotated internally by 2.4° ± 2.3°; these values were significantly larger than the corresponding values of −0.2 ± 1.5 mm and 0.1° ± 2.2° in the control group. However, at 3 weeks postoperatively, the tibia in the ACL-reconstructed knee was over-constrained as compared to that in the control group; it was located posteriorly by 2.5 ± 1.4 mm and rotated externally by 3.4° ± 3.4°. At 6 months postoperatively, no significant difference was observed in the tibial displacements/rotations between the patient and control groups. The side-to-side difference in the anterior knee laxity at the manual maximum anterior load was 0.1 ± 1.2 mm at 6 months postoperatively, with a significant improvement over the preoperative value of 7.4 ± 2.5 mm. ConclusionsAnatomic ACL reconstruction could restore not only the normal anterior knee laxity, but also the normal tibiofemoral relationship even under an anterior tibial load.

Evaluating the Accuracy of Tibial Tunnel Placement After Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction

Background: Anatomic anterior cruciate ligament (ACL) reconstruction improves knee kinematics and joint stability in symptomatic patients who have ACL deficiency. Despite a concerted effort to place the graft within the ACL’s native attachment sites, the accuracy of tunnel placement using contemporary techniques is not well established. Purpose: To use 3-dimensional magnetic resonance imaging (3D MRI) to prospectively evaluate the accuracy of tibial tunnel placement after anatomic ACL reconstruction. Study Design: Case series; Level of evidence, 4. Methods: Forty patients with symptomatic, ACL-deficient knees were prospectively enrolled in the study and underwent 3D MRI of both their injured and uninjured knees before and after surgery through use of a validated imaging protocol. The root ligament of the anterior horn of the lateral meniscus was used as a radiographic reference, and the center of the reconstructed graft was compared with that of the contralateral normal knee. The tunnel angles and intra-articular graft angles were also measured, as was the percentage overlap between the native tibial footprint and tibial tunnel. Results: The reconstructed tibial footprint was placed at a mean ± SD of 2.14 ± 2.45 mm (P < .001) medial and 5.11 ± 3.57 mm (P < .001) posterior to the native ACL footprint. The mean distance between the center of the native and reconstructed ACL at the tibial attachment site was 6.24 mm. Of the 40 patients, 18 patients had a tibial tunnel that overlapped more than 50% of the native footprint, and 10 patients had maximal (100%) overlap. Further, 22 of the 40 patients had less than 50% overlap with the native footprint, and in 12 patients the footprint was missing completely. Conclusion: Despite the use of contemporary surgical techniques to perform anatomic ACL reconstruction, a significant positioning error in tibial tunnel placement remains.

Detecting the presence of anterior cruciate ligament injury based on gait dynamics disparity and neural networks

The aim of this study is to develop a new pattern recognition-based method to model and discriminate gait dynamics disparity between anterior cruciate ligament (ACL) deficient (ACL-D) knee and contralateral ACL-intact (ACL-I) knee in patients with unilateral ACL deficiency by using kinematic features and neural networks. Thereby the capabilities of these features to detect the presence of injury can be assessed. The proposed method consists of two stages. In the first (training) stage, gait analysis is performed. A two-dimensional five-link biped model used for imitating human gait locomotion is employed to demonstrate that functions containing kinematic data of lower extremities, including knee and hip flexion/extension angles and angular velocities, characterize the gait system dynamics. Knee angle-hip angle cyclograms, knee and hip angle-angular velocity phase portraits visually demonstrate the significant disparity of gait dynamics between the lower extremities of patients with unilateral ACL deficiency. Gait dynamics underlying gait patterns of ACL-D and ACL-I knees are locally accurately modeled and approximated by radial basis function (RBF) neural networks via deterministic learning theory. The derived knowledge of approximated gait dynamics is preserved in constant RBF networks. In the second (classification) stage, a bank of dynamical estimators is constructed using the preserved constant RBF networks to represent the learned training gait patterns. By comparing the set of estimators with a test gait pattern, the generated average $$L_1$$ norms of errors are taken as the disparity and classification measure between the training and test gait patterns to differentiate between ACL-D and ACL-I knees. Finally, experiments are carried out on forty-three patients to assess the effectiveness of the proposed method. By using the leave-one-out cross-validation style under normal and fast walking speed conditions, the correct classification rates for discriminating between ACL-D and ACL-I knees are reported to be 95.61$$\%$$ and 93.03$$\%$$, respectively. Compared with other state-of-the-art methods, the results demonstrate that gait alterations in the presence of chronic ACL deficiency can be visualized through cyclograms and phase portraits, and can be detected with superior performance.

