Final answer:
A limitation of Femoral nerve blocks is that they offer limited regional pain relief, do not cover certain areas of the leg, carry a risk of complications, and can cause quadriceps weakness.
Step-by-step explanation:
A limitation to using Femoral nerve blocks (FNB) is that they provide analgesia only to the anterior thigh and knee; they do not provide pain relief for injuries or procedures that affect the posterior or lateral aspects of the thigh, the lower leg, or the foot. Additionally, FNBs carry a risk of complications, such as infection, hematoma, and rarely, nerve damage. Moreover, FNB may lead to muscle weakness in the quadriceps, which can affect mobility and increase the risk of falls, especially in the elderly population or those with underlying mobility issues.