Limitations of the FREE Study

While the FREE study provides strong clinical information due to it’s methodology (e.g. number of patients, selection criteria, follow-up times, randomization to treatment groups, etc.), it has several limitations.

• The study was not blinded (meaning that both the patients and radiologists knew who received kyphoplasty and who did not), and so knowledge of the treatment might have affected the responses used to measure results. The risk is that the responses for either the patients (on the self-reported questionnaires) or the radiologists (reviewing the x-rays) were potentially biased based on their knowledge and pre-conceived notions of the two different treatments.

• The non-surgical treatments provided likely varied across patients in the study, as each participating hospital was directed to provide the non-surgical care they typically prescribe for patients with spinal fractures. There was no set course of non-surgical treatment across hospitals. Since both the balloon kyphoplasty patients and the control group received some amount of non-surgical care, this variability in treatment and potentially in outcomes was present in both groups.
• The relatively high occurrence of new vertebral fractures in both groups (33% and 25% for the balloon kyphoplasty and control groups respectively) might have decreased the improvements in pain and disability reported for the treated fractures.

For additional data and discussion about the FREE study results see:

• FREE results as published in The Lancet (digital object identifier - doi:10.1016/S0140-6736(09)60010-6)
• FREE results discussion for health care professionals on the Medtronic Kyphon Balloon Kyphoplasty website

• Article written by:
• Jeffrey M. Spivak, MD

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