Detecting the presence of anterior cruciate ligament deficiency based on a double pendulum model, intrinsic time-scale decomposition (ITD) and neural networks

The anterior cruciate ligament (ACL) possesses the function of stabilizing the knee joint through limiting anterior tibial translation and controlling tibial rotation. Patients with unilateral ACL deficiency often demonstrate alterations of knee kinematics, kinetics and gait patterns in the deficient side in comparison to the unaffected contralateral side. This also leads to the early onset of osteoarthritis. In order to detect and monitor the progression of ACL deficiency over time, various classification approaches using spatiotemporal gait variables have been presented. In this study we propose a novel method for classifying gait patterns between ACL-deficient (ACLD) knee and unaffected contralateral ACL-intact (ACLI) knee based upon gait system dynamics, intrinsic time-scale decomposition (ITD) and neural networks. First, human leg is modeled as a double-pendulum to imitate and simplify the human walking. Since the lower extremities act as a kinetic chain during dynamic tasks, control of the hip joint will interact with knee motion. Related gait kinematic parameters including knee and hip joint angle and angular velocity are decomposed into a series of proper rotation components (PRCs) and a baseline signal by using the ITD method. The first PRCs of knee and hip joint angle and angular velocity are extracted, which contain most of the kinematic signals’ vibration energy and are considered to be the predominant PRCs. Third, neural networks are then used as the classifier with feature vectors as the input to distinguish between ACLD and ACLI knees based on the difference of gait system dynamics between the two groups. Finally, experiments are carried out on forty-three patients to assess the effectiveness of the proposed method. By using the leave-one-out cross-validation style under normal and fast walking speed conditions, the correct classification rates are reported to be $$95.12\%$$ and $$93.28\%$$, respectively. In comparison to other state-of-the-art methods, the results demonstrate superior performance and the proposed method may serve as a potential assistant tool for the automatic detection of ACL deficiency in the clinical application.

The effects of toe direction on three-dimensional knee kinematics during closed kinetic chain exercise in patients with anterior cruciate ligament deficient knee

Background/ObjectiveClosed Kinetic Chain Exercise (CKC Ex) is a safe rehabilitation method for anterior cruciate ligament deficient (ACLD) and reconstructed knees. However, CKC Ex can be risky based on abnormal toe directions. The purpose was to investigate knee kinematics during CKC Ex under three toe directions in ACLD. MethodsTwenty patients with unilateral ACL injury participated. The subjects performed five weight-bearing-static lunge tests on each limb under three toe directions, including 0 degrees (TN), 20 degrees (TI), and -20 degrees (TO). Three-dimensional knee kinematics were calculated using three-dimensional motion analysis system and were compared among three different toe directions. ResultsAmong three different toe directions, peak values of knee valgus and external rotation on ACLD side were significantly larger in TO than in TN and TI. In addition, the total excursion in the coronal plane on ACLD side was significantly larger in TO than in TN and TI. Regarding the differences between ACLD and ACLI, peak values of internal rotation angle was significantly smaller in ACLD than in ACLI. ConclusionFrom the present results, tibial rotation and knee abduction were strongly affected by toe direction. When considering a safe rehabilitation, it would be better to avoid TI and TO in CKC Ex in patients with unilateral ACL injury.

No difference in postoperative rotational laxity after ACL reconstruction in patients with and without anterolateral capsule injury: quantitative evaluation of the pivot-shift test at 1-year follow-up.

