Association of Scoliosis and Severe Knee Osteoarthritis: A Case-Control Study

Background/Objectives: Scoliosis has been linked to pelvic position and tilt angle, but few studies have explored its relationship with knee pathology, which can be a significant burden for the elderly. Our aim is to investigate the relationship between scoliosis and knee osteoarthritis (OA). Methods: This population-based case-control study using data from the National Health Insurance Database of Taiwan included patients diagnosed with OA who underwent total knee replacement (TKR) for the first time between 2014 and 2019. Propensity score matching was employed to select controls who did not undergo TKR. Scoliotic cases were identified if they had been diagnosed before knee OA and TKR. The study samples included 10,021 patients with OA/TKR and 30,063 patients without OA/TKR. We then utilized logistic regression analysis to calculate the odds ratio (OR) and 95% confidence interval (CI) for the diagnosis of scoliosis prior to the index date. Results: The findings indicate that patients with pre-existing scoliosis have a 1.627 times greater likelihood of undergoing TKR, with significantly higher odds ratios observed across both female (OR = 1.583) and male (OR = 1.909) and younger (OR = 2.102) and older (OR = 1.575) patients. However, a notable limitation of this study is the absence of data on scoliosis curve side, which prevented us from analyzing the relationship between curve direction and knee arthritis laterality. Furthermore, while we included diagnostic codes indicating left or right TKR, the lack of precise measurements for variables such as lower limb length discrepancies may introduce residual confounding. Conclusions: Our research suggests a significant association between scoliosis and the development of knee OA.