Pinnacle Orthopedic Associates Brian Shannon, M.D. Sports Medicine Shasta Van Sickle, PA-C Physician Assistant 3455 Lutheran Parkway, Ste 210 Wheat Ridge, CO 80033 Phone: (303) 403-6580 Fax: (303) 403-7347 Email: [email protected] C Ch ho on nd dr ro om ma alla ac ciia aP Pa atte elllla a What is chondromalacia Patella? The word “chondromalacia” literally means cartilage (chondro) softening (malacia). While this condition may occur in any joint, it is most often used to describe the process under the patella (kneecap). The term chondromalacia patella refers specifically to a pathological condition resulting in structural changes in the cartilage surface of the kneecap. These changes may be as mild as softening and discoloration of the normally firm, white, glistening surfaces. If the process continues, fissuring and fraying may occur with the more advanced stages resulting in full thickness cartilage loss with exposure of the underlying bone. The process may be localized to one small area or it may involve the entire surface of the patella. Because of these variations in the cartilage changes, the symptoms experienced by the patients with chondromalacia may vary tremendously. A) B) Figure 1: As the knee flexes, the patella moves downward in the femoral groove. A) Extension B) Flexion What is the patella? The patella, an oblong shaped bone, lies embedded within the tendon of the quadriceps muscle. The main function of this muscle is to extend (straighten) the knee which occurs when the muscle contracts. The patella aids the quadriceps muscle in extending the knee by improving the mechanical advantage of the muscle at the knee joint. During motion of the knee, flexion and extension, the patella glides downward and upward, respectively, in a groove present at the end of the femur (thigh bone) (Fig. 1). The patella and the femoral groove are each covered by smooth cartilage surfaces which allow the patella to glide during knee motion. The cartilage surface of the patella is the thickest such surface of any bone in the body measuring approximately four to six millimeters. This cartilage helps to absorb and disperse the large forces placed on the knee during various activities. Walking on level ground exerts a force equivalent to ½ the body weight on the patellofemoral joint while climbing stairs increases that force to nearly three times the body weight. Arising from a full squat can generate forces as large as eight times the body weight. Chondromalacia Patella What causes chondromalacia? Chondromalacia may develop following an acute injury to the knee such as a direct blow to the patella or a fracture or dislocation of the patella. More commonly, however, it has an insidious onset not specifically related to any one traumatic event. There may be an underlining anatomical variation of the patella or the femoral groove or excessively tight supporting tissues around the patella. Malalignment of the lower extremity secondary to excessive rotation of the thigh or leg bone, abnormal angle between these bones at the knee (knock-knee, bowleg) or altered foot alignment may also be present. In general, any variation which results in “maltracking” of the patella in the femoral groove during knee motion may expose the cartilage to larger loads than it can withstand resulting in abnormal wear (Fig. 2). A) B) C) Figure 2: X-ray view of the patella in the femoral groove demonstrating A) normal tracking B) Patellar “tilt” and C) patellar “maltracking” (“subluxation”) Who gets chondromalacia? It appears that chondromalacia is somewhat more common in women than men. It is seen most frequently during the adolescent and early adult years but may occur at any age. In most cases a specific activity can be identified that makes the condition symptomatic. It may be recreational, job related, or an activity of daily living. Chondromalacia is seen more often in those individuals involved in activities which require a significant amount of kneeling, squatting and even walking (when stairs and hills are involved). It is also aggravated in some individuals by running and jumping. In runners, increased mileage or hilly terrain may bring on the symptoms of chondromalacia. What are the symptoms? The signs and symptoms of chondromalacia are nonspecific and vary somewhat from individual to individual. Generally there is a dull, aching pain across the front of the knee. The pain may occur during or (more commonly) after an aggravating activity. With symptomatic episodes there may be a mild puffiness or feeling of fullness about the knee. There is often a noticeable “cracking’ or “popping” with knee motion. Prolonged periods of sitting (such as a long trip in the car or sitting through a movie in the theater) often result in an aching stiffness. Squatting, climbing stairs and (in particular) walking down stairs may provoke knee pain. The pain experienced in chondromalacia is thought to result from increased pressure on the bone under the area of abnormal cartilage. Irritation of the lining of the knee joint by tiny particles of cartilage debris can result in swelling and any also contribute to the pain. Chondromalacia Patella How is chondromalacia diagnosed? There is no one test that conclusively establishes the diagnosis of chondromalacia. While x-rays may be helpful in demonstrating anatomic variations associated with chondromalacia, they do not demonstrate the early changes taking place within the cartilage surface of the patella. The diagnosis is generally based upon the patient’s symptoms and examination of the symptomatic knee in the physician’s office. Arthroscopy, a surgical technique which allows the physician to look directly at the cartilage surface of the patella, is rarely necessary to confirm the diagnosis. What is the treatment? Although chondromalacia does represent a mild form of arthritis, rarely does it result in severe, permanent damage to the knee. More typically, the patient with chondromalacia will experience periods of ups and downs in their symptoms usually related to their activities. Treatment is aimed at reducing the frequency and severity of painful episodes and possibly eliminating the symptoms entirely. One way to reduce the symptoms of chondromalacia is to avoid those activities which aggravate the condition. This may involve modification of certain activities or eliminating activities completely if necessary. If one can avoid aggravating the condition, the body will usually (over a period of time) smooth out the roughened surface of the patella. Cycling can sometimes help the body with this remodeling process. A specific exercise program stressing quadriceps muscle strengthening and hamstring muscle stretching often times reduces the symptoms dramatically. Icing the knee after aggravating activities and occasional use of ibuprofen or other anti-inflammatory medications may also be helpful. A patella stabilizing brace is sometimes beneficial in those individuals in whom patella maltracking is contributing to the condition. Swimming is generally the most well tolerated fitness activity. However in choosing any fitness program, one should use pain and swelling as a guide. Despite a conservative treatment program, a small percentage of patients with chondromalacia will continue to experience significant knee pain and disability. Surgery is sometimes elected in these individuals to manage the problem. A variety of surgical procedures have been described in the treatment of chondromalacia. These procedures involve smoothing down that cartilage surface of the patella and/or realigning the quadriceps-patella complex in order to improve the tracking of the patella. These procedures can typically be done arthroscopically. Although occasionally they require a more traditional open surgical technique. In very rare instances it may be decided to completely remove the patella to alleviate the pain. In general, however, surgery for chondromalacia should be considered only after all other treatment methods have failed. Summary Chondromalacia is a condition involving the cartilage surface of the kneecap. It can become symptomatic from a variety of causes. Usually an aggravating activity can be identified. It rarely results in permanent disability. Conservative treatment including activity modification, a well designed exercise program, ice, bracing and inflammatory medication is usually successful in its treatment. Occasionally surgery is elected to help the symptoms of chondromalacia.