[Effect of Unloading Knee Brace on Dynamic Parameters of the Stance Phase of Gait in Patients with Knee Osteoarthritis].

PURPOSE OF THE STUDY Knee joint is the most common place where osteoarthritis may occur. A specific therapy is indicated to patients depending on the degree of disability and other signs. The available methods and their clinical value are regularly assessed in systematic reviews and meta-analysis of clinical studies. The evidence of working mechanism of the specific therapeutic intervention is another important part of evaluating its therapy effect. One of the possibilities of knee osteoarthritis conservative treatment is a functional prophylactic knee brace. This type of knee brace is designed to transfer the load away from the affected part of the knee joint in every step. The main goal of this study was to determine the effect of a prophylactic knee brace on dynamic parameters of the stance phase of gait in patients with knee osteoarthritis. MATERIAL AND METHODS The research involved twelve subjects with predominantly unilateral medial knee osteoarthritis of grade 2 and 3. Six patients did not complete the study. Therefore, the data of six persons were processed (average age 68.3 ± 4.4 years, average weight 83 ± 15.9 kg, average height 170.5 ± 11.7 cm). There were two piezoelectric Kistler 9286AA force plates used to determine the reaction forces. In total, six attempts were evaluated - three attempts with the knee brace and three attempts without it. Each subject completed three measurements. The first one took place at the beginning of the research, the second one after three months of using the brace, and the last one took place three months after the brace removal. The data processing methods were accustomed. At the beginning and at the end of the study the patients completed the WOMAC questionnaire and determined the level of their pain on the visual analogue scale (VAS). RESULTS The minimum value (p = 0.020) and the second maximum value (p = 0.035) of vertical reaction force significantly increased on the unaffected limb after a short-term application of a knee brace. There were significant increases found for walking without a brace in the maximum vertical force in the braking phase on the affected limb (p = 0.006) after three months of bracing, followed by similar results in the maximum vertical force in the braking (p = 0.001) as well as the propulsion (p = 0.035) phase on the unaffected side. Furthermore, we observed a significant extension in the overall duration of the stance phase of gait (p = 0.001) on the affected limb. According to the WOMAC and VAS results, three patients experienced subjective conditional improvement, two subjective deterioration and one participant remained unchanged. DISCUSSION The individualized solutions, i.e. their "adaptation" to a particular type of knee arthrosis in each patient, is the biggest problem in the treatment of knee arthrosis using a prophylactic brace. Our results confirm the usefulness of modern knee orthosis in terms of motion biomechanics. However, it still remains to be proved that it is possible to use the brace for a long time during the active time of the day and that this use brings about a significant relief from troubles, improving the patient's quality of life. CONCLUSIONS The effect of the orthosis application was reflected in force and time parameters of the vertical and anteroposterior component of the reaction force. The use of a prophylactic knee brace can influence the dynamics of gait. The short-term effect of prophylactic brace use is reflected in an increased load on the unaffected limb. From a long-term point of view, a prolongation of the stance phase in both extremities was observed. However, the positive effect of the knee brace use tended to persist even after the brace removal. There were no significant changes in the subjective assessment of pain, stiffness and function of the knee joint. Key words: osteoarthritis, knee joint, knee brace, walking, dynamic analysis, adduction moment.