To compare rotational laxity in anterior cruciate ligament (ACL)-reconstructed knees retrospectively with and without concomitant anterolateral capsule (ALC) injury confirmed by magnetic resonance imaging (MRI) prior to ACL reconstruction. Sixty-two ACL-reconstructed knees (26 men, 36 women; median age 20 (range 13-59)) were included. Pivot-shift test was performed before ACL reconstruction and 1year postoperatively under anesthesia with both clinical grading and quantitative measurement simultaneously. Clinical grading was determined according to the International Knee Documentation Committee (IKDC) criteria (none, glide, clunk, or gross), and an electromagnetic measurement system was used to provide tibial acceleration as a quantitative parameter. The resence of concomitant ALC injury was confirmed retrospectively by MRI. The pivot-shift test was compared between ACL-reconstructed knees with and without ALC injury test for clinical grading and the independent t test for quantitative evaluation. ALC injury was identified in 26 of 62 (42%) knees. Before ACL reconstruction, there was no difference in the pivot-shift test results between the ACL-deficient knees with and without ALC injury in IKDC grading (n.s.) or tibial acceleration (1.1 ± 0.7m/s2 and 1.4 ± 1.1m/s2, respectively, n.s.). At 1year postoperatively, no difference was observed between groups (IKDC, p = 0.90; tibial acceleration, 0.6 ± 0.3m/s2 and 0.8 ± 0.6m/s2, n.s.). Concomitant ALC injury at the time of ACL injury had no effect on the rotational laxity of the knee in the postoperative course after ACL reconstruction. Therefore, additional treatment for ALC injury may not be warranted. IV.

Greater medial tibial slope is associated with increased anterior tibial translation in females with an ACL-deficient knee.

The purpose of the study was to determine the correlation between medial tibial slope (MTS) and anterior tibial translation (ATT) in female patients with an ACL-deficient knee. It was hypothesized that female patients with a greater medial tibial slope had an increased anterior tibial translation compared to males. MTS and ATT were analysed in 276 patients (138 females and 138 males) with a complete ACL rupture from 2012 to 2016. The mean age was 32 ± 12years. Previous surgery or additional ligament injury was excluded. CT scan was used for measuring MTS. Meniscal findings were reported. Anterior tibial translation and side to side difference (SSD) were measured by bilateral Telos™ stress radiography with knee flexion of 20°. There was no significant difference in ATT between females (5.4 ± 3.9) and males (5.8 ± 4.2), nor was there a difference in MTS between females (9.8 ± 2.8) and males (9.8 ± 2.7). A positive correlation was found between MTS and ATT absolute (r = 0.35, p < 0.001) and side to side difference (r = 0.12, p = 0.03). MTS greater or equal to 11° significantly increased the ATT (p < 0.05). For each degree of increase of the MTS, increases in ATT absolute of 0.6mm and SSD of 0.18mm were observed. Greater MTS was identified as a risk factor for an increase of ATT in females (r = 0.37, p < 0.001) but not in males (r = -0.1, n.s). Increases of 1° of MTS increased ATT 0.57mm in female patients (p < 0.001). MTS was influential in ATT despite the presence (r = 0.28 [0.11, 0.44], p = 0.001) or absence (r = 0.48 [0.35, 0.6], p < 0.001) of meniscal lesions. Greater medial tibial slope is associated with increased anterior tibial translation in females with ACL-deficient knees compared to males, despite the presence or absence of meniscal lesions. This could be due to a quadriceps/hamstring imbalance in females and the ability of the hamstring muscles to moderate ATT. III.

A Definition of Significant Instability and a Scoring System for Predicting Meniscal Tears in ACL-Deficient Knees.

Background:Patients with anterior cruciate ligament (ACL)–deficient knees risk recurrent instability of the affected knee, which may predispose to meniscal injuries. Various studies have correlated the incidence of meniscal tear with elapsed time from ACL tear and number of instability events. However, it is not clear how significant an instability event needs to be to contribute to a meniscal tear.Purpose/Hypothesis:The purpose of this study was to (1) define a significant instability episode and (2) develop a checklist and scoring system for predicting meniscal tears based on significant instability episode. We hypothesized that patients with ACL-deficient knees who met the scoring threshold for a significant instability episode would have a higher incidence of meniscal tears compared with those who did not meet the threshold.Study Design:Cohort study (prognosis); Level of evidence, 2.Methods:This retrospective study included patients with magnetic resonance imaging (MRI)–confirmed isolated ACL tear for longer than 3 months. We determined parameters for assessing instability episodes and defined any instability events between the MRI and ACL reconstruction as significant or insignificant. Patients were then grouped into a significant instability group (≥1 significant episode) and an insignificant instability group, and the incidence and types of meniscal tears found during surgery were compared between groups.Results:There were 108 study patients: 62 in the significant instability group and 46 in the insignificant instability group. During surgery, 58 meniscal tears (46 medial, 12 lateral) were recorded, for an overall meniscal injury rate of 53.70%. In the significant instability group, 47 patients (75.81%) had a meniscal tear and 15 (24.19%) had intact menisci (P < .001). In the insignificant instability group, 11 patients (23.91%) had a meniscal tear and 35 (76.08%) had intact menisci (P < .001). Regarding the 58 patients with a meniscal tear, 47 (81.03%) had ≥1 significant episode of instability before surgery, as compared with 11 (18.97%) who had insignificant or no instability. The odds of having a medial meniscal tear at ACL reconstruction was 10 times higher in the significant instability group versus the insignificant instability group.Conclusion:The incidence of a medial meniscal tear was 10 times greater in patients with a significant episode of instability versus those with insignificant instability, as defined using a predictive scoring system. The incidence of lateral meniscal tear did not change with instability episodes.

