JOA - 2026-04-30 - Journal Article
Risk Factors Associated with Osteonecrosis of the Femoral Head after Undergoing Lumbar Decompression and Fusion.
Cullen MM, Cochrane NH, Benvenuti TA, Wellman SS, Bolognesi MP, Seyler TM, Ryan SP
Topics
Key Takeaway
Postoperative PI-LL overcorrection (PI-LL < -10°) after lumbar fusion carries an OR of 17.05 for developing osteonecrosis of the femoral head and a hazard ratio of 9.67 for THA at five years.
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Summary
This retrospective case-control study investigated whether postoperative spinopelvic alignment and intraoperative factors predict ONFH following lumbar fusion in 90 patients (21 ONFH, 69 controls) matched by age and sex. Postoperative PI-LL overcorrection below -10° was the sole significant predictor of ONFH (OR 17.05, 95% CI 1.85–156.97, P=0.01), while intraoperative hypotension, anterior surgical approach, and pelvic fixation were not associated. Overcorrected patients had dramatically worse THA-free survival at both one year (HR 24.71) and five years (HR 9.67) compared to matched and undercorrected groups.
Key Limitation
The ONFH cohort comprised only 21 patients after exclusions, producing confidence intervals spanning two orders of magnitude and severely limiting the reliability of the OR and hazard ratio point estimates.
Original Abstract
INTRODUCTION
Osteonecrosis of the femoral head (ONFH) after spinal fusion is poorly characterized. This study sought to identify factors associated with ONFH following lumbar, lumbo-sacral, or lumbo-pelvic fusion. We hypothesized that abnormal postoperative spino-pelvic alignment and modifiable intraoperative factors may increase ONFH risk. Furthermore, we felt these factors may reduce survivorship free from total hip arthroplasty (THA) after lumbar fusion.
METHODS
We retrospectively reviewed 9,380 lumbar fusion patients from 2013 to 2021 at a single institution. There were 50 patients who had concern for ONFH who were identified and matched by age and sex to 100 fusion patients who did not have ONFH. Exclusion criteria included preoperative ONFH and lack of standing radiographs. Of the 50 ONFH patients, 21 met inclusion criteria, and of the 100 matched controls, 69 met criteria. Variables assessed included spino-pelvic parameters, corticosteroid use, smoking, surgical approach, pelvic fixation, American Society of Anesthesiologists classification, intraoperative hypotension, and postoperative Pelvic Incidence-Lumbar Lordosis alignment (PI-LL). Statistical analyses included t-tests, Chi-square tests, logistic regressions, and survival analyses.
RESULTS
Postoperative overcorrection (PI-LL less than -10°) significantly increased the odds of ONFH (odds ratio (OR): 17.05 (1.85 to 156.97); P = 0.01). Intraoperative hypotension (P = 0.22), anterior approaches (P = 0.52), and pelvic fixation (P = 0.35) were not associated with increased ONFH risk. Overcorrected patients also demonstrated worse THA-free survival at one year (hazard ratio (HR): 24.71 (1.55 to 395.30); P = 0.02) and five years (HR: 9.67 (2.46 to 38.06); P = 0.001) compared with matched and undercorrected groups.
CONCLUSION
Postoperative spino-pelvic overcorrection is strongly associated with femoral head ONFH and inferior THA-free survivorship after lumbar fusion. In contrast, hypotension, anterior approaches, and pelvic fixation were not significant contributors. Careful restoration of sagittal alignment may reduce ONFH risk and improve long-term hip outcomes following spinal fusion.