Fracture Reduction Evaluation (FREE) Clinical Trial Methodology

In the Fracture Reduction Evaluation (FREE) trial, 300 patients with 1 to 3 acute vertebral fractures were enrolled at 21 sites in 8 countries. The FREE study is a 2-year randomized controlled trial comparing balloon kyphoplasty and non-surgical care for treating spinal fractures. The clinical trial was funded by Medtronic Spine LLC, the manufacturer of Kyphon Balloon Kyphoplasty equipment, which was used in the trial.

The patients in the trial all met specific criteria, including:

  • Back pain that the patient described as greater than 4 on a scale of 0-10 (0 meaning no pain, and 10 being the most severe pain)
  • Vertebral height loss of at least 15%
  • Spinal fracture caused by osteoporosis or cancer

Patients who took part in the study had the following characteristics:

  • The mean age was early 70s
  • 77% were female
  • Primary osteoporosis was the cause of spinal fracture in over 95% of cases
  • The spinal fractures were 5.6 weeks old on average in the Kyphoplasty group and 6.4 weeks in the control (non-surgical) group
  • 70% had a grade 2 fracture (>25% deformity), while 29% had a grade 3 fracture (>40% deformity)
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These patients were randomly assigned to receive Kyphon Balloon Kyphoplasty treatment or non-surgical care consisting of pain medications, bed rest, back braces, physical therapy, rehabilitation programs, and walking aids (e.g., canes, walkers) according to standard practices of participating hospitals. 149 patients were assigned to receive balloon kyphoplasty while 151 patients were randomized to non-surgical treatment. Patients in the Kyphoplasty group also received some amount of non-surgical care. As appropriate, patients in both groups were also prescribed calcium and vitamin D supplements and osteoporosis treatment medications such as bisphosphonates (e.g., Fosamax, Boniva, Actonel, Reclast). Most kyphoplasty procedures were done under general anaesthesia.

The study hypothesis was that Kyphon Balloon Kyphoplasty would result in increased improvement in quality of life over non-surgical care for people with spinal fractures. The study assessed two primary factors – efficacy and safety – with emphasis on efficacy at one month after treatment began.

  • Efficacy was determined based on patient responses on multiple questionnaires and radiologist review of patient x-rays. The questionnaires assessed the patient’s pain levels and function. The x-rays were reviewed by two radiologists, assessing for any new or worsening fractures and the presence of bone cement extrusion (vertebrae with any noticeable cement outside the vertebral borders).
  • Safety was assessed by evaluating the occurrence of adverse events and serious adverse events that were related to the treatment or to the kyphoplasty device itself. All adverse events were reported and reviewed.

Most patients in both groups were followed up 1 month after treatment, with the primary comparison being scores on the short-form (SF)-36 physical component summary (PCS) scale, a globally accepted, quality-of-life measure weighted on physical abilities. This and other efficacy and safety measurements involving quality of life, back function and mobility, back pain, and adverse events were also assessed at 3, 6, 12, and 24 months. Data analyses of 24-month results are in process.