Surgical Management of a Torn ACL and Bucket-Handle Meniscal Tear in the Pregnant Patient: A Case Report.

CASE: A 36-year-old, 7-month pregnant woman presented to the office with a locked knee and a displaced bucket-handle medial meniscus tear, in the setting of chronic anterior cruciate ligament (ACL) insufficiency. After thorough discussion with the patient and her husband, the obstetrician, and the anesthesiologist, the patient was treated with left knee ACL reconstruction and medial meniscus repair. CONCLUSION: With sufficient preoperative planning and coordinated multidisciplinary care among orthopaedic, anesthesiologist, and obstetric specialists, elective knee surgery can be performed safely in time-sensitive situations during pregnancy.

Delaying anterior cruciate ligament reconstruction for more than 3 or 6 months results in lower risk of revision surgery.

BACKGROUND: The objective of this study is to investigate the risk of revision surgery when delaying anterior cruciate ligament reconstruction (ACLR) past 3 months or 6 months after injury. MATERIALS AND METHODS: A total of 30,280 patients with isolated ACLR were identified in the Danish Knee Ligament Reconstruction Registry and divided into four groups; ACLR < 3 months, > 3 months, < 6 months, or > 6 months after injury. Primary outcome was revision surgery and secondary outcome were objective and subjective clinical outcome. The 2 year relative risk, crude, and adjusted hazard ratio (HR) were calculated. RESULTS: Comparing ACLR < 3 months to ACLR > 3 months of injury the 2 year relative risk of revision surgery was found to be 1.81 (95% CI 1.46-2.23; P < 0.001) with an adjusted hazard ratio (HR) of 1.27 (95% CI 1.12-1.44; P < 0.001). Comparing ACLR < 6 months to ACLR > 6 months of injury the 2 year relative risk of revision surgery was found to be 1.61 (95% CI 1.34-1.92; P < 0.001) with an adjusted HR of 1.27 (95% CI 1.15-1.40; P < 0.001). CONCLUSION: The risk of revision ACLR surgery was found to be increased when ACLR was performed within 3 months or 6 months of injury compared with later surgery. The 1 year postoperative objective knee laxity and the subjective patient-related outcome was found to be without a clinically significant difference; however, those with early ACLR (< 3 months or < 6 months) were found to have a higher activity level 1 year postoperatively. The information about increased risk of revision when having early surgery should be informed to patients when deciding timing of ACLR treatment. LEVEL OF EVIDENCE: II.

Statistical shape analysis and computational modeling reveal novel relationships between tibiofemoral bony geometry and knee mechanics in young, female athletes.

Young female athletes participating in sports requiring rapid changes of direction are at heightened risk of suffering traumatic knee injury, especially noncontact rupture of the anterior cruciate ligament (ACL). Clinical studies have revealed that geometric features of the tibiofemoral joint are associated with increased risk of suffering noncontact ACL injury. However, the relationship between three-dimensional (3D) tibiofemoral geometry and knee mechanics in young female athletes is not well understood. We developed a statistically augmented computational modeling workflow to determine relationships between 3D geometry of the knee and tibiofemoral kinematics and ACL force in response to an applied loading sequence of compression, valgus, and anterior force, which is known to load the ACL. This workflow included 3D characterization of tibiofemoral bony geometry via principal component analysis and multibody dynamics models incorporating subject-specific knee geometries. A combination of geometric features of both the tibia and the femur that spanned all three anatomical planes was related to increased ACL force and to increased kinematic coupling (i.e., anterior, medial, and distal tibial translations and internal tibial rotation) in response to the applied loads. In contrast, a uniplanar measure of tibiofemoral geometry that is associated with ACL injury risk, sagittal plane slope of the lateral tibial plateau subchondral bone, was not related to ACL force. Thus, our workflow may aid in developing mechanics-based ACL injury screening tools for young, active females based on a unique combination of bony geometric features that are related to increased ACL loading.

Proprioception After Primary Repair of the Anterior Cruciate Ligament.

