Paper of the month February 2023

Double-center observational study of minimally invasive sacroiliac joint fusion for sacroiliac joint dysfunction: one-year results. J Orthop Surg Res. 2022 Dec 28;17(1):570.

Hermans SMM, Knoef RJH, Schuermans VNE, Schotanus MGM, Nellensteijn JM, van Santbrink H, Curfs I, van Hemert WLW

This is an industrial independent report from Netherland.

Dr. Hermans and his colleague, Dr. Knoef research well about the SIJ problems in patients with Ehlers Danlos Syndrome (ESD).  ESD is one of the etiologies for which SIJ fusion is indicated, but I have no experience with it yet.

An acetabular dysplasia of the hip is more frequent in Japan. I was informed by a colleague of mine, a hip surgeon, that many patients with acetabular dysplasia have loose joint capsules and surrounding ligaments. Perhaps there is a subtype of ESD-like condition (loose SIJ) in patients with an acetabular dysplasia.

I am concerned that using iFUSE implants in people with loose joints may cause implant loosening, but in this paper, the cases with implants loosing were not ESD, and Dr. Knoef reports that SIJ fusion using iFUSE seems to be effective in cases of ESD.

I asked the author of this paper as below. He kindly replied to my questions.


Is there substantial vacuum phenomena in the SIJ of ESD patients? In other words, is there any objective way to assess the loosening of the SIJ itself?


EDS: vacuum phenomena is no more often seen in EDS patients comapred to other patients. Maybe we need larger cohorts to find significant differences.


You had two cases in your paper that are requiring revision surgery. What is your revision strategy?


Revision strategy:

We aim to remove the loose implants and place new implants in an additional trajectory. When there is no sufficient additional trajectory available, the new implant will be rotated to ensure proper fixation.

Dr. Hermans, thank you so much for sharing your SIJ expert opinions with us.

Daisuke Kurosawa

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