Tibial and femoral articular cartilage exhibit opposite outcomes for T1ρ and T2* relaxation times in response to acute compressive loading in healthy knees.

Abnormal loading is thought to play a key role in the disease progression of cartilage, but our understanding of how cartilage compositional measurements respond to acute compressive loading in-vivo is limited. Ten healthy subjects were scanned at two timepoints (7 ± 3 days apart) with a 3 T magnetic resonance imaging (MRI) scanner. Scanning sessions included T1ρ and T2* acquisitions of each knee in two conditions: unloaded (traditional MRI setup) and loaded in compression at 40 % bodyweight as applied by an MRI-compatible loading device.

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.

Risk Factors for Concomitant Meniscal Injury With Sport-Related Anterior Cruciate Ligament Injury.

Background: Previous studies of concomitant meniscal injury in athletes with anterior cruciate ligament (ACL) injury have examined age, sex, body mass index (BMI), injury mechanism, and time from injury to surgery as potential risk factors.

Purpose: To identify additional risk factors for concomitant meniscal injury, including preinjury joint laxity and lower extremity alignment, in athletes with sport-related ACL injury.

Study Design: Cross-sectional study; Level of evidence, 3.

Key Thresholds and Relative Contributions of Knee Geometry, Anteroposterior Laxity, and Body Weight as Risk Factors for Noncontact ACL Injury.

Background: Limited data exist regarding the association of tibiofemoral bony and soft tissue geometry and knee laxity with risk of first-time noncontact anterior cruciate ligament (ACL) rupture.

Purpose: To determine associations of tibiofemoral geometry and anteroposterior (AP) knee laxity with risk of first-time noncontact ACL injury in high school and collegiate athletes.

Study Design: Cohort study; Level of evidence, 2.

Does interpolation and intra-user variability affect the accuracy of arthrokinematic measurements in the knee? A dual fluoroscopic imaging and model-based tracking study.

Model-based tracking (MBT) is a time-consuming and semiautomatic approach, and thus subject to errors during the tracking process. The present study aimed primarily to quantify the effects that interpolation and intra-user variability associated with MBT have on the kinematic and arthrokinematic measurements in comparison to a gold standard radiostereometric analysis (RSA). Cadaveric knee specimens were imaged at 125 Hz while simulating standing, walking, jogging, and lunging motions.

A prospective study of joint position sense after anterior cruciate ligament injury, reconstruction with a bone-patella tendon-bone graft, and rehabilitation.

Background: Disruption of the anterior cruciate ligament (ACL) is associated with significant biomechanical and neuromuscular changes including deficits in joint proprioception. While previous studies have assessed joint position sense (JPS) in ACL deficient knees, methods have varied and few have done so with prospective study designs. The specific aim of this investigation was to determine the effect(s) of ACL reconstruction and recovery time may have on JPS.

Intrinsic Risk Factors for First-Time Noncontact ACL Injury: A Prospective Study of College and High School Athletes.

Background: A comprehensive understanding of the intrinsic risk factors for anterior cruciate ligament (ACL) disruption is important for identifying individuals at increased risk for suffering this trauma and developing interventions to mitigate risk.

Hypothesis: A variety of risk factors predispose athletes to first-time, noncontact ACL injury and some of these differ between male and female athletes.

Study Design: Prospective cohort study with nested case-control sampling.

The Duration of Thigh Tourniquet Use Associated With Anterior Cruciate Ligament Reconstruction Does Not Produce Cellular-Level Contractile Dysfunction of the Quadriceps Muscle at 3 Weeks After Surgery.

Background: Anterior cruciate ligament (ACL) trauma and ACL reconstruction (ACLR) are associated with the loss of strength and function of the muscles that span the knee joint. The underlying mechanism associated with this is not completely understood.

Purpose: To determine whether the duration of tourniquet use during ACLR has an effect on knee extensor muscle contractile function and size at the cellular (ie, fiber) level 3 weeks after surgery and at the whole-muscle level at 6 months after surgery.

