To evaluate the muscle activation pattern of lower extremities can be modified by intraarticular injection of hyaluronic acid( IAHA).
Twenty-three subjects with knee OA and 14 age-matched non-knee OA control subjects were recruited from an outpatient clinic. Three-dimensional gait analysis with using the MA- 100 EMG system was applied to measure the muscles activities. The quadriceps (QUA), hamstrings (HAM), tibialis anterior (TA), and medial gastrocnemius (MG) muscles were selected for this study. For the knee OA group, bilateral IA knee joint injections with HA were performed.
During the stance phase of gait cycle, the quadriceps, hamstring, and tibialis anterior muscles had longer muscle contraction duration in the knee OA patients as compared with the control group. The muscle activities of quadriceps, hamstrings, tibialis anterior, and medial gastrocnemius muscles recovered to a pattern similar to the control group after the completion of IA HA injections in knee OA patients. The H/Q ratio improved significantly after the IA HA injections, and also lasted up to a period of six months (p<0.01).
IA HA is an available treatment option as it effectively decreases co-contraction and improves motor activity of the lower extremity muscles. The improved muscle activities lasted up to a period up to six months.