Evaluation of a Treatment Algorithm for Patients With Patellofemoral Pain Syndrome: A Randomized Controlled Trial

Patellofemoral pain syndrome (PFPS) accounts for 25 to 40% of knee pain in young and active individuals. PFPS is described as anterior knee pain around the patella which is aggravated by activity, particularly activities that increase patellofemoral forces such as squatting, ascending or descending stairs, running, and jumping. It is common in adolescents and physically active adults. Females are more likely to experience PFPS than males. PFPS is a multi-factorial condition with no clear etiology and is considered a syndrome and not a diagnosis. Dye has described PFPS as one of the most difficult orthopedic conditions to manage.

Multiple theories exist regarding a cause for PFPS pain. A primary theory for the cause of PFPS is abnormal patellar tracking which results in excessive patellofemoral joint compressive forces. Many factors contributing to abnormal patellar tracking have been suggested including; hip and quadriceps weakness, delayed or diminished activation of vastus medialis obliquus, increased Q-angle, altered lower extremity mechanics and decreased lower extremity flexibility. Due to the number of suggested contributory factors to PFPS pain, a vast amount of interventions exist and are frequently used by clinicians. Although, physical therapy interventions have been shown to be effective over sham interventions, many individuals will have recurrent or chronic pain. Ninety-six percent of patients report having problems four years following their diagnosis of PFPS. A possible reason for the continued pain is that PFPS is a multi-factorial condition and the treatments may not address all of the contributing factors in each individual.

If all of the contributing factors for the patient's PFPS are identified, addressing all of these factors at once may not be the best approach. Performing hip strengthening prior to quadriceps strengthening results in decreased levels of pain with exercise. Individuals with reduced flexibility are more likely to have impaired lower extremity mechanics. Performing traditional lower extremity strengthening exercises when there is impaired lower extremity mechanics results in increased patellofemoral joint contact forces.

In an attempt to better treat individuals with PFPS, classification systems to subgroup patients with PFPS have been proposed, but their effectiveness has not been evaluated. An important clinical question with classification systems is what to do when a patient does not nicely fit into one subgroup. If a patient does not meet or meets the criteria for multiple subgroups, how is the patient treated? No evidence exists on the relative frequency with which patients with PFPS fall into each of these proposed subgroups and whether these subgroups are mutually exclusive.

The clinical classification systems reported in literature only address physical impairments. Psychosocial factors have also been identified as important when treating patients with PFPS. In a study by Piva et al. fear avoidance beliefs were the strongest predictor of outcomes for function and pain. Mental health status on the Medical Outcomes Short Form-36 is correlated with severity of patellofemoral symptoms in athletes. The results of these studies highlight the necessity of addressing psychosocial factors when treating PFPS.