PT Classroom - SI Joint "Simplified" ׀ by Steve Bayer, MSPT, ATC, CSCS, FAAOMPT

The role of the sacroiliac joint (SIJ) in low back pain is often filled with controversy and confusion. Medical schools in the not-so-distant past taught students that the SIJ “doesn’t move”, yet more recent studies confirm there is movement at these important joints. Many physical therapy schools and continuing education programs spend much time instructing therapists in very detailed, and sometimes very complex, systems or approaches to evaluate and treat sacroiliac joint dysfunction (SIJD). These approaches utilize tests that rely on palpation and assessment of joint movement, yet most research on these tests conclude the tests themselves are not reliable or yield conflicting findings. This leads many clinicians to become confused and frustrated when assessing the role SIJD might be playing in their patient’s symptoms. However, SIJ problems are prevalent, and your patient is standing there in front of you with obvious pain and dysfunction, so what should you do? How can you determine if dysfunction at this joint may be contributing to, or is the sole cause of their problem? Taking a more basic or “simplified” approach to evaluating and mobilizing the SIJ using a very basic joint manipulation as part of your treatment plan may be the clinician’s best and most productive option.

SIJ Function

The sacroiliac joint plays a key role in transferring load between the trunk and the lower extremities by functioning as a “stress-relieving” joint. In engineering this is called an “expansion joint”, much like the expansion joints utilized between sections of bridges, sidewalks or railway tracks as shown below.

The key features of an expansion joint are that it must have stability, while at the same time allowing some mobility. The SIJ must fulfill this role by being strong and stable enough to transmit forces between the vertebral column and the legs, while at the same time allowing movement on the pelvis from twisting forces through the legs, but not too large of an amplitude of motion.

Stability of the SIJ is achieved through 2 mechanisms: form closure and force closure. Form closure occurs between closely fitting joint surfaces where the stability is generated by compression. It relies on the shape of joint and ridges/grooves in the joint surfaces to help resist gliding, along with the integrity of the bones, joints and ligaments that make up the SIJ. Because of its structure and orientation to gravity in the standing position, it is well suited to transfer large moments of force, but is vulnerable to shearing. Since the ligaments alone are not enough to tolerate shearing forces of heavy loads, or especially during sustained positions (due to ligament creep), the SIJ also relies on force closure, which is external factors that increase inta-articular compression and stability. This is achieved by an optimally-functioning myofascial system that can be divided into 2 groups:
• The local muscle system, which is comprised of the pelvic floor, transverse abdominus, and multifidus muscles.
• The global muscle system, which is 4 integrated “slings” of muscles:
1) Posterior oblique sling: latissimus dorsi, thoracolumbar fascia and contralateral gluteus maximus.
2) Anterior oblique sling: external oblique, and contralateral internal oblique and adductor muscles.
3) Longitudinal sling: erector spinae, thoracolumbar fascia, biceps femoris.
4) Lateral sling: Gluteus medius, Tensor Fasciae Latae.

SIJD Pain Patterns/Locations:
SIJ dysfunction, or dysfunction at any joint for that matter, can be categorized in one of two basic biomechanical classifications: hypomobility (a joint that lacks adequate joint motion or mobility), or hypermobility (a joint that has excessive motion/mobility). Keep in mind that each of these dysfunctions can occur with or without the presence of pain at the particular time of examination, as the joint can become dysfunctional before it becomes painful. Additionally, SIJD pain can be referred to multiple areas, due to the complex innervations of the SIJ’s capsular and ligamentous structures. These areas include the lumbar spine, groin, lower abdomen, buttock(s), and the posterior thigh. Also keep in mind that although posterior lower extremity pain below the knee is not usually of SIJ origin, it some instances it can be. Finally, pain can sometimes occur on the opposite side of the joint dysfunction, with potential aggravating activities including walking, running, climbing stairs, transitional movements (e.g. sit-to-stand), prolonged standing, and sitting cross-legged or with a leg underneath you. Therefore, given the above-mentioned purpose of the SI joint, the potential presence of SIJD before SIJ pain occurs, and it’s potential pain referral patterns, evaluation (and treatment) of the SI joint should be done regardless of where pain originates in lumbo-pelvic complex! In other words, we should be evaluating for the presence of SIJD in all lumbar patients, hip patients, and lower extremity “repetitive use” injuries if we are to be truly effective clinicians.

