Development of a Predictive Model for Hip Dislocation Following Total Hip Arthroplasty in Patients with Spinal Disorders

Zamani, Mehrdad; Nikpay, Aran; Hashemi Aghdam, Mohammadreza; Dezhpasand, Ali; Sadeghpour, Alireza

doi:10.30491/tm.2025.532396.1851

Development of a Predictive Model for Hip Dislocation Following Total Hip Arthroplasty in Patients with Spinal Disorders

Document Type : Original Article

Authors

Mehrdad Zamani

Aran Nikpay

Mohammadreza Hashemi Aghdam

Ali Dezhpasand

Alireza Sadeghpour

Faculty member of Tabriz University of medical science, Shohada Hospital, Tabriz University of medical science, Tabriz, Iran

10.30491/tm.2025.532396.1851

Abstract

Introduction: Total hip arthroplasty (THA) is an effective treatment for advanced hip conditions, yet postoperative dislocation remains a significant complication, especially in patients with spinal disorders. Altered spinopelvic alignment and reduced spinal mobility can lead to prosthetic instability. Given the growing prevalence of coexisting conditions, this study aimed to develop a predictive model to identify individuals at increased risk of hip dislocation after THA with spinal abnormalities.
Method: This descriptive cross-sectional study was conducted over 10 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, including demographic data, surgical factors, comorbidities, and medication history, were analyzed.
Result: In this study, two predictive models were developed to assess the postoperative risk of hip dislocation 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 nine 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

Subjects