People suffering from severe bone and joint diseases live with pain every moment of their lives. For some, the only solution is a hip or knee replacement, an expensive procedure many around the world cannot afford. An American-based organization called Operation Walk is working to heal people from Tanzania, to Nepal to the United States, who would otherwise not be able to afford treatment.

"You're dealing with the pain constantly 24 hours a day you're getting no peace, " laments Steven McKellar. He is no stranger to pain.

McKellar suffered from osteoarthritis, a joint disease. The simple act of standing up was excruciating. He needed a double hip replacement but couldn't afford it because he didn't have health insurance.

"You just want to give up. You turn into yourself. You close off to the outside world. It is very depressing," he explains.

Operation Walk threw McKellar a lifeline. He had double hip replacement surgery free of charge. The pain he experienced for so long disappeared and so did his depression.

"He was standing tall. He was standing straight," says his wife, Vallie McKellar. "I saw him again, like I got my six-foot husband back again, and I could see the stress in his face had left."

Lawrence Dorr, an orthopedic surgeon in Los Angeles, performed the operation. He founded Operation Walk in 1996. It also provides free surgical treatment for poor people in developing countries including Nepal and Tanzania where people with bone and joint diseases face a stigma.

"If you're crippled, you are an outcast. If you're a woman, you can't get married, and if you're a man you can't get a job," notes Dorr.

Operation Walk went to Tanzania for the first time in June. Many people there have little hope for good medical care.

"There is a lot of poverty. There is a lot of discrepency between private medicine," explains Operation Walk surgeon Ammer Malik. He's from Kenya but practices medicine in Spain. "Maybe 85 percent of the population cannot access that kind of medicine."

Dr. Geoffrey Kibira of the Arusha Lutheran Medical Center says some patients in Tanzania were afraid of getting an artifical hip or knee.

"The problem, majority couldn't understand that you can put artifical things in the hip or the knee and walk again," the doctor says. "After seeing some of the patients improving walking and they are pain-free -- now people are coming."

Dorr says he sees change in many of the volunteer doctors and nurses who help patients in developing countries.

"They realize they can do things they didn't even know they can do," he says. "And they can help people even better than they ever thought they could. And it changes them; it changes them for the good."

Dorr adds that for these volunteers, it becomes a calling that gives meaning to their lives.

People suffering from severe bone and joint diseases live with pain every moment of their lives. For some, the only solution is a hip or knee replacement, an expensive procedure many around the world cannot afford. An American-based organization called Operation Walk is working to heal people from Tanzania, to Nepal to the United States, who would otherwise not be able to afford treatment.

"You're dealing with the pain constantly 24 hours a day you're getting no peace, " laments Steven McKellar. He is no stranger to pain.

McKellar suffered from osteoarthritis, a joint disease. The simple act of standing up was excruciating. He needed a double hip replacement but couldn't afford it because he didn't have health insurance.

"You just want to give up. You turn into yourself. You close off to the outside world. It is very depressing," he explains.

Operation Walk threw McKellar a lifeline. He had double hip replacement surgery free of charge. The pain he experienced for so long disappeared and so did his depression.

"He was standing tall. He was standing straight," says his wife, Vallie McKellar. "I saw him again, like I got my six-foot husband back again, and I could see the stress in his face had left."

Lawrence Dorr, an orthopedic surgeon in Los Angeles, performed the operation. He founded Operation Walk in 1996. It also provides free surgical treatment for poor people in developing countries including Nepal and Tanzania where people with bone and joint diseases face a stigma.

"If you're crippled, you are an outcast. If you're a woman, you can't get married, and if you're a man you can't get a job," notes Dorr.

Operation Walk went to Tanzania for the first time in June. Many people there have little hope for good medical care.

"There is a lot of poverty. There is a lot of discrepency between private medicine," explains Operation Walk surgeon Ammer Malik. He's from Kenya but practices medicine in Spain. "Maybe 85 percent of the population cannot access that kind of medicine."

Dr. Geoffrey Kibira of the Arusha Lutheran Medical Center says some patients in Tanzania were afraid of getting an artifical hip or knee.

"The problem, majority couldn't understand that you can put artifical things in the hip or the knee and walk again," the doctor says. "After seeing some of the patients improving walking and they are pain-free -- now people are coming."

Dorr says he sees change in many of the volunteer doctors and nurses who help patients in developing countries.

"They realize they can do things they didn't even know they can do," he says. "And they can help people even better than they ever thought they could. And it changes them; it changes them for the good."

Dorr adds that for these volunteers, it becomes a calling that gives meaning to their lives.