RESUMO
BACKGROUND: Knee Instability (KI) is described as a sense of knee buckling, shifting, or giving way during the weight bearing activities. High prevalence (60-80%) has been reported for KI amongst the patients with knee osteoarthritis (KOA). In this line, the present study targeted the effect of two interventions on self-reported KI and affected factors. METHODS: In this single blind, randomized, and controlled trial, 36 patients with radiographic grading (Kellgren-Lawrence ≥ II) of KOA were selected. Patients were divided into three groups namely, aquatic (n = 12), Total Resistance exercises (TRX) (n = 12) and control (n = 12) by random. Then both 8-week TRX and aquatic exercises were carried out by experimental groups. The following measure were taken before and after interventions: Pain by visual analog scale (VAS), balance by Berg Balance Scale (BBS), quadriceps strength by dynamometer, knee flexion range of motion (ROM) by inclinometer, knee stiffness with Western Ontario and McMaster Universities Osteoarthritis (WOMAC), and self-reported KI with Felson's questionnaire. RESULTS: The results demonstrated that KI, VAS, BBS improved over time both in TRX and aquatic groups significantly (p < 0.05), but WOMAC(stiffness), knee flexion ROM, and quadriceps strength were significantly improved over time only for TRX (p < 0.05). Post hoc test, also, showed that there were significant differences between interventions and control groups (p < 0.05) for the VAS, KI, BBS, but for WOMAC(stiffness), a significant difference was observed only between TRX and control groups (p = 0.05). CONCLUSIONS: Although TRX and aquatic interventions had a similar effect on the patients' balance, pain and KI, TRX had more effect on WOMAC(stiffness), quadriceps strength, and knee flexion ROM than aquatic exercises. TRIAL REGISTRATION: This study was registered in the Iranian Clinical Trial Center with the number IRCT20181222042070N1, http://www.irct.ir/trial/36221, registered 02 February 2019.
