The posterior condyle grows in the direction of the increasing posterior condylar offset and the inclination angle of the ACL changes accordingly.

Purpose: The purpose of this study was to reveal the changes in the shape of the posterior femoral condyle and the morphology of the ACL, both before and after epiphyseal closure. The hypothesis of this study is that the morphological change of the posterior femoral condyle and that of the ACL may be correlated to some extent.

Methods: Eighty-one patients who underwent surgery for the knee joint (meniscal repair, arthroscopic synovectomy, medial patellofemoral ligament reconstruction) between 2016 and 2021 were included in this study, 48 patients aged 13 years or under (before epiphysis closure; mean age: 10.

Subjective grade of apprehension during the pivot-shift test reflects patient-reported outcomes more than conventional pivot-shift test grade after ACL reconstruction.

Purpose: To investigate whether the pivot-shift test reflects patient-reported outcomes 1 year after anterior cruciate ligament (ACL) reconstruction based on a multicentre prospective cohort study.

Methods: This study included patients who underwent primary ACL reconstruction using the hamstring tendons. The pivot-shift test grades were determined according to the International Knee Documentation Committee (IKDC) form as 0, 1+, 2+ or 3+.

Articular Cartilage Damage in the Patellofemoral Compartment at ACL Reconstruction Predicts Poor Postoperative Subjective Outcomes in Patients Age 40 and Older.

The purpose of this study was to investigate factors that influence clinical outcomes after anterior cruciate ligament (ACL) reconstruction in patients aged ≥40 years. We studied 264 patients aged ≥40 and 154 patients aged ≤20 years who underwent ACL reconstruction at several surgical centers. A logistic regression analysis was conducted to identify factors that influenced the Knee Injury and Osteoarthritis Outcome Score (KOOS) at 1 year post-ACL reconstruction.

Dependence on visual information in patients with ACL injury for multi-joint coordination during single-leg squats: a case control study.

Background: The influence of vision on multi-joint control during dynamic tasks in anterior cruciate ligament (ACL) deficient patients is unknown. Thus, the purpose of this study was to establish a new method for quantifying neuromuscular control by focusing on the variability of multi-joint movement under conditions with different visual information and to determine the cutoff for potential biomarkers of injury risk in ACL deficient individuals.

Methods: Twenty-three ACL deficient patients and 23 healthy subjects participated in this study.

Unique Anatomical Features of the Discoid Lateral Meniscus via Three-Dimensional MRI.

Background The discoid lateral meniscus (DLM) is a unique anatomical variant characterized by a larger, thicker lateral meniscus. For clinical diagnosis of DLM, coronal and sagittal slices in two-dimensional (2D) MRI and arthroscopic imaging are typically employed. However, evaluating the entire shape of the DLM is challenging due to the limited views and details provided by these methods.

Influence of time from injury to surgery on knee biomechanics during walking in patients with anterior cruciate ligament reconstruction.

The pilot study aimed to determine whether the time from injury to surgery influences on postoperative knee biomechanics during walking in patients with anterior cruciate ligament reconstruction (ACLR). Thirty-two patients with unilateral ACLR (early, 10 patients; delayed, 22 patients) and 30 control subjects participated in this study. All examinations for patients with ACLR were performed preoperatively and at 12 months postoperatively and comprised passive knee joint laxity, knee muscle strength, and knee kinematics and kinetics during walking.

Visualization of lateral meniscus extrusion during gait using dynamic ultrasonographic evaluation.

Purpose: Medial meniscus extrusion is one of the risk factors for knee osteoarthritis (OA). However, lateral meniscus extrusion has not been discussed, and detailed information remains unknown. In particular, the lateral meniscus has high mobility and is expected to be difficult to evaluate in terms of its behavior under static conditions.

Current status and future prospects of the Japanese orthopaedic association national registry (JOANR), Japan's first national registry of orthopaedic surgery.

The Japanese Orthopaedic Association National Registry (JOANR) is Japan's first national registry of orthopaedic surgery, which has been developed after having been selected for the Project for Developing a Database of Clinical Outcome approved by the Health Policy Bureau of the Ministry of Health, Labour and Welfare. Its architecture has two levels of registration, one being the basic items of surgical procedure, disease, information on surgeons, surgery-related information, and outcome, and the other being detailed items in the affiliated registries of partner medical associations. It has a number of features, including the facts that, because it handles medical data, which constitute special care-required personal information, data processing is conducted entirely in a cloud environment with the imposition of high-level data security measures; registration of the implant data required to assess implant performance has been automated via a bar code reader app; and the system structure enables flexible collaboration with the registries of partner associations.

Comparison of clinical outcomes between anterior cruciate ligament reconstruction with over-the-top route procedure and anatomic single-bundle reconstruction in pediatric patients.

The purpose of this study is to evaluate the clinical results of over-the-top route (OTTR) reconstruction for pediatric anterior cruciate ligament (ACL) injuries and compare them with results of anatomic single-bundle reconstruction (SBR), which used the bone tunnel technique and was performed early after epiphyseal closure (age ≤15 years). This study included pediatric patients aged 11-15 years who underwent ACL reconstruction. The mean age at surgery was 13.

