ACL-deficient Knee Research Articles

Anterior cruciate ligament-deficient knee induces a posterior location of the femur in the medial compartment during squatting.

Although an anterior cruciate ligament (ACL) deficiency induces knee osteoarthritis, particularly in the medial compartment, the kinematics remains partially unclear. This study investigated the in vivo knee kinematics of ACL-deficient and normal knees by comparing them during squatting. This prospective comparative study included 17 ACL-deficient knees and 20 normal knees. The kinematics was investigated under fluoroscopy using a two- to three-dimensional registration technique. The anteroposterior (AP) translation of the medial and lateral sides of the femur, axial rotation of the femur relative to the tibia, and kinematic pathways were evaluated and compared. At first, the medial AP position of the femur translated anteriorly from 0° to midflexion, afterward it translated posteriorly in both ACL-deficient and normal knees. However, the medial AP position of the femur in the ACL-deficient knees was located significantly posteriorly compared with normal knees at 0-110° flexion. The lateral AP position of the femur translated posteriorly from 0° to 150° flexion in both ACL-deficient and normal knees. The lateral AP position of the femur in the ACL-deficient knees was located significantly posteriorly compared with that in normal knees at 0-10° flexion. The femur showed external rotation from 0° to 150° flexion in both ACL-deficient and normal knees. A medial pivot motion and subsequent bicondylar rollback were observed in both knees in the kinematic pathway. In conclusion, the AP position of the femur relative to the tibia was altered due to ACL deficiency, particularly in the medial compartment.

Double-bundle ACL reconstruction versus anatomic single-bundle ACL reconstruction combined with anterolateral ligament reconstruction: a comparative study of clinical outcome.

Recent studies showed increasing evidences of anterolateral ligament (ALL) reconstruction in conjunction with anterior cruciate ligament (ACL) reconstruction that proves to be more superior to the previous double-bundle (DB) ACLR technique especially in improving knee stability in biomechanic studies. However to date, there have been no studies evaluating the functional outcome of DB-ACLR vs single-bundle (SB) with ALL in ACLR. A total of 138 patients with ACL deficient knee were enrolled to the study. Double-bundle ACL reconstruction (DB-ACLR) was performed in 75 patients and single-bundle ACL reconstruction with anterolateral ligament reconstruction (SB + ALL) ACLR was performed in 63 patients. Surgical outcomes were compared with The International Knee Documentation Committee Subjective Knee Form (IKDC) and the Kujala score at the 3rd, 6th and 9th month post-operative. The IKDC score in the 3rd and 6th month was superior in the SB + ALL group compared to the DB group. However, this difference was not statistically significant. In the meantime, there were no statistically significant difference between the Kujala Score at the 3rd, 6th, and 9thmonths consecutively. There were no statistically significant differences in the functional outcomes of DB-ACLR and SB + ALL groups at the 3rd, 6th, and 9thmonths post-operative period. The functional outcome comparison showed non-superiority of SB + ALL group compared to the DB-ACLR group. The patellar pain was less found in DB-ACLR group at 6- and 9-months post-operative period.

The Clinical Application of Machine Learning Models for Risk Analysis of Ramp Lesions in Anterior Cruciate Ligament Injuries

Background: Peripheral tears of the posterior horn of the medial meniscus, known as “ramp lesions,” are commonly found in anterior cruciate ligament (ACL)–deficient knees but are frequently missed on routine evaluation. Purpose: To predict the presence of ramp lesions in ACL-deficient knees using machine learning methods with associated risk factors. Study Design: Cohort study (Diagnosis); Level of evidence, 2. Methods: This study included 362 patients who underwent ACL reconstruction between June 2010 and March 2019. The exclusion criteria were combined fractures and multiple ligament injuries, except for medial collateral ligament injuries. Patients were grouped according to the presence of ramp lesions on arthroscopic surgery. Binary logistic regression was used to analyze risk factors including age, sex, body mass index, time from injury to surgery (≥3 or <3 months), mechanism of injury (contact or noncontact), side-to-side laxity, pivot-shift grade, medial and lateral tibial/meniscal slope, location of bone contusion, mechanical axis angle, and lateral femoral condyle (LFC) ratio. The receiver operating characteristic curve and area under the curve were also evaluated. Results: Ramp lesions were identified in 112 patients (30.9%). The risk for ramp lesions increased with steeper medial tibial and meniscal slopes, higher knee laxity, and an increased LFC ratio. Comparing the final performance of all models, the random forest model yielded the best performance (area under the curve: 0.944), although there were no significant differences among the models (P > .05). The cut-off values for the presence of ramp lesions on receiver operating characteristic analysis were as follows: medial tibial slope >5.5° (P < .001), medial meniscal slope >5.0° (P < .001), and LFC ratio >71.3% (P = .033). Conclusion: Steep medial tibial and meniscal slopes, an increased LFC ratio, and higher knee rotatory laxity were observed risk factors for ramp lesions in patients with an ACL injury. The prediction model of this study could be used as a supplementary diagnostic tool for ramp lesions in ACL-injured knees. In general, care should be taken in patients with ramp lesions and its risk factors during ACL reconstruction.

