SI-Bone announces publication of two-year iMIA randomised controlled trial results


Two-year results of a randomised controlled trial, published in the Journal of Bone and Joint Surgery, suggest that minimally invasive sacroiliac joint arthrodesis with triangular titanium implants is safe and more effective throughout two years in improving pain, disability, and quality of life compared with conservative management. 

The iMIA (iFuse implant system minimally invasive arthrodesis) trial is a Level 1 randomised controlled trial (RCT), conducted at nine hospitals in four countries in Europe, that assessed the safety and effectiveness of SI joint fusion (SIJF), also referred to as SI joint arthrodesis in the manuscript, with triangular iFuse implants (SI-Bone) compared to conservative management (CM) in patients with chronic SI joint dysfunction.

“What I find remarkable is the consistency of the results between the two-year iMIA and two-year INSITE RCTs,” said David Polly, professor, Department of Orthopedic Surgery at the University of Minnesota, Minneapolis, USA. “The studies, which were well designed and well executed, were conducted at a combined 28 different centres on two different continents, yet the results are almost identical, which only further validates the effectiveness of the use of the iFuse triangular titanium implants for the treatment of patients with chronic SI joint dysfunction who no longer respond to conservative treatment.”

iMIA two-year results were published in the Journal of Bone and Joint Surgery (JBJS), which has an impact factor of 4.84, the highest among orthopaedic journals. According to a press release, “This publication, which is the 67th peer-reviewed iFuse publication, is an indication of the broad acceptance of SI joint surgery as an important topic of study in orthopaedics.”

“The publication of this Level 1 study in a prestigious orthopaedic journal such as JBJS is an important milestone signalling recognition of the sacroiliac joint, like all other joints in the human body, as a pain generator and acknowledgement of the high quality of evidence that supports iFuse as an effective minimally invasive procedure for patients with SI joint pain,” said Daniel Cher, vice president of clinical affairs at SI-Bone.

In the iMIA study, 103 subjects were randomly assigned to CM (n=51) or SIJF (n=52) between 6 June 2013 and 15 May 2015. At two years, mean low back pain (as measured on the Visual Analog Scale, or VAS) improved by 45 points in the SIJF group and 11 points in the CM group (mean difference between groups 34 points, p<0.0001). Mean ODI improved by 26 points in the SIJF group and eight points in the CM group (mean difference 18 points, p<0.0001). Parallel improvements were seen in leg pain and several quality of life measures.

Moreover, objective improvements were observed in SI joint function, including active straight leg raise test and a number of positive physical examination signs for SI joint pain. In the SIJF group, the prevalence of opioid use decreased from 56% at baseline to 33% at two years (p<0.01), while no significant change was observed in the CM group (47.1% and 45.7%). Subjects in the CM group who derived minimal benefit after six months of CM showed improvements in all measures similar to those originally assigned to SIJF after crossing over to surgery. One case of postoperative nerve impingement occurred in the SIJF group.


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