by Emily Kraus, MD, PM&R Sports Medicine Physician, Department of Orthopaedic Surgery, Stanford University
Low back and buttock pain is a common and frustrating ailment in runners, athletes, and even the general population. Identifying the exact pain generator is often challenging, but sacroiliac joint (SIJ) pain and dysfunction is one possibility. The SIJ has gained recent interest in the running community due to several elite athletes withdrawing from the prestigious Boston Marathon (Sara Hall and Dathan Ritzenhein) due to SIJ issues. What is this special joint and why is it sidelining top runners? The purpose of this article is to help you understand basic SIJ anatomy including how it could be such a nagging source of pain, and what you should do if you think SIJ pain may be thwarting your own running goals.
To truly understand the anatomy and function of the SIJ, we must first discuss the pelvis and spine. The pelvis is a stable ring made up of three joints: the two sacroiliac joints and the symphysis pubis (Figure 1). The SIJ connects the sacrum (part of the spine) to the pelvis and plays the important role of absorbing the multidirectional stresses and loads between the spine and pelvis. Several muscles attach to the SIJ, such as the gluteal muscles, while others play a key role in overall stability and motion of the pelvis, such as the piriformis, hamstrings, deeper pelvic muscles, abdominals, hip flexors, and muscles of the lumbar spine. Several of these muscles are illustrated in Figure 2.
Although the SIJ is a true “joint,” it’s different than the ankle or hip joint, with the overall motion being limited to around 2 degrees of rotation and less than a millimeter of movement forward and backward. These numbers may sound minimal, but if the joint becomes hyper- or hypomobile or gets loaded excessively, this can lead to SIJ pain and dysfunction.
Why do runners get SIJ dysfunction?
During running, the pelvis absorbs the shock and load from the legs and transmits this load into the sacrum and up the spine. If the muscles of the hip, spine, and pelvis aren’t providing enough stability (i.e., muscles are weak or firing at the wrong time) or when the ligaments are lax due to hormonal changes (i.e., during pregnancy) the SIJ may go into a hypermobile state. Conversely, a hypomobile state may occur if these muscles are excessively tight or if the joint is restricted due to arthritic changes.
Runners may complain of an achy low back pain which can often be pinpointed to a single location at the sacral sulcus (Figure 3) or it may radiate/shoot to the lower glute, back of the leg, outer thigh, or groin. The pain is often worse with running, climbing stairs, or standing from a seated position. Asymmetric “shearing” motions, such as during use of a stair-stepper or running up/down steep hills, may also exacerbate the pain.
Making the Diagnosis
SIJ dysfunction is a less common cause of low back pain, thus a thorough physical examination is key in making the correct diagnosis. A list explaining other potential causes is provided in the table below. Especially in distance runners, sports medicine physicians should consider stress fracture/reactions to the sacrum and do the appropriate diagnostic testing to rule this injury out. Check out my previous article on sacral stress fractures for more details.
|Other Causes of Low Back and Buttock Pain|
|Injury or Disorder||Description|
|Lumbar Disc Herniation||A disc herniation of the lower lumbar spine can lead to both localized pain and referred pain into the buttocks|
|Spondylolysis||A less common cause of acute SIJ pain with associated fevers and inflammation.|
|Sacroiliitis||A disc herniation of the lower lumbar spine can lead to both localized pain and referred pain into the buttocks|
|Ankylosing Spondylitis||A rheumatologic condition which usually presents as chronic, dull pain in the back, hip, and buttock usually accompanied by morning stiffness (<30 min) which improves with activity|
|Sacral Stress Fracture||Presents as a dull ache in the area of the sacrum with radiation to the glutes, which worsens with walking, running, or hopping. Often seen with an increase in training volume or intensity.|
|Piriformis Syndrome||Another rare, often controversial, diagnosis which usually involves irritation or compression of the sciatic nerve by the piriformis muscle|
Diagnostic work-up for SIJ dysfunction may include imaging such as x-ray, magnetic resonance imaging (MRI), computed tomography (CT), and single-photon emission computed tomography (SPECT), which is a special type of CT scan. To confirm the SIJ is the pain generator, fluoroscopically-guided (via x-ray) injections into the joint can be performed. If concern for infection or an inflammatory or rheumatologic component such as sacroiliitis, additional lab work-up is indicated.
The Treatment Strategy
Once an underlying diagnosis of SIJ dysfunction has been made, the mainstay of treatment is a comprehensive rehabilitation program tailored to the runner. This should include a combination of relative rest or activity modification and rehabilitation focused on strengthening, mobilization, and addressing the underlying issue, whether it’s muscle imbalances, improper training, poor recovery, or even an anatomic issue such as a leg length difference. A biomechanical running evaluation may shed light on compensatory strategies that are overloading one or both joints and can help direct the rehab approach.
Sara Hall noted that while each case is different, for her, the best form of cross training during her injury recovery has been the spin bike.
Manual therapy may play an adjunctive role in management of SIJ dysfunction, but the treatment should be performed by an experienced sports specialist (i.e., sports osteopath, chiropractor, physical therapist, or athletic trainer) and should not be the sole treatment modality.
Depending on how severe and acute the pain is, a short course of non-steroidal anti-inflammatory drugs (NSAIDs) may help with pain control. Therapeutic injections with corticosteroid into the SIJ may be beneficial if symptoms are refractory to more conservative measures. Lastly, bracing may also be helpful in certain situations, for example throughout pregnancy, but is not recommended for most cases.
Return to Running
If symptoms are mild, some athletes may be able to continue running with modifications, such as changing the terrain (less hills or less technical), reducing mileage, decreasing intensity, while also addressing the underlying issue(s) with a comprehensive rehabilitation approach (this is key). If more severe, trying to “run through the pain” could be detrimental and may lead to faulty movement patterns. In these cases, dedicating time to healing and rehabilitation is essential. Exact time to return to running is quite variable and depends on the severity of pain and extent of underlying functional deficit.
As far as prevention, start with training smarter, not harder. Respect the recovery. Avoid drastic increases in running mileage, intensity, or change in terrain. And remember that training is more than just running. Core, glute, and leg strengthening to stabilize the spine and pelvis can play a critical role in keeping runners healthy, happy, and injury-free!
Disclaimer: This blog is for informational purposes only. Doctors cannot provide a diagnosis or individual treatment advice via e-mail or online. Please consult your physician about your specific health care concerns.
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