Viscoelasticity and temperature variations decrease tension and stiffness of hamstring tendon grafts following anterior cruciate ligament reconstruction.

Background: Hamstring tendon grafts used for anterior cruciate ligament reconstruction are typically harvested early in the surgical procedure and are preconditioned prior to reimplantation. Postoperatively, the grafts undergo stress relaxation and warm from the temperature of the operating room to body temperature. The hypothesis of this study was that the tension within semitendinosus and gracilis tendon grafts and the stiffness of the grafts significantly decrease postoperatively because of both stress relaxation and an increase in temperature.

Locking plates improve torsional resistance in the stabilization of three-part proximal humeral fractures.

This study quantified the torsional resistance provided by locking plates and angled blade plates used to stabilize proximal humeral fractures. Three-part proximal humeral fractures were created in 6 pairs of cadaveric humeri. One specimen of each pair was reconstructed with a proximal humeral locking plate, whereas the other specimen was reconstructed with an angled blade plate.

Comparing two estimations of the quadriceps force distribution for use during patellofemoral simulation.

EMG analysis has indicated that the vastus lateralis and vastus medialis contribute less to the quadriceps moment during knee extension than the physiological cross-sectional areas (PCSA's) of the muscles indicate. Both PCSA- and EMG-based quadriceps force distributions were utilized while computationally simulating knee extension. For both distributions, a 10 degrees increase in the Q-angle and a 50% decrease in the force applied by the vastus medialis were simulated, and the influence of these changes on the resultant force and moment applied by the quadriceps muscles and the patella tendon was quantified.

Structural properties of lateral collateral ligament reconstruction at the fibular head.

Background: Anatomical reconstruction of a ruptured lateral collateral ligament using allograft tissue secured within the fibular head with an interference screw has been described.

Hypothesis: Interference fixation at the fibular head does not reproduce the strength of the intact ligament.

Study Design: Controlled laboratory study.