Identification of Kinetic Abnormalities in Male Patients after Anterior Cruciate Ligament Deficiency Combined with Meniscal Injury: A Musculoskeletal Model Study of Lower Limbs during Jogging.

There is little known about kinetic changes in anterior cruciate ligament deficiency (ACLD) combined with meniscal tears during jogging. Therefore, 29 male patients with injured ACLs and 15 healthy male volunteers were recruited for this study to investigate kinetic abnormalities in male patients after ACL deficiency combined with a meniscal injury during jogging. Based on experimental data measured by an optical tracking system, a subject-specific musculoskeletal model was employed to estimate the tibiofemoral joint kinetics during jogging. Between-limb and interpatient differences were compared by the analysis of variance. The results showed that decreased knee joint forces and moments of both legs in ACLD patients were detected during the stance phase compared to the control group. Meanwhile, compared with ACLD knees, significantly fewer contact forces and flexion moments in ACLD combined with lateral and medial meniscal injury groups were found at the mid-stance, and ACLD with medial meniscal injury group showed a lower axial moment in the loading response (p < 0.05). In conclusion, ACLD knees exhibit reduced tibiofemoral joint forces and moments during jogging when compared with control knees. A combination of meniscus injuries in the ACLD-affected side exhibited abnormal kinetic alterations at the loading response and mid-stance phase.

A combined anterior cruciate ligament/Meniscal injury alters the patellofemoral joint kinematics of anterior cruciate ligament-deficient knees during a single-leg lunge exercise: A cross-sectional study.

Anterior cruciate ligament deficiency (ACLD) is often accompanied by concomitant meniscal tears. The study aimed to assess the kinematic alterations of patellofemoral joint (PFJ) in anterior cruciate ligament deficiency knees with or without meniscal tears during a single-leg lunge. Sixty unilateral anterior cruciate ligament deficiency patients were recruited for the study, including 15 isolated anterior cruciate ligament deficiency patients (group 1), 15 anterior cruciate ligament deficiency patients with medial meniscal tears (group 2), 15 patients with lateral meniscal tears (group 3) and 15 patients with combined medial/lateral meniscal tears (group 4). The patellofemoral joint kinematics were determined by a single fluoroscopic image system. Patellofemoral joint kinematics of contralateral anterior cruciate ligament-intact (ACLI) and anterior cruciate ligament deficiency knees were compared. With or without meniscal tears, anterior cruciate ligament deficiency knees had significantly smaller patellar flexion than the anterior cruciate ligament-intact knees (∼5°-10°; p < 0.05). anterior cruciate ligament deficiency knees had more patellar lateral tilting by approximately 1°-2° than the anterior cruciate ligament-intact knees (p < 0.05) in groups 2, 3, and 4. anterior cruciate ligament deficiency groups with medial meniscal deficiencies showed consistent increased lateral patellar translations (2-4mm) compared to the anterior cruciate ligament-intact group during a single-leg lunge. The results indicate that meniscal tears alter anterior cruciate ligament deficiency patients' patellofemoral joint kinematics and the types of the meniscal injuries also affect the patellofemoral joint kinematics. Considering the varying effects of meniscal tears on the patellofemoral joint kinematics, specific treatments for anterior cruciate ligament deficiency patients with meniscal tears should be proposed in some closed kinetic chain (CKC) exercise programs, such as single-leg lunge.

