Validity and reliability of the osteoporotic fracture treatment score (OF score) and outcomes across various treatments in osteoporosis vertebral compression fracture patients.

Background

Osteoporotic vertebral compression fractures (OVF) are fragility fractures of the vertebral body that primarily occur in the thoracolumbar spine [ 1 ]. These fractures are the most prevalent osteoporotic fractures, with a global incidence of one every 22 s among individuals aged 50 and older, regardless of sex [ 2 , 3 ]. OVF increase morbidity and mortality [ 4 , 5 ] and impose substantial healthcare costs, estimated at up to $1 billion annually [ 6 , 7 ]. Also, the incidence of OVF and surgical intervention rates are rising due to population aging [ 8 , 9 ].

Despite its prevalence, consensus on OVF management remains elusive. Treatment is complex and often controversial, particularly regarding surgical intervention thresholds and appropriate surgical methods [ 10 , 11 ]. Recently, the “Osteoporotic Fractures” working group within the Spine Section of the German Society of Orthopedics and Trauma (DGOU) developed the osteoporotic fracture (OF) classification and osteoporotic fracture treatment score (OF score) [ 12 , 13 ], which have been widely adopted. The OF classification includes five types: OF1 (no vertebral deformation), OF2 (deformation with minimal posterior wall involvement), OF3 (deformation with significant posterior wall involvement), OF4 (vertebral frame integrity loss, vertebral body collapse, or pincer-type fracture), and OF5 (distraction or rotational injury). The OF score assesses seven components to guide treatment decisions: the OF classification, bone mineral density, ongoing fracture process, pain, neurological status, mobility status, and patient health status. The scores categorize the recommendations as “nonsurgical” (0–5 points), “nonsurgical or surgical” (6 points), or “surgical” (> 6 points). However, the reliability, validity, and outcomes of the OF classification and OF score have been evaluated in few studies. This study aimed to assess the reliability and validity of the OF score and its treatment recommendations. Additionally, we examined the intermediate outcomes of various surgical strategies for OVF patients.

Methods

Study design and ethical approval

This retrospective cohort study was conducted at a single-center tertiary care hospital. The Siriraj Institutional Review Board of the Faculty of Medicine of Siriraj Hospital, Mahidol University, Bangkok, Thailand, approved the study protocol (COA no. si 864/2022). The requirement for written informed consent was waived because of the retrospective and anonymous nature of the study.

Study population

Data were sourced from the institution’s spinal registry. This retrospective analysis included patients treated for thoracolumbar OVF from 2016 to 2021.

Inclusion and exclusion criteria

The inclusion criteria were the following:

Postmenopausal women and men aged ≥ 50 years who had been diagnosed with thoracolumbar OVF presenting with focal back pain at the fracture level for 4 weeks or less.

The presence of pain or local tenderness consistent with imaging findings, including X-ray, computerized tomography (CT), or magnetic resonance imaging (MRI).

The availability of clinical and radiological data for preoperative OF score assessment.

The exclusion criteria were as follows:

The presence of thoracolumbar fractures that were secondary to spinal tumor diseases (e.g., primary spinal tumors such as spinal hemangioma, spinal metastasis, and hematologic malignancies like multiple myeloma).

Spinal infections (e.g., spondylodiscitis).

Patients with previous spinal surgery.

Data collection

Baseline demographic data, including age, sex, body mass index, history of trauma, underlying diseases, American Society of Anesthesiologists physical status classification, and medication usage, were retrieved. Clinical variables related to pain, neurological status, patient mobility, and bone mineral density were also collected.

OF score assessment

Three orthopedic surgeons (K.M., B.S., and H.K.), blinded to patient details and treatments, independently reviewed the images (X-ray, CT, or MRI) to classify patients via the OF classification and calculate the OF score on the basis of the clinical and radiographic data. The total OF score was further categorized into “stable,” “potentially unstable,” or “unstable,” according to the guidelines for recommended treatments.

