Hip Fracture Risk Following Lumbar Fusion: A Retrospective Cohort Study of Construct Length and Age-Stratified Outcomes

Hip Fracture Risk Following Lumbar Fusion: A Retrospective Cohort Study of Construct Length and Age-Stratified Outcomes | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Hip Fracture Risk Following Lumbar Fusion: A Retrospective Cohort Study of Construct Length and Age-Stratified Outcomes James Anundson, Linus Lee, Sean Bae, Joseph Ferguson, Daniel Portney This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9337626/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 11 You are reading this latest preprint version Abstract Introduction: Lumbar fusion alters spinal biomechanics and may increase hip loading, especially with long-segment constructs. We used a large administrative database to evaluate hip fracture risk after lumbar fusion and assess whether fusion length influences this risk in younger and older adults. Methods Using PearlDiver, we identified patients ≥ 50 with lumbar degenerative disorders across three cohorts: nonoperative controls (n = 66,603), 1–6 level fusion (n = 44,402), and ≥ 7 level fusion (n = 22,201), matched by age and sex. Five-year hip fracture-free survival was estimated via Kaplan-Meier analysis, stratified by age (< 65 vs ≥ 65) and compared with log-rank tests. Results Hip fractures were uncommon across all groups (~ 1–2 per 1,000 person-years), with no significant overall differences between controls and fusion groups. In patients aged < 65, long-segment fusion was associated with significantly lower hip fracture-free survival (χ²=22.11, p < 0.00001) and a threefold higher hazard compared with short-segment fusion (HR 3.07, 95% CI 1.89–4.99; incidence 2.01 vs 0.62 per 1,000 person-years). In patients ≥ 65, hip fracture rates were higher overall but did not differ significantly by fusion length (χ²=0.455, p = 0.50). Conclusion Lumbar fusion was associated with a small increase in hip fracture risk, with long constructs conferring substantially higher risk in adults < 65. Figures Figure 1 Figure 2 Figure 3 INTRODUCTION With increasing life expectancy, the prevalence of osteoporosis and osteopenia continues to rise, placing a growing number of elderly adults at risk for fragility-related musculoskeletal complications. Many patients who undergo lumbar fusion are older adults with pre-existing skeletal fragility, and degenerative lumbar spine conditions are increasingly common in this aging population. Lumbar fusion has become an increasingly utilized surgical treatment for lumbar degenerative disease, deformity, and spinal instability with reliably good clinical outcomes 1 , 2 . However, fusion also alters normal spinal biomechanics. Loss of motion segments increases stiffness across the lumbar spine and can redirect mechanical load to adjacent segments and to the pelvis and hip 3 . This biomechanical burden appears most pronounced with long-segment constructs and spinopelvic fixation, where extensive instrumentation may amplify distal load transfer and alter hip joint forces 4 . Emerging work suggests that longer constructs may accelerate hip degeneration and hip osteoarthritis, supporting a dose-response relationship between fusion extent and hip joint pathology 5 . Osteoporosis and osteopenia are common in this population and may be underdiagnosed or undertreated at the time of surgery 6 . In addition, fusion candidates often have multiple medical comorbidities, reduced mobility, and gait or balance impairments that increase fall risk 7 . These factors combine to elevate baseline risk for fragility fractures, particularly hip fractures, which are associated with substantial morbidity, mortality, and loss of independence in older adults 8 . Prior studies have described an association between lumbar fusion and subsequent vertebral and pelvic insufficiency fractures, including proximal junctional fractures and sacral insufficiency fractures after multilevel constructs and spinopelvic fixation 9 – 15 . In contrast, the relationship between lumbar fusion and hip fracture risk remains less clear, as existing evidence is largely limited to small series and retrospective cohorts with conflicting results 4 . It is also unclear whether hip fracture risk varies by length of fusion construct or is affected by patient age 16 . To our knowledge, no large, construct-specific, age-stratified analysis has quantified hip fracture risk after lumbar fusion. Given these uncertainties, we sought to use a large administrative claims database to evaluate hip fracture risk after lumbar fusion in adults aged 50 years and older. Our primary objective was to compare hip fracture incidence between patients with and without prior lumbar fusion and to determine whether longer fusion constructs confer greater fracture risk, with specific attention to age-related differences. We hypothesized that overall hip fracture risk after fusion would be modestly elevated but remain low in absolute terms, and that effect estimates would vary by patient age and fusion length. METHODS We conducted a retrospective cohort study using the PearlDiver administrative claims database. PearlDiver contains de-identified, HIPAA-compliant medical and procedural claims from a large, national population of over 130 million with longitudinal follow-up, including inpatient and outpatient encounters, diagnoses, and procedures. Cohort definitions and index dates We first identified adults with lumbar degenerative disease using ICD-9 and ICD-10 diagnosis codes for lumbar spondylosis, stenosis, and related conditions (full code list in Supplementary Table 1). Patients were required to be 50-89 years old at the time of their first diagnosis, which we defined as the index date. Within this population, we identified instrumented lumbar fusion procedures using CPT codes. We stratified patients by the extent of posterior instrumentation with short-segment fusion consisting of 1-6 levels fused and long-segment fusion consisting of 7-13+ levels fused based on CPT codes. For fusion patients, we defined the index date as the date of the first qualifying fusion procedure. The nonoperative control group consisted of patients with lumbar degenerative diagnosis who had no history of lumbar fusion. In these patients, we defined the index date as the date of the first qualifying diagnosis of lumbar degenerative disease. We restricted all cohorts to patients aged 50-89 years on the index date. Matching strategy We used a two-step matching strategy to balance demographic characteristics across comparison groups. Short-segment versus long-segment fusion was propensity matched 2:1 on age and sex, yielding 44,402 short