A focal articular cartilage injury is damage limited to a specific area of the cartilage covering the ends of the bones in a joint. Articular cartilage allows the joint surfaces to slide and roll smoothly without pain during movement.
An injury can cause the cartilage to tear, split, or separate from the underlying bone. Because cartilage has no blood supply, it has no potential to heal on its own, making these injuries difficult to treat.
What Is a Cartilage Tear?
Articular cartilage is a durable, complex structure that covers the ends of the bones at a joint and allows the joint surfaces to move smoothly.
A focal injury may cause a tear, split, or separation of the cartilage from the underlying bone. Although cartilage injuries can occur in any joint, they occur most commonly in the knee.
Focal cartilage injuries may progressively worsen over time. If cartilage wears out over a broad area on both sides of the joint, the exposed bone surfaces can rub against each other, resulting in arthritis, inflammation, and pain.
Causes and Risk Factors
Focal articular cartilage injuries typically result from compressive, shearing, or rotational forces caused by direct injury to the joint.
Risk factors include:
- Contact and collision sports
- High levels of athletic activity, especially competitive sports
- Other joint injuries, including ACL tears and patellar dislocations
- Poor physical conditioning, including strength and flexibility
Symptoms
Signs and symptoms may include:
- Swelling and pain
- Giving way
- Locking or catching of the joint
- A sensation of something moving or floating freely within the joint
- Painful crepitation, or a crackling sound, with movement
- Pain and swelling associated with other joint or ligament injuries
Joints may also make painless noises, which typically are not a problem.
Treatment
Conservative treatment may include anti-inflammatory medication, ice, and activity restriction to relieve pain and reduce swelling.
Range-of-motion, stretching, and strengthening exercises may be recommended to correct deficits and restore joint function. Referral to a physical therapist or athletic trainer is often recommended.
For patients with persistent swelling, pain, or functional limitations despite conservative treatment, loose fragments within the joint, or symptomatic cartilage injury identified on MRI, surgery may be recommended.
The first line of surgical treatment usually involves arthroscopic surgery to:
- Remove unstable or loose cartilage fragments
- Stabilize the borders of the cartilage injury
- Stimulate a healing or reparative response in the damaged area
Techniques may include:
- Microfracture: Small perforations are created in the exposed bone at the base of the cartilage defect to allow blood and bone marrow contents to fill the area.
- Abrasionplasty: The surface of the exposed bone is shaved to create a fresh bleeding surface and stimulate a reparative response.
With these techniques, blood and marrow contents form a clot that eventually fills the defect with reparative tissue. This tissue is not cartilage and is not as mechanically durable.
In some cases, unstable or loose cartilage fragments may be reattached.
For larger cartilage injuries or injuries that have not responded to less invasive marrow-stimulating procedures, cartilage restoration procedures may include:
- Autologous osteochondral transfer (OATS): A plug of bone and cartilage is taken from a less important area of the joint and transferred to the damaged area.
- Fresh allograft osteochondral transplant: A plug of bone and cartilage from a recently deceased donor is transplanted into the damaged area.
- Autologous cartilage implantation (ACI): A small piece of healthy cartilage is collected arthroscopically. The cartilage cells are grown in a laboratory and later implanted into the cartilage defect.
Nonsteroidal anti-inflammatory medications such as aspirin and ibuprofen, or minor pain relievers such as acetaminophen, are often recommended as directed by a physician. Stronger pain medication may be prescribed after surgery when necessary.
Recovery and Outcomes
Small areas of articular cartilage injury may not cause problems and may not develop arthritis for some time.
Larger and deeper injuries are more concerning because cartilage does not heal. These injuries can cause pain, swelling, and functional limitations and may worsen over time. Appropriate treatment can improve symptoms and allow a return to activity.
Extensive rehabilitation is required following cartilage restoration procedures. Treatment typically begins with approximately six weeks of bracing, protected weight bearing, and gentle passive movement of the joint.
Range-of-motion, stretching, and strengthening exercises are then used for the joint and surrounding muscles, typically with the assistance of a physical therapist. Return to athletic activities generally takes at least four to six months.
When to See Dr. Chudik
Contact Dr. Chudik’s office if symptoms worsen or if pain, swelling, locking, catching, giving way, or functional limitations persist following a cartilage injury.
Call 630-324-0402, request an appointment online, or email contactus@chudikmd.com.