The Influence On Spine And Pelvis Balance Relations In Ankylosing Spondylitis Patients With Hip Involvement After Total Hip Arthroplasty

Research purposesIn this study, the ankylosing spondylitis (AS) patients with hip involvement underwent cementless total hip arthroplasty(THA) were selected as research subjects during this period of study, with a purpose to assess the influence on sagittal spine and pelvis balance relations in AS patients with hip involvement after the treatment of THA with TCM. With an expectation to guide clinical, without increasing the surgical risk, to improve post-operative sagittal balance between the spine and pelvis as much as possible, as well as to improve the efficacy of surgical treatment of THA with TCM in the AS patients with hip involvement.Materials and methodsWe chosed 10 subjects at random, each case was taken X-rays in radiology by a standing lateral radiograph that included thoracic and lumbar spine, pelvic, and hip before and after THA. The evaluated parameters included thoracic kyphosis(TK), lumbar lordosis(LL), pelvictilt (PT), sacral slope(SS), and pelvic incidence(PI). After that, we chosed 10 normal volunteers at random, Each volunteer was was taken X-rays in radiology by a standing lateral radiograph too. The evaluated parameters also included TK, LL, PT, SS, PI. The obtained data were analized at last. And then we research the correlation of thoracic and lumbar kyphosis with pelvic tilt in the AS group. And to study the prcoperative and postoperative changes in various angles, and their respective differences between normal volunteers. So as to investigate the changes of sagittal balance in the relationship between the spine and pelvis preoperative and postoperative. And then assess the influence on sagittal spine and pelvis balance relations in ankylosing spondylitis patients with hip involvement after the treatment of total hip arthroplasty with TCM.ResultsIn the cases of 10 AS patients,9 were male,1 was female, mean age 29.8±8.6 years; the average height of 165.1±4.1 cm; average weight 55.6±3.4kg; the average age of onset 18.6±6.1 years; the average duration of 11.2±7.1 years. In the cases of 10 normal volunteers,9 were male,1 was female, mean age 29.8±8.6 years; the average height of 165.1±4.1 cm; average weight 55.6±3.4kg. The age distribution, gender ratio, height and weight between the two groups showed no (?)ignificant, so it was comparable. In the AS group before THA, mean PI was 51.2°±7.9°, mean PT was 22.9°±5.9°, mean SS was 28.3°±4.8°, mean TK was 48.6°±5.6°, mean LL was 26.9°±8.3°. In the normal group, mean PI was 45.1°±3.4°, mean PT was 10.9°±2.6°, mean SS was 34.2°±3.5°, mean TK was 35.3°±6.1°, mean LL was 46.2°±8.3°. In the AS group before THA, mean PI was 50.7°±7.1°, mean PT was 20.4°±5.6°, mean SS was 30.3°±4.6°, mean TK was 48.1°±5.7°, mean LL was 28.2°±7.8°. The data of AS group before THA was analized with linear regression. The values of PI and PT, PI and SS, PI and TK, PT and TK noted a linear positive correlation. The values of PI and LL, PT and LL, TK and LL noted a linear negative correlation. There is no linear correlation between PT and SS, SS and TK, SS and LL. We could concluded that the parameter of LL had no relation with pelvic morphology. The PI was important factor that affected pelvic morphology. Therefore, we analized the parameters of TK,LL, PT, and PI with multiple linear regression and found that the LL was more weight than other parameters to PI. The parameters of AS group before and after THA were compared with the normal group respectively using independent samples t test. The results showed that the five parameters all had significantly different between the normal group and AS group before and after THA in statistic. Besides, the parameters of AS group before and after THA were compared using paired sample t test. The result showed that PI parameters had no significantly different. But the other four parameters had significantly different. ConclusionAS patients with hip involvement have thoracolumbar kyphosis, which leading to the pelvic posterior tilt. And lumbar kyphosis was more weight than other parameters to pelvic posterior tilt. The parameter of LL had no relation with pelvic morphology. The LL affected on pelvic morphology more significantly. THA surgery can improve pelvic posterior tilt and thoracic kyphosis to some extent in AS patients with hip involvement, but can not completely correct it to normal level. That is to say, THA surgery can improve the sagittal balance between the pelvis and spine a certain extent in patients with AS. But it does not make it back to the normal force characteristics.