Acute patellar dislocation during eccentric muscle testing on the Biodex dynamometer.

Isokinetic training and muscle torque measurements are commonly used during rehabilitation after knee ligament injuries. Isokinetic maximal muscle strength tests are performed to monitor the progress in muscle rehabilitation. The muscle power is evaluated by measuring the applied force in the direction of motion (concentric muscle power) or the force against the direction of motion (eccentric muscle power). Both legs are examined to compare the total muscle work and peak torques of the involved leg with those of the uninvolved leg. We report the case of an acute patellar dislocation during eccentric testing of the uninvolved leg on the Biodex isokinetic dynamometer testing device (Biodex Corporation, Shirley, NY).