Intra-articular knee joint effusion induces quadriceps avoidance gait patterns

Objectives. (1) To identify adaptations caused by intra-articular knee join t effusion during walking and (2) to determine if knee joint effusion may b e a causative factor in promoting quadriceps avoidance gait patterns. Design. Gait testing of 14 healthy individuals who underwent incremental sa line injections of the knee joint capsule. Background. Gait adaptations have been reported in the literature for knee injured and rehabilitating individuals. Knee joint capsular afferent activi ty can influence knee joint function. Methods. Gait analysis was employed in a pre- and post-test, repeated measu res design to determine lower extremity joint kinematics, kinetics, energet ics and thigh EMG adaptations due to intra-articular knee joint effusion. Results. Knee effusion caused an increase in hip and knee flexion through t he stance phase. Knee extensor torque, impulse and negative and positive wo rk were diminished with increased effusion levels. Quadriceps activity decr eased and hamstring activity increased due to intra-articular knee joint ef fusion. Discussion. These adaptations cannot be attributed to an injury, surgery or rehabilitation. Thus, the results of this experiment suggest knee joint ca psular distention, via knee joint effusion, may be responsible for many gai t adaptations reported for knee injured individuals in previous investigati ons. Conclusions. Knee joint effusion and the subsequent capsular distention can cause major alterations in the normal gait cycle and can be considered a c ausative factor promoting the acquisition of quadriceps avoidance gait patt erns.