Temporal changes of tibial eminence after bi-cruciate retaining total knee arthroplasty.

Background: Bicruciate-retaining (BCR) prostheses have been introduced to recreate normal knee movements by preserving both the anterior and posterior cruciate ligaments. One of the surgical procedures essential to the success of BCR total knee arthroplasty (TKA) is preservation of the tibial eminence. However, in our clinical experience, we found that a well-preserved tibial eminence changed its shape chronologically after the operation.

Influence of Axial Rotation Between the Femoral Neck and Ankle Joint on Kinematics in Normal Knees: A Cross-Sectional Study.

Background: The effect of axial rotation between the femoral neck and ankle joint (total rotation [TR]) on normal knees is unknown. Therefore, this study aimed to investigate the TR effect on normal knee kinematics.

Methods: Volunteers were divided into groups large (L), intermediate (I), and small (S), using hierarchical cluster analysis based on TR in the standing position.

In vivo kinematic analysis of failure cases after nonanatomical anterior cruciate ligament reconstruction: a preliminary study.

Background: Nonanatomical anterior cruciate ligament (ACL) reconstruction occasionally induces ACL failure without an evident injury episode, necessitating revision surgery. Although the in vivo kinematics of ACL deficiency before primary ACL reconstruction are well documented, the kinematics of ACL failure after nonanatomical reconstruction remain unexplored. The aim of this study is to investigate ACL failure kinematics following nonanatomical reconstruction.

Medial pivot total knee arthroplasty for valgus knees provides equivalent medial stability compared to that for varus knees: In vivo kinematic study.

Purpose: The efficacy of medial pivot total knee arthroplasty (MP TKA) in treating valgus knees that may cause medial instability is unknown. The purpose of this study was to investigate the in vivo kinematics of MP TKA for the valgus knees and compare them to those for the varus knees.

Methods: The kinematics of 19 valgus knees and 19 varus knees operated in the MP TKA were investigated under fluoroscopy during squatting using a two- to three-dimensional registration technique.

kinematic comparison of bi-cruciate retaining total knee arthroplasty between mechanical alignment and functional alignment methods.

Background/objective: This study aimed to clarify the kinematics of bi-cruciate-retaining (BCR) total knee arthroplasty (TKA) by comparing the mechanical alignment (MA) and functional alignment (FA) methods and to evaluate differences between the two alignment methods.

Methods: The kinematics of 20 MA TKA and 20 FA TKA knees were investigated under fluoroscopy during squatting using a two-to three-dimensional registration technique. Accordingly, knee flexion angle, axial rotational angle, varus-valgus angle, anteroposterior translation of the medial and lateral low contact points of the femoral component relative to the tibial component and kinematic pathway were evaluated.

Initial graft tension affects patellofemoral alignment during anatomical anterior cruciate ligament reconstruction.

Background: This study aimed to evaluate the effects of the differences in initial graft tension (IGT) on patellofemoral alignment in the axial plane after anatomical anterior cruciate ligament reconstruction (ACLR).

Methods: A total of 102 patients who underwent primary anatomical ACLR using a bone-patellar-tendon-bone autograft were enrolled. The grafts were fixed with maximum manual force at full knee extension (higher graft tension; H group) and with 5-20 N at 20° knee flexion which corresponded to 80 N at full knee extension (lower graft tension; L group) pulls in 39 and 63 patients, respectively.

Baricitinib ameliorates inflammatory and neuropathic pain in collagen antibody-induced arthritis mice by modulating the IL-6/JAK/STAT3 pathway and CSF-1 expression in dorsal root ganglion neurons.

Background: Janus kinase (JAK) inhibitors, such as baricitinib, are widely used to treat rheumatoid arthritis (RA). Clinical studies show that baricitinib is more effective at reducing pain than other similar drugs. Here, we aimed to elucidate the molecular mechanisms underlying the pain relief conferred by baricitinib, using a mouse model of arthritis.

Sitting Sideways Causes Different Femoral-Tibial Rotations in Each Knee.

Purpose According to a previous study, asymmetrical kneeling, such as sitting sideways, does not exhibit asymmetrical movements. Rotational analyses of each femur and tibia help explain why rotational knee kinematics while sitting sideways do not exhibit asymmetrical movement. We aimed to assess the rotation of the femur and tibia in normal knees while sitting sideways.

Intraoperative reliability of the tibial anteroposterior axis "Akagi's Line" in total knee arthroplasty.

Purpose: The tibial anatomical anteroposterior (AP) axis "Akagi's line" was originally defined on computed tomography (CT) in total knee arthroplasty (TKA); however, its intraoperative reproducibility remains unknown. This study aimed to evaluate the intraoperative reproducibility of the Akagi's line and its effect on postoperative clinical outcomes.

Methods: This prospective study included 171 TKAs.

Factors Associated With a Lateral Ankle Sprain in Young Female Soccer Players: A Prospective Cohort Study.

Background: Previous studies have attempted to determine if certain risk factors can predict the occurrence of a lateral ankle sprain (LAS) in female soccer players. Unfortunately, there is limited evidence with regard to risk factors associated with an LAS in female soccer players.

Purpose: To identify intrinsic risk factors for an LAS among young female soccer players.

In vivo three-dimensional kinematic comparison of normal knees between flexion and extension activities.

Background/objective: Normal knee kinematics during flexion and extension activities over the whole range of motion remains unknown. This study aimed to clarify in vivo kinematics during knee flexion and extension activities of normal knees by comparing continuous flexion and extension activities up to a high flexion angle.

