Knee Cartilage Injuries
Cartilage is connective tissue that covers the end of bones that line the surfaces of our joints. Cartilage provides a protective layer over the femur, tibia, and the undersurface of the patella to allow the bones to move smoothly without friction. Articular cartilage has no blood supply of its own making it unlikely to heal on its own once it has been damaged.
Articular cartilage injuries can range from softening of the cartilage to defects exposing the underlying bone. Occasionally the damaged cartilage can break away from the bone causing “loose bodies” in the knee joint which can cause mechanical symptoms such as catching or locking.
Cartilage injuries can be the result of knee trauma, overuse injuries, natural degradation over time, or from conditions such as Osteochonditirs Dissecans. Cartilage damage can cause pain, swelling, and loss of range of motion resulting in decreased knee function.
The most common symptoms of cartilage injuries is a constant dull ache in the knee and swelling with increased activity or sports. If the injury is severe or there are loose bodies in the knee, patients may also experience catching or locking.
The symptoms of a knee cartilage injury can often mimic those of other knee conditions. Diagnosis is made with an extensive history and physical exam to help rule out other conditions that may be causing knee pain. X Rays and MRI are used to help confirm the diagnosis. Occasionally in office diagnostic arthroscopy is needed to further determine the size and extent of the cartilage injury.
Knee cartilage injuries can often be treated without surgery.
- Rest, ice, compression and elevation (RICE) of the knee can often help decrease pain and swelling.
- Physical therapy is often helpful in improving strength and knee mechanics.
- NSAID medication can also help decrease pain and inflammation.
- Injections of cortisone or other biologic agents may help to decrease swelling and pain and improve function.
If the injury is too severe, there are loose bodies causing mechanical symptoms, or conservative treatment options have not provided significant relief, surgical treatment may be recommended. These surgical options include:
- Chondroplasty or Debridement (smoothing) – Chondroplasty or debridement is used to smooth the shredded or frayed cartilage, leading to decreased friction and irritation, reducing the symptoms of swelling and knee joint pain. The procedure is done arthroscopically, where small incisions (portals) are for the arthroscope (camera) and small surgical instruments. If there are loose bodies, they can be removed during the same procedure.
- Microfracture (marrow stimulation) – Microfracture is used to treat damaged areas of articular cartilage in the knee by creating small holes in the bone to allow for blood flow, stimulating healing and new cartilage formation. It can be done along with other procedures.
- Autologous Chondrocyte Implantation (ACI) – ACI involves removing a small piece of cartilage and sending to a laboratory where additional cartilage cells are fostered from the sample. After a waiting period, the new cartilage cells are implanted by injecting the cartilage cells into the defect. These cells eventually grow into new, healthy cartilage. This is often reserved for patients with large cartilage defects
- Osteochondral Allograft transfer – The damaged cartilage is replaced from donor cartilage (allograft). This is usually reserved for large areas of cartilage damage and can be ideal in situations where the underlying bone is damaged as seen in conditions such as Osteochondritis Dissecans
Surgical treatment options depend on the size of articular cartilage injury or defect, injury severity, and the age and activity level of the patient. You and Dr. Faucett will decide the best treatment option for you based on these factors.
The cartilage is a slow healing tissue. This means the rehabilitation has a slow progression in the immediate post-operative phase. Typically, in the first 6 weeks you will require the use of crutches and not be allowed to place any pressure on the repaired cartilage. during this time, you will be attending regular physical therapy sessions to regain your knee range of motion and activate your muscles around the knee. After the prescribed period of non-weight-bearing your therapist will guide you in weaning off of the crutches and begin a strengthening program. It will take four to six months for the cartilage repair to fully heal to allow you to return to sports and impact activities.
For cases involving the chondroplasty procedure, patients are often able to weight-bear immediately and only require crutches for a few weeks.
Cartilage transplantation has a few risks:
- Failure to heal: The cartilage or bone has to heal and can take 3-4 months to heal completely.
- Delamination: In some cases, the cartilage repair or transplant can separate from the bone and become loose in the knee.
- Osteoarthritis: The same area or other areas could degenerate causing a recurrence of your preoperative knee symptoms.
- Infection: This thankfully occurs rarely.
- Knee Stiffness: If your knee does not regain the range of motion with in the first few months, the knee can develop stiff scar tissue in the knee (arthrofibrosis) and require revision surgery to remove the scar tissue.
Surgically replaced cartilage carries a good prognosis. Most cartilage transplantation procedures can last more than 10 years. It’s important to take care of your knee and complete your rehabilitation to give the cartilage repair the best opportunity to heal.