Sacroiliac joint dysfunction can plausibly contribute to hip bursitis through a chain of biomechanical changes that alter how forces travel through the pelvis and into the hip. The connection is not a simple cause-and-effect relationship where one structure inflames another directly; it is an indirect pathway driven by altered gait, muscle weakness, and shifted loads. Making the picture more complicated, much of what people call “hip bursitis” turns out not to be bursitis at all, which matters for anyone trying to figure out whether their SI joint is really behind their lateral hip pain.
How the SI Joint Shapes What Happens at the Hip
The sacroiliac joint sits where the base of the spine meets the pelvic bones. Its main job is transferring the large compressive and bending forces from your trunk down into your legs whenever you stand, walk, or lift something.1PubMed Central. Biomechanics of the Sacroiliac Joint: Anatomy, Function, Biomechanics, Sexual Dimorphism, and Causes of Pain When the joint is stable and functioning well, it allows for smooth load transfer between the trunk and lower limbs during both standing still and moving around.2PubMed. Sacroiliac Joint Hypermobility Biomechanics and What it Means for Health Care Providers and Patients
When something goes wrong with the SI joint, whether it becomes too loose (hypermobile) or too stiff, that load-transfer system breaks down. The forces that should pass cleanly from the spine through the pelvis have to go somewhere else. Muscles around the hip and pelvis start compensating, some overworking while others underperform. This is where the hip starts getting dragged into a problem that originated one joint away.
The Gait Changes That Bridge SI Dysfunction and the Hip
Research on people with confirmed SI joint dysfunction shows measurable changes in how they walk. Compared to healthy controls, they tend to take wider steps, show reduced hip flexion and extension, have elevated pelvic motion, and sway more when standing.3North American Spine Society Journal (NASSJ). Effect of sacroiliac fusion on gait, standing balance, and pelvic mobility for unilateral sacroiliac joint dysfunction These are not subtle academic measurements. A wider stance and reduced hip range of motion mean the muscles and tendons around the hip joint are being loaded differently with every single step.
The greater trochanter, that bony bump on the outside of your hip, is the attachment point for several important muscles and tendons, and a fluid-filled bursa sits over it to reduce friction. When your gait changes, the angle and force with which tendons slide over that bump change too. Repeated abnormal loading is exactly the kind of mechanical irritation that can inflame a bursa or damage a tendon over time. The person feels pain on the outside of the hip and reasonably assumes it is a hip problem, not realizing the root cause may be the pelvis rocking or tilting differently because of an unstable SI joint.
Most “Hip Bursitis” Is Not Actually Bursitis
This is worth pausing on because it changes how you should think about the whole question. A large ultrasound study of 877 patients who came in with pain over the greater trochanter found that only about one in five actually had bursitis. Half had gluteal tendon degeneration (tendinosis), and nearly a third had a thickened iliotibial band. A small number had gluteal tendon tears.4PubMed. Sonography of greater trochanteric pain syndrome and the rarity of primary bursitis The clinical term that has largely replaced “hip bursitis” in orthopedic practice is greater trochanteric pain syndrome, which covers all of these conditions under one umbrella.
Why does this matter for the SI joint question? Because when SI joint dysfunction changes your gait and muscle recruitment patterns, the downstream effect at the hip is more likely to be tendon overload or IT band irritation than true bursal inflammation. Calling it “bursitis” and treating it with a cortisone injection into the bursa may give temporary relief, but if the underlying driver is a dysfunctional SI joint altering pelvic mechanics, the pain tends to come back. If you have been diagnosed with recurrent trochanteric bursitis that keeps returning despite treatment, a dysfunctional SI joint is one of the upstream causes worth investigating.