SI Joint mobility:
A systematic review of the literature published by Goode, et al in 2008 involved studies that measured 3-dimensional movement of the SI joint (1). They concluded there are 2 motions that occur at the SIJ: rotatory and translatory. The amount of rotation that occurs was measured at 1-8 degrees (around any axis, and irregular in direction), and the amount of translation that occurs was measured at 0-8 mm (along any axis, and irregular in direction). They also concluded that the amount of motion was variable between subjects, but within one subject it should be symmetrical between the right and left sides. These conclusions wouldn’t make sense if the joint was for primary movement (such as the knee or hip), but does make sense given the purpose of the SI joint, which again is to function as an expansion joint. However, the authors also concluded that they “feel this amount of motion may be sub-clinically detectable”, and “current clinical methods utilizing palpation for diagnosing SIJ pathology have been found to be unreliable and invalid in the literature and may have limited clinical utility”. Other authors have stated “Movements in the SIJ….are so minute that external determination by manual methods is virtually impossible” (2).

These same authors also state “Static and dynamic palpation has been repeatedly determined to be unreliable and invalid in the literature”, and that “Other studies examining SIJ clinical tests for palpation of motion and position also report varying results” (1). However, those studies utilized varying definitions of what was considered a “positive” test, and the examiners had varying levels of experience or expertise in orthopedic physical examination and treatment skills, with one “classic” study utilizing students to examine their subjects! These same studies and others have concluded that the only individual tests proven “reliable” for diagnosing SIJ pain are described or classified as pain provocation tests, in which manual forces are applied in different ways to the SIJ to attempt to reproduce pain at the joint, such as the Thigh Thrust test, Gaenslen’s test, and Compression and Distraction tests.

These conclusions are rather puzzling when you consider that this same conclusion has not necessarily been arrived at with stability testing for other joints in the body that are commonly used in an orthopedic physical exam. A prominent orthopedic physical examination textbook commonly utilized in orthopedic education programs for multiple professions lists the amount of “normal” available motion when performing the Anterior Drawer test of the knee as 6 mm (Positive test = >6 mm), while that same reference grades the amount of ligament injury detectable when performing a Lachman’s test on the knee based on joint mobility of as little as 3-6 mm of motion (3). These tests of the knee rely on similar small amounts of supposedly “sub-clinically detectable” motion, and also have been found to have very questionable inter- and intra-tester reliability, yet are widely accepted as legitimate examination techniques to evaluate the knee joint (4).

But again, your patient is standing there in front of you with obvious pain and dysfunction, so what should you do? If the only tests of the SIJ thought to be “reliable” based on the literature are ones simply intended to reproduce SIJ pain, how does this help direct your treatment, especially in situations where SIJD may be causing or contributing to their symptoms but currently is not the main source of their pain? The very effective approach I was fortunate to learn during my manual therapy residency and fellowship program (4) is as follows:
1.) Identify the presence of dysfunction, and the side on which the joint dysfunction is present, using a combination of motion and pain provocation tests, palpation and a thorough subjective history.
2.) Manipulate the side of dysfunction.
3.) Re-assess any positive or “asterisk” signs you found in your examination for any changes.

