Why do we know so little about the SI joint?

Some relevant quotes I’ve found:

Dr. Stephen Esses (physiatrist):

“In the first part of the 20th century, sacroiliac (SI) joint syndrome was the most common diagnosis for lumbago (low back pain). Any pain in the low back, buttock, or adjacent leg was usually referred to as SI joint syndrome. Before 1932, SI joint syndrome was a particularly popular diagnosis. There was actually a period referred to as the “Era of the SI Joint.”

In the late 1980s, many physicians “rediscovered” the SI joints as a possible source of back pain. Yet even today, SI joint pain is often overlooked. Many physicians have not been trained to consider it. Many are still reluctant to believe a joint that has so little movement can cause back pain.”

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Interview with Dr. Carter Beck:

One of the things I liked most about this video is that Dr. Beck provided a source of context for why the medical field has overlooked the SI joint for so long.

As a patient who struggled for years to even find a doctor or a PT who knew what I was talking about when I mentioned sacroiliac joint dysfunction, it was incredibly validating for me to hear what Dr. Beck had to say.

According to Dr. Beck, the SI joint is “…one of the last joints that modern medicine has not really fully gotten a handle on.”

He explains that doctors did make some attempts to study and perform surgery on the SI joint decades ago.  However, our surgical procedures back then in general were much more crude– it was harder to be precise, and techniques were more invasive and much more likely to inflict damage on the body.

These initial SI joint surgeries failed to really provide any concrete relief to patients, so doctors moved their attention to pathologies of the spine itself, where their interventions were able to produce much higher levels of improvement.