In the early 20th century, the SI joint was thought to be the main source of low back pain and was the focus of many scientific investigations. In 1934, a published study by Mixter and Barr on rupture of the intervertebral disc quickly changed the direction of these investigations. Over the next four decades, the SIJ was more or less ignored in favor of the disc as the primary cause of back pain.
This resurgence of interest in the SI joint since the 1970s can be traced to the following:
1. A failure of disc resection, and subsequent desperation-measure fusions, to relieve low back pain in a considerable percentage of patients.
2. The recognition of the short- and long-term complications of chymopapaine ‘discectomy’.
3. The evolution of the computed tomography scan and subsequently magnetic resolution imaging, with a recognition of the fact that disc protrusions were common but did not necessarily cause back pain (Magora & Schwartz, 1976).
More recently, interest in rehabilitation involving the SI joint may be attributed in large part to two factors:
1. The recognition the approximately 20-30% of low back pain and referred pain comes from the SI joint itself and/or the surrounding ligaments, muscles and other soft tissues involved in the functioning of the joint, (Maigne et al, 1996, Schwarzer et al, 1995).
2. The international forum for ongoing research on the SI joint and the lumbo-pelvic-hip unit, provided by the Interdisciplinary World Congress on Low Back Pain and its Relationship to the Sacroiliac Joint (San Diego 1992 and 1995, Vienna 1998, and Montreal 2001).
These factors have led to the development of two of the newest theories:
First, the theory of rotational malalignment known today as the Malalignment Syndrome which includes: SI joint upslip/downslip (superior/inferior shear), sacral torsion (hip anterior/posterior rotation), hip outflare/inflare (lateral/medial rotation), (Schamberger, 2002, 2006). Diagnosis of these syndromes is pretty straight forward, as is the treatment/correction of each.
Second, for the past 15 years, a well-known group of PTs, Chiropractors, and Strength/Conditioning Specialists have been developing a newer theory that is known as the Joint-By-Joint Approach. This theory is based on understanding the primary role of the different major joints.
Of course all joints need a combination of mobility and stability, but interestingly, each joint displays a predominant need for either mobility or stability. If we start from the bottom, here’s what it looks like.
Ankles – mobility
Knees – stability
Hips – mobility
Lumbar Spine – stability
Thoracic Spine – mobility
Scapulae – stability
Shoulders – mobility
Cervical Spine (C7-C3) – stability
Cervical Spine (C2, C1) – mobility
Think of mobility as quantity (freedom to move) and stability as quality (resistance to movement). When we move, our CNS chooses mobility before stability. In other words, if a joint that predominantly requires mobility reaches a mobility barrier, the surrounding joints will give up their stability to accomplish the mobility requirement. This appears to be an involuntary survival technique that is controlled by the central nervous system.
For instance, the hips require mobility. When the CNS percieves a lack of mobility (the first mobility barrier) in movement, the lumbar spine automatically relinquishes its stability to accomplish the hip mobility requirement. The relinquishment of this stability opens the door to injury/inflammation/pain at the lumbar spine, most often at L5/S1.
The key here is to increase mobility at the hips so that the lumbar spine can maintain its stability.
The treatment involves first, correcting the tissue extensibility dysfunction at the hips (lack of mobility) and second, restoring the dysfunctional movement pattern of the lumbar spine (core stability). In this case, mobility (think structure) must precede stability (think function). But, even more important is the understanding that the functional stability of core stabilization is pattern specific. What we think of as traditional core work will be both inappropriate and ineffective. You must utilize a technique known as corrective functional movement training. (This is the pattern-specific core stabilization work.) This whole process can sometimes be accomplished in as little as two weeks.
Schamberger, Wolf. The Malalignment Syndrome. Churchill Livingstone, Elsevier Science Limited (2002, 2006).
Boyle, Michael. Advances in Functional Movement Training. On Target Publications, Santa Cruz, CA (2010).
Cook, Gray. Movement: Functional Movement Systems. On Target Publications, Santa Cruz, CA