Detecting side-to-side differences of lower limb biomechanics during single-legged forward landing after anterior cruciate ligament reconstruction.

Background: Motion analysis can be used to evaluate functional recovery after anterior cruciate ligament (ACL) reconstruction; however, the biomechanics parameters of the lower limb that are specifically altered in ACL-reconstructed knees compared to the contralateral side are not well understood. This retrospective study aimed to compare side-to-side differences in lower limb biomechanics during the first 100 milliseconds (ms) after initial contact in a single-leg forward landing task.

Methods: Using three-dimensional motion analysis, lower joint kinematic and kinetic variables were measured 8-10 months postoperatively in 22 patients who had undergone ACL reconstruction.

Comparison of the mechanical properties and mechanical damages to tendon tissue in three suspensory fixation techniques.

Background: Anterior cruciate ligament (ACL) injury is the most common traumatic injury to the knee joint. Suspensory fixation has become popular in ACL reconstruction because of its high primary stability, less invasiveness, and surgical convenience. There are two common types of suspensory fixation devices: those with fixed-length and those with adjustable-length loops.

Posterior wall blowout on computed tomography after anterior cruciate ligament reconstruction.

Background: During anterior cruciate ligament (ACL) reconstruction, even when a posterior wall of the femoral bone tunnel is identified, computed tomography (CT) occasionally demonstrates a breach of the posterior femoral cortex of the femoral bone tunnel, i.e., posterior wall blowout, after ACL reconstruction (posterior wall blowout-like phenomenon).

Effects of limited previously acquired information about falling height on lower limb biomechanics when individuals are landing with limited visual input.

Background: Inhibitions in the acquisition of accurate information about the environment can affect control of the lower extremities and lead to anterior cruciate ligament injury. This study aimed to clarify the effects of limited prior knowledge of the height of the fall, as well as limited visual input, on lower limb and trunk motion and ground reaction force during landing.

Methods: Twenty healthy university students were recruited.

Equivalent outcomes of ACL revision with over-the-top single and double-bundle reconstruction using hamstring tendon compared to anatomical single and double-bundle reconstruction.

Purpose: In revision anterior cruciate ligament reconstruction (ACLR), our procedure of choice is the over-the-top route (OTTR) for cases where it is difficult to use a primary bone tunnel or to create a new bone tunnel due to the enlargement or malposition of the bone tunnel. Depending on the condition of the primary bone tunnel, we choose single (bone tunnel or OTTR) or double (bone tunnel or anteromedial (AM) bundle: OTTR /posterolateral (PL) bundle: bone tunnel) for femoral fixation. This study showed the results of single and double OTTR revision ACLR using the hamstring tendon.

Clinical outcomes of knee joint distraction combined with marrow stimulation procedures for patients with advanced knee osteoarthritis.

Background: Knee joint distraction (KJD) has received much attention as a joint preserving surgery, especially in young patients with advanced knee osteoarthritis (OA).

Methods: This study included 16 patients with advanced knee OA who underwent KJD combined with marrow stimulating techniques and were followed up for more than 2 years. The patients' clinical scores, including the Japanese Orthopaedic Association (JOA) score, Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales, ROM, joint space width, and semiquantitative MRI were evaluated.

A larger side-to-side difference in anterior knee laxity increases the prevalence of medial and lateral meniscal injuries in patients with ACL injuries.

Purpose: The objective of this study was to investigate factors that influence the prevalence of medial and lateral meniscal injuries at the time of anterior cruciate ligament (ACL) reconstruction in patients with ACL injuries.

Methods: Patients with ACL injuries at 9 institutions were enrolled in this multicentre study. Age, sex, duration between injury and surgery, pivot shift test grade, anterior knee laxity determined using the Kneelax 3 arthrometer, and other variables were assessed by logistic regression analysis.

The evaluation of degeneration of posterior cruciate ligament using CT Hounsfield unit in knee osteoarthritis.

Background: Posterior cruciate ligament (PCL) degeneration is often seen in knee osteoarthritis (OA); however, there is no established method for its evaluation. The purpose of this study is to investigate whether the Hounsfield unit (HU) using computed tomography (CT) could be a useful scale to evaluate the degeneration of PCL in knee OA.

Methods: Knee OA treated with total knee arthroplasty (21 patients, 21 knees) and non-osteoarthritic knees (21 patients, 21 knees) were retrospectively observed and studied.

Evaluation of the degenerative pattern of PCL in osteoarthritis patients using UTE-T2 mapping.

Background: The posterior cruciate ligament (PCL) is one of the essential stabilizers of the knee joint and it was demonstrated that its degenerative change related to the knee osteoarthritis (OA). We aimed to evaluate signal of the PCL in OA patients in comparison with healthy young and elderly volunteers using the ultra-short echo timeenhanced (UTE)-T2∗ mapping, and to validate these findings with histology.

Methods: Thirty asymptomatic volunteers, 13 young people (younger group) and 17 elderly people (elder group), and 27 patients who had undergone total knee arthroplasty (OA group) were enrolled in this study.