Surgical correction of limb malalignment for instability of the patella: a comparison of 2 techniques.

Background: Although patients considered "successful" at longer-term follow-up no longer exhibited patellar instability, those with more severe malalignment issues had other, gradually worsening symptoms such as activity-related pain, crepitation, swelling with activities, and pain with weather changes.

Hypothesis: Improvement of patellar tracking by correction of the tubercle-sulcus angle and related ligament deficiencies will result in good to excellent results, regardless of the technique employed.

Study Design: Cohort study; Level of evidence, 3.

Simulation of biceps femoris musculotendon mechanics during the swing phase of sprinting.

Introduction/purpose: Characterization of hamstring mechanics during sprinting is fundamental to understanding musculotendon injury mechanisms. The objective of this study was to use muscle-actuated forward dynamic simulations to investigate musculotendon mechanics of the biceps femoris long head during the swing phase of sprinting.

Methods: We used a three-dimensional linked segment model with 26 Hill-type musculotendon actuators to simulate swing phase dynamics.

Identifying the time of occurrence of a hamstring strain injury during treadmill running: a case study.

Background: While hamstring strain injuries are common during sprinting, the mechanisms of injury are not well understood. In this study, we analyzed the running kinematics of an athlete obtained at the time of an acute hamstring strain injury. The purpose was to identify the period of the gait cycle during which the hamstring was likely injured, as well as to characterize the biomechanical conditions associated with the injury.

Hamstring muscle kinematics during treadmill sprinting.

Introduction/purpose: The objective of this study was to characterize hamstring muscle kinematics during sprinting, so as to provide scientific data to better understand injury mechanisms and differences in injury rates between muscles.

Methods: We conducted three-dimensional motion analyses of 14 athletes performing treadmill sprinting at speeds ranging from 80 to 100% of maximum. Scaled musculoskeletal models were used to estimate hamstring muscle-tendon lengths throughout the sprinting gait cycle for each speed.