New international study evaluates the AO Spine–DGOU osteoporotic fracture score for treatment decision-making

The AO Spine Knowledge Forum Trauma and Infection has initiated a major international multicenter study designed to evaluate the clinical utility of the osteoporotic fracture (OF) classification-based scoring system in thoracolumbar fractures associated with primary osteoporosis.

Led by the AO Spine Knowledge Forum Trauma and Infection, the TL-OF study (The osteoporotic fracture classification-based scoring system for treatment decision in thoracolumbar osteoporotic fractures: An international multicenter prospective study) represents one of the most comprehensive prospective investigations in this patient population to date.

Addressing a growing clinical challenge

Osteoporotic thoracolumbar vertebral fractures represent a rapidly increasing global healthcare burden, driven largely by aging populations. Principal Investigator Klaus Schnake highlighted, that despite their prevalence, treatment decision-making remains complex. “Surgeons frequently face uncertainty when choosing between surgical and nonsurgical management, particularly in patients with symptomatic fractures where mobility, pain, and quality of life are substantially affected.”

The OF classification and scoring system was developed to provide a structured, evidence-informed framework for fracture assessment and treatment guidance. While the scoring system has shown favorable clinical short-term clinical results in a national study in Germany, prospective international validation in real-world clinical practice is  limited. The TL-OF study directly addresses this gap.

Co-Principal Investigator Sebastian Bigdon said the primary objective of the study is to determine whether adherence to the OF score system leads to improved short-term outcomes. “Specifically, investigators aim to assess whether an initial treatment decision aligned with the OF score recommendations result in a faster return to the patient’s pre-injury or pre-symptom mobility level at three months following treatment.”

Co-Principal Investigator Ratko Yurac further explained that the underlying hypothesis is straightforward yet clinically meaningful: “In symptomatic osteoporotic thoracolumbar fractures, adherence to the OF Score recommendations will result in a faster return of mobility at three months compared with treatment decisions that do not adhere to the score.”

International efforts to improve patient outcomes globally

Fifteen international sites across Europe, North and South America, Asia, and the Middle East are participating in the study to ensure the outcomes are truly global in alignment with the mandate of the Knowledge Forums.

Through a rigorous process, the AO Innovation Translation Center, Clinical Evidence team, and Network Clinical Research collaborate to select broad international collaboration, with participating centers located in Brazil, Chile, Egypt, Finland, Argentina, Germany, India, Japan, Malaysia, Romania, Saudi Arabia, Switzerland, the United Kingdom, and the United States.

This global distribution enhances the external validity of the findings and ensures representation of diverse healthcare systems, clinical practices, and patient populations.

Primary objective and hypothesis

Clinically relevant outcome measures

The TL-OF study is a multicenter, international, prospective observational investigation enrolling women over 50 years of age and men over 60 years of age who present with single- or multilevel contiguous thoracolumbar (T1 to L5) fractures resulting from primary osteoporosis. 

The primary outcome measure focuses on patient-reported recovery:

• Return to mobility level before injury or symptom onset, as reported by the patient

Follow-up is conducted at three months for the primary endpoint and extended to twelve months for secondary, long-term outcomes.

Secondary outcomes include:

• Proportion and extent of mobility recovery
• Clinical, patient-reported, and radiological outcomes
• Comparative evaluation of surgical versus nonsurgical treatment
• Complication rates related to surgical techniques and OF subtypes
• Agreement between site investigators and a blinded expert panel
• Validation of the AO Spine Patient-Reported Outcome Spine Trauma (PROST)
• Cost-effectiveness of adherence to OF score recommendations

Study timeline

The recruitment period spans two years, with an enrollment target of 648 patients. Key milestones for the study include:

• Q1 2026—Enrollment of the first patient
• Q1 2028—Completion of patient recruitment
• Q1 2029—Completion of final patient follow-up
• Q4 2029—Availability of study results
• Q1 2030—Announcement of Results and initiation of knowledge translation activities

Anticipated impact on clinical practice and patient outcomes:

The TL-OF study is expected to generate critical evidence regarding the practical value of the OF scoring system.

Anticipated contributions include:

• Providing an evidence-based framework for treatment decision-making
• Supporting the development of international treatment guidelines
• Promoting greater standardization of care
• Enhancing understanding of cost-effectiveness

By evaluating outcomes associated with adherence versus non-adherence to the OF score, the study aims to move beyond theoretical models and deliver clinically actionable data.

Potential benefits for patients

From the patient perspective, the study addresses outcomes that directly impact daily life:

• Faster mobilization
• Improved pain management
• Optimized treatment selection
• Enhanced quality of life

Restoring mobility after osteoporotic fractures remains a central therapeutic goal, particularly in elderly populations where functional decline carries substantial long-term consequences.

Advancing evidence in osteoporotic fracture care

Schnake stresses the TL-OF study represents a significant step forward in the systematic evaluation of decision-support tools in spine trauma and osteoporosis-related fractures. “Through its prospective, multicenter design and focus on patient-centered outcomes, the study seeks to clarify whether structured scoring systems translate into measurable clinical benefit.”

The participating researchers hope that for spine surgeons and researchers, the findings will inform both day-to-day clinical decision-making and future research initiatives aimed at improving outcomes in this expanding patient population.