Introduction:
Total hip arthroplasty (THA) is an effective treatment for advanced hip conditions, yet postoperative dislocation remains a major complication, especially in patients with spinal disorders. Altered spinopelvic alignment and reduced spinal mobility can lead to prosthetic instability. Given the growing prevalence of these coexisting conditions, this study aimed to develop a predictive model to identify individuals at increased risk of hip dislocation after THA in the presence of spinal abnormalities.
Material and methods:
This descriptive cross-sectional study was conducted over ten years until 2023 at shohada Hospital, including 225 patients (75 with spinal disorders and 150 controls) who experienced hip dislocation after total hip arthroplasty. Key variables such as demographic data, surgical factors, comorbidities, and medication history were analyzed. Two predictive models—logistic regression and elastic net regularization—were developed to identify dislocation risk factors, using SPSS and advanced statistical modeling techniques.
Results:
In this study, two predictive models were developed to assess postoperative hip dislocation risk in patients with spinal disorders. Model I, based on logistic regression, included 14 variables and showed moderate discrimination (C-index=0.67) but limited calibration and low R² (0.04). Model II, using elastic net regression, selected 9 key predictors—including hip rotation, anemia, BMI 30–35, and certain medications—and achieved better discrimination (AUC=0.73), though with similarly low explanatory power (R²=0.02).
Conclusion:
This study identified demographic variables (age, BMI), clinical factors (history of psychosis, preoperative anemia), surgical parameters (type of femoral fixation, preoperative hip internal rotation, surgical indication), and medication use (antiepileptic drugs, muscle relaxants, antidiabetic medications) as significant predictors of postoperative hip dislocation risk following total hip arthroplasty in patients with spinal disorders.
Keywords: Total Hip Replacement, Hip Dislocation, Spinal Disorders, Predictive Model, prosthetic instability,