Improvement of muscle strength in osteoarthritic knee patients after intraarticular knee injection of hyaluronan

Objective: The objective of this study was to investigate whether the knee concentric and eccentric muscle strengths can be improved in patients with bilateral knee osteoarthritis after intraarticular hyaluronan injections. Design: A total of 25 patients with bilateral knee osteoarthritis and with a radiographic Ahlbäck grading scale of I or II participated in this study. One session of intraarticular knee injection of hyaluronan was given to both knees (weekly intraarticular knee hyaluronan injections for a total of 5 wks). Knee concentric and eccentric muscle strengths were recorded between 10 and 90 degrees of knee flexion. The recordings were done on two angular velocities, 80 and 240 degrees/sec. This study took place in a tertiary medical center with a gait laboratory and a KIN-COM isokinetic dynamometer. Results: An increase in concentric and eccentric muscle strength adjusted for body weight (P < 0.01) was observed in both knees, ranging between 5.1% and 27.7%. Conclysion: The decreased knee muscle contraction strength (concentric and eccentric) can be improved in knee osteoarthritis patients with an Ahlbäck grading scale of I or II after five weekly intraarticular knee injections of hyaluronan.