Concomitant Anterior Cruciate Ligament Reconstruction and Temporary Hemiepiphysiodesis in the Skeletally Immature: A Combined Technique.

Young athletes with an anterior cruciate ligament (ACL) disruption and limb malalignment pose a treatment dilemma. Little has been published regarding limb malalignment in this population. Our aim is to review the results of combined treatment of an ACL deficient knee and genu valgum in skeletally immature patients. A retrospective review of skeletally immature patients who underwent transphyseal ACL reconstruction and concomitant hemiepiphysiodesis between 2004 and 2015 by 1 surgeon at a single institution was performed. Included patients had at least a year of growth remaining and were followed to skeletal maturity. Patients with a diagnosis of a connective tissue disorder were excluded. Knee stability, rate of retear, the rate of mechanical axis correction, and time to full correction were determined. Ninety skeletally immature patients underwent transphyseal ACL reconstruction, 8 of which met inclusion criteria. Mean time to correction of the valgus deformity was 13 months (0.4 degree/mo). No patient required additional surgeries for malalignment. All patients had improvement in knee stability. One patient had a retear of their ACL reconstruction, for a failure rate of 13%. Preoperative mechanical lateral distal femoral angle and mechanical axis deviation corrected to near-neutral alignment for all treated limbs and were significantly different (P=0.001) than those measured preoperatively. Promising results were seen for simultaneous correction of genu valgum and transphyseal ACL reconstruction. Treatment of both pathologies in a concomitant surgery can be considered in the appropriate population, with expected results comparable to each procedure in isolation. Level IV-case series.

Anatomic anterior cruciate ligament reconstruction for adolescent patients with open physis

Pediatric anterior cruciate ligament reconstruction (ACLR) can be considered a safe procedure with low complication rates, provided that surgery is performed correctly. Correct timing and indication for surgery are of capital importance and should take into consideration the child’s maturation process and his/her individual needs and desires. In recent years, particular attention has been given to the role of conservative treatment and follow-up visits with clinical investigation, magnetic resonance and laxity testing. This appears of special importance, since the young ACL-deficient knee can evolve with patient’s growth. This article provides a synthetic overview on the state of the art of pediatric ACL tears epidemiology, diagnosis, conservative treatment and surgical approaches.

Static Lateral Tibial Plateau Subluxation Predicts the Grade of Rotatory Knee Laxity in ACL-Deficient Knees

