Does back pain on single stance indicate Quadratus Lumborum (QL) involvement, especially with Sacroiliac Joint (SIJ) tenderness and Thoracolumbar (TL) junction tenderness?

Back Pain on Single Stance: Quadratus Lumborum Involvement in Sacroiliac Joint Pain

Back pain on single stance, especially when accompanied by sacroiliac joint (SIJ) tenderness and thoracolumbar (TL) junction tenderness, strongly suggests quadratus lumborum (QL) muscle involvement as part of the pain mechanism.

Relationship Between QL and SIJ Pain

• The quadratus lumborum muscle plays a significant role in stabilizing the spine during single-leg stance, and dysfunction can manifest as pain during this maneuver 1
• Recent research demonstrates that QL dysfunction often accompanies SIJ pain, with the muscle acting in a compensatory mechanism when there is SIJ dysfunction 1
• When SIJ pain is present, there is frequently associated muscle imbalance involving not only the gluteus medius but also the quadratus lumborum 1, 2

Clinical Assessment for QL Involvement

• Pain on single-leg stance that reproduces the patient's symptoms is a clinical indicator of possible QL involvement, especially when combined with tenderness at the TL junction where the QL has attachments 2
• The thoracolumbar junction (T12-L1) is one of the most common sites of spinal involvement in patients with axial pain syndromes, which may explain the tenderness in this region 3
• When SIJ tenderness is present alongside TL junction tenderness, this pattern suggests a functional connection between these regions, often mediated through the QL muscle 1

Diagnostic Considerations

• SIJ pain is present in approximately 15-30% of patients with chronic low back pain, but neither medical history nor physical examination maneuvers alone can reliably diagnose SIJ as the primary pain generator 3
• When evaluating patients with suspected SIJ dysfunction, it's important to consider that the QL may be involved as either a primary pain generator or as part of a compensatory mechanism 1, 2
• The presence of three or more positive SIJ provocative tests (Patrick's Test, Thigh Thrust, Gaenslen's Test, Distraction, Compression, and Sacral Thrust) provides a sensitivity of 94% and specificity of 78% for SIJ pain 3

Treatment Implications

• Treatment approaches that target both the SIJ and the QL muscle show better outcomes than those addressing only one component 1
• Muscle energy technique applied to the quadratus lumborum in combination with gluteus medius strengthening has been shown to be more effective in improving pain, disability, and quality of life compared to conventional treatment of SIJ dysfunction 1
• Bridge exercises, particularly side bridge with hip abduction, effectively activate both anterior and posterior layers of the QL muscle and can be beneficial in rehabilitation programs 4

Clinical Pearls and Caveats

• Pain on single-leg stance is not pathognomonic for QL involvement alone and should be interpreted within the context of other clinical findings 2
• QL stiffness assessment can provide valuable clinical information, as greater muscle softness (reduced stiffness) is associated with higher pain intensity and poorer physical quality of life in patients with low back pain 5
• When treating patients with SIJ pain and suspected QL involvement, a comprehensive approach addressing both structures yields better outcomes than focusing on either component alone 1, 6

In patients presenting with the clinical triad of SIJ tenderness, TL junction tenderness, and pain on single-leg stance, clinicians should strongly consider QL involvement in the pain mechanism and incorporate specific QL-targeted interventions in the treatment plan 1, 2.