Charles Hope, MD: HIP Replacement
Articular cartilage is the smooth, white tissue that covers the ends of bones where they come together to form joints. Healthy cartilage in our joints makes it easier to move. It allows the bones to glide over each other with very little friction.
Articular cartilage can be damaged by injury or normal wear and tear. Because cartilage does not heal itself well, doctors have developed surgical techniques to stimulate the growth of new cartilage. Restoring articular cartilage can relieve pain and allow better function. Most importantly, it can delay or prevent the onset of arthritis.
Surgical techniques to repair damaged cartilage are still evolving. It is hoped that as more is learned about cartilage and the healing response, surgeons will be better able to restore an injured joint.
The main component of the joint surface is a special tissue called hyaline cartilage.When it is damaged, the joint surface may no longer be smooth. Moving bones along a tough, damaged joint surface is difficult and causes pain. Damaged cartilage can also lead to arthritis in the joint.
The goal of cartilage restoration procedures is to stimulate new hyaline cartilage growth.
Identifying Cartilage Damage
In many cases, patients who have joint injuries, such as meniscal or ligament tears, will also have cartilage damage. This damage may be hard to diagnose because hyaline cartilage does not contain calcium and cannot be seen on an X-ray.
If other injuries exist with cartilage damage, doctors will address all problems during surgery
Most candidates for articular cartilage restoration are young adults with a single injury, or lesion. Older patients, or those with many lesions in one joint, are less likely to benefit from the surgery.
The knee is the most common area for cartilage restoration. Ankle and shoulder problems may also be treated.
Many procedures to restore articular cartilage are done arthroscopically. During arthroscopy, your surgeon makes three small, puncture incisions around your joint using an arthroscope.
Some procedures require the surgeon to have more direct access to the affected area. Longer, open incisions are required. Sometimes it is necessary to address other problems in the joint, such as meniscal or ligament tears, when cartilage surgery is done.
In general, recovery from an arthroscopic procedure is quicker and less painful than a traditional, open surgery. Your doctor will discuss the options with you to determine what kind of procedure is right for you.
The most common procedures for cartilage restoration are:
Autologous Chondrocyte Implantation
Osteochondral Autograft Transplantation
Osteochondral Allograft Transplantation
The goal of microfracture is to stimulate the growth of new articular cartilage by creating a new blood supply. A sharp tool called an awl is used to make multiple holes in the joint surface. The holes are made in the bone beneath the cartilage, called subchondral bone. This action creates a healing response. New blood supply can reach the joint surface, bringing with it new cells that will form the new cartilage.
The goal of microfracture is to stimulate the growth of new cartilage by creating a new blood supply.
A sharp tool called an awl is used to make multiple holes in the joint surface. The holes are made in the bone beneath the cartilage, called subchondral bone. This creates a healing response. New blood supply can reach the joint surface. This will bring new cells that will form cartilage.
Microfracture can be done with an arthroscope. The best candidates are young patients with single lesions and healthy subchondral bone.
Drilling, like microfracture, stimulates the production of healthy cartilage. Multiple holes are made through the injured area in the subchondral bone with a surgical drill or wire. The subchondral bone is penetrated to create a healing response.
Drilling can be done with an arthroscope. It is less precise than microfracture and the heat of the drill may cause injury to some of the tissues.
Drilling, like microfracture
When you injure your anterior cruciate ligament, you might hear a “popping” noise and you may feel your knee give out from under you. Other typical symptoms include:
Pain with swelling. Within 24 hours, your knee will swell. If ignored, the swelling and pain may resolve on its own. However, if you attempt to return to sports, your knee will probably be unstable and you risk causing further damage to the cushioning cartilage (meniscus) of your knee.
Loss of full range of motion
Tenderness along the joint line
Discomfort while walking
Physical Examination and Patient History
During your first visit, your doctor will talk to you about your symptoms and medical history.
During the physical examination, your doctor will check all the structures of your injured knee, and compare them to your non-injured knee. Most ligament injuries can be diagnosed with a thorough physical examination of the knee.
Other tests which may help your doctor confirm your diagnosis include:
Although they will not show any injury to your anterior cruciate ligament, X-rays can show whether the injury is associated with a broken bone.
This study creates better images of soft tissues like the anterior cruciate ligament. However, an MRI is usually not required to make the diagnosis of a torn ACL.
Treatment for an ACL tear will vary depending upon the patient’s individual needs. For example, the young athlete involved in agility sports will most likely require surgery to safely return to sports. The less active, usually older, individual may be able to return to a quieter lifestyle without surgery.
A torn ACL will not heal without surgery. But nonsurgical treatment may be effective for patients who are elderly or have a very low activity level. If the overall stability of the knee is intact, your doctor may recommend simple, nonsurgical options.
Your doctor may recommend a brace to protect your knee from instability. To further protect your knee, you may be given crutches to keep you from putting weight on your leg.
As the swelling goes down, a careful rehabilitation program is started. Specific exercises will restore function to your knee and strengthen the leg muscles that support it.
Rebuilding the Ligament
Most ACL tears cannot be sutured (stitched) back together. To surgically repair the ACL and restore knee stability, the ligament must be reconstructed. Your doctor will replace your torn ligament with a tissue graft. This graft acts as a scaffolding for a new ligament to grow on.
Grafts can be obtained from several sources. Often they are taken from the patellar tendon, which runs between the kneecap and the shinbone. Hamstring tendons at the back of the thigh are a common source of grafts. Sometimes a quadriceps tendon, which runs from the kneecap into the thigh, is used. Finally, cadaver graft (allograft) can be used.
There are advantages and disadvantages to all graft sources. You should discuss graft choices with your own orthopaedic surgeon to help determine which is best for you.
Because the regrowth takes time, it may be six months or more before an athlete can return to sports after surgery.
Surgery to rebuild an anterior cruciate ligament is done with an arthroscope using small incisions. Arthroscopic surgery is less invasive. The benefits of less invasive techniques include less pain from surgery, less time spent in the hospital, and quicker recovery times.
Unless ACL reconstruction is treatment for a combined ligament injury, it is usually not done right away. This delay gives the inflammation a chance to resolve, and allows a return of motion before surgery. Performing an ACL reconstruction too early greatly increases the risk of arthrofibrosis, or scar forming in the joint, which would risk a loss of knee motion.
Whether your treatment involves surgery or not, rehabilitation plays a vital role in getting you back to your daily activities. A physical therapy program will help you regain knee strength and motion.
If you have surgery, physical therapy first focuses on returning motion to the joint and surrounding muscles. This is followed by a strengthening program designed to protect the new ligament. This strengthening gradually increases the stress across the ligament. The final phase of rehabilitation is aimed at a functional return tailored for the athlete’s sport.