Patellofemoral Syndrome, also called Chondromalacia, refers to softening or fissuring of the articular surface of the patellar joint. It is a common cause of anterior knee pain.  The most common causes are cumulative trauma, traumatic dislocations of the patella, patellar malalignment, increased patellar compression (associated with obesity and/or weight lifting), and osteoarthritis.

Pathogenesis:

Patellofemoral syndrome is thought to occur via two mechanisms. One is a malalignment of the patella; the other is a repetitive microtrauma due to overuse of the patellofemoral joint, such as running or jumping. These two mechanisms first can lead to inflammation in the joint. After repetitive stress/injury degenerative changes on the articular surface of the patellar joint and on the femoral sulcus develop.  Other predisposing factors include: quadriceps and hamstrings muscles and iliotibial band tightness, relative weakness of the quadriceps muscles, femoral anteversion, genu valgum, genu recurvatum, or excessive foot pronation.

Clinical Symptoms of Patellofemoral Syndrome:

Patients typically complain of anterior knee pain that is worse after prolonged sitting (theater sign), climbing stairs, jumping, or squatting. The pain can be dull or aching and some patients may report knee buckling or a sticking sensation of the patella.

Physical examination:

Diffuse pain in the knee that increases with knee flexion. Crepitus and cracking noises may be felt or heard during range of motion. Tenderness on the undersurface of the patella can be elicited by manually moving the patella, and palpating the surface with the opposite hand.  Increased “Q” angle, excessive internal femoral torsion (internal rotation of the hip exceeds external rotation by more than 30º) can also be found.

Treatment of Patellofemoral Syndrome:

All patients should be started on a program of quadriceps (especially VMO) strengthening and flexibility. Initially, full-arc quadriceps exercise (0-90º) should be avoided and short-arc activities (0 to 15º) emphasized.  Once adequate quadriceps strength and flexibility has been obtained, cycling to increase ROM can be started.  Use of neoprene sleeve, NSAIDS cryotherapy (ice application) or patellar strapping may be helpful.  Weight loss is recommended.  If 6-12 weeks of documented rehabilitation (non-surgical treatment) shows no benefit, an arthroscopic procedure is indicated.