BACKGROUND: Primary repair of the anterior cruciate ligament (ACL) has some potential advantages over the reconstruction technique, which include but are not limited to better knee sensation due to preservation of the natural ACL tissue in patients compared with tendon graft. Proprioception is impaired after ACL injuries and the sense of the joint position is lost. PURPOSE/HYPOTHESIS: The purpose of this study was to compare arthroscopic ACL primary repair and ACL reconstruction techniques clinically and functionally and analyze the differences in proprioception. It was hypothesized that primary repair would restore knee joint proprioception more successfully because the original tissue of the ACL is preserved. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 63 patients (34 underwent reconstruction and 29 underwent primary repair between 2017 and 2020) and 33 healthy controls, as well as the healthy knees of the operated groups, were evaluated between 24 and 48 months (mean, 29 months) postoperatively. Patients with proximal femoral avulsion tears and stump quality suitable for repair underwent primary repair, and those with tears outside these criteria underwent reconstruction using hamstring tendon autograft. Proprioception was evaluated using the active joint position sensation method during weightbearing, with a digital inclinometer used to measure differences between the target and achieved flexion angles of 15°, 30°, and 60°. RESULTS: At 15° of knee flexion, the deviation angles for the healthy knee of the reconstruction and primary repair groups were significantly smaller than those of the control group (P < .001), but there was no statistically significant difference between the groups in terms of deviation angle at 30° and 60° of flexion. The deviation angle of the operated knees was statistically significantly larger in the reconstruction group than in the primary repair group at all angles. The deviation angles at 15°, 30°, and 60° were 2.83°, 2.66°, and 2.66° in the reconstruction group and 1.00°, 1.00°, and 1.33° in the primary repair group, respectively (P < .001). There was no statistically significant difference between the reconstruction and primary repair groups in terms of clinical scores. CONCLUSION: Primary ACL repair can preserve proprioception in a well-selected patient group. In short-term follow-up, primary repair of the ACL in patients with proximal femoral avulsion tears and stump quality suitable for repair appears to be proprioceptively protective. Future studies are needed to clarify the long-term consequences of primary repair on proprioception in a larger population.

Gender differences in the impact of anatomical factors on non-contact anterior cruciate ligament injuries: a magnetic resonance study.

PURPOSE: To identify MRI-detected anatomical risk factors for non-contact anterior cruciate ligament (ACL) injuries across genders. METHODS: A retrospective analysis was performed on 141 ACL-reconstructed patients (35 females, 106 males) and 142 controls (37 females, 105 males) from January 2020 to April 2022. Inclusion criteria were primary non-contact ACL injuries. The tibial plateau slope, lateral femoral condyle index, Insall-Salvati index, and patellar tendon angle were measured, using binary logistic regression for gender-specific risk evaluation. RESULTS: Increased lateral tibial plateau slope, reduced intercondylar notch width index, lateral femoral condyle index, and patellar tendon angle correlated with ACL injuries in both genders. The Insall-Salvati index was a significant risk factor in females but not in males. CONCLUSION: This study identifies the lateral tibial plateau slope, notch width index, lateral femoral condyle index, and patellar tendon angle at near-extension as risk factors for ACL injuries in both genders, with the Insall-Salvati index also implicated in females.

Estimation of Kinetics Using IMUs to Monitor and Aid in Clinical Decision-Making during ACL Rehabilitation: A Systematic Review.

After an ACL injury, rehabilitation consists of multiple phases, and progress between these phases is guided by subjective visual assessments of activities such as running, hopping, jump landing, etc. Estimation of objective kinetic measures like knee joint moments and GRF during assessment can help physiotherapists gain insights on knee loading and tailor rehabilitation protocols. Conventional methods deployed to estimate kinetics require complex, expensive systems and are limited to laboratory settings. Alternatively, multiple algorithms have been proposed in the literature to estimate kinetics from kinematics measured using only IMUs. However, the knowledge about their accuracy and generalizability for patient populations is still limited. Therefore, this article aims to identify the available algorithms for the estimation of kinetic parameters using kinematics measured only from IMUs and to evaluate their applicability in ACL rehabilitation through a comprehensive systematic review. The papers identified through the search were categorized based on the modelling techniques and kinetic parameters of interest, and subsequently compared based on the accuracies achieved and applicability for ACL patients during rehabilitation. IMUs have exhibited potential in estimating kinetic parameters with good accuracy, particularly for sagittal movements in healthy cohorts. However, several shortcomings were identified and future directions for improvement have been proposed, including extension of proposed algorithms to accommodate multiplanar movements and validation of the proposed techniques in diverse patient populations and in particular the ACL population.

