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　　Millions of people in the United States suffer from osteoarthritis, or degenerative joint² disease. The most severe cases requiring joint replacement³ surgery.
数百万的美国人患有骨关节炎，又称退化性关节疾病。病情严重的需要做人工关节替换手术。
These replacement joints⁴ can be made of combinations of metal alloys⁵, plastic and ceramic⁶, but new research shows that it might be possible to regenerate⁷ damaged joints using a patient's own stem cells.
人工关节可能是用合金、塑料和陶瓷制成的。不过，新的研究显示，利用病人自己的干细胞，有可能修复受损的关节。
Chronic⁸ disability
Osteoarthritis is the result of infection, trauma⁹ or simply age, and is the leading cause of chronic disability worldwide.
骨关节炎是炎症、创伤，或年龄造成的，是世界范围慢性残障疾病的主要原因。
The disease causes cartilage-protecting joint surfaces to degrade, allowing painful bone-to-bone contact. Osteoarthritis is usually treated with pain relievers and anti-inflammatory drugs, but in severe cases, the damaged joint can be replaced with an artificial one. However, this option may not work well for the growing population of younger arthritic¹⁰ patients.
这种病使保护关节表面的软骨磨损，导致骨骼直接摩擦而产生疼痛。骨关节炎通常使用止痛剂和消炎药治疗。但是病情严重时，可以考虑用人工关节替换受损的关节。不过，这种选择并不适于人数越来越多的年轻患者。
"The average lifespan of the metal joints is about 10 to 15 years," says Jeremy Mao at the Columbia University Medical Center. "So as you can imagine, if you are say 50, 55 or younger, the surgeons will be very hesitant to place these metal joints in your body because knowing that in 10 to 15 years, there's a chance these would fail."
哥伦比亚大学医学中心的杰里米·毛说：“金属关节的平均使用寿命是10年到15年。因此可以想见，如果你只有50岁、55岁，甚至更年轻的话，外科医生可能不愿意为你换金属关节，因为他知道，过10到15年，人工关节可能就不能用了。”
In order to address this concern, Mao is exploring new ways to regenerate joints.
为解决这个问题，杰里米·毛正在探索让关节再生的新方法。
Growing new joint cells
Mao replaced a portion of a rabbit's upper arm joint with a biomaterial scaffold, providing a place for cells to grow. In order to attract the rabbit's own stem cells to re-grow the cartilage, channels in the scaffold were filled with a growth factor protein.
他用生物材料支架替换一只兔子的前肢的部分关节，并留出细胞生长空间。为了诱导兔子本身的干细胞重生软骨，支架管道内注入了生长蛋白质。
"What we found was with one protein that we delivered in the micro-channels in the scaffolds, that was sufficient to regenerate the entire joint surface with cartilage and with bone and with blood vessels," says Mao. "So when we observe these animals with the replacement joints, what we found was there was regeneration of the entire joint that allowed the animals to resume weight-bearing and locomotion¹¹."
杰里米·毛说：“我们发现，我们注入支架细微管道里的一种蛋白质，足以重新生成整个关节的软骨、骨骼和血管。我们发现，这些装了替换关节的动物，再生了整个关节，恢复了承重和活动的能力。”
This return to normalcy occurred just four months after the surgical¹² procedure, with newly grown cartilage fully¹³ covering the joint surface. When the mechanical properties of this new cartilage were tested, they showed that the regenerated¹⁴ cells were just as effective as the rabbit's naturally formed cartilage.
进行替换关节手术的四个月之后，一切恢复正常。新生的软骨覆盖住整个关节的表面。新软骨的机械性能测试结果显示，再生细胞和兔子自然生长的软骨，有同样的功能。
Added benefits
While human trials are still a long way off, scientists in the field are excited and encouraged by the research.
虽然距离人类试验有很长的路要走，但科学家们已经因为这次的试验而感到振奋和鼓舞了。
"It's absolutely necessary that we continue to push the envelope in terms of try to develop new innovative¹⁵ and more natural ways of effectively treating arthritis¹," says Dr. Mary O'Connor, chairperson of Orthopedic Surgery at the Mayo Clinic in Florida.
佛罗里达州梅奥诊所骨骼外科主任玛丽·奥康纳说：“继续努力研发有效治疗关节炎的更自然的方法，是绝对必要的。”
O'Connor says there is significant benefit to using this type of treatment for arthritis in the knee.
奥康纳医生说，用这种方法治疗膝关节特别有利。
"When we do a knee replacement, we remove one or sometimes both of the cruciate ligaments - which are the ligaments in the center of the knee. So one of the potential advantages of this growing joint technique is perhaps the ability to preserve more of those tissues inside the knee, which would hopefully translate into more natural mechanics of the knee."
“当我们做膝关节替换手术时，要切除一个或两个关节的前十字韧带，那是膝盖中心的韧带。所以，关节再生技术的一个好处就是保护膝盖里更多的组织。希望这些组织可以导致更好的机械功能，使膝盖的机械功能更自然。”
O'Connor says cost could be a factor in deciding to use this treatment. While it may not be worthwhile for older patients, younger patients are more likely to regard anything that gives them a lifelong working knee joint as well worth the cost.
奥康纳说，费用可能是决定是否使用这种疗法的因素。对老年病患，它或许不值得。年轻病人可能更愿意考虑能够使他们终生拥有健康膝关节的任何治疗方法，他们会觉得这笔钱花得物有所值。