KNEE EFFUSION AND QUADRICEPS MUSCLE STRENGTH

Ten healthy subjects with no musculoskeletal problems were tested usin g a computerized exercise dynamometer. Quadriceps femoris concentric p erformance was examined during maximal effort isokinetic knee extensio n 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 inc rements, and peak torque and power tests were undertaken with knee eff usions 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 p eak torque and power were not significantly affected by the amount of knee effusion at either joint angular velocity when submaximal exercis e was performed prior to the maximal effort test. However, peak torque s were significantly decreased during isokinetic muscle action without prior submaximal muscle work. It was suggested that these findings ma y be related to fluid movement in the knee joint compartments, the com pliance of the joint capsule, and the location that fluid was injected into the joint cavity. Joint swelling is a common symptom of individu als with osteoarthritis and rheumatoid arthritis, as well as those suf fering acute joint trauma. This study has extended previous work on jo int swelling by examining quadriceps function during joint movement, t hus more effectively simulating joint and muscle activity which occurs during functional activities. Patients with knee joint swelling are t hought to experience greater difficulty undertaking quadriceps exercis es, and will not perform these exercises effectively until swelling in the joint is reduced. The current study provides some evidence to sug gest that a moderate amount of swelling does not impair performance. A ssuming that patients do not have other symptoms that contraindicate e xercise, they can be encouraged to do more active muscle work.