Reliability of a New Clinical Instrument for Measuring Internal and External Glenohumeral Rotation.

Background: The shoulder plays a critical role in many overhead athletic activities. Several studies have shown alterations in shoulder range of motion (ROM) in the dominant shoulder of overhead athletes and correlation with significantly increased risk of injury to the shoulder and elbow. The purpose of this study was to measure isolated glenohumeral joint internal/external rotation (IR/ER) to determine inter- and intraobserver reliability of a new clinical device.

Anatomic Single-Graft Anterior Cruciate Ligament Reconstruction Restores Rotational Stability: A Robotic Study in Cadaveric Knees.

Purpose: First, we aimed to investigate the ability of a single bone-patellar tendon-bone graft placed in the anatomic center of the femoral and tibial attachment sites to restore normal tibiofemoral compartment translations and tibial rotation. Second, we aimed to investigate what combination of anterior load and internal rotation torque applied during a pivot-shift test produces maximal anterior tibiofemoral subluxations.

Methods: We used a 6-df robotic simulator to test 10 fresh-frozen cadaveric specimens under anterior cruciate ligament (ACL)-intact, ACL-sectioned, and ACL-reconstructed conditions measuring anterior translations of the medial, central, and lateral tibiofemoral compartments and degrees of tibial rotation.

Effect of anteromedial and posterolateral anterior cruciate ligament bundles on resisting medial and lateral tibiofemoral compartment subluxations.

Purpose: This study analyzed the interaction of the anteromedial and posterolateral portions of the anterior cruciate ligament (ACL) in resisting medial and lateral tibiofemoral compartment subluxations under multiple loading conditions.

Methods: By use of a 6-df robotic simulator, 10 human cadaveric knees were tested in 3 states: intact ACL, partial ACL (loss of either the anteromedial bundle [AMB] or posterolateral bundle [PLB]), and deficient ACL. The testing profile involved anterior-posterior translation and internal-external rotation, as well as 3 pivot-shift loading conditions with varying internal rotation torque (1- or 5-Nm) and coupled anterior force (35- or 100-N).

Anterior cruciate ligament function in providing rotational stability assessed by medial and lateral tibiofemoral compartment translations and subluxations.

Background: Rotational knee stability provided by the anterior cruciate ligament (ACL) in the pivot-shift phenomena involves analysis of more complex robotic testing profiles and resulting tibiofemoral compartment kinematics and subluxations.

Hypotheses: Using anterior-posterior tibial forces along with internal and valgus tibial moments will produce a major anterior subluxation of both tibiofemoral compartments not obtained with internal and valgus moments alone. Increasing the internal torque in pivot-shift testing will constrain the anterior subluxations of the medial and central tibial compartments.

One- and two-strand posterior cruciate ligament reconstructions: cyclic fatigue testing.

This study examined how one- and two-strand posterior cruciate ligament (PCL) reconstructions resist the return of posterior translation during repetitive knee cycling. The femoral attachment of the one-strand graft and the anterior strand of the two-strand (AD2) grafts were located within the anterior one-third of the femoral PCL footprint. The second strand was placed within the middle third of the femoral footprint in one of three locations: middle-distal (MD), middle-middle (MM), or middle-proximal (MP).

Two-bundle posterior cruciate ligament reconstruction: how bundle tension depends on femoral placement.

Background: Clinically, one-bundle posterior cruciate ligament reconstructions frequently result in the return of abnormal posterior translation. We hypothesized that the return of posterior translation is caused by a nonuniform distribution of load among the graft fibers. The purpose of the present study was to determine how the femoral attachment location of the second bundle of a two-bundle posterior cruciate ligament reconstruction affects the anterior bundle tension and the load distribution between the graft bundles.

Posterior cruciate ligament femoral insertion site characteristics. Importance for reconstructive procedures.

Background: Previous descriptions of the insertion site of the posterior cruciate ligament are inadequate.

Hypothesis: More than one reference system is required to adequately represent the anatomy of the femoral attachment.

Study Design: Descriptive anatomic study.