Back (Lumbar)
Sacroiliac Joint Dysfunction
천장관절 기능장애
Buttock pain from inflammation or instability of the sacroiliac joint
- How common
- Common (15–30% of chronic low back pain)
- Typical age
- Ages 20–50, postpartum women
What is it?
Pregnancy, trauma, or asymmetric loading causes SI joint inflammation or hypo/hypermobility leading to pain.
Commonly affected: Lower SI joint and posterior ligaments most affected
How it develops
- Altered Joint LoadTrauma or pregnancy stretches ligaments or increases load
- Ligament Laxity / InflammationLigaments become lax or inflamed
- Joint MalalignmentAsymmetric SI motion provokes pain
- Chronic DysfunctionRecurrent irritation, muscle compensation
Symptoms
- Unilateral Buttock PainFocal pain over PSIS (posterior superior iliac spine)
- Transitional PainSevere pain with sit-to-stand transitions
- Groin/Thigh ReferralPain referred to groin or posterior thigh
- Unilateral Weight AvoidanceAvoids bearing weight on painful side
How it is examined
- FABER TestHip flexion-abduction-external rotation reproduces pain
- Thigh Thrust TestPosterior thigh compression reproduces pain
- Gaenslen TestHanging-leg stress provokes SI pain
- PSIS TendernessTenderness just inferior to PSIS
Imaging
Pelvis AP X-ray excludes fracture and assesses SI shape.
- Normal or irregular SI space
- Often normal X-ray
- Exclude inflammatory sacroiliitis
MRI assesses sacroiliitis and bone marrow edema.
- SI bone marrow edema (STIR)
- Capsular edema
- Differentiate from AS
Non-surgical care
- PT / Pelvic StabilizationCore and pelvic muscle training
- NSAIDs + HeatShort-term NSAIDs with heat therapy
- SI BeltPelvic stabilization belt, esp. postpartum
- Intra-articular Steroid InjectionImage-guided SI joint injection
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
6-month conservative failure, positive diagnostic block
Procedures that may be discussed
- SI joint radiofrequency ablation
- Minimally invasive SI fusion (iFuse)
Outlook
Most improve with rehab and injections.