Biomechanical comparison of a novel tensioned cable construct versus tension band wiring for transverse patella fracture fixation.

Purpose: Tension band wiring (TBW) is the most widely accepted method for patella fracture fixation. The purpose of our study was to compare the biomechanical efficacy of a novel cable construct to TBW for the fixation of transverse patella fractures. The tensioned cable construct was hypothesized to have less fracture gapping after cyclic flexion-extension loading and greater ultimate load to failure as compared to TBW.

The Lateral Femoral Condyle Index Is Not a Risk Factor for Primary Noncontact Anterior Cruciate Ligament Injury.

Background: The lateral femoral condyle index (LFCI)-a recently developed measure of the sphericity of the lateral femoral condyle-was reported to be a risk factor for anterior cruciate ligament (ACL) injury. However, issues have been raised regarding how the index was measured and regarding the patient group and the knee in which it was measured.

Purpose: To investigate the association between the LFCI and the risk of sustaining a primary, noncontact ACL injury, and to examine whether this association was moderated by the posterior-inferior-directed slope of the lateral tibial plateau.

Incidence of anterior tibial spine fracture among skiers does not differ with age.

Purpose: Injury to the anterior cruciate ligament (ACL) is common in alpine skiing in the form of either an intra-substance ACL tear or anterior tibial spine fracture (ATSF). Anterior tibial spine fractures are typically reported in children. However, several case reports describe these injuries in adults while skiing.

Compliance and Fidelity With an Injury Prevention Exercise Program in High School Athletics.

Background: Use of injury prevention programs (IPPs) by high school athletes has increased but their success in reducing injury depends on program compliance and fidelity of exercise performance.

Hypothesis: Compliance with the 11+ IPP and exercise performance fidelity by high school athletic teams depend on sex, sport, and level of play.

Study Design: Secondary analyses of data from a randomized controlled trial (RCT).

Articular cartilage thickness changes differ between males and females 4 years following anterior cruciate ligament reconstruction.

Anterior cruciate ligament injury and reconstruction (ACLR) affects articular cartilage thickness profiles about the tibial, femoral, and patellar surfaces; however, it's unclear whether the magnitudes of change in cartilage thickness, as well as the locations and areas over which these changes occur, differ between males and females. This is important to consider as differences exist between the sexes with regard to knee biomechanics, patellofemoral pain, and anatomic alignment, which influence risk of an index and repeated injury. Subjects underwent ACLR with a bone-patella tendon-bone autograft.

Association of Geometric Characteristics of Knee Anatomy (Alpha Angle and Intercondylar Notch Type) With Noncontact ACL Injury.

Background: The femoral intercondylar notch type and the alpha angle (the angle between the femoral notch roof and the long axis of the femur) are easily measured in clinical settings; however, their associations with anterior cruciate ligament (ACL) injury remain unclear.

Hypothesis/purpose: The purpose was to determine if the alpha angle and the femoral notch type are associated with noncontact ACL injury univariately and in combination with previously identified knee geometric risk factors. We hypothesized that the alpha angle and the femoral notch type are associated with noncontact ACL injury and that the association differs between men and women.

Clinical-Grade MRI-Based Methods to Identify Combined Anatomic Factors That Predict ACL Injury Risk in Male and Female Athletes.

Background: Recently developed multivariate sex-specific statistical models can predict anterior cruciate ligament (ACL) injury risk using various knee anatomic factors. However, screening tools able to identify individuals at an increased injury risk are unlikely to be developed based on these models, given that sophisticated and time-consuming methods were used to measure those factors on research-grade resolution magnetic resonance images (MRIs).

Purpose: To determine whether simpler methods, amenable to using clinical-grade resolution MRIs, can identify the same knee anatomic factors previously found to contribute to ACL injury risk using sophisticated methods and research-grade resolution images.

Skeletal muscle cellular contractile dysfunction after anterior cruciate ligament reconstruction contributes to quadriceps weakness at 6-month follow-up.

