The aim of this clinical trial is to determine if vertebroplasty is an effective treatment for acute, painful vertebral fractures due to osteoporosis.

The focus of the study is on the physical activity and mobility of participants.

The main questions the trial aims to answer are:

• Does vertebroplasty lead to increased physical activity as measured by accelerometer?
• Does vertebroplasty lead to increased mobility as measured by GPS (global positioning system)?
• Do physical activity and mobility correlate with pain, disability and quality of life?

Researchers will compare vertebroplasty to sham (simulated surgery without active intervention) to understand if vertebroplasty improves physical activity and mobility.

Participants will

• Undergo vertebroplasty or sham procedure
• Wear an accelerometer and a GPS-reciever in a belt for 1 week before to 4 weeks after the surgery
• Answer questionnaires regarding pain, disability and quality of life at regular intervals.

The knowledge gained from this can help determine who would benefit from vertebroplasty.

Despite attempts at prevention, osteoporotic vertebral fracture occurs with increasing frequency as lifespans increase.

Patients with this disease can experience severe pain and disability, and when conservative treatment is inadequate, vertebroplasty is an option.

In this surgical procedure, polymethyl metacrylate, or "bone cement" is injected into the fractured vertebral body. However, the procedure is currently controversial for the treatment of osteoporotic vertebral fractures because there is not yet consensus on the efficacy.

By investigating the effect of vertebroplasty on mobility and physical activity, this study aims to contribute to resolution of the controversy.

The study is a prospective, double-blind, randomized, sham-controlled clinical trial, where participants will be randomized to either vertebroplasty or a sham operation.

The study is embedded in the ongoing trial "Percutaneous Vertebroplasty Vs. Sham for Osteoporotic Vertebral Compression Fractures Focusing on Pain and Economy (VOPE2)" with ClinicalTrials.gov ID NCT06141187.

A subset of the participants in VOPE2 will, in addition to previously planned activities, be equipped with wearable accelerometers and a global positioning system (GPS).

The trial is designed in accordance with the SPIRIT guidelines.

Potential participants will be identified by referral to the Center for Spine Surgery and Research from general practitioners, chiropractor, physiotherapist, or from hospital inpatient and emergency departments in the region of Southern Denmark.

Participants will then be examined in an outpatient clinic by a spine surgeon, and have MRI scans and X-ray images analyzed by experienced neuro-radiologists.

If eligible, they will be offered to participate following informed consent. An accelerometer and GPS-reciever attached to an elastic waist band are initiated following inclusion.

Subjects will initially be stratified into two groups based on the number of OVCFs into 1-2 levels or 3-4 levels.

Within each of these two groups, randomization sheets in varying blocks of 8 with an equal number of PVP and sham patients in each block will be generated using software (www.randomizer.org) and will be placed in numbered, opaque, sealed envelopes.

Treatment group assignment is 1:1 and will be performed by a scrub nurse in the surgical theatre after the patient is draped but prior to skin incision.

Throughout the trial, only the surgeon and the OR-nurse will have knowledge of the treatment assignment.

The patient and all assessors remain blinded to the treatment group throughout the study. Spine surgeons who are experienced in PVP will perform the surgical procedures.

Anaesthesiologists and spine surgeons are present at the facility in case of complications, following recommendations by the National Health Authority and have the capacity/capability to decompress the spinal canal in case of cement leakage

Based on qualitative studies and clinical experience, patients with painful osteoporotic vertebral fractures restrict their movement because of pain.

This in turn leads to reduced physical activity and diminished ability to move oneself around and away from home, defined here as mobility.

If vertebroplasty is effective, it is expected to lead to increased physical activity and mobility compared to sham, and the outcomes derived from accelerometers and GPS-recievers can supplement patient reports due to their continuous and objective nature.

Inclusion Criteria:

• Patients aged 50+ and diagnosed with symptomatic osteoporotic spinal compression fractures between T6 and L5 (incl).
• Focal tenderness on the level of the vertebral fracture.
• Fractures verified with oedema of the relevant vertebra on the MRI STIR sequence.
• Osteoporotic Fractures type 1-4.
• Fracture involves no more than 4 vertebral body levels.
• Vertebroplasty can be done in one session.
• Back pain score measured on a Visual Analog Scale (VAS, 0 to 100) ≥ 60.
• Able to understand and read Danish.
• Written informed consent.
• Relevant pain started ≤ 3 months prior to enrollment.

Exclusion Criteria:

• Contra-indications for spine surgery.
• Platelets < 30 mia/l.
• Osteoporotic Fractures type 5 and Pincer-type.
• Complete collapse of the vertebral body precluding insertion of needle.
• Presence of neurologic deficit.
• Contraindications for MRI scanning.
• Psychological or psychiatric disorder that is expected to interfere with compliance.
• Active malignancy.
• Mini Mental State Examination (MMSE) test score below 24.
• History of chronic back pain requiring ongoing opiate use.
• Systemic or local infection of the spine.

Data from questionnaires, accelerometers and GPS-records will be made available in an anonymized form to researchers who present a proposal for the use that is reasonable and can be approved by the study authors.

The IPD and data will be stored for five years from the completetion of the study at the trial site followed by archiving at the Danish National Archives.

Researchers can request access to the information by contacting the investigator via email at soren.wittorff.sorensen@rsyd.dk