Influence of Gonarthrosis on Sagittal Spinal Alignment

ABSTRACT

STUDY DESIGN: Research using radiographic findings. OBJECTIVES: To compare spinopelvic parameters in detail between normal subjects and those who had bilateral gonarthrosis with or without spondylosis. SUMMARY OF LITERATURE REVIEW: The relationship between knee joint flexion contracture and hypolordosis in the lumbar spine has been well established. However, spinopelvic parameters in subjects with gonarthrosis without flexion contracture have not been well described in the literature. MATERIALS AND METHODS: Fifty-seven male subjects in their 60s with bilateral gonarthrosis over Kellgren-Lawrence grade III were included. They were subdivided into the KS group (with spinal osteoarthritis, n=32) and the KN group (without spinal osteoarthritis, n=25). Normal asymptomatic subjects without disease in their back or leg were analyzed as the control group (NN; n=84). The following spinopelvic parameters were measured and compared; C7 plumbline (C7PL), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI). RESULTS: In the KS group, the C7PL was significantly anteriorly displaced compared to the KN group (1.7±4.5 cm vs. −0.6±2.9 cm, p=0.031) and the NN group (1.7±4.5 cm vs. −0.5±2.9 cm, p=0.014). TK in the KN group was significantly smaller than in the NN group (25.4±8.8° vs. 30.1±8.3°, p=0.041). The KS group had the smallest value of LL, while the NN group had the largest value of LL (−23.2±48.7° vs. −44.9±33.8° vs. −57.3±8.5°, p<0.001). No significant difference was observed in PI, SS, or PT among the 3 groups. A strong correlation was found between LL and SS in the NN group (R=−0.776, p<0.01), while this correlation was moderate in the KN group (R=−0.355, p<0.01). CONCLUSIONS: Overall balance was maintained in the subjects who had gonarthrosis without spinal osteoarthritis. Subjects with gonarthrosis showed less LL, especially if they had spinal osteoarthritis. Further studies are needed to characterize the differences in these pelvic parameters, and to evaluate changes in individuals with knee joint flexion contracture.