[Research progress of femoral bone tunnel positioning in anterior cruciate ligament reconstruction].

Objective: To review the concept and methods of femoral bone tunnel positioning in anterior cruciate ligament (ACL) reconstruction, in order to provide a reference for clinical treatment. Methods: The relevant literature on the concept and methods of femoral bone tunnel positioning in ACL reconstruction in domestic and international research was extensively reviewed. Results: The position of the femoral bone tunnel is a key factor in determining the prognosis of ACL reconstruction. The concept of femoral bone tunnel positioning in ACL reconstruction has experienced isometric reconstruction, anatomical reconstruction, Ribbon-like theory, I.D.E.A.L. theory, and nearly isometric reconstruction theory. The femoral bone tunnel positioning technique is also changing with the in-depth study of the anatomy and biomechanics of the ACL, and each bone tunnel positioning technique has its own advantages and disadvantages. Over-The-Top technique is now mainly used for ACL revision; the clock-face positioning method is basically no longer applicable due to the large error, poor stability, and low retrievability; the bone landmarks positioning method (the lateral condyle of the femur's Resident's ridge and bifurcation ridge, and the the apex of the deep cartilage), which is now mostly used clinically due to the more constant anatomical landmarks. The quadrant method under X-ray fluoroscopy is more cumbersome to implement intraoperatively, so it is mainly used for academic research; computer navigation-assisted positioning has gradually become popular in recent years, which is highly accurate, avoids the influence of human factors on the positioning of the bone tunnel, and has a very good prospect of application; three-dimensional printing-assisted positioning technology, which is accurate in positioning, with a high degree of reproducibility and a short learning curve. Conclusion: The concept of femoral bone tunnel positioning for ACL reconstruction has undergone several evolutions, reflecting the deepening of the understanding of ACL and the improvement of the clinical results of reconstruction. The precision, personalization, and intelligence of positioning techniques are the focus of current and future development.

Robot-assisted anterior cruciate ligament reconstruction based on three-dimensional images.

Background Tunnel placement is a key step in anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to evaluate the accuracy of bone tunnel drilling in arthroscopic ACL reconstruction assisted by a three-dimensional (3D) image-based robot system. Methods Robot-assisted ACL reconstruction was performed on twelve freshly frozen knee specimens. During the operation, three-dimensional images were used for ACL bone tunnel planning, and the robotic arm was used for navigation and drilling. Twelve patients who underwent traditional arthroscopic ACL reconstruction were included. 3D computed tomography was used to measure the actual position of the ACL bone tunnel and to evaluate the accuracy of the robotic and traditional ACL bone tunnel. Results On the femoral side, the positions of robotic and traditional surgery tunnels were 29.3 ± 1.4% and 32.1 ± 3.9% in the deep-to-shallow direction of the lateral femoral condyle (p = 0.032), and 34.6 ± 1.2% and 21.2 ± 9.4% in the high-to-low direction (p < 0.001), respectively. On the tibial side, the positions of the robotic and traditional surgical tunnels were located at 48.4 ± 0.9% and 45.8 ± 2.8% of the medial-to-lateral diameter of the tibial plateau (p = 0.008), 38.1 ± 0.8% and 34.6 ± 6.0% of the anterior-to-posterior diameter (p = 0.071), respectively. Conclusions In this study, ACL reconstruction was completed with the assistance of a robot arm and 3D images, and the robot was able to drill the bone tunnel more accurately than the traditional arthroscopic ACL reconstruction.

Additional suture augmentation to anterior cruciate ligament reconstruction with hamstring autografts bring no benefits to clinical results, graft maturation and graft-bone interface healing.

