Gastrocnemius injection is a useful diagnostic and therapeutic procedure for myofascial pain.
After informed consent is obtained, the patient is placed in a supine position. The gastrocnemius and soleus muscles are palpated from the knee to the ankle. 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. 67-33).
FIGURE 67-33. Gastrocnemius and soleus trigger points and referred pain patterns.
The patient should be fully familiar with the stretching program for the gastrocnemius muscle and be instructed in a home program. Failure to include a home stretching program usually results in short-term relief. The referred pain pattern for the gastrocnemius and soleus muscles often involves the posterior knee, calf, heel, and plantar aspect of the foot.
Significant complications are uncommon with gastrocnemius trigger point injections.