Identifying the presence of and side of dysfunction:
It is thought we can improve the accuracy of determining the presence of and the side of dysfunction using a cluster of tests and techniques. Cibulka (5) reported increased exam reliability, specificity and sensitivity by using multiple different SIJ exam techniques, along with palpation and thorough history. He defined SIJD as being present if at least 3 of the 4 following tests are positive:
1. Palpation of bony landmarks
2. Standing flexion test
3. Supine to long sitting test
4. Prone knee flexion (Deerfield) test

Other studies have either supported or disagreed with these findings when combinations of these same 4 tests were studied. However, a key component is that they were used in conjunction with palpation exam and a thorough patient subjective examination to arrive at their conclusions, as opposed to just the tests themselves. A good clinician knows to never base their entire conclusion on only one or two physical tests (would you jump to the conclusion that a patient has a meniscal tear based soley on the presence of a positive McMurray’s or Apley’s Compression test?).

Therefore, likely the best way to determine the presence of and side of dysfunction is to perform a series of examination techniques to help arrive at this conclusion. A good template of these techniques to follow is given below. Remember: don’t give too much weight to the results of any one individual test!

EXAMINATION
Standing:

1.) Lumbar AROM - Hypomobility:
• SIJD regularly produces pain and/or loss of ROM with single plane lumbar AROM (often into extension, and/or sidebending to same side).
• Be sure to ask the patient to specify the exact location of pain during the AROM (often localized to the SIJ area)

2.) Pelvic landmarks (mainly PSIS and iliac crests) – assessing for asymmetry in height.

3.) Standing flexion test – Patient bends forward while examiner palpates the PSIS bilaterally. When in dysfunction one PSIS will move sooner/further than the other.

Supine:

1.) Supine-to-long sitting leg length test: The patient lies supine with legs flat and shoes off. Even out their pelvis by distracting both legs. Palpate the distal edge of both medial malleoli (using your thumbs or index fingers) to assess for any asymmetry in leg length. Have the patient sit up with their legs flat and repeat this assessment.
• Positive = ANY asymmetry in length that changes (Long to short, long to even, etc.), especially if there is full crossover (short-to-long, long-to-short).
• A change from long to short is thought to indicate the presence of an anteriorly rotated iliac dysfunction on that side, and a change from short to long a posterior rotation.
• Skip the long-sitting portion of the test if patient is not appropriate to assume this position, with any asymmetry in supine alone indicating a “possible” positive.
• Clinical observation: Results can sometimes be skewed by hip flexor tightness, especially if ipsilateral.

2.) ASIS levels – assessing for asymmetry in height (superior/inferior)
• Be sure to use tips of your thumbs inferior to the edge of bony prominences

3.) Hip PROM – Assessing ROM, end-feel, and location of any pain reproduced.
a. Single Knee to Chest (SKC)
b. Hip IR/ER
c. Piriformis flexibility: Normal = Flex 90 degrees, ADD 20 degrees (midline), and IR 20 degrees
d. FABER (assessing ROM, but this is also a “pain provocation” test)

4.) Pelvic compression/distraction “pain provocation” tests

5.) Thomas test – one hip flexed to flatten the lumbar spine, other leg relaxed to table.
• Normal: hip flexion = 0 degrees, no hip ABD/ADD, and knee flexion = 75 degrees.
• Iliopsoas tightness and/or spasm often present with SIJD.
• Adding overpressure to the legs = pain provocation test
• A loss of only 10 degrees hip extension significantly affects pelvic position and force transmission!
• Can follow up with palpation of iliacus and psoas muscles to assess mobility/tenderness.

Prone:

1.) Prone knee flexion leg length (Deerfield) test: Patient lies prone with legs flat and shoes off. Even out their pelvis by distracting both legs. Bring feet close together in slight dorsiflexion and palpate the distal (plantar) edge of both heels to assess for any asymmetry in leg length, then bend their knees to 90 degrees and re-assess both heels.
• Positive = ANY asymmetry in length that changes (Long to short, long to even, etc.), especially if there is full crossover (short-to-long, long-to-short).
• Clinical observation: Results seem to be less skewed by hip flexor tightness.

