Accelerated versus nonaccelerated rehabilitation after anterior cruciate ligament reconstruction: a prospective, randomized, double-blind investigation evaluating knee joint laxity using roentgen stereophotogrammetric analysis.

Background: The relationship between the biomechanical dose of rehabilitation exercises administered after anterior cruciate ligament (ACL) reconstruction and the healing response of the graft and knee is not well understood.

Hypothesis: After ACL reconstruction, rehabilitation administered with either accelerated or nonaccelerated programs produces the same change in the knees' 6 degrees of freedom, or envelope, laxity values.

Study Design: Randomized controlled trial; Level of evidence, 1.

The effect of coordinate system choice and segment reference on RSA-based knee translation measures.

Roentgen stereophotogrammetric analysis (RSA) can be utilized to accurately describe joint kinematics, but even when measuring small displacements within radiographically discernible structures, standardized reference frames are imperative for useful comparison across patients and across studies. In the current paper, accurately controlled laboratory models demonstrated the considerable influence that a mere 1.9-cm offset of the origin of the coordinate system from the rotation axes could exert on translation measures when rotations were occurring.

The effect of estradiol and progesterone on knee and ankle joint laxity.

Background: Female athletes suffer a higher incidence of anterior cruciate ligament injuries compared to their male counterparts, and they appear to be at increased risk for these injuries when they have increased anterior-posterior knee laxity and at specific phases of the menstrual cycle. Although the mechanism by which these factors combine to increase injury risk is unclear, studies suggest that cyclic variations in joint laxity produced by hormone fluctuation during the menstrual cycle predispose an athlete to increased risk of ligamentous injury. Little is known about whether joint laxity varies cyclically during the menstrual cycle and if so, whether it is modulated by cyclic variations of estradiol (E2) and progesterone (P4).

Measurement of anterior-posterior knee laxity: a comparison of three techniques.

Several non-invasive techniques have been developed to assess anterior-posterior (A-P) laxity of the knee, however, their accuracy remains unclear. Roentgen Stereophotogrammetry Analysis (RSA) is a three-dimensional motion analysis method that has been shown to be an accurate tool for evaluating joint kinematics. Thus.