Hip adductor muscle injection is a useful diagnostic and therapeutic procedure for myofascial pain.
After informed consent is obtained, the patient is placed in the supine position and the affected limb flexed, adducted, and externally rotated. The adductor longus, adductor brevis, and adductor magnus are palpated along the medial aspect of the humerus and thigh. The injection sites are identified as points of maximal tenderness to deep palpation, reproducing the patient’s pain complaint. This may or may not result in referred pain. The patient is prepared in a standard aseptic fashion over an area large enough to allow palpation of landmarks, and sterile technique is used throughout the procedure. A 1½-in. (4-cm), 21- to 25-gauge needle is inserted at the point of maximal tenderness and advanced to the area of the trigger point. After negative aspiration, the trigger point area is injected with 4 mL of local anesthetic (Fig. 67-32).
FIGURE 67-32. Hip adductor trigger points and referred pain patterns.
The referred pain pattern for the adductor muscles of the hip often involves the proximal hip, medial thigh, anterior thigh, and knee. The patient should be fully familiar with the stretching program for the adductor muscle and be instructed in a home program. Failure to include a home stretching program usually results in short-term relief.
Significant complications are uncommon with hip adductor trigger point injections.