Gluteal Weakness Ties the Two Together
One of the clearest links between SI joint dysfunction and lateral hip problems is gluteal muscle weakness. A study of patients with confirmed SI joint dysfunction found significant weakness in the gluteus maximus on the affected side. After a targeted strengthening program over ten physical therapy visits, those patients saw measurable strength gains and reduced pain, and all were able to return to normal daily activities.5PubMed Central. Strengthening the Gluteus Maximus in Subjects with Sacroiliac Dysfunction
The gluteus maximus and gluteus medius are the primary stabilizers of the pelvis during walking. When the gluteus maximus is weak on one side because SI joint pain has caused you to guard that side or shift your weight away from it, the gluteus medius on that same side has to pick up the slack. The gluteus medius tendon inserts right at the greater trochanter. Overwork it, and you get tendinopathy. Overwork the structures sliding over the trochanter, and you can get bursitis. The SI joint dysfunction creates the weakness; the weakness creates the overload at the hip.
This also explains why treating only the hip often fails. Injecting the bursa, stretching the IT band, or even resting the hip does nothing to address the gluteal weakness, which itself does nothing to address the SI joint dysfunction that started the whole cascade. Patients bounce between providers, getting treatment for the symptom while the cause persists one joint upstream.
Leg Length Differences as a Shared Risk Factor
Sometimes SI joint dysfunction and hip bursitis are not linked in a neat cause-and-effect chain but instead share a common upstream driver. One of the most established is leg length inequality. Even a modest discrepancy in leg lengths creates pelvic obliquity, a tilt of the pelvis to one side, which stresses both the SI joint and the structures around the greater trochanter. Research has associated leg length inequality with low back pain, greater trochanteric bursitis, and degenerative hip disease, and the pelvic tilt it creates can also contribute to degenerative changes in the lumbar spine.6Seminars in Arthritis and Rheumatism. Rheumatic disease aspects of leg length inequality
In these cases, a person may develop SI joint pain and lateral hip pain at roughly the same time or in sequence, and assume one caused the other, when in fact both are downstream consequences of the same leg length discrepancy. This distinction matters for treatment. Addressing the SI joint alone would leave the leg length problem in place, and the hip pain would persist, and vice versa. A heel lift or orthotic correction that addresses the underlying asymmetry can help both problems simultaneously.
When Foot and Ankle Problems Feed the Chain
The biomechanical chain does not start at the pelvis; it starts at the ground. Flat feet, overpronation, and other foot mechanics issues can change pelvic alignment from below. Research on young adults with flatfoot found that wearing custom foot orthotics reduced pelvic tilt by supporting the foot arch, which in turn prevented the compensatory pelvic motion that flatfoot walking creates.7PubMed Central. Effects of wearing functional foot orthotic on pelvic angle among college students in their 20s with flatfoot If a collapsed arch is causing your pelvis to tilt, that tilt can stress both the SI joint and the lateral hip structures in the same way a leg length discrepancy does.
This is worth considering if you have both SI joint pain and hip pain and no one can find a clear structural cause for either. A foot and ankle evaluation that examines how your arches behave during walking, not just standing, can reveal a contributor that no amount of pelvic examination or hip imaging would pick up. Orthotics are inexpensive relative to injections or surgery, so this is often a reasonable early step.
SI Joint Surgery and Trochanteric Pain
Here is an ironic twist. In a randomized trial comparing SI joint fusion surgery to non-surgical management, trochanteric bursitis appeared among the procedure-related events in the surgical group.8PubMed Central. Sacroiliac Joint Fusion Using Triangular Titanium Implants vs. Non-Surgical Management: Six-Month Outcomes from a Prospective Randomized Controlled Trial While the numbers were small (four cases out of the surgical cohort), the finding underscores how tightly coupled the SI joint and the lateral hip are. Even a procedure designed to fix SI joint problems can temporarily provoke the hip, likely because of changes in how forces are distributed across the pelvis during the healing and adaptation period after fusion.
For patients considering SI joint fusion partly because they believe it will resolve their hip bursitis symptoms, this is a reality check. Fusion changes pelvic biomechanics in ways that can be beneficial long term but stressful in the short term. Most patients in that trial did improve in pain and function overall, but the appearance of new trochanteric symptoms in some patients shows that the pelvis does not rearrange its force distribution without a transition period.
