Why is testing for equinus in cerebral palsy best performed under general anesthesia?

• A. Because the spastic nature can make awake ROM unreliable
• B. Because anesthesia reduces pain
• C. Because it helps visualizing bone
• D. Because it is faster

Answer: (A)

In cerebral palsy, the amount you can move the ankle into dorsiflexion when the patient is awake is heavily influenced by spasticity and involuntary muscle activity, so the measured range can be unreliable. Under general anesthesia, the muscles are relaxed and neural input is minimized, allowing you to assess the true passive length of the plantarflexor group without spastic resistance. This helps distinguish whether equinus is mainly a dynamic, spastic problem or a fixed, structural contracture. If dorsiflexion improves under anesthesia, spasticity is the key contributor and the plan may focus on addressing the dynamic component; if there’s little or no improvement, a fixed contracture is present, guiding surgical decision-making. The other choices don’t address why anesthesia clarifies the true passive ROM in CP.