Patellar chondromalacia refers to pain around the front (anterior) part of the knee. In the past, it was often a wastebasket term for describing anterior knee pain. However, patellar chondromalacia refers to a specific diagnosis of the knee.
Description of Patellar Chondromalacia
Injuries, wear and tear, or genetics may play a role in the breakdown of the cartilage under the knee (the patella) and on the distal end of the femur, which is called the trochlea. In a healthy knee, the cartilage surfaces of the patella and trochlea are extremely smooth. The joint fluid creates an extremely efficient gliding surface, which is about 1/6 that of ice on ice. When there is a breakdown of the cartilage, this efficient gliding surface no longer exists. Any breakdown of the cartilage surface is a form of arthritis, which is commonly classified into grades of chondromalacia. Thus, chondromalacia occurs when the cartilage surface has broken down and early arthritis has formed. Unfortunately, the strongest point of the cartilage is the surface, which is called the lamina splendens. As the cartilage surface of the knee wears down, the deeper cartilage surfaces which are weaker subsequently wear out even faster, leading to a greater development of knee arthritis.
Symptoms of patellar chondromalacia include:
In some cases, patients can have patellar chondromalacia without any of these symptoms
Treatment for Patellar Chondromalacia
The first step in treating patellar chondromalacia is to identify its cause. For patients who have anterior knee pain, a physical exam, x-rays, and possibly an MRI scan are necessary to evaluate the cause of the pain. The treatments can include rest, activity modification, physical therapy, stretching, bracing, injections, or arthroscopic surgery.
Arthroscopic surgery for patellar chondromalacia involves placing instruments into the knee to shave down any unstable cartilage flaps on the patella and the trochlear groove. In most circumstances, some surface cartilage will remain present. Physical therapy after surgery will work to strengthen the muscles around the knee and to make sure the patella does not scar in. It is also recommended to avoid any activities that can cause further cartilage wear, breakdown, and swelling in the knee. In general, except for a very high-level athlete, we recommend avoiding any high-impact activities, and squatting and lunging activities, to try slow down the rate of wear of the cartilage surface.
The postoperative treatment for trimming of the unstable cartilage surfaces of the patella and trochlea involves working on maintenance and regaining of muscle strength, limiting swelling after surgery, and working on patellar mobility with one’s physical therapist. It is especially important to mainly work on kneecap motion and avoiding knee swelling in patients who has more than relatively small areas that needed to be trimmed. This is because if one strives to work on aggressive strengthening too soon after this particular surgery, the body may form an increased amount of scar tissue, which is often painful, in response to the increase of activities. Thus, it is usually recommended to work on light low impact activities for the first 6 weeks after surgery to avoid irritating the knee and causing an aggressive scar tissue healing response.