BACKGROUND: From the perspective of graft protection and early rehabilitation during the maturation and remodeling phases of graft healing, suture augmentation (SA) for anterior cruciate ligament reconstruction (ACLR) has attracted more and more attention. STUDY DESIGN: Retrospective study. PURPOSE: To determine whether the additional SA affects clinical results, graft maturation and graft-bone interface healing during two years follow-up after ACLR. METHODS: 20 ACLRs with additional SA (ACLR-SA group) and 20 ACLRs without additional SA (ACLR group) were performed between January 2020 and December 2021 by the same surgeon and were retrospectively analyzed. Pre- and postoperative International Knee Documentation Committee (IKDC) scores, Lysholm scores, graft failure and reoperation were evaluated. The signal/noise quotient (SNQ) of autografts and the signal intensity of graft-bone interface were analyzed. All 40 patients in ACLR-SA group and ACLR group completed 2-years follow-up. RESULTS: There was no patient in the two cohorts experienced graft failure and reoperation. The postoperative IKDC and Lysholm scores have been significantly improved compared with preoperative scored in both ACLR-SA group and ACLR group, however, there was no significant difference between two groups. The SNQ of proximal graft of ACLR-SA group (14.78 ± 8.62 vs. 8.1 ± 5.5, p = 0.041) was significantly greater while the grades of graft-bone interface healing of posterior tibial was significantly lower than that of ACLR group at 1-year postoperatively (p = 0.03), respectively. There were no significant differences between the two groups of the SNQ of proximal, distal medial graft segments, and the graft-bone interface healing grades of anterior femoral, posterior femoral, anterior tibial and posterior tibial at other time points (p>0.05). CONCLUSIONS: The additional SA in ACLR had no effect on IKDC scores, Lysholm scores, graft maturation and graft-bone interface healing at 2-year postoperatively. Our research does not support the routine use of SA in ACLR.

Computational study of extrinsic factors affecting ACL strain during single-leg jump landing.

BACKGROUND: Non-contact anterior cruciate ligament (ACL) injuries are a major concern in sport-related activities due to dynamic knee movements. There is a paucity of finite element (FE) studies that have accurately replicated the knee geometry, kinematics, and muscle forces during dynamic activities. The objective of this study was to develop and validate a knee FE model and use it to quantify the relationships between sagittal plane knee kinematics, kinetics and the resulting ACL strain. METHODS: 3D images of a cadaver knee specimen were segmented (bones, cartilage, and meniscus) and meshed to develop the FE model. Knee ligament insertion sites were defined in the FE model via experimental digitization of the specimen's ligaments. The response of the model was validated against multiple physiological knee movements using published experimental data. Single-leg jump landing motions were then simulated on the validated model with muscle forces and kinematic inputs derived from motion capture and rigid body modelling of ten participants. RESULTS: The maximum ACL strain measured with the model during jump landing was 3.5 ± 2.2%, comparable to published experimental results. Bivariate analysis showed no significant correlation between body weight, ground reaction force and sagittal plane parameters (such as joint flexion angles, joint moments, muscle forces, and joint velocity) and ACL strain. Multivariate regression analysis showed increasing trunk, hip and ankle flexion angles decreases ACL strain (R2 = 90.04%, p < 0.05). CONCLUSIONS: Soft landing decreases ACL strain and the relationship could be presented through an empirical equation. The model and the empirical relation developed in this study could be used to better predict ACL injury risk and prevention strategies during dynamic activities.

[Comparison of the early analgesic efficacy of three different drugs after anterior cruciate ligament reconstruction].

