Review Article Knee–Hip–Spine Syndrome: Improvement in PreoperativeAbnormal Posture following Total Knee Arthroplasty

n ergonomic upright body posture is maintained by the alignment of the spine, pelvis, and lower extremities, and the musclestrength of body trunk and lower extremities. The posture varies with age because of the degenerative changes in the involvedstructures and the weakening of the muscles. The compensatory mechanisms underlying these changes have recently beenevaluated, and the loss of lumbar lordosis results in spinal kyphosis, pelvic retroversion, hip extension, knee flexion, and ankledorsiflexion. These mechanisms are referred to as the hip–spine and knee–spine syndromes. The spine, hip, and knee areanatomically connected, and the pain and discomfort of the lower back, hip, and knee frequently arise due to degenerative changesof these structures. Thus, these mechanisms are considered as the knee–hip–spine syndrome. Spinal fusion, total hip arthroplasty,and total knee arthroplasty are the surgical procedures for severe degeneration, and their clinical outcomes for the affected sites arepromising. However, despite surgeries, other structures may degenerate and result in complications, such as proximal junctionalkyphosis and hip dislocation, following spinal fusion. Therefore, it is necessary to evaluate each patient under specific conditionsand to treat each section while considering associations between the target structure and entire body. The purpose of this articleis to introduce postural maintenance, variations with age, and improvements with surgical interventions of spine, hip, and knee asthe knee–hip–spine syndrome