fusions and 22,201 long fusions. A combined fusion cohort was propensity matched 1:1 to nonoperative controls, again matched on age and sex, resulting in 66,603 matched controls. The final three large, propensity matched cohorts included patients with no fusion, patients with 1-6 fused levels, and patients with 7-13+ fused levels (Table 1). Outcome definition and follow-up The primary outcome was operatively treated hip fracture. We identified hip fractures using CPT codes for hip fracture fixation and arthroplasty (Supplementary Table 1). We followed each patient from the index date until the first hip fracture procedure, the end of continuous database enrollment, or five years, whichever occurred first. Patients who did not experience a hip fracture during follow-up were censored at their last available claim or at five years. Statistical analysis Five-year hip fracture-free survival was estimated using Kaplan-Meier analysis for each matched cohort. We first generated five-year Kaplan-Meier curves comparing matched controls, matched 1-6 level fusions, and matched 7-13+ level fusions. Given the strong association between age, osteoporosis, and fragility fracture risk, we then stratified the fusion cohorts into ages 50-64 and ≥65 years and repeated the Kaplan-Meier analysis to evaluate the association between fusion length and hip fracture risk within each group. We compared survival curves using log-rank tests. A Cox proportional hazards model was performed with fusion length as an independent variable. We reported hazard ratios (HRs) with 95% confidence intervals (CIs). All tests were two-sided, and a p < 0.05 was considered statistically significant. All analyses were performed using the built-in statistical software within the PearlDiver platform [R v3. 6. 1]. RESULTS Following propensity matching, the final study sample included 66,603 patients without prior lumbar fusion, 44,402 patients with prior short-segment lumbar fusion, and 22,201 patients with prior long-segment fusion. Baseline characteristics, including the prevalence of osteoporosis and other comorbidities, are summarized in Table 1 . In the overall matched cohort of adults aged ≥ 50 years, hip fractures were uncommon across all treatment groups. The incidence rate was 1.51 fractures per 1,000 person-years (95% CI 1.36–1.66) in the nonoperative control group, 1.48 fractures per 1,000 person-years (95% CI 1.28–1.68) in the short-segment fusion group, and 2.08 fractures per 1,000 person-years (95% CI 1.43–2.73) in the long-segment fusion group. Five-year Kaplan-Meier curves for hip fracture-free survival showed substantial overlap among controls, short-segment fusion, and long-segment fusion (Fig. 1 ). Pairwise log-rank tests showed no significant differences in hip fracture-free survival between controls and 1–6 level fusion (χ² = 0.06, p = 0.80), controls and 7–13 + level fusion (χ² = 1.84, p = 0.17), or between 1–6 and 7–13 + level fusion (χ² = 2.13, p = 0.14). When stratified by age, some differences were noted in hip fracture rates between short- and long-segment lumbar fusion. In patients 50–64 years old, the incidence of hip fracture was 0.41 fractures per 1,000 person-years (95% CI 0.30–0.51) in the control cohort, 0.62 fractures per 1,000 person-years (95% CI 0.58–0.68) after short-segment fusion, and 2.01 fractures per 1,000 person-years (95% CI 1.05–2.97) after long-segment fusion. Five-year hip-fracture free survival differed between the short- and long-segment fusion groups in younger patients (χ² = 22.11, p < 0.00001). Kaplan-Meier curves for this age group showed earlier and more frequent events in the long-segment cohort (Fig. 2 ). When adjusted for age and sex, long-segment fusion was associated with a higher risk of hip fracture compared with short-segment fusion, with an HR of 3.07 (95% CI 1.89–4.99). Among patients aged ≥ 65 years, overall hip fracture incidence was higher than in the 50–64 years of age group but did not differ by fusion length. The incidence rate was 2.24 fractures per 1,000 person-years (95% CI 2.02–2.45) in the control cohort, 2.20 fractures per 1,000 person-years (95% CI 2.10–2.30) in the short-segment fusion cohort, and 2.23 fractures per 1,000 person-years (95% CI 1.30–3.16) in the long-segment fusion cohort. Five-year hip fracture-free survival did not differ between the short- and long-segment fusion cohorts (Fig. 3 ). There was no significant difference in hip fracture-free survival between short- and long-segment fusion among patients aged ≥ 65 years (χ² = 0.455, p = 0.50). DISCUSSION Lumbar fusion is increasingly used to treat degenerative spine disease in older adults who often have concurrent osteoporosis or osteopenia, elevating their fragility fracture risk. Longer constructs can alter spinopelvic mechanics and plausibly shift load to the hip. Given limited and conflicting prior data on hip fractures after lumbar fusion across construct lengths and age groups, we used a large administrative claims database to better quantify this risk. In this large, matched cohort of adults with lumbar degenerative disease, we found that the five-year risk of surgically treated hip fractures was low across all patients and that lumbar fusion did not greatly increase overall hip fracture risk. However, within the fusion population, long-segment constructs involving 7–13 + levels were associated with a higher relative risk of hip fracture in adults aged 50–64 years compared with 1–6 level fusion, while no difference by fusion length was observed in patients aged ≥ 65 years. These findings suggest that in younger patients, long lumbar fusion constructs confer a significant relative risk of hip fracture in a population that is otherwise not classically considered high-risk. The age-dependent pattern we observed is consistent with the biomechanical effects of long-segment fusion and spinopelvic fixation. By eliminating motion across multiple lumbar segments and extending instrumentation to the sacrum or pelvis, long constructs increase stiffness of the fused spine and likely redirect more motion and load to the hips and lower extremities 4 . Experimental and modeling studies suggest that changes in lumbar lordosis, pelvic tilt, and spinopelvic alignment can alter hip joint contact forces, particularly during gait and transfers 4 , 17 . In a younger, more active patient, who would otherwise have a low risk of hip fracture, these elevated loads might modestly increase the risk of developing an insufficiency fracture of the hip. Our finding of a three-fold higher hazard of hip fracture after long-segment fusion in patients aged 50–64 years supports this biomechanical rationale and a dose–response