OBJECTIVE: The pain-relieving effect and safety of compound aminopyrine phenacetin tablets, tramcontin (tramadol hydrochloride sustained-release tablets) and dolantin in the early stage of autologous tendon reconstruction of the anterior cruciate ligament (ACL) of the knee joint were compared. METHODS: Retrospective analysis of postoperative pain and drug analgesia in 45 patients performed by the same group from November 2018 to February 2019. The random area group design was divided into two groups according to whether ACL rupture was combined with meniscal injury, group A was 24 patients with ACL reconstruction of knee joint and group B was 21 patients with ACL fracture combined with meniscus injury. The two groups were divided into three subgroups respectively according to the actual treatment of postoperative analgesic drugs received by the patients, including 4 cases of compound aminopyrine phenacetin tablets, 11 cases of oral tramcontin, 9 cases of intramuscular dolantin combined with phenergan in group A; 3 cases of compound aminopyrine phenacetin tablets, 10 cases of oral tramcontin, and 8 cases of intramuscular dolantin combined with phenergan in group B. When the early postoperative patients complain about pain and actively ask for analgesia. When the patients complained about pain after the operation and actively asked for analgesia, they were randomly given painkillers, tramcontin or dolantin combined with phenergan to relieve pain. Pain visual analogue scale (VAS) was used to evaluate pain relief and observe the occurrence of adverse reactions. RESULTS: There were no significant dif-ferences in gender, age, body mass index, and time of hospital stay between the two groups of patients (P > 0.05). In the patients who used tramcontin and dolantin combined with phenergan to relieve pain judging by VAS score before and 1 h after taking the drug, it was found that the pain situation of the patient was significantly relieved, and the difference before and after taking the drug had statistical significance (P < 0.05). Pairwise comparisons of the three drugs applied in the two groups showed significantly greater pain relief in the dolantin combined with phenergan group than in the remaining two drugs. There was no significant difference (P > 0.05). Dolantin was prone to nausea and vomiting, but the application of phenergan was also used to reduce side effects. In terms of adverse reactions, only 1 case of nausea occurred in the tramcontin group for simple ACL reconstruction, and none of the patients in the other groups showed serious complications and allergic reactions. CONCLUSION: Whether in cruciate ligament reconstruction alone or combined with meniscus molding or suture, compound aminopyrine phenacetin tablets, tramcontin, dolantin combined with phenergan can effectively relieve pain. Among the three drugs, dolantin caused the largest pain relief. At the same time, the combination of phenergan effectively reduced the adverse reactions, such as vomiting and nausea, and increased the drug safety.

[Subtuberosity anterior closing wedge osteotomy to correct the increased posterior slope of the tibial plateau]. / Subtuberositäre anterior schließende Osteotomie zur Korrektur der erhöhten posterioren Reklination des Tibiaplateaus.

OBJECTIVE: Reduction of increased reclination of the tibial plateau (posterior slope) to improve the anterior stability of the knee joint. INDICATIONS: Increased posterior reclination of the tibial plateau greater than 12° in combination with recurrent instability after anterior cruciate ligament (ACL) reconstruction. CONTRAINDICATIONS: Hyperextension of more than 15° (relative). SURGICAL TECHNIQUE: Anterior skin incision approximately 8-10 cm above the tibial tuberosity. Insertion of two converging guidewires directly below the patellar tendon ending obliquely in the area of the posterior cruciate ligament (PCL) insertion. Control of the wire position with the image intensifier core. Oscillating saw osteotomy. Removal of the wedge and closure of the osteotomy. Osteosynthesis with interfragmentary screw and medial angle-stable plate. POSTOPERATIVE MANAGEMENT: Partial load with 10-20 kg for 2 weeks, then step by step increase in load. Mobility: free. RESULTS: To date we have operated on 36 patients with recurrent instability after ACL reconstruction (20 men, 16 women, average age 34.4 years) in the manner described in this article. In 25 cases, enlarged bone tunnels were filled with allogeneic bone at the same time. The posterior slope of the tibial plateau could be reduced from an average of 14.5° to 8.8°. In 28 cases another ACL reconstruction was performed after an interval of 4-12 months. The Lysholm score significantly increased from 76.3 points to 89.2 points.

Differences in lower-limb biomechanics during single-leg landing considering two peripheral fatigue tasks.

