Effects of unloading bracing on knee and hip joints for patients with medial compartment knee osteoarthritis.

Background: Osteoarthritis affects the whole body, thus biomechanical effects on other joints should be considered. Unloading knee braces could be effective for knee osteoarthritis, but their effects on the contralateral knee and bilateral hip joints remain unknown. This study investigated the effects of bracing on the kinematics and kinetics of involved and contralateral joints during gait.

Methods: Nineteen patients with medial compartment knee osteoarthritis were analysed. Kinematics and kinetics of the knee and hip joints in frontal and sagittal planes were measured during walking without and with bracing on the more symptomatic knee.

Findings: The ipsilateral hip in the braced condition showed a lower adduction angle by an average of 2.58° (range, 1.05°-4.16°) during 1%-49% of the stance phase, and a lower abduction moment at the second peak during the stance phase than the hip in the unbraced condition (P<0.05 and P<0.005, respectively). With bracing, the contralateral hip showed a more marked peak extension moment and lower abduction moment at the first peak (P<0.05), and the contralateral knee adduction angle increased by an average of 0.32° (range, 0.21°-0.45°) during 46%-55% of the stance phase (P<0.05), compared to no bracing.

Interpretation: Unloading bracing modified the contralateral knee adduction angle pattern at a specific time point during gait. It also affected the frontal plane on the ipsilateral hip and the frontal and sagittal planes on the contralateral hip joint. Consideration should be provided to other joints when treating knee osteoarthritis.