How to Tell Which Problem Came First
If you have both SI joint pain and lateral hip pain, figuring out which is driving which is not always straightforward. A few clinical clues help sort things out:
- Location of the worst pain: SI joint pain typically centers over the dimples of the low back (the posterior superior iliac spines) and can refer into the buttock, groin, or back of the thigh. Greater trochanteric pain sits right over the bony prominence on the outside of the hip and often hurts most when lying on that side.
- Provocative movements: SI joint pain tends to flare with transitions like standing up from sitting, rolling over in bed, or climbing stairs on the affected side. Trochanteric pain is more likely to worsen with prolonged walking, crossing legs, or direct pressure.
- Response to targeted injection: A diagnostic injection of local anesthetic into the SI joint that eliminates the SI joint pain can clarify whether the hip pain is secondary. If the hip pain persists after the SI joint is numbed, the hip problem is more likely independent.
Many clinicians use a combination of physical examination maneuvers and, when needed, diagnostic injections to tease apart overlapping pelvic pain generators. The challenge is that both conditions share the same neighborhood of the body and can refer pain into similar zones. A thorough examiner will test the SI joint and the hip separately rather than attributing all pelvic-region pain to one structure.
Treating the Chain, Not Just the Link
The most effective approach to concurrent SI joint dysfunction and lateral hip pain treats the whole kinetic chain rather than targeting one structure. In practice, that usually means a combination of strategies:
- Gluteal strengthening: Targeted exercises for the gluteus maximus and medius address the muscle weakness that SI joint dysfunction creates and that predisposes the hip to overload. The evidence from SI joint dysfunction patients specifically shows that a structured strengthening program reduces pain and restores function.5PubMed Central. Strengthening the Gluteus Maximus in Subjects with Sacroiliac Dysfunction
- Pelvic stabilization: SI joint belts, manual therapy, and core stabilization exercises aim to restore normal SI joint mechanics so the gait abnormalities do not continue feeding the hip problem.
- Addressing asymmetry from below: If a leg length discrepancy or flat feet are contributing to pelvic tilt, orthotics or heel lifts correct the foundation so the structures above can normalize.
- Activity modification: Reducing activities that exacerbate both problems, such as prolonged single-leg stance or running on banked surfaces, gives the irritated structures time to calm down while rehabilitation addresses the root mechanics.
Injections into the trochanteric bursa can help manage acute flares, but they are a temporizing measure when the underlying driver is mechanical. If the SI joint dysfunction persists and the gait remains altered, the bursa or tendons at the hip will be re-irritated once the injection wears off. The same logic applies in reverse: injecting the SI joint without rehabilitating the gluteal weakness and correcting gait deficits leaves the hip vulnerable.
Why This Connection Gets Missed
The SI-joint-to-hip link gets overlooked partly because of how medical specialties are organized. A patient with lateral hip pain is likely to see an orthopedic surgeon who focuses on the hip, while a patient with low back and buttock pain may see a spine specialist. Neither may evaluate the other region thoroughly, especially if the patient presents with a complaint that fits neatly into one specialist’s domain. The gait and muscle weakness data suggest these complaints frequently co-occur, and treating one without evaluating the other leaves patients undertreated.
Another reason it gets missed is the “bursitis” label itself. Once lateral hip pain is labeled as bursitis, the treatment algorithm is familiar and comfortable: rest, anti-inflammatories, maybe an injection. The label discourages further investigation into why the bursa became irritated, which is where the SI joint connection lives. The ultrasound data showing that most greater trochanteric pain is not even bursitis makes this doubly problematic. A label that is often wrong to begin with gets used to close the diagnostic loop prematurely.4PubMed. Sonography of greater trochanteric pain syndrome and the rarity of primary bursitis
If your lateral hip pain has been treated multiple times without lasting improvement, it is reasonable to ask your provider to evaluate your SI joints. A physical therapist who performs a comprehensive pelvic and lower-extremity assessment can often identify the movement dysfunction connecting the two, even when imaging of the hip looks unremarkable. The evidence consistently points toward a biomechanical relationship between these structures, and acknowledging that relationship is often the first step toward treatment that actually sticks.