relationship between fusion extent and distal skeletal complications, even though absolute fracture rates in this group remained low. In contrast, among patients aged 65 years and older, overall hip fracture incidence was higher but did not differ by fusion length. Older adults often have established osteoporosis, sarcopenia, impaired balance, and a higher burden of medical comorbidities and medications that increase fall risk 18 . These factors likely dominate hip fracture risk and may overshadow the incremental biomechanical effect of adding additional fused levels. In this context, whether a patient receives a short- or long-segment construct may be of less significance than their global fragility profile. The nearly identical incidence rates and overlapping survival curves between short- and long-segment fusion in this age group are consistent with this interpretation and suggest that fusion length contributes relatively little beyond age-related baseline risk. Our results extend prior work on skeletal complications after lumbar fusion. Previous studies have described vertebral and sacral insufficiency fractures at or near the ends of long constructs, as well as junctional failure, particularly in the setting of deformity correction and spinopelvic fixation 11 , 15 . Other reports have suggested that extensive lumbar fusion and altered spinopelvic alignment may accelerate hip osteoarthritis or increase the need for later hip arthroplasty 5 , 19 , 20 . In contrast, the literature quantifying hip fracture risk after spine surgery has been limited and heterogeneous. Li and colleagues reported higher hip fracture risk after lumbar spine surgery compared with matched controls (adjusted HR ~ 1.63), with the greatest risk after long-segment fusion, and elevated risk among patients aged 60–79 but not ≥ 80 years—consistent with baseline fragility attenuating detectable differences in the oldest patients 21 . By leveraging a large national database, defining fusion length a priori, and stratifying risk by age, our study provides construct-specific, age-stratified estimates of surgically treated hip fracture after lumbar fusion that further clarify how fusion extent and patient age interact. These findings have practical implications for preoperative planning. For patients in their 50s and early 60s requiring long-segment fusion, the relative risk of hip fracture is meaningfully higher than with shorter constructs, despite low absolute risk. Surgeons should use these data to counsel patients and support routine preoperative bone health evaluation. This study has important strengths. We used a large, national administrative database with longitudinal follow-up, allowing us to study a rare outcome in over 130,000 patients with lumbar degenerative disease followed over five years. The two-step propensity scored matching strategy created large, demographically balanced cohorts of nonoperative controls, short-segment fusion, and long-segment fusion patients. Several limitations also warrant consideration. As with all claims-based studies, our analysis is vulnerable to misclassification of diagnoses and procedures. We lacked patient-specific data such as bone mineral density, smoking status, and radiographic spinopelvic alignment, all of which influence fracture risk. We were also unable to distinguish low-energy fragility fractures from high-energy trauma based on claims codes alone. Follow-up was limited to five years, and we did not account for the competing risk of death, which may lead to modest overestimation of hip fracture risk in older adults. Finally, our findings may not generalize to uninsured patients or health systems outside the database’s contributing payers. Future work should incorporate prospective designs with patient-level data including radiographic spinopelvic parameters, bone density assessment, gait analysis, and fall risk evaluation. In older adults, overall fragility and fall risk likely outweigh construct length in driving hip fracture risk; counseling should emphasize that absolute hip fracture risk after fusion remains low while prioritizing osteoporosis management and fall prevention regardless of fusion length. In conclusion, long-segment spinal fusion was associated with an approximately threefold higher five-year risk of surgically treated hip fractures in adults aged < 65 years, supporting shared decision-making and targeted perioperative bone health optimization in higher-risk patients. Declarations Ethical Approval and Informed Consent : No informed consent was required. Waived from Author Contribution J.A. performed the PearlDiver database coding and statistical data analysis and wrote the main manuscript text. L.L. contributed to manuscript editing and writing. S.B. conducted the literature review and contributed to preliminary writing. D.P. conceived the study idea and provided overall project oversight and final manuscript review. J.F. provided senior surgical oversight as the attending spine surgeon. All authors reviewed and approved the final manuscript. Data Availability The data used in this study were obtained from the PearlDiver administrative claims database (PearlDiver Technologies, Inc., Colorado Springs, CO). Access to PearlDiver requires a licensing agreement with the vendor. The data are not publicly available. Researchers interested in replicating these analyses may apply for access through PearlDiver Technologies at www.pearldiverinc.com. References Reid PC, Morr S, Kaiser MG (2019) State of the union: a review of lumbar fusion indications and techniques for degenerative spine disease. Published online July 1. 10.3171/2019.4.SPINE18915 Phillips FM, Slosar PJ, Youssef JA, Andersson G, Papatheofanis F (2013) Lumbar Spine Fusion for Chronic Low Back Pain Due to Degenerative Disc Disease: A Systematic Review. Spine 38(7):E409–E422. 10.1097/BRS.0b013e3182877f11 Ebrahimkhani M, Arjmand N, Shirazi-Adl A (2021) Biomechanical effects of lumbar fusion surgery on adjacent segments using musculoskeletal models of the intact, degenerated and fused spine. Sci Rep 11(1):17892. 10.1038/s41598-021-97288-2 Kozaki T, Lundberg HJ, Mell SP et al (2023) Effect of Lumbar Fusion and Pelvic Fixation Rigidity on Hip Joint Stress: A Finite Element Analysis. Spine 48(20):E355–E361. 10.1097/BRS.0000000000004791 Kawai T, Shimizu T, Goto K et al (2021) Number of Levels of Spinal Fusion Associated with the Rate of Joint-Space Narrowing in the Hip. J Bone Jt Surg 103(11):953–960. 10.2106/JBJS.20.01578 Wagner SC, Formby PM, Helgeson MD, Kang DG (2016) Diagnosing the Undiagnosed: Osteoporosis in Patients Undergoing Lumbar Fusion. Spine 41(21):E1279–E1283. 