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Chondromalacia / Patellofemoral Pain Syndrome Print

Chondromalacia is a descriptive term, which literally means softening of cartilage.

Chondromalacia Patellofemoral Pain Syndrome, Dr. Allen F. Anderson, Nashville, Orthopaedic Sports Medicine, Figure 1 Chondromalacia Patellofemoral Pain Syndrome, Dr. Allen F. Anderson, Nashville, Orthopaedic Sports Medicine, Figure 2

As the name applies to the clinical diagnosis of knee pain by patient symptoms and patient examination, chondromalacia refers to pain that usually involves the front of the knee. Alternative names for chondromalacia are anterior knee pain and patellofemoral pain syndrome. The diagnosis of chondromalacia requires careful evaluation of the history and physical exam to rule other causes of anterior knee pain.

Chondromalacia Patellofemoral Pain Syndrome, Dr. Allen F. Anderson, Nashville, Orthopaedic Sports Medicine, Figure 3History

Most patients will complain of pain on the front of the knee that is exacerbated by stair climbing, squatting maneuvers, kneeling, and prolonged sitting. Pain may begin with a minor traumatic event that causes the patient to avoid using the thigh muscles, which subsequently causes quadriceps muscle atrophy. Muscle atrophy leads to imbalance in the muscles that control movement of the patella within its groove on the end of the femur. This imbalance leads to pain due to increased pressure on the joint surfaces of the kneecap joint. Alternatively, there may be a gradual, insidious onset of pain due to an overuse syndrome that also leads to a muscle imbalance and pain.

The pain associated with chondromalacia is often dull and aching in quality but occasionally may be sudden and sharp. The pain is often worsened by activities that require bending the knee for a prolonged period or with increased load (e.g. stairs or squatting). Pain may be associated with a grating or popping sensation of the knee. The grinding or popping may not actually cause pain but is noticed by the patient as abnormal and thus may cause patient distress. Another distressing symptom is the sudden giving way of the knee while walking or turning or twisting. This giving way may indicate that there is some ligament insufficiency of the knee. However, most giving way related to chondromalacia is due to muscle weakness or due to pain associated with movement that causes the muscle to suddenly stop contracting as a reflex to that pain. There may also be swelling about the patella, but the actual development of a joint effusion occurs much less often.

Chondromalacia Patellofemoral Pain Syndrome, Dr. Allen F. Anderson, Nashville, Orthopaedic Sports Medicine, Figure 4Physical Examination

Examination should begin with the patient standing to observe overall limb alignment.

Certain limb alignments may predispose to improper tracking of the patella within the femoral trochlea (groove). The Q angle describes the alignment of the extensor mechanism from the angle the quadriceps inserts onto the patella and the insertion of the patella tendon into the tibial tubercle.

Careful inspection and palpation may reveal the presence of soft tissue swelling or the presence of an effusion fluid within the knee itself. Palpation of the quadriceps muscle may reveal gross atrophy of the quadriceps when compared to a normal uninvolved contralateral quadriceps. Careful palpation of the soft tissues about the patella is required to localize tenderness to the retinacular structures that serve as ligamentous support for the patella.

In addition, it is important to determine if there is excessive mobility of the patella or excessive tightness of the retinaculum, which restricts motion of the patella. Both abnormalities may cause abnormal tracking of the patella within the femoral trochlea. Mobility of the patella is assessed with the knee slightly flexed and the quadriceps muscle relaxed. 

If the patella can be moved medially 25% or less of the patella width, the lateral retinaculum is tight. The lateral retinaculum is also tight if the lateral patella can be tilted 15° or less from horizontal. An excessively tight lateral retinaculum can lead to excessive pressure on the lateral patella with subsequent pain. Pushing and tilting the patella is also necessary to adequately palpate the retinaculum to localize pain to retinaculum and underlying patellar facets and synovium.

In addition to testing for a tight lateral retinaculum, it is important to test the medial retinaculum by displacing the patella laterally. This may result in pain or apprehension felt by the patient. Pain in the area of the medial retinaculum with the patient feeling as if the patella will dislocate is indicative of lateral patella instability.