Increased Time to Surgery After Anterior Cruciate Ligament Tear in Female Patients Results in Greater Risk of Medial Meniscus Tear: A Study of 489 Female Patients

This study assessed the incidence of meniscal tears in ACL deficient knees considering the time between injury and reconstruction in a large sample of female patients. Furthermore, we evaluated whether the rate of meniscal repair or meniscectomy was affected by age and BMI. The medical records of 489 patients who underwent ACL reconstructive surgery between January 2011 and April 2021 were analyzed to collect data on the prevalence of meniscal tears, surgical timing, patient age, and BMI. Logistic regression was performed to estimate the association between the prevalence of meniscal tears and the independent variables of surgical timing, age, and BMI. Between 24 and 60 months after their injury, female patients show a statistically significant increase in the presence of associated meniscal lesions when compared to ACL reconstruction performed earlier [OR= of 3.58 (95% CI)] especially for medial meniscal tears with an OR of 1.94 (95% CI 1.23-3.05, p=0.004) between 12 and 24 month. There is a statistically significant difference after 12 months in the rate of meniscal suturing for medial meniscus tears [OR: 3.30 CI 1.37-7.91 p=0.007). Increasing age was associated with a higher prevalence of meniscal tears up to 30-50 years ], but there was no clear association between BMI and associated lesions other than a higher rate of meniscectomies CONCLUSION: In female patients who experienced an ACL injury, a delay in surgery greater than 12 months is associated with a gradual increase in the risk of non-repairable medial meniscal tear; this risk becomes statistically significant after 24 months. A high BMI does not seem to have relevance in the onset of associated lesions in women but results in a higher rate of meniscectomies compared to meniscal sutures, while age between 30 and 50 is associated with a greater risk of associated injuries.

How Does Anterior Cruciate Ligament Incompetence Influence the Varus Osteoarthritic Knee?

Introduction: The aims of our study were: (i) to assess the correlation of anterior cruciate ligament (ACL) deficiency with severity of preoperative varus deformity in osteoarthritic knees, (ii) to compare posterior medial femoral condyle (MFC) changes in ACL deficient vs ACL competent knees, and (iii) to compare the mean femoral external rotation of ACL deficient vs ACL competent knees. Methods: 250 consecutive ACL deficient and ACL competent patients each, undergoing total knee arthroplasty (TKA) for osteoarthritis with a varus deformity were reviewed retrospectively. Data from a prospectively collected computer navigation assisted TKA database was analyzed for an association between ACL insufficiency and: severity of the varus deformity, incidence of posterior MFC compensatory changes, and the magnitude of femoral component external rotation. Results: A statistically significant positive correlation was found between ACL incompetence and- (1) Severity of the knee varus deformity (p < 0.001), (2) Incidence of compensatory posterior MFC hypertrophy (p < 0.001) and (3) Femoral component external rotation required to balance the knee in flexion during TKA (p < 0.001). Conclusion: ACL deficiency is associated with an increase in the severity of the varus deformity. A significantly higher incidence of posterior MFC hypertrophy and increased values of the combined Whiteside-PCA angle are noted in ACL deficient knees compared with knees with an intact ACL. Multiple intraoperative landmarks must be assessed for setting femoral component rotation while performing TKA in the ACL deficient knee.

No Difference Unicompartmental Knee Arthroplasty for Medial Knee Osteoarthritis With or Without Anterior Cruciate Ligament Deficiency: A Systematic Review and Meta-analysis