Objectives: In anterior cruciate ligament-deficient (ACL-D) knees, injury pattern and bony morphology have been shown to influence both static anterior tibial subluxation relative to the femur and dynamic rotatory knee laxity. Therefore, the relationship between static anterior tibial subluxation and dynamic rotatory knee laxity was investigated. The goal of this study was to determine if static tibial subluxation as measured on magnetic resonance imaging (MRI) was associated with the grade of rotatory knee laxity in ACL-D knees. Methods: Two-hundred and fifty-eight knees underwent preoperative, image-guided assessment of lateral knee compartment translation during quantitative pivot shift (QPS). Subluxations of the medial and lateral tibial plateaus were measured on preoperative MRI in a subset of primary ACL-D knees meeting criteria for high-grade (QPS &gt; 5.2 mm) and low-grade (QPS &lt; 2.4 mm) rotatory laxity. Tibial subluxations on MRI were compared between patients with high- and low-grade rotatory laxity using pairwise t-test, and analyzed using uni- and multivariate logistic regression. Significance was set at p&lt;0.05. Results: On MRI, greater anterior subluxation of the lateral tibial plateau was observed in patients with high-grade compared to low-grade rotatory knee laxity (4.5 mm vs. 2.3 mm; p&lt;0.05). No similar relationship was observed for the medial tibial plateau (-0.9 mm vs. -0.4 mm; p&gt;0.05). Univariate logistic regression demonstrated that static subluxation of the lateral tibial plateau was associated with high-grade rotatory knee laxity (Odds ratio [OR] 1.2; p&lt;0.05). An optimal cut-off of 2.95 mm of static lateral tibial subluxation was associated with high-grade rotatory knee laxity (sensitivity: 75%; specificity: 63%). Lateral meniscus injury was the first variable to enter a multivariate regression analysis and proved to be most associated with high-grade rotatory knee laxity ([OR] 6.8; p &lt; 0.05). When lateral meniscus injury was excluded from multivariate regression analysis, static anterior subluxation of the lateral tibial plateau alone was associated with high-grade rotatory knee laxity ([OR] 1.2; p&lt;0.05). Conclusion: Data from this MRI study of two distinct rotatory knee laxity groups showed that static anterior subluxation of the lateral tibial plateau of 2.95 mm or greater was associated with high-grade rotatory knee laxity, and each millimeter increase of lateral tibial plateau subluxation was associated with a 1.2-fold odds of high-grade rotatory knee laxity. Anterior subluxation of the lateral tibial plateau on MRI was not independently associated with high-grade rotatory knee laxity in the presence of concomitant lateral meniscus injury. Static measurements made pre-operatively may aid in predicting high-grade rotatory knee laxity and refining the indications for individualized knee surgery.

Lateral Extra-Articular Tenodesis Reduces Failure of Hamstring Tendon Autograft ACL Reconstruction -Two Year Outcomes from the STABILITY Study Randomized Clinical Trial

Objectives: Persistent anterolateral rotatory laxity following anterior cruciate ligament reconstruction (ACLR) has been correlated with poor outcome and graft failure. We hypothesized that anterolateral complex reconstruction by way of a Lateral Extra-articular Tenodesis (LET) in combination with single bundle ACLR would reduce the risk of persistent rotatory laxity in young individuals who are deemed as being at high risk of failure. Methods: This is a pragmatic, multicenter, randomized clinical trial comparing standard hamstring tendon ACLR with combined ACLR and LET, utilizing a strip of iliotibial band (Modified Lemaire). Patients aged 25 years or less with an ACL deficient knee were included. They also had to have two of the following three criteria: 1) Grade 2 pivot shift or greater; 2) Returning to high risk/pivoting sports; 3) Generalized ligamentous laxity. The primary outcome was graft failure defined as either the need for revision ACLR or symptomatic instability associated with a positive asymmetric pivot shift, indicating persistent rotational laxity. Secondary outcome measures included the P4 pain scale, KOOS, IKDC. Patients were followed for two years with visits at 3, 6, 12 and 24 months postoperatively. A sample size of 300 per group was calculated based on a relative reduction in graft failure by 40%, with type 1 error of 5%, 80% power and 15% loss to follow-up rate. Results: 624 patients were randomized with a mean age of 18.9 (range: 14-25), 293 male. 436 (87.9%) patients presented pre-operatively with high-grade rotatory laxity (grade 2 pivot or greater) and 215 (42.1%) were diagnosed as having generalized ligamentous laxity (Beighton Score of 4 or greater). 523 of the 624 patients are at least 2 years postoperative; 29 lost to follow-up (˜5%). In the ACLR group 104/252 (41%) of patients suffered the primary outcome compared to 61/242 (25%) of the ACLR+LET patients (RR=0.61, 95%CI 0.47 to 0.79), p&lt;0.0001. 39 patients suffered graft rupture, 28/252 (11%) in the ACLR group compared to 11/242 (4.5%) in the ACL+LET group (RR=0.41, 95%CI 0.21 to 0.80, p&lt;0.001). At 3 months postoperative, patients in the ACLR group had less pain (p=0.004); at 3 and 6 months all KOOS subdomains, the IKDC favored the ACLR alone group (p=0.03). At 12 and 24 months, no important between-group differences were observed in any patient reported outcome. Conclusion: The addition of LET to a hamstring autograft ACLR in young active patients significantly reduces graft failure and persistent anterolateral rotatory laxity at 2 years post operatively.

