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Anatomy of the Hip Joint
The hip is made up of two bones:
- the femur (femoral head) — located in the upper thigh
- the acetabulum (hip socket) — holds the femur in place
Surrounded by thick muscles of the back, buttocks, and thigh, the hip joint is known as a ball-and-socket joint. The bones are covered with articular cartilage which is about 1/4 inch thick. It is tough and very slick, allowing the surfaces to slide against one another without damaging either surface.
For further descriptions of the hip joint, see Hip Joint and Hip Flexors.
Why does a hip need to be replaced?
As the cartilage around the joint wears away, the bone is increasingly damaged. Eventually, the ends of the bone will grind together — with no cartilage left at all. Pain, swelling and stiffness may result, and a replacement of the hip joint is possibly the only option.
There are several conditions which might contribute to the destruction of the cartilage. They are:
Osteoarthritis: Often referred to as the "wear and tear" arthritis, osteoarthritis is the most common reason why hips need to be replaced.
Rheumatoid Arthritis: With this disease, the tissue surrounding the joints is often inflamed; as a result, the cartilage slowly deteriorates.
Post-Traumatic Arthritis: Injury to the hip may cause permanent damage to the ligaments which will lead to an unstable hip. In time, a hip replacement may be considered, depending upon the severity of the damage.
Avascular necrosis: This condition results from an inadequate supply of blood to the bone end inside the joint; as a result, the cartilage wears away. Once it is gone, hip surgery is inevitable.
When is a hip replacement done?
This is a decision made between the patient and the doctor, but pain usually becomes the main issue. Some tests may be required to rule out other possibilities; others will wait for as long as possible before having the surgery. It is mostly a personal decision.
Sometimes, however, it is best not to delay the inevitable. If you are already in your 80's, and you are having a lot of pain, it might be well worth it to get it done before you reach 90. Other health conditions can show up as you age which will make surgery problemmatic later.
Once a hip replacement is being considered, you need to do your homework. Find out what is involved, how it will affect your life, and the advantages and disadvantages of going through with the surgery. Your doctor may be able to answer all your questions, but there is also a wealth of information on the internet.
What types of hip replacements are there?
Thus far, surgeons have developed two distinct types of surgery. They are:
Cemented Prosthesis: A cemented prosthesis is held in place by a type of epoxy cement that attaches the metal to the bone.
Uncemented Prosthesis: An uncemented prosthesis has a finemesh of holes on the surface area that touches the bone. The mesh allows the bone to grow into the mesh and "become part of" the bone.
What happens during hip replacement surgery?
The steps for replacing the hip begin with making an incision about 8 inches long over the hip joint. After the incision is made, the ligaments and muscles are separated to allow the surgeon access to the bones of the hip joint. 2
Here are the steps in the procedure:
Removing the Femoral Head: The femoral head is removed by cutting through the femoral neck (using a powerful surgeon's saw).
Reaming the Acetabulum: The cartilage is removed from the acetabulum, using a drill and special tool called a reamer. The reamer makes the bone in a hemispherical shape — this will fit exactly the metal shell of the acetabular component.
Inserting the Acetabular Component: This is done first on a trial basis to assure that a right size and fit will be found. Something different happens here, depending on whether a cemented or uncemented prosthesis is used.
Preparing the Femoral Canal: Rasps are used to shape and hollow out the femur — this will exactly match the shape of the metal stem of the femoral component. The surgeon always does a trial first to ensure the correct size and shape.
Inserting the Femoral Stem: Again, what is done here depends on whether a cemented or uncemented prosthesis is used.
Attaching the Femoral Head: The metal ball that replaces the femoral head is attached to the femoral stem.
Completed Hip Replacement: Before the incision is closed, an x-ray is made to make sure the new prosthesis is in the correct position.
Is there "life" after hip replacement?
Of course! Joint replacement operations have proven to be a very successful treatment. The ability to do daily functions are often greatly improved afterwards — thus improving a person's quality of life. Believe it or not, after joint replacement, athletic and recreational activities sometimes increase.
However, there are guidelines and protocols that you should follow to be sure that you do not do too much too soon. You may never do high-impact aerobics again, but after healing and doing specific exercises to strengthen the muscles that surround the joint, you will probably be able to do more than you ever expected to!
After your operation, precautions are designed to protect the hip from dislocation through the incision in the joint capsule. The amount of risk depends on the type of surgery that is performed. There should be minimal swelling of the involved lower extremity and the incision should be completely healed before the client begins an exercise program. Until they heal, which takes about a month to six weeks, there are special precautions to prevent dislocation of the new hip joint.
Exercise is good to strengthen the hip abductors, gluteals, hip rotators, and quadriceps. Be sure to use proper spine mechanics and practice functional activities (e.g. sit-to-stand, balance, dressing). Aquatic exercise is an excellent choice at this stage of recovery.
Some suggested exercise modifications are:
- Decrease lower body range-of-motion movements.
- Prevent impact and jarring movements and activities.
- Avoid activities that have a risk of falling.
- Get on and off equipment very carefully, or have someone near to assist you.
- If you are cycling, adjust the saddle and handlebars to decrease hip flexion.
If, during exercise, you experience low-back pain or excessive fatigue, you should discontinue your exercises and see a healthcare provider. Other symptoms which should also not be ignored are fever, sign of hip disolcation, or sudden swelling of the leg.
The final Decision is Yours
So keep your options open, talk to your doctor, and together make the decision when and if a hip replacement is the right decision for you.
Thanks to the two textbooks: Special Populations by On the Edge Fitness Education and Exercise and Arthritis by Stephanie Harris and Gwen Hyatt.
- Hip Joint
- Hip Flexors
- Exercise and Osteoporosis
- Joints and Exercise
- Dem Bones Dem Bones: The Skeleton
- Hip Replacement: The Basics
I am a BCRPA-certified fitness instructor in Vancouver, BC. I teach four classes at the West End Community Centre in Vancouver, BC, mostly designed for the older adult. The Inevitable Disclaimer: Everything published here expresses only my opinion, based on my training and research. What you do with the information is entirely your own responsibility. I am not liable for any injury you suffer that seems to be related to anything you read here. Always consult your doctor before beginning an exercise program. For other articles, return to the table of contents.