10.1097/BRS.0000000000001612 Janssen ERC, Prestigiacomo FG, van Leent EAP, van Meeteren NLU, Hulsbosch M (2022) Exploring clinically relevant risk profiles in patients undergoing lumbar spinal fusion: a cohort study. Eur Spine J 31(10):2473–2480. 10.1007/s00586-022-07325-5 Zhao AY, Agarwal AR, Durand WM et al (2024) Prior Fragility Fractures are Associated With a Higher Risk of Bone Health-Related Complications Within Eight Years Following Lumbar Fusion. Spine 49(15):1046–1051. 10.1097/BRS.0000000000004867 Lee SH, Kim DH, Park JH, Lee DG, Park CK, Kang DH (2024) Incidence and Risk Factors of Sacral Fracture Following Lumbosacral Fusion for Degenerative Spinal Stenosis with a Minimum Follow-Up of 2 Years: A Case–Control Study. World Neurosurg 191:e633–e643. 10.1016/j.wneu.2024.09.014 Baumann AN, Trager RJ, Yazdanpanah S et al (2025) Is osteoporosis an independent risk factor for sacral fracture after lumbosacral spinal fusion in adults? 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Spine 33(16):1806–1811. 10.1097/BRS.0b013e31817b8f23 Velluto C, Marciano A, Vavalle G et al (2025) Sacral and Pelvic Insufficiency Fractures Following Adult Spinal Deformity Surgery: A Case Report and Systematic Literature Review. J Clin Med 14(21):7572. 10.3390/jcm14217572 Badhiwala JH, Karmur BS, Hachem LD et al (2020) The Effect of Older Age on the Perioperative Outcomes of Spinal Fusion Surgery in Patients With Lumbar Degenerative Disc Disease With Spondylolisthesis: A Propensity Score-Matched Analysis. Neurosurgery 87(4):672–678. 10.1093/neuros/nyz444 Miura T, Miyakoshi N, Saito K et al (2021) Association between global sagittal malalignment and increasing hip joint contact force, analyzed by a novel musculoskeletal modeling system. PLoS ONE 16(10):e0259049. 10.1371/journal.pone.0259049 Hung WW, Egol KA, Zuckerman JD, Siu AL (2012) Hip Fracture Management: Tailoring Care for the Older Patient. JAMA 307(20):2185–2194. 10.1001/jama.2012.4842 Lum ZC, Klineberg EO, Danielsen B, Giordani M, Meehan JP (2019) Female Sex and Longer Fusion Constructs Significantly Increase the Risk of Total Hip Arthroplasty Following Spinal Fusion. J Bone Jt Surg 101(8):675–681. 10.2106/JBJS.18.00667 Kwak JM, So SP, Jeon IH (2022) Staged revision still works for chronic and deep infection of total elbow arthroplasty? SICOT-J 8:21. 10.1051/sicotj/2022019 Li CY, Chang CL, Tai TW (2018) Incidence and risk factors for hip fracture in elderly patients undergoing lumbar spine surgery: a nationwide database study with 11-year follow-up. Osteoporos Int 29(12):2717–2723. 10.1007/s00198-018-4734-z Table Table 1. Baseline Demographic and Clinical Characteristics of the Matched Study Cohorts Characteristic Controls: lumbar degeneration, no fusion (n = 66,603) Short-segment fusion (1–6 levels) (n = 44,402) Long-segment fusion (7–13+ levels) (n = 22,201) Age category, n (%) 50–64 years 28,926 (43.4%) 19,710 (44.4%) 9,700 (43.7%) ≥65 years 37,677 (56.6%) 26,183 (59.0%) 12,698 (57.2%) Sex, n (%) Female 34,353 (51.6%) 22,902 (51.6%) 11,451 (51.6%) Male 32,250 (48.4%) 21,500 (48.4%) 10,750 (48.4%) Baseline Characteristics, n (%) Bone Health (Osteopenia/Osteoporosis) 11181 (16.8%) 8959 (20.2%) 5395 (24.3%) Tobacco 15302 (22.9%) 12823 (28.9%) 6812 (30.7%) Obesity 19272 (28.9%) 17070 (38.4%) 7807 (35.2%) Diabetes 9356 (14.0%) 6583 (14.8%) 2946 (13.3%) Renal Failure 1993 (3.0%) 1229 (2.8%) 923 (4.2%) Additional Declarations No competing interests reported. Supplementary Files SupplementaryTables.docx Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 21 Apr, 2026 Reviews received at journal 20 Apr, 2026 Reviewers agreed at journal 20 Apr, 2026 Reviewers agreed at journal 19 Apr, 2026 Reviewers agreed at journal 15 Apr, 2026 Reviews received at journal 13 Apr, 2026 Reviewers agreed at journal 13 Apr, 2026 Reviewers invited by journal 13 Apr, 2026 Editor assigned by journal 11 Apr, 2026 Submission checks completed at journal 11 Apr, 2026 First submitted to journal 06 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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05:43:34","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":15209,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryTables.docx","url":"https://assets-eu.researchsquare.com/files/rs-9337626/v1/8c4556fb60e9e36de373925b.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Hip Fracture Risk Following Lumbar Fusion: A Retrospective Cohort Study of Construct Length and Age-Stratified Outcomes","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eWith increasing life expectancy, the prevalence of osteoporosis and osteopenia continues to rise, placing a growing number of elderly adults at risk for fragility-related musculoskeletal complications. Many patients who undergo lumbar fusion are older adults with pre-existing skeletal fragility, and degenerative lumbar spine conditions are increasingly common in this aging population. Lumbar fusion has become an increasingly utilized surgical treatment for lumbar degenerative disease, deformity, and spinal instability with reliably good clinical outcomes\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e,\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. However, fusion also alters normal spinal biomechanics. Loss of motion segments increases stiffness across the lumbar spine and can redirect mechanical load to adjacent segments and to the pelvis and hip\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. This biomechanical burden appears most pronounced with long-segment constructs and spinopelvic fixation, where extensive instrumentation may amplify distal load transfer and alter hip joint forces\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. Emerging work suggests that longer constructs may accelerate hip degeneration and hip osteoarthritis, supporting a dose-response relationship between fusion extent and hip joint pathology\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eOsteoporosis and osteopenia are common in this population and may be underdiagnosed or undertreated at the time of surgery\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. In addition, fusion candidates often have multiple medical comorbidities, reduced mobility, and gait or balance impairments that increase fall risk\u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e. These factors combine to elevate baseline risk for fragility fractures, particularly hip fractures, which are associated with substantial morbidity, mortality, and loss of independence in older adults\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003ePrior studies have described an association between lumbar fusion and subsequent vertebral and pelvic insufficiency fractures, including proximal junctional fractures and sacral insufficiency fractures after multilevel constructs and spinopelvic fixation\u003csup\u003e\u003cspan additionalcitationids=\"CR10 CR11 CR12 CR13 CR14\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. In contrast, the relationship between lumbar fusion and hip fracture risk remains less clear, as existing evidence is largely limited to small series and retrospective cohorts with conflicting results\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. It is also unclear whether hip fracture risk varies by length of fusion construct or is affected by patient age\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. To our knowledge, no large, construct-specific, age-stratified analysis has quantified hip fracture risk after lumbar fusion.