Before evaluating the OF score, all reviewers reviewed the OF classification and OF scoring systems described in the original articles by Schnake et al. [ 13 ] and Blattert et al. [ 12 ]. Discrepancies in OF classifications and OF scores were resolved by a fourth reviewer (W.S.) through discussion, establishing a consensus classification and score for validity analysis. Interobserver agreement was assessed by comparing the initial classifications of the three evaluators. Intraobserver reliability was evaluated 6 weeks later by the same raters, using patient cases presented in random order to minimize recall bias. To assess the validity of the OF score in predicting treatment, the recommended treatments based on the consensus OF score were compared with the treatments administered to each patient.

Outcome measures

Patients with at least 1 year of follow-up were included in the outcome analysis. The primary outcomes measured were back pain via the visual analog scale (VAS; 0–100 mm, where 0 indicates “no pain” and 100 represents “the worst pain”), the Oswestry Disability Index (ODI), the EQ-5D-5 L, and the EQ-VAS. These parameters were assessed at baseline and at the 1-year follow-up.

Radiographic outcomes were evaluated using lateral plain radiographs in the upright position. Sagittal Cobb angles were measured at the superior and inferior endplates of the vertebra adjacent to or spanning the fracture site, defined as the local kyphotic angle (Fig. 1 ). Kyphotic correction was determined by comparing the preoperative and postoperative local kyphotic angles. Postoperative kyphotic progression was defined as an increase in the local kyphotic angle of more than 10 degrees compared with the immediate postoperative measurement. Additionally, the rates of adjacent-level fractures and reoperations were recorded and analyzed.

Surgical treatment classification

Surgical treatments for OVF were classified according to the DGOU treatment recommendations [ 12 ]:

Stand-alone cement augmentation (CA) : This technique includes vertebroplasty or kyphoplasty without posterior instrumentation.

Short-segment posterior instrumentation (SS-PI) : This method involves instrumentation of one segment above and below the fractured vertebra.

Long-segment posterior instrumentation (LS-PI) : This technique requires instrumentation of at least two segments above and below the fractured vertebra.

Sample size calculation

Sample size calculations were performed to ensure adequate power for assessing interobserver reliability and the validity of the OF score. Using Walter’s formula with a minimum acceptable intraclass correlation coefficient (ICC) of 0.6, an expected ICC of 0.75, a significance level of α = 0.05, a power of 80%, and three raters, a total of 67 patients were needed. For the validity analysis, the sample size was estimated via a proportion formula. Assuming a proportion (p) of 71% based on Ullrich et al. [ 14 ], an error margin (d) of 10%, and α = 0.05, a total of 157 samples were necessary.

Statistical analysis

Interobserver and intraobserver reliability for total OF scores among the three raters were assessed using a two-way mixed-effects model and the ICC. Each OF score component—the OF classification, bone mineral density, ongoing fracture, pain, neurological deficit, mobilization, and health status—was evaluated for interobserver agreement via Fleiss’s kappa and for intraobserver agreement using Cohen’s weighted kappa. Agreement levels were interpreted on the basis of Koo and Li’s grading [ 15 ] for ICC values and Landis and Koch’s grading [ 16 ] for kappa values.

The validity of treatment decisions based on the OF score was determined by calculating the percentage of correct treatment predictions, sensitivity, specificity, positive predictive value, and negative predictive value. Receiver operating characteristic (ROC) curve analysis with Youden’s index was performed to estimate the area under the curve (AUC) and identify the OF score cutoff value, along with its sensitivity and specificity, for surgical treatment recommendations.

Continuous data are presented as means ± standard deviations for normally distributed variables and as medians with interquartile ranges for nonnormally distributed variables. Categorical data are described as numbers and percentages. Comparisons of continuous data were performed via Student’s t test or the Mann–Whitney U test, whereas categorical data were compared using the chi-square test or Fisher’s exact test. A P value of less than 0.05 was considered statistically significant. Bonferroni correction was applied to adjust for multiple comparisons, setting the significance threshold at P < 0.013 (0.05 divided by 3). All the statistical analyses were conducted with IBM SPSS Statistics, version 29.0.2.0 (IBM Corp, Armonk, NY, USA).