BackgroundA functional intact anterior cruciate ligament (ACLI) is considered to be a prerequisite for unicompartmental knee arthroplasty (UKA). However, UKA has been shown to have good clinical efficacy in ACL-deficient (ACLD) knees at 3 to 10 years follow-up. Therefore, the role of ACLD in UKA remains controversial, and more evidence is needed to clarify the role of ACLD in UKA. MethodsPubMed, the Web of Science, EMBASE, and Cochrane Central were queried for articles comparing the results of the ACLD and ACLI groups after UKA. Outcomes of interest included the Tegner Activity Scale, the Oxford Knee Score (OKS), postoperative slope of the implant (PSI), the Knee Injury and Osteoarthritis Outcomes Score (KOOS), the Lysholm score, and revision rate. There were eight studies included. The mean age was 66 years (range 49 to 87 year old) and the mean follow-up time was 6.9 years (range 1.3 to 16.6 years). There was baseline comparability regarding mean age, duration of follow-up, and body mass index (P > .5) between the ACLD and ACLI groups. ResultsThe ACLD and ACLI groups had improved postoperative functional indicators, and that postoperative revision rate (mean difference [MD], 1.24; 95% confidence interval [CI], 0.75 to 2.04; P = .4), Tegner score (MD, −0.1; 95% CI, −0.26 to 0.05; P = .19), and Lysholm score (95% CI, −2.46 to 7.32; P = .33) were similar between the groups, with no significant differences; however, the ACLD groups had significantly better KOOS Activities of Daily Living scores, with a significant difference (MD, 4.53; 95% CI, 1.75 to 7.3; P = .001). Also, there were no significant differences between two groups in the PSI, OKS, KOOS. ConclusionACL deficiency is not always a contraindication for UKA. With correct patient selection, UKA could be considered for medial knee osteoarthritis with ACL deficiency without antero-posterior instability, especially these people over 60 years of age.

Importance of posterior tibial slope in joint kinematics with an anterior cruciate ligament-deficient knee.

To fully quantify the effect of posterior tibial slope (PTS) angles on joint kinematics and contact mechanics of intact and anterior cruciate ligament-deficient (ACLD) knees during the gait cycle. In this controlled laboratory study, we developed an original multiscale subject-specific finite element musculoskeletal framework model and integrated it with the tibiofemoral and patellofemoral joints with high-fidelity joint motion representations, to investigate the effects of 2.5° increases in PTS angles on joint dynamics and contact mechanics during the gait cycle. The ACL tensile force in the intact knee was significantly affected with increasing PTS angle. Considerable differences were observed in kinematics and initial posterior femoral translation between the intact and ACLD joints as the PTS angles increased by more than 2.5° (beyond 11.4°). Additionally, a higher contact stress was detected in the peripheral posterior horn areas of the menisci with increasing PTS angle during the gait cycle. The maximum tensile force on the horn of the medial meniscus increased from 73.9 N to 172.4 N in the ACLD joint with increasing PTS angles. Knee joint instability and larger loading on the medial meniscus were found on the ACLD knee even at a 2.5° increase in PTS angle (larger than 11.4°). Our biomechanical findings support recent clinical evidence of a high risk of failure of ACL reconstruction with steeper PTS and the necessity of ACL reconstruction, which would prevent meniscus tear and thus the development or progression of osteoarthritis.Cite this article: Bone Joint Res2022;11(10):708-719.

Relooking at double-bundle versus single-bundle anterior cruciate ligament reconstruction: A biomechanical model to evaluate which can confer better rotatory stability

BackgroundTo treat anterior cruciate ligament (ACL) injuries, double-bundle ACL reconstruction has been proposed as a more anatomical approach relative to single-bundle reconstruction. However, controversy remains over which technique is superior in addressing knee instability, particularly rotational laxity. We hypothesize that double-bundle reconstruction better restores rotational knee laxity, while both methods are similar in restoring anterior knee laxity, to intact knee levels. MethodsA controlled laboratory study. Eight cadaveric knees were tested accordingly: (1) static anterior laxity testing under 150 N-anterior tibial loading at 20°, 60° and 90° knee flexion using a material testing machine, followed by (2) dynamic simulated pivot-shift with knee-specific loading involving iliotibial band forces, valgus and internal rotation torques, while the knee was brought from extension to 90° flexion on a 6°-of-freedom custom-designed rig. Tibiofemoral kinematics were recorded using an electromagnetic tracking system for the ACL-intact, ACL-deficient, single-bundle and double-bundle ACL-reconstructed knee conditions. FindingsDouble-bundle reconstruction reduced internal rotation under pivot-shift to levels not significantly different from ACL-intact conditions (P > .173), unlike single-bundle that remained significantly higher at 10–40° flexion (P < .05). For anterior laxity, there was no significant difference between double-bundle, single-bundle, and ACL-intact conditions under static testing (P > .175) or pivot-shift (P = .219). The maximum extent of knee envelope laxity was significantly reduced for double-bundle relative to single-bundle, particularly for the rotatory component (P = .012). InterpretationDouble-bundle was biomechanically superior to single-bundle in addressing envelope of rotation, while both techniques restored anterior knee laxity to ACL-intact levels.