\u003c/p\u003e \u003cp\u003eGiven these uncertainties, we sought to use a large administrative claims database to evaluate hip fracture risk after lumbar fusion in adults aged 50 years and older. Our primary objective was to compare hip fracture incidence between patients with and without prior lumbar fusion and to determine whether longer fusion constructs confer greater fracture risk, with specific attention to age-related differences. We hypothesized that overall hip fracture risk after fusion would be modestly elevated but remain low in absolute terms, and that effect estimates would vary by patient age and fusion length.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003eWe conducted a retrospective cohort study using the PearlDiver administrative claims database. PearlDiver contains de-identified, HIPAA-compliant medical and procedural claims from a large, national population of over 130 million with longitudinal follow-up, including inpatient and outpatient encounters, diagnoses, and procedures.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eCohort definitions and index dates\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe first identified adults with lumbar degenerative disease using ICD-9 and ICD-10 diagnosis codes for lumbar spondylosis, stenosis, and related conditions (full code list in Supplementary Table 1). Patients were required to be 50-89 years old at the time of their first diagnosis, which we defined as the index date.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWithin this population, we identified instrumented lumbar fusion procedures using CPT codes. We stratified patients by the extent of posterior instrumentation with short-segment fusion consisting of 1-6 levels fused and long-segment fusion consisting of 7-13+ levels fused based on CPT codes. For fusion patients, we defined the index date as the date of the first qualifying fusion procedure.\u003c/p\u003e\n\u003cp\u003eThe nonoperative control group consisted of patients with lumbar degenerative diagnosis who had no history of lumbar fusion. In these patients, we defined the index date as the date of the first qualifying diagnosis of lumbar degenerative disease. We restricted all cohorts to patients aged 50-89 years on the index date. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eMatching strategy\u003c/em\u003e\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe used a two-step matching strategy to balance demographic characteristics across comparison groups. Short-segment versus long-segment fusion was propensity matched 2:1 on age and sex, yielding 44,402 short fusions and 22,201 long fusions. A combined fusion cohort was propensity matched 1:1 to nonoperative controls, again matched on age and sex, resulting in 66,603 matched controls. The final three large, propensity matched cohorts included patients with no fusion, patients with 1-6 fused levels, and patients with 7-13+ fused levels (Table 1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eOutcome definition and follow-up\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe primary outcome was operatively treated hip fracture. We identified hip fractures using CPT codes for hip fracture fixation and arthroplasty (Supplementary Table 1). We followed each patient from the index date until the first hip fracture procedure, the end of continuous database enrollment, or five years, whichever occurred first. Patients who did not experience a hip fracture during follow-up were censored at their last available claim or at five years.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStatistical analysis\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFive-year hip fracture-free survival was estimated using Kaplan-Meier analysis for each matched cohort. We first generated five-year Kaplan-Meier curves comparing matched controls, matched 1-6 level fusions, and matched 7-13+ level fusions. Given the strong association between age, osteoporosis, and fragility fracture risk, we then stratified the fusion cohorts into ages 50-64 and \u0026ge;65 years and repeated the Kaplan-Meier analysis to evaluate the association between fusion length and hip fracture risk within each group. We compared survival curves using log-rank tests. A Cox proportional hazards model was performed with fusion length as an independent variable. We reported hazard ratios (HRs) with 95% confidence intervals (CIs). All tests were two-sided, and a \u0026nbsp;p \u0026lt; 0.05 was considered statistically significant. All analyses were performed using the built-in statistical software within the PearlDiver platform [R v3. 6. 1].\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eFollowing propensity matching, the final study sample included 66,603 patients without prior lumbar fusion, 44,402 patients with prior short-segment lumbar fusion, and 22,201 patients with prior long-segment fusion. Baseline characteristics, including the prevalence of osteoporosis and other comorbidities, are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eIn the overall matched cohort of adults aged\u0026thinsp;\u0026ge;\u0026thinsp;50 years, hip fractures were uncommon across all treatment groups. The incidence rate was 1.51 fractures per 1,000 person-years (95% CI 1.36\u0026ndash;1.66) in the nonoperative control group, 1.48 fractures per 1,000 person-years (95% CI 1.28\u0026ndash;1.68) in the short-segment fusion group, and 2.08 fractures per 1,000 person-years (95% CI 1.43\u0026ndash;2.73) in the long-segment fusion group. Five-year Kaplan-Meier curves for hip fracture-free survival showed substantial overlap among controls, short-segment fusion, and long-segment fusion (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Pairwise log-rank tests showed no significant differences in hip fracture-free survival between controls and 1\u0026ndash;6 level fusion (χ\u0026sup2; = 0.06, p\u0026thinsp;=\u0026thinsp;0.80), controls and 7\u0026ndash;13\u0026thinsp;+\u0026thinsp;level fusion (χ\u0026sup2; = 1.84, p\u0026thinsp;=\u0026thinsp;0.17), or between 1\u0026ndash;6 and 7\u0026ndash;13\u0026thinsp;+\u0026thinsp;level fusion (χ\u0026sup2; = 2.13, p\u0026thinsp;=\u0026thinsp;0.14).