Results

Study population

A total of 181 patients were initially eligible for the study. After applying the exclusion criteria; 12 fractures secondary to spinal tumors, 8 fractures secondary to spinal infections, and 4 fractures with previous spinal surgery, 157 patients were enrolled in this study. Of these, 132 patients had at least one year of follow-up and were included in the intermediate outcome analysis.

Baseline demographic and clinical characteristics

The baseline demographic and clinical characteristics are summarized in Table 1 . The mean age of the participants was 74.2 ± 10.5 years, with 84.7% being female. A history of trauma was reported by 54.8% of the patients. Most fractures occurred at the thoracolumbar junction (T11–L2; 83.4% of cases). According to the OF classification, OF4 was the most prevalent type (49.04%, n = 77), followed by OF3 (40.8%, n = 64), OF2 (8.9%, n = 14), and OF5 (1.3%, n = 2).

Reliability of the OF score

The interobserver reliability for the total OF score among the three raters was excellent, with an ICC of 0.774 (95% CI: 0.653–0.858), indicating good agreement. Intraobserver reliability demonstrated an ICC of 0.833 (95% CI: 0.721–0.900), also reflecting good agreement. Detailed analyses of each OF score component’s interobserver and intraobserver reliability and their levels of agreement are presented in Table 2 .

Validity of the OF score for treatment prediction

Among the 157 patients (Table 3 ), 116 (73.89%) underwent surgical treatment, whereas 41 (26.11%) received conservative treatment. On the basis of the OF score, 28 patients (17.83%) were recommended for conservative treatment (OF score < 6), and 118 patients (75.16%) were recommended for surgical treatment (OF score ≥ 7). Eleven patients (7%) had indeterminate recommendations (OF score = 6); of these, 6 were treated conservatively, and 5 underwent surgery. Overall, 121 patients (82.88%) received treatment consistent with the OF score recommendations.

The validity of the OF score in predicting surgical treatment is summarized in Table 4 . The ROC curve analysis revealed an AUC of 0.77 (95% CI: 0.67–0.86), indicating fair discriminative ability [ 17 ]. When a cutoff OF score of > 6.5 was used, the sensitivity and specificity for predicting surgical treatment were 87.9% and 61.0%, respectively ( Fig. 2 ) .

Clinical outcomes of surgical treatments

Among the 132 patients included in the outcome analysis, 106 (80.3%) received surgical treatment, while 26 (19.7%) were treated nonsurgically. The surgically treated patients were categorized into three groups: CA ( n = 49), SS-PI ( n = 29), and LS-PI ( n = 28). The demographic and clinical characteristics of these groups are detailed in Table 5 . There were no significant differences in demographic characteristics or clinical risk factors across the groups. The majority of patients in each group were classified as OF4, followed by OF3, and most fractures were located at the thoracolumbar junction. Notably, the LS-PI group had a significantly greater mean OF score (9.1 ± 1.9; P = 0.011) than did the CA group. Additionally, neurological deficits were more prevalent in the LS-PI group ( P < 0.001). The median follow-up duration was consistent across the groups at 48 weeks.

Preoperative measures (back pain VAS score, ODI, EQ-VAS score, EQ-5D-5 L score, and initial local kyphotic angle) were not significantly different between the treatment groups ( P > 0.05; Table 6 ). Postoperatively, kyphotic reduction varied significantly among the groups, with the LS-PI group achieving the most substantial reduction (median 13.0°, P = 0.004). Pairwise comparisons revealed significant differences between the CA and SS-PI groups and between the CA and LS-PI groups ( P = 0.002). Kyphotic progression also differed significantly, with the CA group experiencing greater progression (mean 15.3°) than the SS-PI (9.4°) and LS-PI (5.1°) groups did ( P < 0.001). Pairwise comparisons revealed significant differences in kyphotic progression between CA and SS-PI as well as between CA and LS-PI ( P < 0.001).

