Intra-articular knee joint effusion induces quadriceps avoidance gait patterns

Objectives. (1) To identify adaptations caused by intra-articular knee joint effusion during walking and (2) to determine if knee joint effusion may be a causative factor in promoting quadriceps avoidance gait patterns. Design. Gait testing of 14 healthy individuals who underwent incremental saline 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 activity can influence knee joint function. Methods. Gait analysis was employed in a pre- and post-test, repeated measures design to determine lower extremity joint kinematics, kinetics, energetics and thigh EMG adaptations due to intra-articular knee joint effusion. Results. Knee effusion caused an increase in hip and knee flexion through the stance phase. Knee extensor torque, impulse and negative and positive work were diminished with increased effusion levels. Quadriceps activity decreased and hamstring activity increased due to intra-articular knee joint effusion. Discussion. These adaptations cannot be attributed to an injury, surgery or rehabilitation. Thus, the results of this experiment suggest knee joint capsular distention, via knee joint effusion, may be responsible for many gait adaptations reported for knee injured individuals in previous investigations. Conclusions. Knee joint effusion and the subsequent capsular distention can cause major alterations in the normal gait cycle and can be considered a causative factor promoting the acquisition of quadriceps avoidance gait patterns.