你的膝蓋是否未老先衰?

醫師說：「你的膝蓋需要進行手術治療！」年僅31歲的艾利森·傑克森已經有雙70多歲的膝蓋了!多年下來的運動負荷以及不斷增加的的體重導致艾利森的膝蓋未老先衰，現在每天需要冰敷六次來緩解疼痛。

艾利森·傑克森所患的，是近年患病率不斷飆升且好發於女性的退化性關節炎（相關文章：甚麼是退化性關節炎）。這是一種漸進式的老化退化疾病，常常發生在膝關節的位置。在2000年，僅有53000名20-39歲的女性診斷出退化性關節炎，但經過短短10年歲月，這個患病數字已飆升到230,000， Zackary Vaughn醫師表示，甚至還有20歲的女性已經到了需要置換人工關節的病情。這個原本應好發於老年人的退化性疾病為什麼會悄悄找上年輕女性呢?

男女天生不平等

退化性關節好發於一些反覆讓關節沉受重量像是常爬樓梯的族群，或是過早開始且長期專精於某項運動的女性族群。

然而是甚麼原因導致男女的關節差異呢?最新的研究發現關節肌肉在女性月經週期的不同時期運作方式也不同，女性荷爾蒙會影響關節結構的不穩定性進而導致關節傷害。現今越來越多的女性參與足球、籃球、排球、跳高、跳遠等校園運動，這些運動本身就會增加膝關節傷害的風險，只要小小失衡或是扭傷，可能會瞬間毀了你的膝關節。

男女神經系統傳導速度的差異同樣扮演很重要的角色：俄勒岡大學的科學家們發現，男性對神經刺激的反應比女性快出許多，意謂著在危急情況發生時，男性可以有更多時間作出正確的應變對策。

軟骨（相關文章：認識你的關節結構）

前十字韌帶損傷的統計數字顯示，女性運動員前十字韌帶受傷的比例是男性運動員的8倍之多，這或許與女性在跳躍時膝蓋不自覺傾向內八字著地，因而增加前十字韌帶撕裂的風險有關。前十字韌帶主要提供支撐穩固關節結構之用，一旦撕裂或斷裂，關節結構就有如鋼筋斷裂的房子一樣

而不幸的事大多數前十字韌帶受傷的女性患者在往後的十年內都會出現退化性關節炎的症狀。

同樣地是與組織損傷有關的，是作為緩衝墊的半月軟骨受損。脆弱的半月軟骨可能因不正確的蹲下姿勢或是拾物動作而導致受傷，一旦受傷後因其缺少神經末梢、初期難以感覺到疼痛而導致治療拖延，此外半月軟骨血管分佈少且不均，不易自行修復。這三項原因加起來，導致退化性關節炎成為一種漸進式的、難以修復的退化疾病。

膝關節自保守則

雖然我們無法違逆生物器官組織（包含關節）老化退化的自然法則，但還是有一些可以做的事情：

1. 控制體重：肥胖是退化性關節炎的一大危險因子，減重絕對可以減緩軟骨磨損的速度！
2. 戒菸：若你是位菸癮君子，又出現退化性關節炎的症狀，就要特別注意了！香菸中的一些化學成份會傷害你身體的細胞、組織、器官，其中當然包含關節健康，還是一句老話「吸菸有害身體健康！」
3. 少穿高跟鞋：兩吋以上的高跟鞋會縮短你的步伐，加速你膝蓋內側磨損。
4. 強化肌肉力量的運動：強健的肌力可以分散你的關節受力。要保護你的膝蓋，平時不仿多訓練你的大腿股四頭肌。相關連結：六種保護膝蓋的運動

開始緊張你患有退化性關節炎嗎

事實上我們在運動後常常會感到關節疼痛，這時候我們的軟骨正經歷輕中度的退化性關節炎，但這種情況往往在數天後會緩解，不需要過度緊張。但如果你的關節某個特定點持續性疼痛、僵硬、腫脹、或發生聲響超過2-3週，而非類固醇止痛藥物也不能緩解你的疼痛，這時候就請趕緊就醫。相關連結：退化性關節炎的治療方法

文章出處 http://www.prevention.com/health/osteoarthritis-and-joint-pain

翻譯人員 http://myhealthbiosystems.blogspot.tw/

轉載請註明出處

原文如下:

Are You Walking Around On Prematurely Old Knees?

Allyson Jackson is 31, but she walks on the knees of a senior citizen. Years of playing sports, followed by weight gain and a boxing injury, stressed her joints until they needed a surgical fix. Now, she sometimes ices her knees up to six times a day.