The complication and reoperation rates did not differ significantly between the groups ( P = 0.227 and P = 0.309, respectively). Adjacent-level fractures occurred in 20.5% of CA patients, 23.1% of SS-PI patients, and 22.2% of LS-PI patients, with no significant differences ( P = 0.964) ( Table 6 ). Regardless of treatment type, all patients showed significant improvements in back pain VAS, ODI, EQ-5D-5 L, and EQ-VAS scores, with no significant differences between the treatment groups (Table 7 ).

Discussion

Historically, the initial management for OVF is primarily conservative, including short-term bed rest, analgesic medication, orthotic support, and the initiation of anti-osteoporotic medication to increase bone mineral density [ 10 , 18 ]. Surgical management is generally reserved for patients who have failed conservative treatment. Nowadays, the clinical guidelines for managing OVF have been inconsistent, with no established consensus [ 19 ]. To address this inconsistency, the DGOU developed the OF classification and OF score. These tools are designed to assess OVF severity and guide treatment decisions. However, their reliability and validity have been evaluated in only a few studies, predominantly by the original developers. Notably, no prior research has comprehensively assessed the reliability of the OF score.

Our study demonstrated good interobserver and intraobserver reliability for the overall OF score, with ICCs of 0.774 and 0.833, respectively. These findings suggest strong agreement among raters and within the same rater over time. However, the reliability of individual OF score components varied. The OF classification achieved substantial agreement (kappa = 0.608), which was slightly lower than the kappa value reported by the DGOU (kappa = 0.63) [ 13 ]. Similar results were observed in recent studies, which reported kappa values of 0.59 [ 20 ] and ICC values of 0.62 [ 21 ].

The observed differences in reliability may stem from variations in evaluator experience. The DGOU study involved six expert spine surgeons, which likely contributed to higher agreement levels. Additionally, the use of advanced imaging techniques can impact reliability. At our institution, OVF patients are evaluated primarily via conventional radiography, with CT scans and MRIs employed selectively. This limited use of advanced imaging may hinder the accurate assessment of endplate involvement and posterior vertebral height, which is critical for distinguishing between the OF2, OF3, and OF4 classifications. Consequently, these challenges can affect the overall OF score evaluation in clinical settings, as changes in OF fracture type can lead to significant score alterations.

The “ongoing fracture” component of the OF score exhibited only moderate agreement, possibly due to difficulties in evaluating fracture progression with conventional radiography, especially in elderly patients with osteopenia and degenerative scoliosis. Conversely, score components such as “mobilization” and “health status” showed substantial agreement, whereas bone mineral density, pain measured by the VAS, and neurological deficits achieved near-perfect agreement. These latter components are more straightforward to assess, contributing to their higher reliability.

Despite adequate agreement levels, certain challenges remain in scoring specific components. There is a lack of clear definitions for sufficient analgesia and the precise site for bone mineral density measurement (e.g., total hip, femoral neck, or lumbar spine). Additionally, patient mobility varies widely, ranging from short-distance ambulation to the need for gait aids or caregiver assistance. These factors likely contribute to the lower kappa value observed in the mobilization component. Enhancing the reliability of the OF score may require more explicit definitions and standardized assessment protocols for these components.

The OF score provides therapeutic guidance with high accuracy (82.88%) and sensitivity (91.89%), demonstrating fair discriminative performance (AUC = 0.77). The ROC analysis identified a cutoff value of > 6.5, which aligns with the current threshold of an OF score ≥ 7 for recommending surgical treatment. However, the specificity of the OF score is relatively low (54.3%). Among patients with an OF score above 7, 16 patients (13.5%) were successfully treated conservatively. Notably, half of these patients (8/16) were classified as OF type 4 without neurological deficits or limited mobility. On follow-up X-rays, these patients showed no ongoing fractures, yet they reported pain with a VAS score ≥ 4. These findings suggest a risk of over-recommending surgical treatment when relying solely on the OF score. This could lead to unnecessary surgical interventions, particularly for type 4 OF patients, who may still be suitable candidates for conservative treatment despite an OF score exceeding 7 [ 22 ].