\u003c/p\u003e \u003cp\u003eWhen stratified by age, some differences were noted in hip fracture rates between short- and long-segment lumbar fusion. In patients 50\u0026ndash;64 years old, the incidence of hip fracture was 0.41 fractures per 1,000 person-years (95% CI 0.30\u0026ndash;0.51) in the control cohort, 0.62 fractures per 1,000 person-years (95% CI 0.58\u0026ndash;0.68) after short-segment fusion, and 2.01 fractures per 1,000 person-years (95% CI 1.05\u0026ndash;2.97) after long-segment fusion. Five-year hip-fracture free survival differed between the short- and long-segment fusion groups in younger patients (χ\u0026sup2; = 22.11, p\u0026thinsp;\u0026lt;\u0026thinsp;0.00001). Kaplan-Meier curves for this age group showed earlier and more frequent events in the long-segment cohort (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). When adjusted for age and sex, long-segment fusion was associated with a higher risk of hip fracture compared with short-segment fusion, with an HR of 3.07 (95% CI 1.89\u0026ndash;4.99).\u003c/p\u003e \u003cp\u003eAmong patients aged\u0026thinsp;\u0026ge;\u0026thinsp;65 years, overall hip fracture incidence was higher than in the 50\u0026ndash;64 years of age group but did not differ by fusion length. The incidence rate was 2.24 fractures per 1,000 person-years (95% CI 2.02\u0026ndash;2.45) in the control cohort, 2.20 fractures per 1,000 person-years (95% CI 2.10\u0026ndash;2.30) in the short-segment fusion cohort, and 2.23 fractures per 1,000 person-years (95% CI 1.30\u0026ndash;3.16) in the long-segment fusion cohort. Five-year hip fracture-free survival did not differ between the short- and long-segment fusion cohorts (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). There was no significant difference in hip fracture-free survival between short- and long-segment fusion among patients aged\u0026thinsp;\u0026ge;\u0026thinsp;65 years (χ\u0026sup2; = 0.455, p\u0026thinsp;=\u0026thinsp;0.50).\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eLumbar fusion is increasingly used to treat degenerative spine disease in older adults who often have concurrent osteoporosis or osteopenia, elevating their fragility fracture risk. Longer constructs can alter spinopelvic mechanics and plausibly shift load to the hip. Given limited and conflicting prior data on hip fractures after lumbar fusion across construct lengths and age groups, we used a large administrative claims database to better quantify this risk.\u003c/p\u003e\n\u003cp\u003eIn this large, matched cohort of adults with lumbar degenerative disease, we found that the five-year risk of surgically treated hip fractures was low across all patients and that lumbar fusion did not greatly increase overall hip fracture risk. However, within the fusion population, long-segment constructs involving 7\u0026ndash;13\u0026thinsp;+\u0026thinsp;levels were associated with a higher relative risk of hip fracture in adults aged 50\u0026ndash;64 years compared with 1\u0026ndash;6 level fusion, while no difference by fusion length was observed in patients aged\u0026thinsp;\u0026ge;\u0026thinsp;65 years. These findings suggest that in younger patients, long lumbar fusion constructs confer a significant relative risk of hip fracture in a population that is otherwise not classically considered high-risk.\u003c/p\u003e\n\u003cp\u003eThe age-dependent pattern we observed is consistent with the biomechanical effects of long-segment fusion and spinopelvic fixation. By eliminating motion across multiple lumbar segments and extending instrumentation to the sacrum or pelvis, long constructs increase stiffness of the fused spine and likely redirect more motion and load to the hips and lower extremities\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e. Experimental and modeling studies suggest that changes in lumbar lordosis, pelvic tilt, and spinopelvic alignment can alter hip joint contact forces, particularly during gait and transfers\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. In a younger, more active patient, who would otherwise have a low risk of hip fracture, these elevated loads might modestly increase the risk of developing an insufficiency fracture of the hip. Our finding of a three-fold higher hazard of hip fracture after long-segment fusion in patients aged 50\u0026ndash;64 years supports this biomechanical rationale and a dose\u0026ndash;response relationship between fusion extent and distal skeletal complications, even though absolute fracture rates in this group remained low.\u003c/p\u003e\n\u003cp\u003eIn contrast, among patients aged 65 years and older, overall hip fracture incidence was higher but did not differ by fusion length. Older adults often have established osteoporosis, sarcopenia, impaired balance, and a higher burden of medical comorbidities and medications that increase fall risk\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. These factors likely dominate hip fracture risk and may overshadow the incremental biomechanical effect of adding additional fused levels. In this context, whether a patient receives a short- or long-segment construct may be of less significance than their global fragility profile. The nearly identical incidence rates and overlapping survival curves between short- and long-segment fusion in this age group are consistent with this interpretation and suggest that fusion length contributes relatively little beyond age-related baseline risk.\u003c/p\u003e\n\u003cp\u003eOur results extend prior work on skeletal complications after lumbar fusion. Previous studies have described vertebral and sacral insufficiency fractures at or near the ends of long constructs, as well as junctional failure, particularly in the setting of deformity correction and spinopelvic fixation\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e,\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. Other reports have suggested that extensive lumbar fusion and altered spinopelvic alignment may accelerate hip osteoarthritis or increase the need for later hip arthroplasty\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e,\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e. In contrast, the literature quantifying hip fracture risk after spine surgery has been limited and heterogeneous. Li and colleagues reported higher hip fracture risk after lumbar spine surgery compared with matched controls (adjusted HR\u0026thinsp;~\u0026thinsp;1.63), with the greatest risk after long-segment fusion, and elevated risk among patients aged 60\u0026ndash;79 but not \u0026ge;\u0026thinsp;80 years\u0026mdash;consistent with baseline fragility attenuating detectable differences in the oldest patients\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e. By leveraging a large national database, defining fusion length a priori, and stratifying risk by age, our study provides construct-specific, age-stratified estimates of surgically treated hip fracture after lumbar fusion that further clarify how fusion extent and patient age interact.