Understanding Osteoarthritis of the Knee

By: Rajit Saluja, MD

Woman suffering from bone marrow edema, holding knee

Osteoarthritis (OA) is a common condition that occurs when cartilage in a joint deteriorates. Movement in a damaged joint produces friction and can cause significant pain. Knees are particularly susceptible to OA. Our understanding of OA has changed significantly from what we knew 20 years ago. Previously, we looked at OA as a wear-and-tear disease and focused on the narrowing of the knee joint space and subsequent formation of bone spurs. However, we have now learned that OA-related pain may largely be related to chronic inflammation in the joint. This inflammation can cause additional damage to the bone just below the joint and present as bone marrow edema or swelling. Although the loss of cartilage volume and thickness in the joint does cause pain, the damage to the bone affects the marrow and is likely to blame in many cases of chronic joint pain.

Why You Need to Know About Bone Marrow Edema and Lesions

Edema is described as swelling caused by inflammation. In osteoarthritis, the cartilage, which provides a cushion in a normal knee joint, is worn out. This leads to an overload of stress in your knee causing swelling or edema and can cause damage both in the joint and in the bone just below the joint, known as the subchondral bone. As a result, the damage to the subchondral bone appears as bone marrow edema on an MRI scan. These areas of bone marrow edema are also known as bone marrow lesions.

Bone marrow edema can be serious. Bones and bone marrow are comprised of living cells that require healthy blood flow. If that blood flow is cut off, the cells may die. Left untreated, the bone marrow lesions can lead to more severe damage, and in some cases, collapse the joint. It has been shown that knees with bone marrow edema are nine times more likely to lead to total knee replacement.

When to Ask Your Doctor About Bone Marrow Lesions?

If you have experienced any of the following conditions, please seek an evaluation for possible bone marrow lesions.

  1. You are being treated for torn cartilage and the MRI shows mild to moderate OA with bone marrow edema.
  2. You have previously undergone arthroscopic surgery to repair the damaged meniscus, but your pain fails to improve.
  3. You have been diagnosed with mild to moderate OA, but your symptoms are not improving with injections – either cortisone or hyaluronic acid.
  4. You have been diagnosed with osteonecrosis in the knee region.

Solving Bone Marrow Lesions & Osteoarthritis Pain

The good news about bone marrow edema, which can accompany mild to moderate OA, is that it can be treated with less invasive methods. Your doctor will assess the severity of your case, your overall health, and other factors before selecting a course of treatment that is right for you. Initial treatment is nonsurgical and can include rest, avoiding weight-bearing activity, injections, wearing a support brace, and modifying your activity. If surgery is required and you are a MOSH patient, we will likely pursue a new biological approach to treatment known as intraosseous bioplasty (IOBP). This treatment is less invasive than a knee replacement where arthroscopy is first performed to repair or clean out any torn cartilage or meniscus. Blood from your bone marrow, which contains stem cells, is obtained during the surgery and concentrated for injection and mixed with the bone matrix. This material is then injected into the subchondral bone to stimulate the healing of the bone marrow lesions. Surgery is followed by three to four weeks of partial weight-bearing and light strengthening exercises. Next, patients will participate in physical therapy to rebuild strength and prepare to return to normal activities.

We have seen excellent pain relief, improvement in activities, and better day-to-day function after IOBP. For more information about OA, bone marrow edema, or IOBP, please contact your MOSH physician.