Our results are consistent with those of Ullrich et al. in the EOFTT study, which prospectively validated 518 OVF. They reported a high accuracy level (71%) but slightly lower discriminative ability (AUC = 0.684) for the OF score, with a cutoff value of 6.5 [ 14 ]. In contrast, our ROC analysis demonstrated a higher sensitivity (87.9% vs. 60%), indicating greater reliability in identifying OVF patients who genuinely need surgical intervention.

This study comprehensively evaluated three surgical treatments for OVF: stand-alone CA, SS-PI, and LS-PI. Regardless of the surgical strategy, all the treatments significantly improved the back pain VAS, ODI, EQ-VAS, and EQ-5D-5 L scores. LS-PI achieved the most substantial correction of the local kyphotic angle, whereas CA was associated with the greatest postoperative kyphotic progression after 1 year of follow-up. Additionally, the length of the construct (SS-PI vs. LS-PI) did not lead to significant differences in radiologic outcomes.

Most of our OVF patients were classified as having OF4 or OF3 injuries. According to the DGOU’s guidelines, LS-PI is recommended for OF4 injuries, and SS-PI is advised for OF3 injuries. However, nearly half of our patients (46%) were treated with stand-alone CA and achieved comparable clinical outcomes. Previous investigations have reported similar results. For instance, Ulrich et al. [ 22 ] evaluated OF4 in the EOFTT study and reported similar short-term outcomes across the three treatments. Gu et al. [ 23 ] also found comparable outcomes between CA and SS-PI but noted greater postoperative kyphotic progression and vertebral height loss in the CA group.

The kyphotic progression observed in the CA group may be attributed to alterations in load transfer and stress distribution caused by the cement, potentially leading to endplate damage or adjacent fractures [ 24 , 25 ]. These cement-induced changes can result in postoperative kyphotic progression, especially in osteoporotic fractures with endplate injuries (OF4). However, our study found no significant difference in the rate of adjacent fractures between the treatment groups.

Despite the DGOU’s surgical recommendations, CA may be a viable treatment option for OVF, even in patients with loss of posterior wall integrity (OF3) or both types of endplate involvement (OF4). Nevertheless, the potential for postoperative kyphotic progression remains a major consideration, given that this condition can lead to late deformity and chronic back pain in OVF patients. These findings suggest that treatment decisions should not rely solely on the OF score but should also consider individual patient characteristics and clinical assessments.

Limitations

Several limitations of this study must be acknowledged. First, the single-center, retrospective design may have led to an overestimation of the kappa values of certain components, such as bone mineral density, pain VAS score, and neurological deficits. In real-world settings, assessing bone mineral density in patients with acute OVF can be challenging, as these patients may be unable to tolerate supine positioning or experience prolonged waiting times. Alternative bone quality assessment methods, such as quantitative CT [ 26 ], could increase the accuracy and clinical utility of the OF score. Future studies should employ a multicenter, prospective design to strengthen generalizability and validity in real clinical practice. Second, the relatively low number of conservatively treated OVF patients, due to high rates of unavailable data and short follow-up periods, introduced the potential for selection bias. Consequently, the positive predictive value and negative predictive value of the OF score should be interpreted with caution. This limitation also restricts comparisons between conservative and surgical treatments. However, our primary aim was to evaluate the long-term outcomes of various surgical strategies recommended by the DGOU; thus, comparisons were limited to surgically treated patients.

Conclusions

This study confirms the reliability and validity of the OF score, highlighting its utility in guiding treatment decisions for OVF, particularly in identifying patients suitable for conservative management. Stand-alone CA, SS-PI, and LS-PI are all effective surgical options for treating OVF. However, careful consideration is necessary when selecting CA for patients with OF3 or OF4 fractures because of the procedure’s limitations in correcting kyphotic angles and the risk of postoperative kyphotic progression.

