Effect of Hip Abductor Strengthening Exercises in Patients With Knee Osteoarthritis

Osteoarthritis (OA) is a chronic disease affecting the joint and its tissues, primarily leading to progressive damage to articular cartilage and, subsequently, to the subchondral bone and surrounding synovial structures. This chronic degenerative disease affects approximately one-third of adults, and its prevalence increasing with advancing age. The knee is one of the most common joints affected by the OA. Systematic reviews indicate a global prevalence of knee osteoarthritis (KOA) is 22.9% among individuals aged 40 and older, affecting an estimated 654.1 million people worldwide, with variations across countries and increasing with age.

Knee osteoarthritis (KOA) is a multi etiological, chronic disabling disease that affects the entire knee joint, which is the most common site of involvement in OA. KOA patients mostly suffer from progressive stiffness and knee pain. Gradually, they have some difficulties in performing daily activities, such as walking, squatting, and climbing and doing housework, as the disease progresses. Ultimately, pain and disability associated with the disease lead to a loss of functional independence and a profound reduction in quality-of- life. Impairments that are caused by KOA include knee pain, limited ROM of the knee, muscle weakness and knee instability.

The hip abductor muscles influence knee joint loading through their control of the pelvis in the frontal plane. Researchers have proposed that during the single-limb stance phase of gait, weakness of the stance-limb hip abductor muscles may lead to drop of the pelvis toward the contralateral limb, shifting the body's center of mass away from the stance limb toward the swing side. These adjustments, theoretically, could lead to higher knee adduction moments and greater medial knee joint loading.

Knee adduction moment is the moment that acts on the joint in the frontal plane. The knee adduction moment is generated by the combination of the ground reaction force, which passes medial to the centre of the knee joint during gait, and the perpendicular distance of this force from the centre of the joint. . This moment tends to adduct the tibiofemoral joint, causing an increase in medial compartment pressure, and people with knee OA have demonstrated larger than normal peak knee adduction moments in their gait patterns.

OA of the knee is characterized by changes in gait kinematics. High dynamic loads of the medial knee, as assessed by the external peak knee adduction moment, have been associated with tibiofemoral OA severity progression, and knee pain. The aging process impairs postural control more in a medial-lateral (ML) direction than in an anterior-posterior (AP) direction, which is linked with increased falling risk. Postural control stability in the ML direction, in orthostatic stance and during compensatory step, is dependent on hip abductor-adductor muscle torque .The hip abductor muscles are also needed to stabilize the lumbar-pelvic joint during gait and during balance recovery after external disturbance (postural responses of hip and step) This study aims to find the effect of hip abductor strengthening exercises on improving range of motion, functional activities, balance and minimizing pain in individuals affected by the knee OA.