Chondromalacia patellae (also known as CMP, Patello-femoral Pain Syndrome, or Runner’s Knee) is a term for a large and disparate group of medical conditions that can cause pain in the front of the knee. It is common in young adults, especially soccer players, cyclists, rowers, tennis players, ballet dancers, horseback riders, and runners. Snowboarders are especially prone to this injury, particularly those specializing in jumps where the knees are under great stress. The condition may result from acute injury to the patella or from chronic friction between the patella and the groove in the femur through which it passes during motion of the knee. CMP specifically refers to a knee that has been structurally damaged, while the more generic term Patello-femoral Pain Syndrome refers to the earlier stages of the condition, where symptoms are often fully reversible using treatments such as the RICE method(an acronym for Rest, Ice, Compression, Elevation), anti-inflammatory painkillers, physiotherapy and treatment of any underlying cause of the pain. It is often simply an overuse injury.
“Runner’s knee” often affects young and otherwise healthy athletes. One of the most important treatments is to avoid the activity that caused the problem. Use of RICE – rest, ice, compression, elevation – should help , as well as exercise such as cycling or swimming, straight leg raises, achilles tendon stretches.
The treatment will depend on the specific source of a person’s pain. Most sportspersons will use variations on the RICE method and anti-inflammatories, to rule out a simple overuse injury. If the pain is very severe or does not pass, they may consult a doctor. As noted above, “chondromalacia” and “patello femoral syndrome” are not diagnoses, as they do not help explain the source of pain. If pain is due to a tight iliotibial band, treatment will be focused on stretching of that band. If a person suffers from irritation of the infrapatellar branch of the saphenous nerve, treatment might consist of a small injection. If core stability is the issue, treatment might consist of physical therapy focused on the abdomen, pelvis and hips. If the condition is exacerbated by flat feet, these can be treated by orthotics.
What treatment options are available?
Nonoperative treatment is usually recommended for this problem. Getting the pain and inflammation under control is the first step. The overall goals for a rehab plan are to improve muscle function and flexibility while providing pain relief or pain control.
Your physician may suggest rest and anti-inflammatory medications, such as aspirin or ibuprofen, especially when the problem is coming from overuse. Acetaminophen (Tylenol®) may be used for pain control if you can’t take anti-inflammatory medications for any reason. Activity modification, flexibility, and strengthening are key parts of the rehab program. Physical therapy can help in the early stages by decreasing pain and inflammation. Your physical therapist may use ice massage and ultrasound to limit pain and swelling.
Bracing or taping the patella can help you do exercises and activities with less pain. Most braces for patellofemoral problems are made of soft fabric, such as cloth or neoprene. You slide them onto your knee like a sleeve. A small buttress pads the side of the patella to keep it lined up within the groove of the femur.
An alternative to bracing is to tape the patella in place. The therapist applies and adjusts the tape over the knee to help realign the patella. The idea is that by bracing or taping the knee, the patella stays in better alignment within the femoral groove. This in turn is thought to improve the pull of the quadriceps muscle so that the patella stays lined up in the groove. Patients report less pain and improved function with these forms of treatment.
As the pain and inflammation become controlled, your physical therapist will work with you to improve flexibility, strength, and muscle balance in the knee. Quadriceps strengthening exercises to address deficits in knee extension strength include non-weight-bearing single-joint (e.g., knee extension) and weight-bearing multiple-joint exercises (e.g., seated leg press).
Non-weight bearing exercises are also known as open kinetic chain exercise. Weight-bearing exercises are referred as closed-chain exercise. Closed-chain exercises place less stress on the patellofemoral joint and may be used first to achieve improved function before progressing to open kinetic chain exercises. Studies also show greater VMO activity with closed kinetic chain exercise. And a closed-chain exercise program also addresses hip muscle weakness at the same time as knee muscle deficits.
The therapist will adjust your rehab program to provide you with the most pain free and effective method of treatment. The overall rehab program will include a home exercise program of stretching, agility exercises, balance activities, and strengthening designed to return you to your former level of pain free participation in sports and other activities.