Small Lateral Meniscus Tears Propagate and are Detrimental to Knee Kinematics and Contact Forces

Aims and Objectives: To quantify propagation of small vertical lateral meniscus tears located in the posterior horn during simulated cyclic cutting maneuvers on a robotic testing system and the resulting changes in knee kinematics and forces. Materials and Methods: 14 fresh-frozen human cadaveric knees (mean age: 74.8 ± 14.4) were mounted onto a 6-DOF robotic testing system. Knees with osteoarthritis greater than grade II were excluded. A small vertical tear in the posterior horn of the lateral meniscus medial to the popliteus tendon was created via a posterior arthrotomy. Tear length was measured with a custom-made device (accuracy 0.2 mm, inter-rater reliability 0.914). In 6 specimens, the ACL was resected arthroscopically, whereas in 8 knees the ACL was left intact. 10Nm valgus and 5Nm external rotation moment combined with 250N of axial compression were applied while the knees were continuously flexed from full extension to 90° of flexion for 500 cycles. Meniscus tear length was measured after each 100 cycles. After the measurements, the posterior capsule and skin were closed in a standardized fashion. Knee kinematics, the in situ force in the ACL, the resultant force in the lateral meniscus, and bony contact forces at the tibiofemoral joint were calculated at 30°, 60°, and 90° of knee flexion. A repeated measures ANOVA was used to compared the outcome parameters between knee states (p &lt; 0.05). Results: In intact knees, small vertical lateral meniscus tears propagated significantly from baseline to 100, 200, 300, 400, and 500 cycles (all p &lt; 0.001). This corresponds to a tear propagation of 28.7% ± 5.4%. Similarly, in ACL deficient knees meniscus tear propagation was significant throughout all sets of cycles (p = 0.001). This corresponds to a tear propagation of 26.1% ± 8.3%. While in intact knees, external tibial rotation was significantly increased by up to 45.5% after meniscus tear propagation, knee kinematics were not significantly affected in ACL deficient knees (NS). The resultant forces in the lateral meniscus increased with tear propagation in the intact knees by up to 54.1%. Likewise, the resultant forces in the lateral meniscus increased in the ACL deficient knees by up to 116.5% (p &lt; 0.05). In intact knees, bony contact forces at the tibiofemoral joint increased with meniscus tear propagation by up to 91.9% (p &lt; 0.05), which was comparable to ACL deficient knees. Conclusion: The data of this study suggest, that small vertical lateral meniscus tears propagate significantly regardless of the integrity of the ACL and after only 100 cycles of knee loading. The findings of the current robotic study are in contrast to recent clinical studies that found that small, vertical and stable tears in the posterior horn of the lateral meniscus could be left in situ. However, based on the current data, such tears do propagate over time regardless of the integrity of the ACL, which might alter knee kinematics and resultant forces in the lateral meniscus as well as bony contact forces at the tibiofemoral joint.

Slope reduction osteotomy decreases ACL graft forces and reduces anterior tibial translation under axial load - a biomechanical study