Dynamic knee valgus (DKV) occurs during landing after a fatigue task involving the lower extremity. However, the manner in which different peripheral fatigue tasks affect DKV remains unknown. In this study, we investigated the DKV via electromyography during single-leg landing considering the hip-joint fatigue task (HFT) and knee-joint fatigue task (KFT) performed by healthy men. We recruited 16 healthy male participants who performed a single-leg jump-landing motion from a height of 20 cm before and after an isokinetic hip abduction/adduction task (HFT) and knee extension/flexion task (KFT). Three-dimensional motion analysis systems were attached to the left gluteus medius and quadriceps, and surface electromyography was used to analyze the lower limb kinematics, kinetics, and muscle activity. The primary effects and interactions of the task and fatigue were identified based on the two-way repeated-measures analysis of variance. The results of the average angle during landing indicated that DKV occurs in KFT, whereas HFT applies external forces that adduct and internally rotate the knee at peak vertical ground reaction force (vGRF). Furthermore, both KFT and HFT exhibited an increase in muscle activity in the quadriceps. The analysis revealed that the occurrence of DKV varies depending on the peripheral fatigue task, and the effects on average DKV during landing and DKV at peak vGRF vary depending on the peripheral fatigue task.

Current views on preoperative rehabilitation practice after anterior cruciate ligament injury among licensed physical therapists in Saudi Arabia: An online-based cross-sectional survey.

Preoperative rehabilitation is an important stage to both physically and mentally prepare patients for anterior cruciate ligament reconstruction (ACLR) and postoperative rehabilitation. This study aimed to investigate the current preoperative rehabilitation practice after anterior cruciate ligament injury among licensed physical therapists in Saudi Arabia. This was an online-based cross-sectional survey. A total of 114 physical therapists completed the survey. The survey consisted of 16 mandatory questions about management strategies, prescribed exercises, patients' physical and psychological concerns, and discussions about nonoperative management. The majority of the respondents used the following preoperative interventions: education (89.5%), closed kinetic chain exercises (66.7%), stretches (63.2%), open kinetic chain exercises (61.4%), proprioceptive exercises (59.6%), cold (56.1%), and activity modification advice (52.6%). More than half of the respondents would recommend patients awaiting ACLR to complete the exercises 2 to 4 times weekly (56.1%) for up to 8 weeks (80.7%) before ACLR. The respondents (73.7%) reported that patients awaiting ACLR did not receive preoperative rehabilitation due to 2 primary factors: the orthopedic team did not refer patients to rehabilitation specialists, and there was a lack of awareness about preoperative rehabilitation. Most therapists (86%) would discuss conservative management if a patient returned to their preinjury level of function before surgery. The surveyed physical therapists reported using various interventions and preoperative rehabilitation lengths with patients awaiting ACLR. The majority of the therapists indicated that patients awaiting ACLR did not receive preoperative rehabilitation. Future studies are needed to establish a consensus on the optimal preoperative rehabilitation program.

Bilateral movement asymmetries exist in recreational athletes during a 45° sidestep cut post-anterior cruciate ligament reconstruction.

Individuals post-ACL reconstruction (ACLR) are at elevated risk for ACL re-injury. While several studies have examined biomechanical asymmetries post-ACLR during landing, less is known about asymmetries during a sidestep cut. Therefore, the purpose of this study was to compare sagittal and frontal plane biomechanics at the hip and knee during a 45° sidestep cut in post-ACLR participants and healthy controls. Nineteen athletes post-ACLR and nineteen healthy controls performed a bilateral 45° sidestep cut while three-dimensional kinematics and kinetics were measured. Sagittal and frontal plane kinematics and kinetics were examined at the hip and knee during stance phase. A linear mixed model compared biomechanical differences between the limbs of ACLR and healthy control participants (α = 0.05). In the post-ACLR group, peak hip extension, peak knee flexion, sagittal hip and knee excursion, and the peak knee extensor moment were significantly lower in the ACLR surgical limb compared to the non-surgical limb (p < 0.05). The peak knee flexion angle and peak knee extensor moment were also lower in the ACLR surgical limb compared to the matched control limb (p < 0.05). In summary, post-ACLR participants exhibited altered sagittal plane movement in their surgical limb that was not demonstrated in the non-surgical limb or in control participants, which may suggest avoidance, or reduced utilization of the ACLR limb.

Retrospective study of patellar fractures and damage of accessory soft tissue based on MRI.