The posterior cruciate ligament-posterior femoral cortex angle: a reliable and accurate MRI method to quantify the buckling phenomenon of the PCL in ACL-deficient knees.

The aim was to validate a new MRI method to measure the buckling phenomenon of the PCL, representative of anterior tibial translation, by comparing its reliability and accuracy to identify anterior cruciate ligament (ACL)-deficient knees with existing methods. Patients were selected retrospectively and separated into a group of primary ACL injuries and ACL-intact knees. Exclusion criteria were: skeletal immaturity, PCL or a concomitant collateral ligament injury, signs of osteoarthritis (> 1 Kellgren and Lawrence score), tibial plateau fracture, previous ACL reconstruction or displaced meniscal bucket handle tear. The assessment of the curvature of the anterolateral bundle of the PCL was performed on T2 sagittal MRI slices according to 3 methods: (1) the PCL angle (PCLA), (2) the PCL inclination angle (PCLIA) and (3) a new method: the PCL-posterior cortex angle (PCL-PCA), representing the angle between the vertical part of the PCL-ALB and the posterior diaphyseal cortex of the femur. For each method, the inter- and intra-observer reliability was measured. The ability to discriminate both ACL-deficient and ACL-intact knees was evaluated using ROC curves. Twenty-four patients were included in each group. Intra-observer reliability was excellent for all 3 methods (ICCs > 0.90). Inter-observer reliability was excellent for the PCL-PCA (ICC > 0.90) and good for the PCLA and the PCLIA (ICCs between 0.75 and 0.90). The PCL-PCA had the highest precision (lowest standard error of measurement: 2.7°). It yielded an excellent discrimination between the ACL and CTL groups (AUC 0.80 [0.67-0.93]) with the highest sensitivity (71% [52.8-89.2]) and specificity (88% [75-100]) for a positive threshold when the angle was ≤ 22.7°. The PCLA and PCLIA methods led to acceptable discrimination and lower sensitivities and specificities (PCLA: AUC 0.71, sensitivity 63%, specificity 79%, threshold ≤ 117.9°; PCLIA: AUC 0.62, sensitivity 50%, specificity 83%, threshold ≤ 21.4°). In comparison with previously described methods, the PCL-PCA was the most reliable and accurate method to measure the PCL buckling phenomenon on MRI in anterior cruciate ligament (ACL)-deficient knees. It offers an easy and objective method for the follow-up of ACL-injured patients and can therefore be recommended for routine use. IV.

Unicompartmental Knee Arthroplasty in the ACL Deficient Knee

Unicompartmental Knee Arthroplasty in the ACL Deficient Knee

Combined Anterior Cruciate Ligament and Lateral Extra-Articular Reconstruction

AbstractThe anterolateral complex (ALC) of the knee has received renewed research interest because of the potential role of this anatomic region in anterior cruciate ligament (ACL) tear biomechanics and surgical treatment outcomes. The primary structures of the ALC include the iliotibial band deep (Kaplan) fibers, the anterolateral ligament (ALL), and the capsulo-osseous layer (COL) of the iliotibial band, although there remains disagreement on the precise anatomic locations and biomechanical relevance of these structures. Sectioning studies in the ACL-deficient knee have revealed a contribution of the ALC in restraining tibial internal rotation and anterior translation. Biomechanical studies have revealed a potential role for lateral extra-articular reconstruction as an augmentation to ACL reconstruction in knees with combined ACL and ALC sectioning. Clinical studies have reported a reduced ACL reconstruction failure rate with both ALL reconstruction and lateral extra-articular tenodesis procedures.

Walking in the Absence of Anterior Cruciate Ligament: The Role of the Quadriceps and Hamstrings

The actual need for surgical reconstruction of an injured anterior cruciate ligament (ACL) is still a matter of debate. The aim of this study was to quantify and analyze the knee kinematics and the ligament force redistribution resulting from the ACL sacrifice and the consequent effects of changing the quadriceps and hamstring activity during walking. A three-dimensional musculoskeletal model was used to simulate the behavior of the knee joint during the gait cycle, in different testing conditions: an ACL-deficient knee, an ACL-deficient knee with hamstrings inactivated and an ACL-deficient knee with quadriceps inactivated. Our results showed that in the ACL-deficient knee, the medial collateral ligament (MCL) was the main passive stabilizer of the anterior translation of the tibia. Furthermore, the compensation effects produced by the hamstrings and quadriceps in the ACL-deficient knee during walking were quantified and analyzed. In the case of ACL sacrifice, reducing the quadriceps activity would allow for relieving all ligaments in general, except for the posterior cruciate ligament, which required more consistent recruitment in the support phase. Meanwhile, hamstring activity was crucial not only to compensate for the absence of ACL in limiting the anterior tibial displacement but also to reduce the risk of MCL injury.

