Joint Replacement: When Joints
Cause Pain


Andrew M. Star, MD
Medical Director of the Orthopaedic and Spine Institute at Abington Health

As the U.S. population ages, orthopaedic surgeons are performing more joint replacement surgeries than ever. The number of knee replacements alone has spiked 165 percent in the last two decades and, according to the Journal of the American Medical Association, could surpass 3.5 million by 2030. You can learn more about the procedure at Dr. Star’s live web chat: Joint Replacement: Are You a Candidate for Minimally-Invasive Hip or Knee Replacement?

Joints, or the places where bones meet, can be affected by injury and disease, but often, they simply wear out.  The most commonly replaced joints are hips and knees, with the latter being twice as common, particularly among women.

The hip is known as a ball-and-socket joint, in which the rounded surface of a bone fits into the concave portion of another bone, allowing it to move in almost all directions. In a healthy joint, the protective cartilage pad that separates the bones is nice and smooth. When the cartilage deteriorates, however, the bones come into direct contact with each other, which can cause pain, inflammation, and a limited range of motion.

Your knee joint is even more complex. A hinge joint that connects the two longest bones in your body, it includes an extra layer of what is called meniscus cartilage between those bones, as well as ligaments. If any of these parts deteriorate, tear, or otherwise cease working, the joint becomes unstable.

The fact that both these joints, and the knees in particular, are weight-bearing make them susceptible to injury, and carrying excess weight can increase the risk of joint problems. In fact, researchers at Wake Forest University studied obese patients and found that for every 1 pound of body weight lost, there was a 4-pound reduction in the load exerted on the knee for each step taken during daily activities.

Genetics, injury, and both overuse and inactivity can also contribute to the weakening of joints. If you are experiencing joint pain or stiffness, talk to your primary care physician and consider consulting a specialty physician.

Join Dr. Star’s live Health Chat with Abington Health on Thursday, January 16th at 7 pm: Joint Replacement: Are You a Candidate for Minimally Invasive Hip or Knee Replacement? Sign up now.