Allyson's experience is part of a growing—and scary—trend: Osteoarthritis (OA), a progressive joint disease, is increasingly striking young women, most commonly in the knees. In 2000, just over 53,000 women ages 20 to 39 saw a doctor for a diagnosis of OA; 10 years later, that number skyrocketed to 230,000. "Doctors are even beginning to see women in their twenties with end-stage joint disease," says orthopedic surgeon Zackary Vaughn, MD.

Damage Inequity

The dramatic rise in so-called older people's knee problems in young women is due, in part, to a more even playing field. Following the mandate for equal opportunity in sports in the 1970s, more women started participating in high school and college soccer, basketball, and volleyball, where the fast pace, high jumps, and quick pivots put knees in danger. Jumping and landing even a tiny bit off balance, or twisting the knee after planting the foot on the ground, can destroy the knee in seconds.

Starting young and specializing in one sport is especially bad for knees, but nonathletes are seeing the same cartilage-crushing effects from fitness routines overloaded with repetitive motion (say, pumping away on the stair-climber or logging miles on the treadmill). Moreover, women are three to eight times more likely to do in their knees than men are.

What gives? For one, basic biology. Hormones can make women's joints more susceptible to damage. Recent research found that knee muscles work differently at different points in your menstrual cycle, which can destabilize the joints and set them up for injury.

Gender variations in the nervous system may also play a role: Scientists at Oregon State University found that men's muscles respond to nerve impulses at a much faster rate than women's, a difference that suggests females' muscles may be less likely to react efficiently during crucial moments.

And then there's the fact that those of us graced with two X chromosomes simply move differently. Women tend to land knock-kneed from jumps, with one knee pointing toward the other, potentially putting the anterior cruciate ligament (ACL)–which is crucial for stabilizing the knee–in danger of ripping free, according to recent research.

The Cartilage Connection

Those ACL injuries aren't just causing painful short-term damage. More than half of women with this type of injury will end up with OA, most likely within 10 years. This stat is particularly troubling because ACL injuries are on the rise: Studies show young female athletes are up to eight times more likely to tear their ACL than their male counterparts are.

Also damaging—and much more common–are injuries to the meniscus, the cartilage that cushions the knee. "Injuring the meniscus increases your odds of developing OA by more than half, because some cartilage can't heal itself, so small injuries get worse over time," says orthopedic surgeon Donald Goodfellow, M.D. Being off balance during a simple task like squatting and twisting to pick up a dropped object can cause tears, even in a healthy woman with no prior knee injury. What's worse, you can have a small injury to cartilage and not even realize it until it worsens, since cartilage doesn't have nerve endings, says Rick Wright, M.D., an orthopedic surgeon at Washington University in St. Louis, Missouri.

Knee Savers

Though you can't entirely ward off OA (cartilage naturally breaks down as we age), you can keep it at bay by giving your knees a little TLC. Obesity is a big OA risk factor, so keeping a healthy weight is key–according to experts, as little as five or 10 extra pounds can add strain to the joint.

Smoking is also a no-no, because ingredients in cigarettes may harm cells that keep cartilage healthy. High heels (as little as two inches) also stress your joints because they make you walk with a shortened gait, which puts extra force on the inside of the knee, says Constance Chu, M.D., of Stanford University's Sports Medicine Clinic.

Worried you've already damaged your joints? Mild or moderate pain that comes and goes with exercise is common, but if you regularly feel the same pain in the same part of the knee for more than three weeks and it doesn't respond to OTC nonsteroidal anti-inflammatory drugs, a reduced exercise regimen, or ice, it's time to get the knee evaluated by a specialist, says Vaughn. Swelling, clicking, popping, dull throbbing in cold weather, or feeling that the knee is unsteady are also signs of damage, says Vaughn. Injections that stop inflammation and replace joint fluid can help ease pain now; on the near horizon are treatments with lab-grown cartilage transplants, which aim to fix small defects–kind of like filling potholes.

In the meantime, a knee-friendly fitness plan with plenty of variety can keep wear and tear to a minimum. Cross-training and aerobic fitness improve coordination and balance, making tumbles less likely; jumps and modified squats boost core strength, which stabilizes your knees and prevents that knock-kneed collapse on landings. Low-impact workouts on a stationary bike or elliptical build leg muscles while going easy on the joints.

"Muscle mass and strength around the knee can give you better joint longevity, because strong muscles share more of the load," says Chu. The time and sweat you put into keeping your knees healthy will help you get–and stay–pain-free.

This article "How Old Are Your Knees?" originally ran onWomensHealthMag.com.