Is combined robotically assisted unicompartmental knee arthroplasty and anterior cruciate ligament reconstruction a good solution for the young arthritic knee?

Anterior cruciate ligament (ACL) deficiency can be a consequence or a cause of femoro-tibial osteoarthritis (OA). Several studies have published satisfactory outcomes of unicompartimental knee arthroplasty (UKA) and combined ACL reconstruction despite its absence classically being considered a contraindication. A major challenge in the ACL deficient knee is obtaining appropriate gap balancing and limb axis. Robotically assisted UKA allows for precise control of these factors; however, it's utilisation as a tool with combined ACL reconstruction and UKA has not been described. The purpose of this study was to evaluate the clinical and radiological outcomes of robotically assisted UKA with combined ACL reconstruction. This was a retrospective single-centre study of ten patients operated by a single surgeon from 2016 to 2020. All surgery was performed using a cemented fixed bearing UKA prosthesis (Journey uni, Smith and Nephew®) (8 medial, 2 lateral) inserted with the assistance of an image-free robotic-assisted system (BlueBelt, Navio, Smith and Nephew®). All ACL reconstructions were performed using hamstring autograft. Clinical assessment included International Knee Score (IKS) score, Tegner score and patient satisfaction. Radiological assessment was performed to assess radiolucent lines, progression of OA in the other compartments, Hip-Knee-Ankle angle and Posterior Tibial Slope. There were eight females (80%), mean age was 57 ± 7 [48-70], mean BMI was 26 ± 3 [22-31]. The mean follow-up was 45months ± 13months [24-66]. Mean post-operative IKS knee and function score were respectively 96 ± 4.5 [88-100] and 93 ± 8.2 [74-100], mean Tegner score was 4.5 ± 1.4 [3-6]. Nine patients (90%) returned to sport; one patient (10%) was dissatisfied because of residual pain preventing a return to a desired level of sport. 100% of the radiological objectives were achieved. No radiolucent lines were seen at the last follow-up. There were two re-operations (20%) for stiffness requiring arthroscopic arthrolysis at two and threemonths respectively following surgery, with full recovery of the flexion at the last follow-up in both cases. No other complications were observed. Robotic UKA associated with ACL reconstruction provides satisfactory early patient outcomes and accurate implant positioning. The first results in terms of return to sports were promising.

Effect of Time After Injury on Tibiofemoral Joint Kinematics in Anterior Cruciate Ligament-Deficient Knees During Gait.

Background:Anterior cruciate ligament (ACL) injury can lead to changes in tibiofemoral kinematics during gait, but the detailed short-term kinematic changes after ACL injury are still unknown.Purpose:To measure tibiofemoral kinematics during gait in ACL-deficient (ACLD) knees over time after ACL injury.Study Design:Controlled laboratory study.Methods:The authors categorized 76 patients with unilateral ACLD knees into 4 groups based on the time from injury: <3 months (group 1), 3 to 6 months (group 2), >6 to 12 months (group 3), and >12 months (group 4). The controls were 20 participants with ACL-intact knees. Changes in the knee kinematics and range of motion during gait were compared among ACLD groups and those with ACL-intact knees.Results:Compared with controls, the range of motion of flexion in group 1 was significantly lower (6°; P = .033), and the mean knee flexion was significantly increased (0.7°-3.4°) in groups 1 to 4 (all P ≤ .004). There was more internal tibial rotation (2.9°-4.3°) in group 1 and 2, and more anterior tibial translation (4.3 mm) in group 1 during the stance or swing phases than in controls (P ≤ .049 for all). The mean internal tibial rotation and anterior tibial translation significantly decreased from group 1 to group 4 (P < .001 for both). Compared with controls, the mean medial tibial translation was significantly greater (1.2-2.5 mm) in all groups, and more medial tibial translations (2.4-3.7 mm) were observed during the stance phase in groups 1, 3, and 4 (P ≤ .047 for all).Conclusion:ACLD knees displayed a motion impairment walking strategy within 3 months, and a higher-flexion walking strategy increased with time after injury. Excessive anterior translation and internal rotation of the tibia tended to return to normal, while excessive medial translation of the tibia increased in ACLD knees after 6 months postinjury. These results may provide new insight into the compensatory mechanisms and risk factors for premature osteoarthritis in ACLD knees.

