Kinematic characteristics of anterior cruciate ligament deficient knees with concomitant meniscus deficiency during ascending stairs

Finite element analysis of meniscus contact mechanical behavior based on kinematic simulation of abnormal gait

The meniscus plays a crucial role in the proper functioning of the knee joint, and when it becomes damaged, partial removal or replacement is necessary to restore proper function. Understanding the stress and deformation of the meniscus during various movements is essential for developing effective materials for meniscus repair. However, accurately estimating the contact mechanics of the knee joint can be challenging due to its complex shape and the dynamic changes it undergoes during movement. To address this issue, the open-source software SCONE can be used to establish a kinematics model that monitors the different states of the knee joint during human motion and obtains relevant gait kinematics data. To evaluate the stress and deformation of the meniscus during normal human movement, values of different states in the movement gait can be selected for finite element analysis (FEA) of the knee joint. This analysis enables researchers to assess changes in the meniscus. To evaluate meniscus damage, it is necessary to obtain changes in its mechanical behavior during abnormal movements. This information can serve as a reference for designing and optimizing the mechanical performance of materials used in meniscus repair and replacement.

Meniscal Suture Influence on Driving Ability 6 Weeks after Anterior Cruciate Ligament Reconstruction with Hamstring Autograft

The purpose of this study was to determine if driving ability 6 weeks after anterior cruciate ligament (ACL) reconstruction is affected by the addition of a meniscal suture. It was also hypothesized that no differences in the driving performance would be found between right or left knee surgery subgroups. A total of 82 people participated in this prospective cohort study: 36 healthy controls, 26 patients undergoing isolated ACL (iACL) reconstruction with hamstring autograft, and 20 patients undergoing ACL and meniscal suture (ACL-MS) reconstruction. ACL-MS group followed a weight-bearing and movement restriction protocol during the first 2 postoperative weeks, whereas patients undergoing iACL could start range-of-motion exercises and full weight-bearing ambulation on the first postoperative day. A driving simulator that reproduced real-life driving conditions was used to evaluate driving ability. The software analyzed multiple driving and braking variables. Driving performance in the sixth postoperative week was compared with that of a healthy control group. Subgroup analysis considering additional procedures (iACL, ACL-MS) and the side of the operated knee (right, left) was also performed. No statistically significant differences were found in the demographic characteristics nor in the driving performance (collisions, p = 0.897; sidewalk invasions, p = 0.749; pedestrian impact, p = 0.983) between iACL, ACL-MS, and control groups. No statistically significant differences were found in right-left subgroup analysis. The results of the present study show that patients in their sixth postoperative week after right or left ACL reconstruction showed similar driving performance as compared with a healthy control group, regardless of associating or not a meniscal suture, suggesting it is safe to resume driving 6 weeks after the mentioned surgeries.

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.

Lateral meniscal slope negatively affects post-operative anterior tibial translation at 1 year after primary anterior cruciate ligament reconstruction

PURPOSE

The aim of this study was to assess the correlation between posterior tibial slope and meniscal slope over postoperative anterior tibial translation during the first 18 months after primary anterior cruciate ligament (ACL) reconstruction. The main hypothesis was that PTS and MS would be positively correlated with post-operative ATT-SSD after ACL reconstruction.

METHODS

Patients (28 males and 15 females) with confirmed ACL tears were selected from an in-house registry and included if they were over 16 years old, had primary ACL-reconstruction and healthy contralateral knee. Patients meeting one of the following criteria were excluded: previous knee surgeries, intraarticular fractures, associated ligamentous lesions, previous or concomitant meniscectomy or extraarticular procedures. Lateral posterior tibial slope, medial posterior tibial slope, lateral meniscal slope and medial meniscal slope were measured using preoperative MRIs. The side-to-side-difference in anterior tibial translation was evaluated 9-18 months postoperatively.

RESULTS

Forty-three patients were included, (28 males/15 females; mean age 25 ± 8 years). Mean postoperative anterior tibial translation was 1.0 ± 1.1 mm at a mean time of 12 ± 1 months. Mean slope values were: lateral posterior tibial slope 4.7° ± 2.2°, medial posterior tibial slope 4.0° ± 2.8°, lateral meniscal slope 3.0° ± 2.2° and medial meniscal slope 2.0° ± 2.8°. The anterior tibial translation was significantly correlated with lateral meniscal slope (r = 0.63; p < 0.01). For each 1° increase in lateral meniscal slope, a 0.3 mm 95% CI [0.2, 0.4] (p < 0.01) increase in anterior tibial translation was observed. A lateral meniscal slope greater or equal to 4.0° was estimated as optimal threshold for increased risk of abnormal side-to-side difference in postoperative anterior tibial translation (≥ 1.2 mm).

CONCLUSION

The lateral meniscal slope was positively correlated to side-to-side difference in anterior tibial translation after primary ACL reconstruction. A lateral meniscal slope greater or equal to 4.0° was detected as threshold for an increased risk of abnormal side-to-side difference in postoperative anterior tibial translation in patients who underwent primary ACL reconstruction. This confirms that soft tissue slopes have an impact on the outcomes after reconstructive surgery. Level of evidence III.

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.

Kinematic outcomes following ACL reconstruction

Anterior cruciate ligament (ACL) reconstruction aims to restore the translational and rotational motion to the knee joint that is lost after injury. However, despite technical advancements, clinical outcomes are less than ideal, particularly in return to previous activity level. A major issue is the inability to standardize treatment protocols due to variations in materials and approaches used to accomplish ACL reconstruction. These include surgical techniques such as the transtibial and anteromedial portal methods that are currently under use and the wide availability of graft types that will be used to reconstruct the ACL. In addition, concomitant soft tissue injuries to the menisci and capsule are frequently present after ACL injury and, if left unaddressed, can lead to persistent instability even after the ACL has been reconstructed. Advances in the field of biomechanics that help to objectively measure motion of the knee joint may provide more precise data than current subjective clinical measurements. These technologies include extra-articular motion capture systems that measure the movement of the tibia in relation to the femur. With data gathered from these devices, a threshold for satisfactory knee stability may be established in order to correctly identify a successful reconstruction following ACL injury.