2.) Pelvic landmark palpation asymmetries
a. PSIS levels – assessing for asymmetry in height (superior/inferior)
• Be sure to use tips of your thumbs inferior to the edge of bony prominences.
b. Sacral sulcii (anterior/posterior asymmetry)
c. Sacral inferior lateral angles (ILA) – lateral edges (superior/inferior asymmetry ) and posterior surfaces (anterior/posterior asymmetry)

3.) Ligament tenderness palpation – palpate inferior to PSIS; sacral sulcus; ILA

4.) Sacral P/A mobility – Assessing P/A mobility and pain at the ILA on the right vs. left

Although this template of assessment techniques appears lengthy, with practice it actually becomes a quick and easy portion of your lumbo-pelvic examination, and it gives you a wealth of information regarding the possible presence of dysfunction, which side appears to be hypomobile, and even possibly the specific “position” of the dysfunction (i.e. anterior vs. posteriorly rotated ilium, right vs. left sacral torsion, etc.) that is often taught in most SIJ courses. However, since the individual tests themselves may have “questionable” reliability and specificity, and since the tests can at times yield conflicting results (i.e. anterior vs. posteriorly rotated ilium), to simplify the process it is often best initially to just use a combination of this information to identify the side that currently appears to be in dysfunction, which is usually the hypomobile or “stuck” side.

Treatment:
Once this side has been identified, it can be quickly treated with a very basic technique often referred to as a prone leg pull manipulation. This technique is often taught to specifically treat the presence of an “upslip” of either ilium. However, it works very well as a general/overall SIJ manipulation to restore normal mobility and landmark symmetry on the involved side. This manipulation should be performed on the side of dysfunction (hypomobile side), even if it is the “long leg” side as determined by the leg length tests. There are 2 versions of this manipulation. The first one is performed with the assist of another person to stabilize the sacrum as the treating therapist performs a long axis distraction manipulation using the patient’s leg. The other version can be performed when another person is not available, where the therapist uses their hands to stabilize the sacrum and at the same time uses their thighs to provide the long axis thrust on the patient’s leg. Both versions are shown and detailed below:

Prone Leg Pull Manipulation – with assistant:
Patient prone. Assistant stabilizes the sacrum, with the force directed anterior and superior. Therapist holds distal tibia, with the hip in the closed-pack position (extension and internal rotation). Therapist applies a long axis distraction of the leg, then thrusts in caudal direction.

Prone Leg Pull Manipulation – no assistant:
Patient prone with their legs off the bottom edge of the table. Therapist stands over involved leg, holding patient’s leg in close pack position (extension and internal rotation) between therapist’s thighs. Use both hands to stabilize sacrum with pressure directed anterior and superior. Therapist performs long axis distraction of the leg, then thrusts in caudal direction by quickly extending his hips and knees.

Once the manipulation is performed, you should re-assess the leg length tests and pelvic landmark symmetry to see if the manipulation was successful for any immediate changes/improvements. If successful (i.e. those tests are now negative), other aspects of the examination that indicated a dysfunction may be present should also be re-assessed for any immediate change (sometimes referred to as an “asterisk sign”). This could include changes in hip PROM, pain provocation tests, or lumbar AROM. Any change for the better (decreased pain, increased motion) can be considered “clinical evidence” that SIJD is at least a component of the patient’s problem, and subsequent appropriate treatment techniques to correct contributing factors to the dysfunction (such as decreased hip flexibility, decreased local/global muscle system strength or motor control, etc.) should be incorporated. If there is no change or only partial improvement in these examination signs, you can then either re-assess to try and further determine the specific dysfunction using other assessment techniques, or perform different mobilization/manipulation/muscle energy techniques you have been taught that may be more specific to the dysfunction you think is present (such as a specific joint manipulation technique to correct an anterior innominate, posterior innominate, etc.). If the symptoms or other signs of lumbo-pelvic dysfunction still persist after, SIJD can likely be ruled out as a significant component of the patient’s problem, and further examination of the lumbar spine and hip is necessary.

While this approach alone won’t fix all forms of SIJD (e.g. chronic SIJ hypermobilities, pubic symphysis dysfunctions), the vast majority of sacroiliac joint dysfunctions that present in your clinic can be greatly improved using this “simplified” treatment approach.