Patellofemoral pain syndrome (PFPS)
Patellofemoral pain syndrome (PFPS) is referred to as ‘Chondromalacia patella’ or ’anterior knee pain syndrome’ or ’patellar dysfunction. PFPS is characterized by retropatellar and peripatellar pain that usually refers to the anterior aspect of the knee. It is more common in adolescents and is caused by abnormal motion of patella on underlying trochlear groove with activities such as squatting, running, stair climbing and descending.
It is suggested that PFPS can result from overuse due to muscular imbalance between hamstring, quadriceps, tensor fascia latae (TFL), gluteus medius, vastus medialis and vastus lateralis. PFPS can also be caused by misalignment within the sulculs of the femur leading to oblique lateral tracking, or lateral and medial ligamentous imbalances eventually resulting in excessive lateral pressure in the patellofemoral articulation. Direct trauma, faulty seat height and even new shoes can cause PFPS. Factors associated with PFPS are decreased ﬂexibility of the lower extremity muscles lower hip extension strength, lower knee extension strength, faulty ankle/foot mechanics, and faulty hip/pelvis/trunk mechanics.
The signs and symptoms of PFPS are: crepitus, and anterior knee pain worsened by running, jumping, squatting or descending stairs. Also, those with PFPS experience pain when the knee is put in full flexion position. Catching and locking of the knee with sensations of stiffness and swelling is common. Some may have “buckling” sensations in walking.
Before diagnosis is made, other types of knee pathologies including iliotibial band friction syndrome, Osgood Schlatter syndrome, intra-articular pathologies like osteoarthritis and traumatic injuries like injured ligaments, meniscal tears and other related conditions must be ruled out. There are some orthopedic tests like resisted knee extension test and Clarke’s compression test that help to make the diagnosis. Moreover, for PFPS, patients are positive during Apprehension and Kneeling tests.
Interventions that use a combination of stretching and strengthening exercises are the best for PFPS. Although the optimal type and frequency of the exercise therapy has not yet determined, but studies have shown that exercise therapy results in clinically important reduction in pain and improvement in functional ability, as well as enhancing long-term recovery. It is also suggested that combination of knee and hip exercises are more effective in decreasing the pain compared to knee exercise alone.
- Kay M Crossley, Joshua J Stefanik, James Selfe,Natalie J Collins, Irene S Davis, Christopher M Powers, Jenny McConnell, Bill Vicenzino, David M Bazett-Jones, Jean-Francois Esculier, Dylan Morrissey, Michael J Callaghan. Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. 2016.
- van der Heijden RA, Lankhorst NE, van Linschoten R, Bierma-Zeinstra SM, van Middelkoop M. Exercise for treating patellofemoral pain syndrome. 2015. Cochrane Database of Systematic Reviews.