Differences in standing and forward bending in women with chronic low back or pelvic girdle pain: indications for physical compensation strategies.

STUDY DESIGN: This cohort study compares motion characteristics during forward bending of a group of chronic female patients either with low back pain (LBP) or pelvic girdle pain (PGP) and healthy subjects using computer-video analysis.

OBJECTIVE: This study determines whether subcategories of back pain patients could be distinguished by motion characteristics of the pelvis and lumbar spine.

SUMMARY OF BACKGROUND DATA: Compared with healthy subjects, patients with low back pain bend forward in distinct manners. Clustering these motion patterns into specific patient subgroups has been challenging since a basis for subcategorizing was lacking. Chronic LBP can be distinguished from PGP using specific evidence-based diagnostic tests. This allows comparing the motion characteristics of subgroups of chronic patients with either LBP or PGP.

METHODS: Forward bending was recorded in both female patients groups and healthy female individuals, using a computer video analysis system. Trunk motion, pelvic tilt, and lumbar lordosis are represented as sagittal plane angles. From these angles, the relative contribution of the lumbar spine and hip joint to forward bending can be derived.

RESULTS: Specific and discriminating motion characteristics were found between groups. During erect stance in the PGP group, the pelvis is significantly tilted backwards. At maximally forward bending, the ROM of the trunk is limited in all patient groups, but only the PGP group has significantly limited hip motion. During the initial part of forward bending, lumbar motion is increased in PGP patients and decreased in LBP patients. In the final part of forward bending contribution of the lumbar spine is increased in both patient groups.

CONCLUSION: BP and PGP patients show specific, consistent, and distinct motion patterns. These motion patterns are assumed to be functional compensation strategies, following altered neuromuscular coordination.