Phelps Test

What is the "Phelps Test" used for?

• Assess contracture of the gracilis muscle
• Differentiate whether limited hip abduction is caused by muscular tightness rather than joint pathology

How to perform the "Phelps Test"?

• The patient lies prone on the examination table. The knees remain fully extended.
• The examiner first passively abducts both legs as far as possible while the knees are extended.
• Next, the examiner flexes both knees to 90°.
• With the knees flexed, the examiner again attempts to abduct the hips further.

What is the positive result?

• Positive Phelps’ Test: If hip abduction increases after the knees are flexed to 90°, the test is positive. This indicates a contracture of the gracilis muscle, as flexing the knees relaxes the gracilis and allows greater abduction.
• Negative Test: If hip abduction does not improve, the limitation is likely due to other structures—possibly the adductor longus, adductor brevis, joint pathology, or capsular tightness.