“The leg bone is connected to the thigh bone, the thigh bone is connected to the…”  Kids learn the parts of their body through this kindergarten song.  Later on in life, they learn it’s not as simple as the song suggests.

The ends of two or more bones connected by thick tissue are what form a joint.  For example, the lower leg bone, called the tibia, is joined to the thigh bone, called the femur, by the knee joint.  The ends of the bones are covered in a smooth layer of cartilage which prevents friction during movement.  In addition, each joint is enveloped by a pocket of synovium, which releases fluid in the joint to further prevent friction and wear in the joint.  A joint with healthy cartilage and enough synovium should be a joint free of pain.   

But what does it mean when pain is present in a joint?  What is involved in joint replacement?  Does it really work?  The American Academy of Orthopaedic Surgeons offers explanations and advice for individuals faced with total joint replacement surgery.

Pain in a joint arises due to cartilage damage.  This may be from injury, wear and tear, or arthritis in the joint.  As a result, the joint becomes less mobile and painful.  The goal of replacement is to relieve the pain caused by the damage.

Initially, if a person is feeling pain in their joints, it’s likely they will undergo some tests to determine the extent of the damage.  A physical examination will be given, as well as laboratory tests and x-rays.  A physician may decide on joint replacement only if other attempts to relieve the pain fail.   

During joint replacement the surgeon substitutes the damaged part of the joint with a prosthesis, an artificial joint. The prosthesis is made of two parts: a metal piece that fits snugly into a matching plastic piece. It is modeled to fit the joint in a way that allows for movement and function to be restored to that area without the presence of pain.

Recovery after joint replacement surgery involves moving the “new” joint to prevent stiffness.  Initially, the joint and affected muscles may be painful due to previous inactivity and healing tissues.  It typically lasts a few weeks or months. 

The orthopedic doctor will design a program that meets the patient’s needs.  The range of motion in the joint experienced after surgery depends on how tight the joint was prior to the replacement.  A very stiff or inactive joint will take longer to heal and may not resume full range of motion.

Because joint replacement is surgery, there are certain complications that could arise in a small percentage of cases. Infection, blood clots, dislocation, and the like are possible.  To make the most of the surgery and minimize risk of complications, it is important for patients to tell their orthopedic surgeon about any medical conditions that could affect surgery and adhere to the recovery program designed for the new joint.

The track record for joint replacement is very good.  According to the American Academy of Orthopedic Surgeons, joint replacement is successful for more than nine out of ten people.  It may give years of pain-free and mobile living that may not have been possible otherwise.  Older patients may expect their replacement to last 15 to 20 years, while younger patients may require an additional replacement.

If you are experiencing joint pain talk to your physician and contact the American Academy of Orthopedic Surgeons at www.aaos.org for more information.

Dr. Williams is certified by and a Fellow of the American Academy of Orthopaedic Surgeons.  He is on staff at Des Peres Hospital and is president of the St. Louis Arthroscopy Association.