ORTHOPEDICS/HIP & KNEE/HIP SWITCHING SURGERY
Hip arthritis is a hip pain frequent cause.
When hip arthritis becomes serious, a hip switching technique may be performed.
With Hip arthritis, the joint normal smooth cartilage surface is defected over the time.
As this cartilage is damaged gradually, the bone is became exposed and the normal hip movements became problematic, such as walking, getting up from a chair, or even sleeping.
To remind, the hip joint is a ball-and-socket joint, the ball normally rotates within the socket to allow hip movements in all directions.
The ball and the socket are covered with a coating of smooth cartilage. This cartilage allows the hip joint to move freely.
When the joint cartilage coating is defecting, hip movements become inflexible and painful.
- The Damaged Hip Joint Ball Removal
A hip switching surgery first step consist remove the damaged hip cartilage and bone.
The hip joint has two sides, a ball (the femoral head), and the socket (the acetabulum). When the hip joint becomes arthritic, the normally smooth cartilage surface is defected.
To remove the damaged ball of the ball-and-socket hip joint, the femur is cut to remove the femoral head.
Note that the damaged bone and cartilage must first be removed in order to insert a new joint.
The hip can be reached in different ways.
Some specialists get to the hip through the joint back (Technique called a posterior approach), while others come at the hip through the joint front (an anterior approach).
Recently, this anterior approach is becoming more popular as it seems it allows recovery faster.
- The Damaged Hip Joint Socket Removal
Once the arthritic ball is removed, the damaged socket is addressed. Different from the ball, the socket cannot be cut off being part of the pelvis bone.
In order to remove the arthritis of the hip socket, a special instrument called a reamer is used to scrape away the damaged cartilage and bone.
This procedure leaves a smooth and perfectly rounded surface, ready to receive the new hip switching implant.
- The Acetabular Component installation
Once the worn out bone has been removed from the acetabulum, the new socket of the hip switching can be inserted.
The pelvis is called the acetabulum, and the part of the hip switching inserted into the socket is called the acetabular component, also called the “cup.”
The acetabular component is held firmly in the pelvis by making the socket slightly smaller than the acetabular component, and lodging the implant into the bone.
The implant has an irregular surface to allow the bone growing into the surface of the implant over the time.
- Femur Preparation
Now that the socket has been addressed, attention turn to the ball of the ball-and-socket hip joint.
This ball is supported with an implant inserted down the hollow center of the thighbone (femur). This implant is called the femoral stem.
Similar to the acetabular socket, the femoral stem must be held firmly in the bone. Specific instruments are used to shape the thighbone center to fit appropriately the femoral stem.
- Stem Installation
With the bone ready to receive the stem of the hip switching implant, the femoral stem is inserted. The stem can be held in the bone with or without cement.
When the bone is held with cement, the cement is inserted in a liquid form, and the stem is then fixed.
Within a few minutes, the cement enduringly hardens to hold the implant fixed within the bone.
Some switching surgery did not use cement; the implant is called “press-fit.” This technique means that the implant is lodged firmly into the bone and the rough surface coating the implant allows bone to grow into the implant over the time.
- The Ball Insertion
With the stem inserted down the thighbone center, the ball of the ball-and-socket hip joint can be inserted on stem top.
A metal ball is firmly fit onto the stem top.
Actually there is a new process of hip switching where the ball is resurfaced rather than switched, meaning there is less implanted material in the body.
This process of hip switching is called hip resurfacing surgery.
- Final Hip Switching Implant
With the socket, stem, and ball all inserted, the switched hip is installed in its final position.
It is important to ensure the hip switching implants are steady.
Hip switching implants that are not steady may displace occurring a serious complication of hip switching surgery.