PFPS: High-intensity exercises shown most effective in rehab

The latest recommendations from new research regarding the rehabilitation of patellofemoral pain syndrome concur with the long-accepted form of treatment for this condition. The difference with this research is that the results suggest that exercise intensity is key to success.

What is patellofemoral pain syndrome?

Patellofemoral pain syndrome (PFPS) is a common condition at the knee joint that can affect many different groups of people. It is especially common in females due to a wider pelvis, creating a larger Q angle at the knee joint, but can also occur in males. It can develop at any age from the teenage years up.

The condition is due to friction between the patella and the underlying structures. The most common cause for this is excess lateral movements of the knee cap when the knee is flexed.

When this occurs, rather than the patella running smoothly in the trochlea groove (formed by the femur and tibia), it starts to rub against the lateral lip of the groove. Eventually, this causes irritation, leading to inflammation and pain. In some cases, the irritation may come about due to less common patella positions, such as a tilted or rotated patella.

Due to knee flexion being a primary cause of irritation, exercise and other activities that require repeated knee bending often aggravate the injury. Pain on climbing or descending stairs is a frequent complaint, as is pain after exercise or when sitting with the knees bent for long periods (often called movie-goer's knee).

How is it treated?

Treatment of this condition is aimed at correcting the biomechanical causes behind its development. Problems such as weak hip abductor muscles, tight lateral knee and thigh musculature and excess or rapid overpronation of the foot or fallen arches can all affect patella tracking.

Exercises to strengthen the outer hip muscles, such as gluteus medius, have long since been recognized as a key target when treating this condition. Strengthening of the vastus medialis oblique (VMO) muscle will also improve patella tracking.

Working on tibialis posterior strength and eccentric control, coupled with shoe orthotics where necessary, will help slow and reduce overpronation. Soft tissue work may also be beneficial to help reduce traction forces on the patella from the lateral quads and lateral retinaculum on the outer knee.

Exercise is a key factor when it comes to treating such a condition. This is well known. The difficult area for therapists is just how hard they should work their PFPS patients. We are always taught that exercising into pain is not recommended, and that pain is a signal for damage, or at least increased stress to an injury.

Latest research

A new paper published in the Journal of Physiotherapy has investigated two differing exercise regimes for those with PFPS to determine the effectiveness of low intensity vs high intensity rehabilitation.

The study, performed at the Sør-Trøndelag University College in Trondheim, Norway, used 40 volunteers with PFPS, split into two groups. The control group performed low-intensity, low-repetition exercises, while the intervention group performed high-intensity, high-rep exercises.

Increased intensity was gained by increasing sets and reps per exercise, as well as the number of exercises performed and total time spent performing aerobic/global exercises. Both groups completed three workouts a week, for a 12-week period.

The outcome measures taken before and after the 12-week program were pain (using a visual analogue scale) and function (using the step-down test and a modified functional index questionnaire). After the 12-week program, the intervention group demonstrated significantly less pain and increased function, when compared to the control group.

This demonstrates that while exercise is often an aggravating factor for people with PFPS, the right exercises can be used effectively to ease symptoms and regain full function of the joint. Therapists can be confident in pushing their patients to push themselves. While acute, sharp pain at the time of exercise is best avoided, exercise therapy can still be used in even the most acute of cases.

Initially, where pain is limiting exercise, the patella can be taped medially to help prevent excess lateral motion until muscle imbalances are corrected and movement patterns improved.

The early stages should largely focus on increasing the strength of the hip abductor muscles to help regain good knee alignment on weight bearing knee flexion. This should not cause the patient any discomfort in the knee as the movement emphasis is on the hip joint using exercises such as "the clam" and "hip hitch" (aka "hip drop").

Close-range quad-setting exercises are also recommended to begin VMO strengthening and should not cause the majority of patients any discomfort.

Conclusion

Rehabilitative exercises are recommended for those with PFPS, even those patients where exercise is an aggravating factor. A high-intensity exercise program appears to be more effective in decreasing pain and improving knee function over a 12-week period.

Patients can be pushed hard using such a program, provided pain is kept to a minimum by taping the patella and focusing on hip strengthening and end-range knee-flexion exercises.