Radiographic and Anatomic Evaluation of Tibial Tubercle to Trochlear Groove Distance.

 A lateralized tibial tubercle is an important anatomic predictor of patellar instability and can be used as an indication for a distal realignment procedure. Currently, tibial tubercle to trochlear groove (TT-TG) distance is measured on computed tomography (CT); however, radiographs could be a safer and more efficient modality. The aim of this study is to evaluate and compare TT-TG measurements obtained using CT, anatomical dissections, and a novel radiographic technique.

Anterior Cruciate Ligament Graft Isometry is Affected by the Orientation of the Femoral Tunnel.

Purpose: The purpose of this study was to compare anterior cruciate ligament (ACL) graft length and tension throughout knee range of motion with transtibial, anteromedial (AM) portal, and all-epiphyseal drilling techniques with suspensory and apical femoral fixation.

Methods: The three different femoral tunnel drilling techniques using the same intra-articular starting point within the center of the femoral footprint were performed on fresh-frozen cadaveric specimens. All groups underwent standard tibial drilling in the center of the ACL tibial footprint.

How do spanning external fixators on knee dislocation patients affect the use of MRI and knee stability?

This study sought to determine the following: (1) Does the external fixator compromise quality of imaging obtained? (2) How do findings from the evaluation under anesthesia at the time of external fixator removal compare with the initial magnetic resonance imaging (MRI) findings? This was a retrospective study of a consecutive patient series at an academic level 1 trauma center. There were 19 consecutive patients with traumatic knee dislocations and spanning external fixator applied. Each patient had a knee MRI with the external fixator in place and examination at the time of external fixator removal.

The role of magnetic resonance imaging in a Division I university sports medicine program.

Objective: To prospectively document musculoskeletal magnetic resonance imaging (MRI) use and how it affects diagnosis, playing status, and treatment of Division I university athletes. We hypothesized that MRI often has little or no effect on the diagnosis or treatment plan.

Design: Cross-sectional study.

Missed rotator cuff tears in polytraumatized patients.

If not identified early, rotator cuff tears in polytraumatized patients can become debilitating. Traumatic rotator cuff tears are often massive, and generally retract over a short period of time. If a tear is missed or becomes irreparable, the consequences are profound, and can be devastating, especially to a younger, active person.

Biomechanical comparison of long head of biceps tenodesis with interference screw and biceps sling soft tissue techniques.

Purpose: The purpose of our study was to compare biomechanically a long head biceps tenodesis using an all soft tissue biceps sling technique versus an interference screw technique.

Methods: Six paired fresh frozen shoulder specimens were separated into 2 groups. One group used an all soft tissue biceps sling technique for tenodesis.

Isolated hyoid bone fractures in collegiate football players: a case series and review of the literature.

Hyoid fractures in athletes are rare injuries that can be difficult to diagnose. Typically resulting from a direct blow to the anterior neck, hyoid fractures can lead to subcutaneous edema and subsequent airway compromise. The treatment of this fracture depends largely on the severity of the presenting symptoms.

Arthroscopic evaluation of knee lateral compartment widening after lateral ligamentous injury.

Purpose: To evaluate whether diagnostic arthroscopy of the lateral tibiofemoral compartment can determine the presence of a lateral ligamentous knee injury.

Methods: Nine cadaveric knee specimens were used with varus stresses of 12 Nm and the force at which no further lateral opening occurred. Arthroscopic measurements were taken of the lateral compartments with knees at 30°, 45° and 90°.

Leg intramuscular pressures and in vivo knee forces during lower body positive and negative pressure treadmill exercise.

Quantifying muscle and joint forces over a broad range of weight bearing loads during exercise may provide data required to improve prosthetic materials and better protect against muscle and bone loss. Collectively, leg intramuscular pressure (IMP), ground reaction force (GRF), and the instrumented tibial tray force measurements provide a comprehensive assessment of leg muscle and joint biomechanical effects of gravity during exercise. Titration of body weight (BW) by lower body negative pressure (LBNP) and lower body positive pressure (LBPP) can reproducibly modulate IMP within leg muscle compartments.

Intramuscular pressures in antigravity muscles using gravity-independent, pneumatic hardware.

Introduction: Resistive exercise helps prevent muscle atrophy in microgravity, but better exercise equipment is needed. Therefore, the purpose of this study was to determine if a pneumatic, gravity-independent leg-press device (LPD) provides sufficient force to leg musculature. We hypothesized that intramuscular pressure (IMP), a quantitative index of muscle force, is greater in the antigravity superficial posterior and deep posterior compartments than in the non-antigravity anterior compartment during bilateral leg-press exercise.

The effect of kneeling during spine surgery on leg intramuscular pressure.

Background: Acute compartment syndrome has been an underreported complication during spine surgery with the patient positioned on the so-called 90/90 kneeling frame (with 90 degrees of both hip and knee flexion), presumably because of elevated intramuscular pressures in the dependent leg compartments. The purpose of the present study was to characterize and quantify certain parameters that affect the risk for acute compartment syndrome experimentally and to make objective comparisons with other spine surgery positions.

Methods: Eight healthy volunteers were positioned in three spine surgery positions: the 90/90 kneeling position, the so-called 45/45 suspended position (with the hips and knees both flexed to 45 degrees with the legs suspended on a sling), and the prone position.

Ambulation in simulated fractional gravity using lower body positive pressure: cardiovascular safety and gait analyses.

The purpose of this study is to assess cardiovascular responses to lower body positive pressure (LBPP) and to examine the effects of LBPP unloading on gait mechanics during treadmill ambulation. We hypothesized that LBPP allows comfortable unloading of the body with minimal impact on the cardiovascular system and gait parameters. Fifteen healthy male and female subjects (22-55 yr) volunteered for the study.

Space exercise and Earth benefits.

The detrimental impact of long duration space flight on physiological systems necessitates the development of exercise countermeasures to protect work capabilities in gravity fields of Earth, Moon and Mars. The respective rates of physiological deconditioning for different organ systems during space flight has been described as a result of data collected during and after missions on the Space Shuttle, International Space Station, Mir, and bed rest studies on Earth. An integrated countermeasure that simulates the body's hydrostatic pressure gradient, provides mechanical stress to the bones and muscles, and stimulates the neurovestibular system may be critical for maintaining health and well being of crew during long-duration space travel, such as a mission to Mars.

EMG power spectra of intercollegiate athletes and anterior cruciate ligament injury risk in females.

Purpose: Females have a disproportionately high incidence of anterior cruciate ligament (ACL) injuries compared with males in analogous sports. Although the pathogenesis of this higher frequency has not been elucidated, gender differences in neuromuscular control of the knee may play an important role. This study evaluates EMG power spectra of the quadriceps and hamstring muscles during dynamic, fatiguing exercise to examine differences between male and female intercollegiate athletes.