Assessing Quadriceps Femoris Muscle Bulk with-Girth Measurements in Subjects with Patellofemoral Pain.

This study was conducted to determine the validity of estimating quadriceps femoris muscle bulk with girth measurements in individuals with chronic unilateral patellofemoral pain. Testing included measurements of thigh girth and B-mode ultrasound scans of quadriceps femoris muscle thickness in 26 males and 18 females. Comparison of the control and symptomatic limbs demonstrated significant reductions in muscle thickness in both the male (p < 0.000) and female (p < 0.007) subjects. No significant differences were noted at either the midthigh or suprapatellar girths between limbs, except in the male subjects at the midthigh site (p < 0.006). Estimating muscle atrophy with girth measurements was more accurate in the male versus the female subjects. Clinicians should realize that very small reductions in thigh girth (1%) may be an indicator of significant reductions in muscle bulk (13%), in individuals with prolonged joint pain and disability. Even though the assessment of quadriceps muscle atrophy with girth measurements is somewhat inaccurate, girth measurements probably remain clinically useful. J Orthop Sports Phys They 1987;9(5):177-183.