Palpation of the patellofemoral articulation during active and passive range of motion of the knee will determine if there is crepitation of the joint or abnormal tracking of the patella within the femoral trochlea. Compression of the patella against the femur at varying degrees of knee flexion may elicit articular pain. Another way to test this is to manually resist the upward movement of the patella as the patient actively contracts the quadriceps. Manipulating the patella with simultaneous compression of the patellofemoral joint may elicit pain but may more importantly identify areas of significant cartilage wear on the joint surfaces.

Chondromalacia Patellofemoral Pain Syndrome, Dr. Allen F. Anderson, Nashville, Orthopaedic Sports Medicine, Figure 5

The examination is completed by thorough evaluation of the ligaments of the knee. This includes examination of the medial and lateral collateral ligaments as well as examination of the anterior and posterior cruciate ligaments. Joint line tenderness and crepitation of the joint may identify medial and lateral meniscus tears with provocative maneuvers such as McMurray testing.

Radiographs

Standard radiographs are usually obtained for the initial evaluation of anterior knee pain. The standard x-ray views obtained are AP, Lateral, and Skyline Views. Rarely, additional studies may be obtained. These might consist of skyline views at varying degrees of knee flexion to evaluate patellar tilt and patella subluxation. Computed tomography (CT), magnetic resonance imaging (MRI), and bone scans are other x-rays studies that may be obtained very rarely to further identify possible causes of knee pain associated with anterior knee pain.

Treatment

The treatment of patellofemoral pain syndrome is primarily non-surgical with emphasis on strengthening the quadriceps within a painfree arc of motion. This is usually initiated by a physical therapist to instruct the patient in the proper technique of performing the exercises. The use of ice and anti-inflammatory medication is beneficial to initially decrease the pain associated with this condition. Avoidance of activities that place excessive load across the patellofemoral joint is also important. This would include minimizing stair climbing and squatting or kneeling activities until quadriceps strength is restored and the inflammatory response has subsided. The physical therapist may also use taping to decrease pain about the patella while the patient is exercising. There are also elastic knee braces available which have adjustable pads to help maintain patella alignment. The brace is usually worn for athletic activities.

Specific exercises for chondromalacia include stretching exercises for the quadriceps, hamstrings, and the iliotibial band. The quadriceps may be stretched standing, supine or prone. The standing quadriceps stretch is performed with the patient standing on the unaffected leg and the affected leg is flexed with the ankle brought up towards the buttock. The supine stretch is performed on the side of a bed or treatment table with the affected leg suspended and flexed off the edge of the table. With the knee held flexed by grasping the ankle, the hip is extended and the rectus femoris muscle is stretched. The prone stretch is performed by lying face down on a table and the affected knee is flexed back towards the buttock. This stretch requires someone else to push on the leg to provide the stretching force.

Stretching the hamstring muscles may be performed sitting, supine, or standing. The hurdler's stretch is performed sitting with the opposite knee flexed such that the ankle is brought back to the buttock. The stretch is then performed by leaning the trunk over the extended leg which is being stretched. The supine stretch is performed lying on the back with the opposite leg remaining straight. The leg to be stretched is then flexed at the hip with the knee remaining straight. The hamstrings may also be stretched while standing by bending forward at the waist and keeping the knees straight. Stretching the iliotibial band is also performed while standing. The leg to be stretched is crossed over the opposite leg and the trunk is flexed to the opposite side to place a stretch on the outside of the thigh.

Strengthening exercises consist of straight-leg raises, quadsets, short arc knee extensions and partial squats or leg presses in a graduated and progressive fashion. As the knee becomes stronger and less irritated, more weight, greater rnumber of repetitions and the more strenuous exercises are added to the strengthening program. Bicycling may also be added to maintain cardiovascular conditioning. It is important to adjust the bicycle seat height such that the knee remains flexed 15-20° at the end of the down stroke on the pedal.

The treatment outlined above will control the symptoms of patellofemoral pain syndrome in more than 85% of patients. A minimum of six months of conservative treatment should be performed prior to considering surgical options. The results of surgery are not normally predictable. The success rate for patellofemoral pain surgery is between 60 and 80% compared to 90 - 95% success rate for ligament or cartilage injuries. Consequently, surgery for patellofemoral pain should be considered a last resort.

 
© Allen F. Anderson, M.D. 2017