Evaluation of Pivot Shift under Anesthesia in Anterior Cruciate Ligament (ACL) Deficient knees

Background: Knee injuries are common injuries sustained in sports or accidents (domestic, road traffic, etc.).These injuries affect the different structures of the knees, affecting the skin, muscles, bone, ligaments, tendons, etc. Some of the structures are extra-articular and others are intra-articular. There are a lot of different ways that the anterior cruciate ligament (ACL) can be torn. The most common are low-speed, non-contact, deceleration, and contact injuries with a rotational component. Contact sports can also cause twisting, valgus stress, or hyperextension from direct contact or collision-related ACL secondary injuries. The pivot is one of these injuries. The shift test for anterolateral stability of the knee It is a painful test, so most of the patients will not cooperate if not under anesthesia. Objective: This study evaluates the angle of displacement of the tibia in relation to the femur at 30-degree knee flexion, knee extension, and the difference between knee flexion and knee extension. It also determined the angular estimation as outlined above after reconstruction. To compare the angular displacement in the pivot shift before and after reconstruction in an ACL-deficient knee. Methods: This study was conducted in the department of orthopedics, arthroscopy, and sports medicine at Aware Global Hospital, Hyderabad, India. The study was initiated from January 2015 to March 2015. Through inclusion criteria, 15 patients with knee instability were included in the study. Results: After completing the pivot shift test using spinal anesthesia, the knee was flexed to 30 degrees. Three K-wires are placed in three key locations. Compared to the affected knee, the angular displacement in flexed and extended knees is a more reliable and sensitive method for screening anterior instability of the knee due to ACL tear. It is also a low-cost method when specialized medical diagnostic tests are not available. Compared to MRI, it is a dynamic modality and has proven to be just as reliable in diagnosing ACL injuries.

Kinematic Analysis of Lateral Meniscal Oblique Radial Tears in Anterior Cruciate Ligament–Reconstructed Knees: Untreated Versus Repair Versus Partial Meniscectomy

Background: Lateral meniscal oblique radial tears (LMORTs) affect joint and meniscal stability in anterior cruciate ligament (ACL)–deficient knees. Purpose: To determine the clinically relevant kinematics associated with the most common posterior horn LMORT lesion types, types 3 (LMORT3) and 4 (LMORT4), untreated versus arthroscopic repair versus partial meniscectomy in combination with ACL reconstruction (ACLR). Study: Controlled laboratory study. Methods: Sixteen cadaveric knees underwent robotic testing for anterior drawer and pivot-shift simulations at multiple knee flexion angles in ACL-intact and ACL-deficient states, followed by sequential testing of arthroscopic ACLR, LMORT3 lesion, LMORT3 repair, and partial meniscectomy (n = 8). The same testing sequence was performed for LMORT4 lesions (n = 8). Results: ACLR restored kinematics in ACL-deficient knees to intact levels for all metrics tested. For anterior drawer, ACLR + LMORT3 tear and partial meniscectomy resulted in significantly greater anterior translation compared with ACL-intact at all angles (P < .05) and compared with ACLR at 60° and 90° (P < .014). For pivot shift, compared with ACL-intact knees, ACLR + LMORT3 tear resulted in significantly more anterior translation at 15° (P = .041); and for ACLR + partial meniscectomy, at both 0° and 15° (P < .03). ACLR + LMORT4 tear and partial meniscectomy resulted in significantly greater anterior translation for anterior drawer (P < .04) and pivot-shift testing (P < .05) compared with intact and ACLR knees at all angles tested. ACLR + LMORT3 repair and ACLR + LMORT4 repair restored kinematics to ACLR and intact levels at all angles tested. ACLR + LMORT3 tear (P < .008) and both LMORT4 tear and partial meniscectomy (P < .05) resulted in increased meniscal extrusion compared with intact and ACLR statuses at all tested angles for anterior drawer and pivot shift, while repairs restored meniscal stability to ACLR and intact levels. Conclusion: Untreated LMORT tears increased anterior translation, pivot shift, and meniscal extrusion after ACLR, while partial meniscectomy further exacerbated these detrimental effects in this cadaveric model. In contrast, arthroscopic side-to-side repair of LMORT lesions effectively restored measured knee kinematics. Clinical Relevance: LMORT lesions are common with ACL tears and adversely affect joint stability and meniscal extrusion. This study highlights the importance of repair of LMORT 3 and 4 lesions at the time of ACLR.

