“They can sense your emotions and feelings,” he said, patting a mustang. “If you are tense, they are going to be tense. If you are anxious, they are going to be anxious. Especially, if you are in pain, they are going to sense you are in pain as well.”

A Permanent Companion

In recent years, insurers have started cracking down on doctors who overprescribe narcotics. But it is not clear when, or if, they will embrace alternative pain treatments. Critics of the military and the Department of Veterans Affairs say the pace of change in those organizations has been too slow.

At bases like Fort Hood, soldiers like Sergeant Savage can spend years heavily medicated while awaiting a medical discharge, Ms. Savage said.

“I call it purgatory — you are not in heaven, and you are not in hell,” she said. “I can go in there and I can immediately spot people that are on narcotics or on drugs.”

Changing how doctors practice is not easy, but experts like Dr. Spevak and Dr. Seal are trying to push alternatives to opioids further down the chain of treatment so that patients will get them more quickly after an injury. Dr. Spevak, for example, said he expected this year to give 130 lectures about such techniques to military doctors working worldwide.

In January, Sergeant Savage underwent another operation to reconstruct his foot. He took narcotic painkillers for only a few days, and initially the procedure appeared to have stabilized his foot and reduced his pain. Then, that procedure also failed. Now, after four years of struggle, Sergeant Savage plans to undergo an amputation of part of his left leg, from the midcalf down. He’ll use a prosthetic device in place of the missing limb.

His commanders at Fort Hood recently nominated him for an honor known as the Meritorious Service Medal in recognition of his volunteer work. He expects to leave the Army by the end of this year or in early 2015. Once that happens, he said, he hopes to find a job that will allow him to spend most of his time outdoors, such as running a therapy program for other veterans.