BACKGROUND: To better understand the pathophysiological mechanisms of patellar fractures, MRI was utilized to identify the imaging signs of various types of patellar fractures. METHODS: A retrospective study was performed using MRI images of 52 patients with patellar fractures. Observing the development of patellar and femoral morphology and the imaging manifestations of different fracture types, such as fracture displacement, and damage to accessory ligaments, tendons, and meniscus, type of joint cavity effusion, and damage to surrounding accessory bones were identified. RESULTS: There were 21 tangential fractures (40.4%), 8 transverse fractures (15.4%), 8 longitudinal fractures (15.4%), 4 oblique fractures (7.7%), and 11 comminuted fractures (21.2%) among the 52 patients with patellar fracture. Tangential fractures begin at a younger age than the other four forms of fractures. When tangential fractures were compared to other types of fractures, medial patellar retinaculum and anterior and posterior cruciate ligament injuries were statistically significant (P< 0.05). The detection rate of trochlear dysplasia, type II and type III patellar was higher in patients with tangential fractures than in other fractures. CONCLUSIONS: Tangential fractures are less common to cause anterior and posterior cruciate ligament injuries than other types of fractures, but they are more likely to cause medial patellar retinaculum injuries.

Anterior cruciate ligament injury should not be considered a contraindication for medial unicompartmental knee arthroplasty: Finite element analysis.

PURPOSE: The research objective of this study is to use finite element analysis to investigate the impact of anterior cruciate ligament (ACL) injury on medial unicompartmental knee arthroplasty (UKA) and explore whether patients with ACL injuries can undergo UKA. METHODS: Based on the morphology of the ACL, models of ACL with diameters ranging from 1 to 10mm are created. Finite element models of UKA include ACL absence and ACLs with different diameters. After creating a complete finite element model and validating it, four different types of loads are applied to the knee joint. Statistical analysis is conducted to assess the stress variations in the knee joint structure. RESULTS: A total of 11 finite element models of UKA were established. Regarding the stress on the ACL, as the diameter of the ACL increased, when a vertical load of 750N was applied to the femur, combined with an anterior tibial load of 105N, the stress on the ACL increased from 2.61 MPa to 4.62 MPa, representing a 77.05% increase. Regarding the equivalent stress on the polyethylene gasket, a notable high stress change was observed. The stress on the gasket remained between 12.68 MPa and 14.33 MPa in all models. the stress on the gasket demonstrated a decreasing trend. The equivalent stress in the lateral meniscus and lateral femoral cartilage decreases, reducing from the maximum stress of 4.71 MPa to 2.61 MPa, with a mean value of 3.73 MPa. This represents a reduction of 44.72%, and the statistical significance is (P < 0.05). However, under the other three loads, there was no significant statistical significance (P > 0.05). CONCLUSION: This study suggests that the integrity of the ACL plays a protective role in performing medial UKA. However, this protective effect is limited when performing medial UKA. When the knee joint only has varying degrees of ACL injury, even ACL rupture, and the remaining structures of the knee joint are intact with anterior-posterior stability in the knee joint, it should not be considered a contraindication for medial UKA.

Relationship of Knee Abduction Moment to Trunk and Lower Extremity Segment Acceleration during Sport-Specific Movements.

The knee abduction moment (KAM) has been identified as a significant predictor of anterior cruciate ligament (ACL) injury risk; however, the cost and time demands associated with collecting three-dimensional (3D) kinetic data have prompted the need for alternative solutions. Wearable inertial measurement units (IMUs) have been explored as a potential solution for quantitative on-field assessment of injury risk. Most previous work has focused on angular velocity data, which are highly susceptible to bias and noise relative to acceleration data. The purpose of this pilot study was to assess the relationship between KAM and body segment acceleration during sport-specific movements. Three functional tasks were selected to analyze peak KAM using optical motion capture and force plates as well as peak triaxial segment accelerations using IMUs. Moderate correlations with peak KAM were observed for peak shank acceleration during single-leg hop; peak trunk, thigh, and shank accelerations during a deceleration task; and peak trunk, pelvis, and shank accelerations during a 45° cut. These findings provide preliminary support for the use of wearable IMUs to identify peak KAM during athletic tasks.