Paper 34: Kinematic Analysis of Lateral Meniscus Oblique Radial Tears in Anterior Cruciate Ligament Reconstructed Knees: Untreated versus Repair versus Partial Meniscectomy

Objectives:Objectives: Previous analyses have characterized the incidence of lateral meniscus oblique radial tears (LMORT) commonly seen with ACL tears, and their impact on joint and meniscus stability in the presence of ACL deficiency.Purpose:To determine the clinically relevant kinematics associated with LMORT lesions untreated versus arthroscopic repair versus partial meniscectomy in combination with anterior cruciate ligament reconstruction (ACLR).Methods:Sixteen cadaver knees underwent robotic testing for anterior drawer (AD) and pivot shift (PS) simulations at multiple knee flexion angles in intact and ACL-deficient states, followed by sequential testing of arthroscopic ACL reconstruction (ACLR), creation of a LMORT 3 lesion, LMORT 3 repair, and partial meniscectomy (PM; n=8). The same testing sequence was performed for LMORT 4 lesions (n=8). Changes (Δ) from the intact state for anterior translation, internal rotation, and valgus displacements, as well as ultrasoundographic measurements of meniscal extrusion, were measured and comparatively analyzed.Results:ACLR restored kinematics in ACL-deficient knees to intact levels for all metrics tested.For AD, ACLR + LMORT3 tear and PM resulted in significantly greater anterior translation (0.8-2.1 mm differences) compared to ACL-intact at all angles (P < 0.05) and compared to ACLR at 60o and 90o (P < 0.014). For PS, ACLR + LMORT3 tear had significantly more anterior translation (1-1.4 mm differences) at 15o than intact knees (P=0.041), and at 0o and 15o for PM (P < 0.03).ACLR + LMORT4 tear and PM resulted in significantly greater anterior translation (0.9-2.3 mm differences) for AD (P < 0.04) and PS testing (P < 0.05) compared to intact and ACLR knees at all angles tested. ACLR+LMORT 3 repair and ACLR+LMORT4 repair restored kinematics to ACLR and intact levels at all angles tested.ACLR + LMORT3 tear (P < 0.008) and both LMORT4 tear and PM (P < 0.05) resulted in increased meniscal extrusion (1.8-11 mm differences) compared to intact and ACLR statuses at all tested angles for AD and PS while repairs restored meniscus stability to ACLR and intact levels.Conclusions:Untreated LMORT 3 and 4 tears increased anterior translation, pivot shift, and meniscus extrusion even after ACLR, while partial meniscectomy further exacerbated these detrimental effects. In contrast, arthroscopic side-to-side repair of LMORT lesions effectively restored measured knee kinematics.UPLOAD-https://planion-client-files.s3.amazonaws.com/AOSSM/blobs/6bf43418-abf1-49bd-b78b-cc0c501a2da0/1/AOSSM__Images.docx UPLOAD-https://planion-client-files.s3.amazonaws.com/AOSSM/blobs/b0f0bf53-a166-4cec-bf73-176ea452b905/1/AOSSM__CHART.docx

Time from Injury of Anterior Cruciate Ligament (ACL) to Reconstruction Has an Important Role in Saving Meniscus, a Commentary on an Article by Seyed Mohammad Javad Mortazavi et al.

Complete article title: Time from Injury of Anterior Cruciate Ligament (ACL) to Reconstruction Has an Important Role in Saving Meniscus, a Commentary on an Article by Seyed Mohammad Javad Mortazavi et al. “Time from Injury Is the Key Predictor of Meniscal Injury in ACL-Deficient Knees”&#x0D; The Article Abstract is not available.