Acknowledgements

All authors gratefully acknowledge Mister Pongsathorn Samphaotong of the Orthopaedic Research Unit, Department of Orthopaedic Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, for data analysis and coordination of the journal submission process. The authors are also indebted to Mr. David Park for the English-language editing of this paper.

Abbreviations

Area under the curve

Cement augmentation

Computerized tomography

German Society of Orthopedics and Trauma

Intraclass correlation coefficient

Long-segment posterior instrumentation

Magnetic resonance imaging

Oswestry Disability Index

Osteoporotic fracture

Osteoporotic fracture treatment score

Osteoporotic vertebral compression fracture

Receiver operating characteristic

Short-segment posterior instrumentation

Visual analog scale

Author contributions

KM contributed to the data gathering, statistical analysis, and writing of the initial manuscript. BS, HK, and WS contributed to the data analysis. EK, MR, and WS contributed to the original idea, supervised the work, performed validations, and prepared the final manuscript. All authors read and approved the final manuscript.

Funding

The authors received no financial support for the research, authorship, or publication of this article.

Open access funding provided by Mahidol University

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

The protocol for this study was approved by the Siriraj Institutional Review Board of the Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand (COA no. Si 864/2022).

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Footnotes

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

References

1. Migliorini F, Giorgino R, Hildebrand F, Spiezia F, Peretti GM, Alessandri-Bonetti M et al. Fragility fractures: risk factors and management in the Elderly. Med (Kaunas). 2021;57(10).

2. Johnell O, Kanis JA. An estimate of the worldwide prevalence and disability associated with osteoporotic fractures. Osteoporos Int. 2006;17(12):1726–33.

3. Ballane G, Cauley JA, Luckey MM, El-Hajj Fuleihan G. Worldwide prevalence and incidence of osteoporotic vertebral fractures. Osteoporos Int. 2017;28(5):1531–42.

4. Cauley JA, Thompson DE, Ensrud KC, Scott JC, Black D. Risk of mortality following clinical fractures. Osteoporos Int. 2000;11(7):556–61.

5. Jalava T, Sarna S, Pylkkänen L, Mawer B, Kanis JA, Selby P, et al. Association between vertebral fracture and increased mortality in osteoporotic patients. J Bone Min Res. 2003;18(7):1254–60.

6. Burge R, Dawson-Hughes B, Solomon DH, Wong JB, King A, Tosteson A. Incidence and economic burden of osteoporosis-related fractures in the United States, 2005–2025. J Bone Min Res. 2007;22(3):465–75.

7. Kim HY, Ha YC, Kim TY, Cho H, Lee YK, Baek JY, et al. Healthcare costs of osteoporotic fracture in Korea: information from the National Health Insurance Claims Database, 2008–2011. J Bone Metab. 2017;24(2):125–33.

8. Choi SH, Kim DY, Koo JW, Lee SG, Jeong SY, Kang CN. Incidence and Management Trends of Osteoporotic Vertebral Compression fractures in South Korea: a Nationwide Population-based study. Asian Spine J. 2020;14(2):220–8.

9. Hadji P, Klein S, Gothe H, Häussler B, Kless T, Schmidt T, et al. The epidemiology of osteoporosis—bone evaluation study (BEST): an analysis of routine health insurance data. Deutsches Ärzteblatt International. 2013;110(4):52.

10. Jang HD, Kim EH, Lee JC, Choi SW, Kim HS, Cha JS, et al. Management of osteoporotic vertebral fracture: review update 2022. Asian Spine J. 2022;16(6):934–46.

11. Liu Y, Liu J, Suvithayasiri S, Han I, Kim JS. Comparative efficacy of Surgical interventions for Osteoporotic Vertebral Compression fractures: a systematic review and network Meta-analysis. Neurospine. 2023;20(4):1142–58.