\u003c/p\u003e\n\u003cp\u003eThese findings have practical implications for preoperative planning. For patients in their 50s and early 60s requiring long-segment fusion, the relative risk of hip fracture is meaningfully higher than with shorter constructs, despite low absolute risk. Surgeons should use these data to counsel patients and support routine preoperative bone health evaluation.\u003c/p\u003e\n\u003cp\u003eThis study has important strengths. We used a large, national administrative database with longitudinal follow-up, allowing us to study a rare outcome in over 130,000 patients with lumbar degenerative disease followed over five years. The two-step propensity scored matching strategy created large, demographically balanced cohorts of nonoperative controls, short-segment fusion, and long-segment fusion patients.\u003c/p\u003e\n\u003cp\u003eSeveral limitations also warrant consideration. As with all claims-based studies, our analysis is vulnerable to misclassification of diagnoses and procedures. We lacked patient-specific data such as bone mineral density, smoking status, and radiographic spinopelvic alignment, all of which influence fracture risk. We were also unable to distinguish low-energy fragility fractures from high-energy trauma based on claims codes alone. Follow-up was limited to five years, and we did not account for the competing risk of death, which may lead to modest overestimation of hip fracture risk in older adults. Finally, our findings may not generalize to uninsured patients or health systems outside the database\u0026rsquo;s contributing payers.\u003c/p\u003e\n\u003cp\u003eFuture work should incorporate prospective designs with patient-level data including radiographic spinopelvic parameters, bone density assessment, gait analysis, and fall risk evaluation. In older adults, overall fragility and fall risk likely outweigh construct length in driving hip fracture risk; counseling should emphasize that absolute hip fracture risk after fusion remains low while prioritizing osteoporosis management and fall prevention regardless of fusion length. In conclusion, long-segment spinal fusion was associated with an approximately threefold higher five-year risk of surgically treated hip fractures in adults aged\u0026thinsp;\u0026lt;\u0026thinsp;65 years, supporting shared decision-making and targeted perioperative bone health optimization in higher-risk patients.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eEthical Approval\u003c/h2\u003e \u003cp\u003e\u003cb\u003eand Informed Consent\u003c/b\u003e: No informed consent was required. Waived from\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eJ.A. performed the PearlDiver database coding and statistical data analysis and wrote the main manuscript text. L.L. contributed to manuscript editing and writing. S.B. conducted the literature review and contributed to preliminary writing. D.P. conceived the study idea and provided overall project oversight and final manuscript review. J.F. provided senior surgical oversight as the attending spine surgeon. All authors reviewed and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data used in this study were obtained from the PearlDiver administrative claims database (PearlDiver Technologies, Inc., Colorado Springs, CO). Access to PearlDiver requires a licensing agreement with the vendor. The data are not publicly available. Researchers interested in replicating these analyses may apply for access through PearlDiver Technologies at www.pearldiverinc.com.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eReid PC, Morr S, Kaiser MG (2019) State of the union: a review of lumbar fusion indications and techniques for degenerative spine disease. Published online July 1. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3171/2019.4.SPINE18915\u003c/span\u003e\u003cspan address=\"10.3171/2019.4.SPINE18915\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePhillips FM, Slosar PJ, Youssef JA, Andersson G, Papatheofanis F (2013) Lumbar Spine Fusion for Chronic Low Back Pain Due to Degenerative Disc Disease: A Systematic Review. 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SICOT-J 8:21. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1051/sicotj/2022019\u003c/span\u003e\u003cspan address=\"10.1051/sicotj/2022019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi CY, Chang CL, Tai TW (2018) Incidence and risk factors for hip fracture in elderly patients undergoing lumbar spine surgery: a nationwide database study with 11-year follow-up. Osteoporos Int 29(12):2717\u0026ndash;2723. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00198-018-4734-z\u003c/span\u003e\u003cspan address=\"10.1007/s00198-018-4734-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003e\u003cstrong\u003eTable 1. Baseline Demographic and Clinical Characteristics of the Matched Study Cohorts\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"683\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCharacteristic\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eControls: lumbar degeneration, no fusion\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n = 66,603)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eShort-segment fusion (1\u0026ndash;6 levels)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n = 44,402)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eLong-segment fusion (7\u0026ndash;13+ levels)\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(n = 22,201)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge category, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003e50\u0026ndash;64 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e28,926 (43.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e19,710 (44.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e9,700 (43.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003e\u0026ge;65 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e37,677 (56.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e26,183 (59.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e12,698 (57.