The purpose of the research project is to compare the effectiveness of non-thrust mobilization and exercise versus thrust manipulation and dry needling in patients with sacroiliac dysfunction. Physical therapists commonly use both approaches to treat sacroiliac joint dysfunction, and this study is attempting to determine if one approach is more effective than the other.

Patients with sacroiliac pain will be randomized to receive 1-2 treatments per week for 6 weeks (up to 10 sessions total) of either: 1. High-velocity, low-amplitude (HVLA) thrust manipulation and dry needling group, or 2. conventional physical therapy (Stabilization, force closure, motor control exercises and manual therapy) group.

Inclusion Criteria:

1. Patient must report sacroiliac dysfunction, defined as:

   • Pain of any duration (acute, subacute, or chronic) in the Fortin region (the pain may also project to the groin, thigh, lower leg and/or foot; however, it may only be local Fortin region pain in some subjects).
   • Pain does NOT centralize with repeated movements or sustained postures
   • A minimum of 3 positive pain provocation tests using either the Laslett et al. (2003, 2005) or van der Wurff et al (2006) multi-test regiments:
   • 3 or more of the following 6 pain provocation tests (Laslett et al, 2003, 2005):
   • Posterior thigh thrust
   • Gaenslen's test (right)
   • Gaenslen's test (left)
   • ASIS distraction
   • ASIS compression
   • Sacral compression

2. A minimum pain rating of 2/10 using the NPRS (Numeric Pain Rating Scale 0---10)

3. A minimum ODI score of 10/50 (i.e. 20% minimum on Oswestry Disability Index)

Exclusion Criteria:

1. Cauda Equina Syndrome
2. Neurologic presentation consistent with upper or lower motor neuron dysfunction due to spinal involvement (ie myelopathy or nerve compression, hyperreflexia, pathologic reflexes, depressed or absent reflexes in the lower extremities, motor weakness involving major muscle groups of lower extremity, unsteady gait, diminished or absent pin prick sensation in the legs and/or feet)
3. Spinal fractures
4. Currently pregnant
5. Co-existing medial problems / comorbidities (e.g., severe osteoporosis, tumors, inflammatory or infectious conditions, diabetes, angina, severe hypertension, RA, etc.)
6. Involvement in litigation of worker's compensation claim for low back
7. Physical therapy or chiropractic treatment for low back pain in the 3 months before initial examination
8. Any indication that might contraindicate spinal manipulative therapy.
9. Recent surgery to the lumbar or thoracic spine.