12. Blattert TR, Schnake KJ, Gonschorek O, Gercek E, Hartmann F, Katscher S, et al. Nonsurgical and Surgical Management of osteoporotic vertebral body fractures: recommendations of the spine section of the German Society for Orthopaedics and Trauma (DGOU). Global Spine J. 2018;8(2suppl):S50–5.

13. Schnake KJ, Blattert TR, Hahn P, Franck A, Hartmann F, Ullrich B, et al. Classification of osteoporotic Thoracolumbar spine fractures: recommendations of the spine section of the German Society for Orthopaedics and Trauma (DGOU). Global Spine J. 2018;8(2suppl):S46–9.

14. Ullrich BW, Schnake KJ, Schenk P, Katscher S, Bäumlein M, Zimmermann V, et al. Clinical evaluation of the osteoporotic fracture treatment score (OF-Score): results of the evaluation of the osteoporotic fracture classification, treatment score and therapy recommendations (EOFTT) study. Global Spine J. 2023;13(1suppl):s29–35.

15. Koo TK, Li MY. A Guideline of selecting and reporting Intraclass correlation coefficients for Reliability Research. J Chiropr Med. 2016;15(2):155–63.

16. Landis JR, Koch GG. The measurement of observer agreement for categorical data. biometrics. 1977:159 – 74.

17. Janssens ACJW, Martens FK. Reflection on modern methods: revisiting the area under the ROC curve. Int J Epidemiol. 2020;49(4):1397–403.

18. Migliorini F, Maffulli N, Colarossi G, Eschweiler J, Tingart M, Betsch M. Effect of drugs on bone mineral density in postmenopausal osteoporosis: a bayesian network meta-analysis. J Orthop Surg Res. 2021;16(1):533.

19. Parreira PCS, Maher CG, Megale RZ, March L, Ferreira ML. An overview of clinical guidelines for the management of vertebral compression fracture: a systematic review. Spine J. 2017;17(12):1932–8.

20. Quinteros G, Cabrera JP, Urrutia J, Carazzo CA, Guiroy A, Marré B, et al. Reliability evaluation of the New AO Spine-DGOU classification for osteoporotic thoracolumbar fractures. World Neurosurg. 2022;161:e436–40.

21. Schönrogge M, Lahodski V, Otto R, Adolf D, Damm R, Sitte-Zöllner A, et al. Inter- and intraobserver reliabilities and critical analysis of the osteoporotic fracture classification of osteoporotic vertebral body fractures. Eur Spine J. 2022;31(9):2431–8.

22. Spiegl UJA, Schenk P, Schnake KJ, Ullrich BW, Osterhoff G, Scheyerer MJ, et al. Treatment and outcome of osteoporotic thoracolumbar vertebral body fractures with deformation of both endplates with or without posterior wall involvement (OF 4): short-term results from the prospective EOFTT Multicenter Study. Global Spine J. 2023;13(1suppl):s36–43.

23. Gu Y-T, Zhu D-H, Liu H-F, Zhang F, McGuire R. Minimally invasive pedicle screw fixation combined with percutaneous vertebroplasty for preventing secondary fracture after vertebroplasty. J Orthop Surg Res. 2015;10(1):31.

24. Polikeit A, Nolte LP, Ferguson SJ. The effect of cement augmentation on the load transfer in an osteoporotic functional spinal unit: finite-element analysis. Spine (Phila Pa 1976). 2003;28(10):991–6.

25. Berlemann U, Ferguson SJ, Nolte LP, Heini PF. Adjacent vertebral failure after vertebroplasty. A biomechanical investigation. J Bone Joint Surg Br. 2002;84(5):748–52.

26. Zou D, Li W, Deng C, Du G, Xu N. The use of CT Hounsfield unit values to identify the undiagnosed spinal osteoporosis in patients with lumbar degenerative diseases. Eur Spine J. 2019;28:1758–66.

Associated Data

Data Availability Statement

No datasets were generated or analysed during the current study.