Methods: Twenty knees of 10 Japanese volunteers were enrolled in this study.

Lower hamstring to quadriceps muscle strength ratio and lower body weight as factors associated with noncontact anterior cruciate ligament injury in male American football players: A prospective cohort study.

Background: Previous studies have aimed to determine the use of certain risk factors in predicting the occurrence of noncontact anterior cruciate ligament (ACL) injuries. Unfortunately, evidence regarding noncontact ACL injuries in male American football players is limited. This prospective cohort study aimed to identify intrinsic risk factors for noncontact ACL injury among male American football players.

Short-term clinical results of bicruciate-retaining total knee arthroplasty using personalized alignment.

Background: Bicruciate-retaining (BCR) prosthesis has been introduced to recreate normal knee movement by preserving both the anterior and posterior cruciate ligaments. However, the use of BCR total knee arthroplasty (TKA) is still debatable because of several disappointing reports. We have been performing BCR TKAs with personalized alignment (PA).

Postoperative quadriceps weakness and male sex are risk factors for patellofemoral articular cartilage lesions after anatomical anterior cruciate ligament reconstruction.

Purpose: Patellofemoral (PF) compartment cartilage lesions are a frequent problem after anterior cruciate ligament (ACL) reconstruction. This study aimed to determine the factors that influence PF cartilage lesions after anatomical ACL reconstruction.

Methods: This study enrolled a total of 114 patients who did not manifest PF compartment cartilage lesions during anatomical ACL reconstruction and underwent second-look arthroscopy 18 months postoperatively.

Comparison of finite helical axis of the knee joint before and after bi-cruciate-preserving knee arthroplasty.

Background: Difference in the finite helical axis of the knee joints before and after anterior cruciate ligament-preserving knee arthroplasties such as unicompartmental knee arthroplasty and bi-cruciate-retaining total knee arthroplasty remains unknown. This study compared the knee finite helical axes before and after bi-cruciate-preserving knee arthroplasty.

Methods: Patients undergoing medial unicompartmental knee arthroplasty and bi-cruciate-retaining total knee arthroplasty were included.

Risk factors for hamstring strain injury in male college American football players -a preliminary prospective cohort study.

Background: Given the frequency of hamstring strain injuries (HSI) among male college American football players, several studies have attempted to determine whether certain risk factors can predict their occurrence. However, no consensus on modifiable risk factors for HSIs in male college American football players has yet been reached to prevent these injuries. This study aimed to clarify risk factors for HSI prospectively in college male American football players.

Developmental stage and lower quadriceps flexibilities and decreased gastrocnemius flexibilities are predictive risk factors for developing Osgood-Schlatter disease in adolescent male soccer players.

Purpose: This study aimed to elucidate the influential predictive risk factors of Osgood-Schlatter disease (OSD) on the support (non-kicking) leg among adolescent soccer players considering peak height velocity (PHV) age and investigate the cut-off values of the predictive variables.

Methods: A cohort of 302 Japanese adolescent male soccer players aged 12-13 years were followed over 6 months. All players underwent physical examination, tibial tubercle ultrasonography, anthropometric and whole-body composition measurements, and muscle flexibility test of the support leg at the baseline.

Bicruciate-retaining total knee arthroplasty procedure reduced tensile force in the middle and posterior components of lateral collateral ligament during deep knee flexion activities with no effect on tensile force of the medial collateral ligament.

Purpose: To analyse the effects of bicruciate-retaining total knee arthroplasty (BCR-TKA) on the tensile force of the collateral ligaments during two deep knee flexion activities, cross-leg sitting and squatting.

Methods: Thirteen patients (15 knees) treated using bicruciate-retaining total knee arthroplasty (BCR-TKA) for knee joint osteoarthritis were analysed. Knee joint kinematics during cross-leg sitting (open-chain flexion) and squatting (closed-chain flexion) were evaluated through fluoroscopy.

Impact of the COVID-19 Pandemic on Injury Incidence in Japanese Male Professional Soccer Players.

Background: The outbreak of the 2019 novel coronavirus disease (COVID-19) led to an enforced quarantine period and limited training and match activities for athletes.

Purpose: To report the influence of the COVID-19 pandemic on the occurrence of injury in Japanese male professional soccer players.

Study Design: Descriptive epidemiology study.

Intraoperative femoral rotational kinematics are similar in varus and valgus knees during medial pivot total knee arthroplasty.

Background: Medial-pivot type total knee arthroplasty is designed to reproduce physiological femoral rotational kinematics during knee flexion; however, its rotational kinematics in valgus knees remain unknown. This study's hypothesis is that its kinematics show the similar medial pivot motion in valgus knees as in varus knees.

Methods: This retrospective study included 50 cases of primary medial-pivot type total knee arthroplasty performed with navigation for knee osteoarthritis.

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.

Lateral posterior tibial slope does not affect femoral but does affect tibial tunnel widening following anatomic anterior cruciate ligament reconstruction using a Bone-Patellar Tendon-Bone graft.

Background: Tunnel widening (TW) after anterior cruciate ligament (ACL) reconstruction has been a research area of interest in ACL reconstruction. In recent years, it has been noted that posterior tibial slope (PTS) affects several types of outcomes after ACL reconstruction including TW. However, the relationships between femoral and tibial TW and between PTS and TW following anatomical ACL reconstruction using a bone-patellar tendon-bone (BTB) graft are often not understood.