Preoperative Abnormal Posture Improves After Total Knee Arthroplasty: Knee–Hip–Spine Syndrome

Background

Spinal, pelvic, and lower extremity alignment is crucial for maintaining a healthy body posture. However, with aging, this posture becomes challenging to maintain due to muscle weakness and skeletal degeneration. Osteoarthritis (OA) of the hip and knee can also lead to abnormal posture, known as hip-spine and knee-spine syndrome. Total knee arthroplasty (TKA) can help relieve pain and improve lower extremity alignment. This may also improve abnormal posture, such as in knee–hip–spine syndrome. However, the condition of the contralateral knee may affect this improvement. This study evaluated the effects of TKA on clinical outcomes and radiographic body posture.

Methods

Patients scheduled for primary one-sided TKA were divided into 2 groups: the unilateral group comprised patients who had contralateral knee OA conditions. The bilateral group included patients who had prior contralateral TKA. Knee range of motion, the Knee Injury and Osteoarthritis Outcome Score, radiographic lateral femorotibial angle, hip and knee flexion angles, and sagittal vertical axis while standing were measured 24 months after TKA.

Results

Both groups showed improved knee extension, the Knee Injury and Osteoarthritis Outcome Score, and radiographical femorotibial angle and hip and knee flexion angles 24 months after TKA. The sagittal vertical axis also improved 6 months after TKA in both groups and was maintained in the bilateral group, while it deteriorated again in the unilateral group 24 months after TKA.

Conclusions

A TKA can improve abnormal body posture due to knee OA as in knee–hip–spine syndrome. However, the condition of a contralateral knee can affect TKA outcomes.

Level of Evidence

Level III; prospective case-control study.