Muscle dysfunction following anterior cruciate ligament reconstruction (ACLR) may evolve from alterations in muscle contractility at the myofilament protein level. Using a prospective, within-subject case-control design, we evaluated cellular-level contractility, cross-sectional area (CSA), and myosin heavy chain (MHC) isoform expression on single muscle fibers 3 weeks post ACLR, and evaluated their relationship to whole muscle strength and patient-oriented outcomes 6 months post operation. Biopsies of the vastus lateralis were performed 3 weeks post ACLR in 11 subjects (5 females, mean age ± SD = 24.

Perioperative Family Updates Reduce Anxiety and Improve Satisfaction: A Randomized Controlled Trial.

Purpose: This study aimed to determine if standardized updates at specific perioperative events affect anxiety and satisfaction of the family members and if the length of surgical procedure affects the satisfaction with updates.

Methods: This study was a randomized control trial. In the control group, surgeons communicated with the family only once near the completion of the procedure.

Wrist Fractures in Skiers and Snowboarders: Incidence, Severity, and Risk Factors Over 40 Seasons.

Purpose: To determine and compare the incidence and severity of wrist fractures in skiers and snowboarders.

Methods: A university-run orthopedic clinic at the base of a major ski resort has maintained an injury database spanning the years 1972 to 2012. Demographic information, equipment type, ability level, trail type and conditions, number of falls, circumstances surrounding the injury, and radiographs were collected on participants sustaining wrist fractures and compared with uninjured control participants asked the same questions, but in reference to their last fall where no injury resulted.

Comparison of Tip- Versus Hub-Oscillating Saw Blade Control in a Total Knee Arthroplasty Model.

Background: Oscillating saws are commonly used for bone preparation in total knee arthroplasty but can cause injury to the posterior neurovascular bundle during tibial resection. Tip-oscillating saw blades are a recent innovation that could improve saw control due to decreased excursion; however, the tactile feedback to the surgeon is different.

Methods: To compare traditional hub and new tip-oscillating saw blades, 16 participants of varying levels of experience were video-recorded during composite tibial bone model resections to measure posterior saw blade plunge.

Utility of Neuromuscular Electrical Stimulation to Preserve Quadriceps Muscle Fiber Size and Contractility After Anterior Cruciate Ligament Injuries and Reconstruction: A Randomized, Sham-Controlled, Blinded Trial.

Background: Anterior cruciate ligament (ACL) injuries and reconstruction (ACLR) promote quadriceps muscle atrophy and weakness that can persist for years, suggesting the need for more effective rehabilitation programs. Whether neuromuscular electrical stimulation (NMES) can be used to prevent maladaptations in skeletal muscle size and function is unclear.

Purpose: To examine whether early NMES use, started soon after an injury and maintained through 3 weeks after surgery, can preserve quadriceps muscle size and contractile function at the cellular (ie, fiber) level in the injured versus noninjured leg of patients undergoing ACLR.

A Cyber-Physical System for Near Real-Time Monitoring of At-Home Orthopedic Rehabilitation and Mobile-Based Provider-Patient Communications to Improve Adherence: Development and Formative Evaluation.

Background: Knee extensor muscle performance is reduced after lower extremity trauma and orthopedic surgical interventions. At-home use of neuromuscular electrical stimulation (NMES) may improve functional recovery, but adherence to at-home interventions is low. Greater benefits from NMES may be realized with closer monitoring of adherence to at-home prescriptions and more frequent patient-provider interactions.

Combined Injury to the ACL and Lateral Meniscus Alters the Geometry of Articular Cartilage and Meniscus Soon After Initial Trauma.

Combined injury to the anterior cruciate ligament (ACL) and meniscus is associated with earlier onset and increased rates of post-traumatic osteoarthritis compared with isolated ACL injury. However, little is known about the initial changes in joint structure associated with these different types of trauma. We hypothesized that trauma to the ACL and lateral meniscus has an immediate effect on morphometry of the articular cartilage and meniscus about the entire tibial plateau that is more pronounced than an ACL tear without meniscus injury.