Patellofemoral pain syndrome (also known as anterior knee pain) is characterized by pain around the kneecap that increases with prolonged activity or prolonged sitting. It is more common in females and is associated with weakness of the hip, particularly hip abductors, extensors and rotators (Prins et al. 2009) as Dr. Janda had proposed. This weakness is thought to lead to biomechanical deficits at the knee, most notably an increased knee abduction torque, which may alter patellar alignment over the distal femur at the knee. In addition, researchers (Leetun et al. 2004) have found that athletes with weak hip abductors and extensors in pre-participation screenings are more likely to be injured.
Therapeutic exercise programs strengthening the ‘proximal’ musculature (hip and core) have been successful in relieving symptoms of anterior knee pain. A research article in the American Journal of Sports Medicine reported on the outcomes of an exercise program in a series of young females with patellofemoral pain syndrome. After the 8-week exercise program, 17 out of 19 (89%) of the participants had successful outcomes. They had significant improvements in pain, functional ability, core endurance, and hip strength, as well as improvement in the knee abduction angle during gait. The main limitation of this study was the lack of a true control group, which would be able to identify if the exercise program was responsible for the improvements observed.
It would have been beneficial if the authors had identified specific muscle imbalance patterns within the individuals and prescribe an individualized program. In the current study, all participants performed the same exercises regardless of the presence of muscle imbalance. Such information would be helpful in determining if an individualized therapeutic exercise program can be more efficient and effective by targeting specific impairments.
Females with patellofemoral pain syndrome can benefit from a proximal strengthening program. A true control group and long-term follow-up would have been beneficial in further validating the efficacy of the program.
REFERENCE: Earl JE, Hoch AZ. A proximal strengthening program improves pain, function, and biomechanics in women with patellofemoral pain syndrome. Am J Sports Med. 2011 Jan;39(1):154-63. Epub 2010 Oct 7.