The goal of this study was to determine whether or not the intraarticular administration of hyaluronic acid can improve functional parameters, such as isokinetic muscle strength or total work and clinical test results in patients with osteoarthritis (OA) of the knee.
As part of a prospective, controlled study 43 patients with osteoarthritic changes of both knees (radiographic Kellgren stage II-III) were followed in a right/left comparison. The influence of intraarticularly injected hyaluronic acid (20mg hyaluronic acid/2ml Hyalart) on functional and clinical parameters was analysed. We used the isokinetic system Cybex 600 for measuring maximal isokinetic muscle strength and total work. A total of 20 males and 23 females fulfilled the inclusion criteria with an age between 55-78 years and underwent five injections of hyaluronic acid (one injection per week). The injected knee represented the treatment group, while the contralateral knee served as the control.
The maximum peak torque of the knee extensors in the treatment group was measured between 57+/-26.15/32.33+/-19.63Nm prior to the injections and 77.17+/-32.54/47.83+/-21.43Nm following the hyaluronic acid therapy (P< 0.01). The analysis of the knee flexors at angular velocities of 60 degrees /s and 180 degrees /s revealed values of 40.44+/-21.58/22.89+/-16.64Nm and 53.55+/-24.26/34.05+/-17.37Nm (P< 0.01) respectively. The evaluation of the total work of the knee flexors and extensors revealed a significant difference (P< 0.01) between the treatment and control group. The Lequesne score was reduced from 13.57+/-1.88 prior to the injections to 7.94+/-2.53 after the treatment (P< 0.01). The pain score was documented with the help of a visual analog scale. The VAS values were reduced at rest from 3.83+/-1.72cm to 1.36+/-1.42cm and during weight bearing from 7.57+/-1.34cm to 3.75+/-1.32cm in the treatment group (P< 0.01).
This controlled prospective clinical trial confirmed that 5 weekly intraarticular injections of HA (Hyalart) in patients with OA of the knee provide pain relief and functional improvements.