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSex, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e34,353 (51.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e22,902 (51.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e11,451 (51.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e32,250 (48.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e21,500 (48.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e10,750 (48.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBaseline Characteristics, n (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003eBone Health (Osteopenia/Osteoporosis)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e11181 (16.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e8959 (20.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e5395 (24.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003eTobacco\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e15302 (22.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e12823 (28.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e6812 (30.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003eObesity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e19272 (28.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e17070 (38.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e7807 (35.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003eDiabetes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e9356 (14.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e6583 (14.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e2946 (13.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 147px;\"\u003e\n \u003cp\u003eRenal Failure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 204px;\"\u003e\n \u003cp\u003e1993 (3.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 179px;\"\u003e\n \u003cp\u003e1229 (2.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 153px;\"\u003e\n \u003cp\u003e923 (4.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-orthopaedic-surgery-and-traumatology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejos","sideBox":"Learn more about [European Journal of Orthopaedic Surgery \u0026 Traumatology](http://link.springer.com/journal/590)","snPcode":"590","submissionUrl":"https://submission.springernature.com/new-submission/590/3","title":"European Journal of Orthopaedic Surgery \u0026 Traumatology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-9337626/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9337626/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eIntroduction:\u003c/h2\u003e \u003cp\u003eLumbar fusion alters spinal biomechanics and may increase hip loading, especially with long-segment constructs. We used a large administrative database to evaluate hip fracture risk after lumbar fusion and assess whether fusion length influences this risk in younger and older adults.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eUsing PearlDiver, we identified patients\u0026thinsp;\u0026ge;\u0026thinsp;50 with lumbar degenerative disorders across three cohorts: nonoperative controls (n\u0026thinsp;=\u0026thinsp;66,603), 1\u0026ndash;6 level fusion (n\u0026thinsp;=\u0026thinsp;44,402), and \u0026ge;\u0026thinsp;7 level fusion (n\u0026thinsp;=\u0026thinsp;22,201), matched by age and sex. Five-year hip fracture-free survival was estimated via Kaplan-Meier analysis, stratified by age (\u0026lt;\u0026thinsp;65 vs\u0026thinsp;\u0026ge;\u0026thinsp;65) and compared with log-rank tests.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eHip fractures were uncommon across all groups (~\u0026thinsp;1\u0026ndash;2 per 1,000 person-years), with no significant overall differences between controls and fusion groups. In patients aged\u0026thinsp;\u0026lt;\u0026thinsp;65, long-segment fusion was associated with significantly lower hip fracture-free survival (χ\u0026sup2;=22.11, p\u0026thinsp;\u0026lt;\u0026thinsp;0.00001) and a threefold higher hazard compared with short-segment fusion (HR 3.07, 95% CI 1.89\u0026ndash;4.99; incidence 2.01 vs 0.62 per 1,000 person-years). In patients\u0026thinsp;\u0026ge;\u0026thinsp;65, hip fracture rates were higher overall but did not differ significantly by fusion length (χ\u0026sup2;=0.455, p\u0026thinsp;=\u0026thinsp;0.50).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eLumbar fusion was associated with a small increase in hip fracture risk, with long constructs conferring substantially higher risk in adults\u0026thinsp;\u0026lt;\u0026thinsp;65.\u003c/p\u003e","manuscriptTitle":"Hip Fracture Risk Following Lumbar Fusion: A Retrospective Cohort Study of Construct Length and Age-Stratified Outcomes","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-22 05:43:25","doi":"10.21203/rs.3.rs-9337626/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-21T07:00:07+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-20T17:46:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"103962590427129734447372804559209586258","date":"2026-04-20T09:39:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"150762686591110911747940924797358008251","date":"2026-04-20T00:58:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"19710292509664103703379560688700470697","date":"2026-04-15T17:43:35+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-13T18:30:54+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"20643476245678370254890985799069056707","date":"2026-04-13T17:49:12+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-13T17:14:46+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-11T09:39:36+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-11T09:39:11+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Journal of Orthopaedic Surgery \u0026 Traumatology","date":"2026-04-06T23:16:32+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-orthopaedic-surgery-and-traumatology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejos","sideBox":"Learn more about [European Journal of Orthopaedic Surgery \u0026 Traumatology](http://link.springer.com/journal/590)","snPcode":"590","submissionUrl":"https://submission.springernature.com/new-submission/590/3","title":"European Journal of Orthopaedic Surgery \u0026 Traumatology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"4937839c-56f6-4d60-8b83-bf693abf43e2","owner":[],"postedDate":"April 22nd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-17T19:53:32+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-22 05:43:25","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9337626","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9337626","identity":"rs-9337626","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}