Innominate segment deformation during passive hip abduction and external rotation

Area of Science:

• Biomechanics
• Orthopedics
• Kinesiology

Background:

• Electromagnetic palpation-digitization measures innominate motion using innominate vector length in neutral (NEUT) and hip abduction and external rotation (HABER) positions.
• The innominate vector length (anterior superior iliac spine to posterior superior iliac spine) may deform, potentially causing errors in innominate rotation measurements.

Purpose of the Study:

• To investigate if significant deformation occurs in the innominate vector length when the hip is loaded into the HABER test position.

Main Methods:

• A cross-sectional study involved 16 healthy individuals and one tester.
• Four pelvic landmarks (left and right ASIS and PSIS) were digitized using a 3D Polhemus electromagnetic tracking device.
• Measurements were taken in NEUT and 50° HABER hip positions, calculating innominate vector lengths for each.

Main Results:

• Paired t-tests showed no statistically significant differences (p > 0.05) in innominate vector lengths.
• This applied to both the loaded and opposite innominate sides, regardless of whether the right or left hip was loaded.

Conclusions:

• No significant bone deformation was observed in the innominate segment during the HABER test position.
• The findings support the reliability of the electromagnetic palpation-digitization technique for measuring innominate motion.