Aims and Objectives:To perform an anterior closing wedge osteotomy by 10° for slope reduction and investigate the effect of axial load and anterior drawer on forces on ACL graft, strain and femoro-tibial kinematics in a native, ACL-deficient and reconstructed knee.Materials and Methods:Ten cadaveric knees with an increased native slope were selected for this study based on CT meas-urements. An anterior closing-wedge osteotomy was performed by 10° and fixed with an external fixator. Tibial axial load (200 N, 400 N) was applied, while the tibial side was mounted on a free mov-ing X-Y-table with open rotation in 30° of knee flexion. Additionally, an anterior drawer (134 N) was performed with and without axial load (200 N). Specimens underwent native testing, cut ACL, and reconstructed ACL with a standardized quadruple semi-t/gracilis-allograft. Each condition was ran-domly tested with native slope and reduced slope. Change of forces on ACL-graft (attached load-cell) and strain on native ACL (via DVRT) were recorded. Throughout testing, 3D motion tracking captured anterior tibial translation (ATT) and rotation versus the fixed femur.Results:Preoperative, specimens showed an averaged lateral and medial slope of (average ±SD) 10° ± 1.4°, and age 48.2 ± 5.8years.Slope reduction significantly decreased forces on ACL graft by 17% (p=0.001) at 200 N and by 33% (p=0.0001) at 400 N of axial load. Furthermore, ATT was significantly decreased after slope reduc-tion in native (p=0.01), cut (p=0.005), and ACL-graft (p=0.01) status. Strain in native ACL de-creased by 9.7 ± 0.13% (p<0.0001) after slope reduction without any load. However, anterior drawer without axial load maintained significantly higher anterior tibial translation (native-pre 4.12 ± 0.65 mm vs. native-post 5.82 ± 1.51 mm, cut-ACL-pre 9.35 ± 1.57 mm vs cut-ACL-post 12.0 ± 3.53 mm, ACL-recon-pre 4.60 ± 0.97 mm vs. ACL-recon-post 5.73 ± 1.45 mm) and significantly higher forces on ACL graft (p=0.0006) after osteotomy. When axial load was combined with anterior drawer no significant change on ATT after osteotomy was observed. Rotational analysis did show a significant effect in the ACL cut condition due to slope correction. Overall, native and reconstruct-ed ACL showed the same tibial kinematics throughout testing.Conclusion:In general, osteotomy lowered ACL graft force and ACL strain when the joint was axially loaded. Anterior tibial translation was reduced even in an ACL deficient knee. When anterior drawer was performed without axial load, ATT was higher after slope reduction in every condition.

The Stability study: a protocol for a multicenter randomized clinical trial comparing anterior cruciate ligament reconstruction with and without Lateral Extra-articular Tenodesis in individuals who are at high risk of graft failure

BackgroundThe purpose of anterior cruciate ligament reconstruction (ACLR) is to restore stability to the knee. Persistent rotational laxity following ACLR has been correlated with poor outcome and graft failure. We hypothesize that anterolateral complex reconstruction by way of a Modified Lemaire Lateral Extra-articular Tenodesis (LET) in combination with single bundle ACLR would reduce the risk of persistent rotatory laxity in young individuals who are deemed as being at high risk of failure. We will conduct a pragmatic, multicenter, randomized clinical trial comparing standard single bundle hamstring ACLR with combined ACLR and LET.MethodsSix-hundred patients (300 per group) aged 25 years or less with an ACL deficient knee that meet two of the following three criteria will be included: 1) Grade 2 pivot shift or greater; 2) Returning to high risk cutting or pivoting sports; 3) Generalized ligamentous laxity. Participants will be seen at 3-months, 6-months, 12-months and 24-months post-operatively. The primary outcome measure is graft failure requiring revision ACLR or symptomatic instability associated with a positive asymmetric pivot shift indicating persistent rotational laxity. Patients will complete secondary outcome measures at each follow-up visit including patient-reported outcome measures, functional and biomechanical testing, and magnetic resonance imaging.DiscussionThis protocol is the first adequately powered randomized clinical trial investigating the effects of augmenting ACLR with an LET in patients at high-risk of graft failure. The successful completion of this trial has the potential to change surgical practice and provide evidence for the role of the LET in ACLR.Trial registrationThe trial is registered at ClinicalTrials.gov: NCT02018354, 23-12-2013.

Ramp lesions are frequently missed in ACL-deficient knees and should be repaired in case of instability

PurposeThe aim of the current study was (1) to provide an overview of common definitions and classification systems of ramp lesions (RL) and (2) to systematically review the available literature with regard to the diagnosis and treatment of RLs in anterior cruciate ligament (ACL)-deficient knees.MethodsFollowing the PRISMA guidelines, MEDLINE and Scopus were searched for articles (1) reporting on acute or chronic ACL injuries, (2) with concomitant medial meniscus injury, (3) located at the posterior meniscocapsular attachment site (and red–red zone). Ex vivo studies, reviews and technical notes were excluded.ResultsTwenty-seven studies were included based on the criteria mentioned above. RLs are common in ACL-deficient knees with a prevalence ranging from 9 to 24%. RLs should especially be suspected in younger patients, patients with an increased meniscal slope and in patients with prolonged time from injury to surgery. The sensitivity of MRI for the detection of RLs ranges from 48 to 86% at a specificity of 79–99%. For arthroscopy, RLs are easily missed through standard anterior portals (sensitivity 0–38%). RL repair leads to a significant improvement of subjective knee scores, regardless of the specific fixation technique. For stable RLs, the literature suggests equivalent postoperative stability for trephination and abrasion compared to surgical RL repair.ConclusionRamp lesions are frequently missed in ACL-deficient knees on standard arthroscopy with anterior portals only. If a RL is suspected, exploration via an additional posteromedial portal is indicated. In case of instability, RL repair should be performed.Level of evidenceIV.

