Knee effusion and quadriceps muscle strength.

Ten healthy subjects with no musculoskeletal problems were tested using a computerized exercise dynamometer. Quadriceps femoris concentric performance was examined during maximal effort isokinetic knee extension at joint angular velocities of 2.09 and 4.18 rad s(-1). A saline and dextrose solution was injected into the knee joint cavity in 30-ml increments, and peak torque and power tests were undertaken with knee effusions of 0, 30, 60, and 90 ml. A protocol which included and excluded a local skin anaesthetic and submaximal exercise prior to the maximal effort test was also undertaken. The results showed that quadriceps peak torque and power were not significantly affected by the amount of knee effusion at either joint angular velocity when submaximal exercise was performed prior to the maximal effort test. However, peak torques were significantly decreased during isokinetic muscle action without prior submaximal muscle work. It was suggested that these findings may be related to fluid movement in the knee joint compartments, the compliance of the joint capsule, and the location that fluid was injected into the joint cavity. Joint swelling is a common symptom of individuals with osteoarthritis and rheumatoid arthritis, as well as those suffering acute joint trauma. This study has extended previous work on joint swelling by examining quadriceps function during joint movement, thus moreeffectivelysimulating joint and muscle activity which occursduring functional activities. Patients with knee joint swelling are thought to experience greater difficulty undertaking quadriceps exercises, and will not perform these exercises effectively until swelling in the joint is reduced. The current study provides some evidence to suggest that a moderate amount of swelling does not impair performance. Assuming that patients do not have other symptoms that contraindicate exercise, they can be encouraged to do more active muscle work.