Muscular Force Patterns during Level Walking in ACL-Deficient Patients with a Concomitant Medial Meniscus Tear.

Background The abnormal knee joint motion patterns caused by anterior cruciate ligament (ACL) deficiency are thought to be associated with articular cartilage degeneration. High rates of meniscus tear combined with ACL rupture are observed, and these knees suffer a higher risk of early cartilage degeneration. Research Question This study investigated lower limb muscular force patterns of ACL-deficient knees with a concomitant medial meniscus tear. Methods 12 volunteers and 22 patients were recruited, including 12 patients with isolated ACL deficiency (ACLD) and 10 ACL-deficient patients with a concomitant medial meniscus tear (ACLDM). Level walking data at a self-selected speed were collected before surgery. Then, a musculoskeletal dynamic analysis system, AnyBody, was applied to simulate tibiofemoral flexion moments and muscle forces. Results Our results indicate that the tibiofemoral peak flexion and extension moments in ACLDM patients are significantly lower than in controls. The rectus femoris force in ACLDM patients was significantly lower than in isolated ACL-deficient patients and the controls during mid and terminal stance phase, while no significant difference was found in hamstring and vastus force. Additionally, the gastrocnemius force in ACL-deficient patients both with and without a medial meniscus tear was lower than in controls during mid-stance phase. Significance The ACLDM patients had lower peak tibiofemoral flexion moment, lower gastrocnemius force in mid-stance phase, and lower rectus femoris force during the mid and terminal stance phase. These results may help clinicians to better understand the muscle function and gait pattern in ACL-deficient patients with a concomitant medial meniscus tear.

Influence of a posteromedial meniscocpsular injury on the tibiofemoral joint laxity: A cadaveric study

Objectives Up to 61% of meniscal tears can be associated with ACL ruptures. These lesions lead to anterior and rotary laxity increase. Posterior peripheral meniscocaspsular tear of medial meniscus is also called ramp lesion. Prevalence of this kind of lesion is 9% to 17% in adults and up to 23% in pediatric popultation. The aim of this study was to determined anterior laxity of cadaveric ACL deficient knees. Hypothesis was to find a correlation between size of ramp lesion and laxity in order to determine a threshold of size for which reparation is mandatory. Methods Twelve fresh cadaveric knees were explored for the study. Two knees was excluded because they presented major lesions of osteoarthritis and ACL and meniscal tears. 10 remaining knees were from 3 males and 2 females. Mean age at time of death was 86 years old. Dynamic laximetry with GNRB device was made in several conditions: Knee without any intervention, full of water knee, after ACL rupture and after ACL rupture and increasing sizes of ramp lesions up to 30 mm. Anteroposterior laxity was measured at each time with 3 kind of loading charge (134 N, 200 N and 250 N). Results After ACL section only, tibiofemoral joint anterior laxity was significatively increased. Mean increasing was 156% whatever is the loading force. No statistical laxity difference was find between knees with ACL tears only and knees with ACL and meniscal tears for each size of ramp lesions. Increasing size of ramp lesion was not correlated to increasing of laxity. We could not be able to determine a threshold for ramp lesion reparation. Conclusion: GNRB® is a valid device of knee laxity measure, escpecially for ACL deficient knee. Despite use of this performing tool, we can’t confirm our hypothesis. Stephen et al in 2015 have shown, with cadaveric study, significant increase of anterior tibial translation and rotary laxity in knees with extended ramp lesions. There is no data about a ramp lesion size threshold with clinical relevance. GNRB gives reliable measures of laxity in ACL deficient knees. We could not find a threshold size of ramp lesion which increase tibial anterior laxity. Cadaveric rotary laxity has to be also studied to find this threshold.