Patellofemoral pain syndrome (PFPS) is a common type of knee pain in which the symptoms appear behind or around the kneecap. American Family Physician describes the cause of PFPS as an imbalance of the forces that keep the kneecap in alignment during knee extension and flexion. This imbalance can increase the risk of muscle dysfunction, poor quadriceps flexibility, overuse, trauma and a host of other musculoskeletal problems. In other words, during PFPS, the kneecap does not glide back easily on its “track” to the femur. Despite its simple description, there is still no effective treatment for PFPS because there are multiple types and causes of knee pain. Thus, health professionals tend to get entrenched in dogma which has not been proven to cause knee pain. Aside from massage therapy and knee surgery, which has little effect in treating PFPS, some health professionals, such as physical therapists and athletic trainers, recommend corrective exercise as a self-care method for patients. Despite the prevalence of corrective exercise prescriptions, current evidence shows that this intervention may not always effectively treat knee pain and could be a waste of time.
Corrective exercise principles are based on the biomechanical premise that the kneecap is out of alignment, has tight or weak muscles, or that there is poor joint alignment elsewhere in the body. For example, a foam rolling technique known as self-myofascial release (SMR) or other stretching and strengthening exercises are typically suggested to alleviate the tension and tight tissue adhesions in the muscles that may contribute to movement dysfunction and pain. However, studies have shown that PFPS may not always be a biomechanical problem.
A 2006 Swedish study from the Department of Physiology and Pharmacology at Karolinska Institutet examined 80 patients who were clinically diagnosed with PFPS. Among them, 17 of them had a type of pathology in the knee while another 29 patients had “slow bone turnover disease.” Five patients had dropped out of the study. In the remaining 29 patients with PFPS, no pathologies or any indication of knee abnormality was found. In fact, researchers could not differentiate between the last group of patients with the control group that had no knee pain and were not diagnosed with PFPS. Thus, the principles behind corrective exercise may provide little or no benefit to some people with PFPS.
However, there is some evidence that exercise – corrective or otherwise – can decrease knee pain and improve function. A Dutch systematic review published in International Journal of Sports Physical Therapy showed that programs that emphasize knee strength yielded a 37 percent decrease in pain and a 21 percent increase in function, while programs that emphasize hip strength yielded a 65 percent decrease in pain and a 38 percent increase in function. Of course, the researchers suggested that physical therapists should “consider using proximal interventions for treatment of patellofemoral pain.”
Another recent review that was published in Journal of Orthopaedic and Sports Physical Therapy on June 2014 showed that quadriceps strengthening in isolation is “more effective in reducing pain and improving function than advice and information alone.” Combined with other interventions, when quadriceps training is compared to advice and information or a placebo, strong evidence shows that it “may be more effective in reducing pain immediately postintervention and after 12 months, but not in improving function,” the researchers mentioned.
Even with such benefits, exercise is not the cure-all for knee pain. “Exercise can help, but probably not because it’s ‘correcting’ anything,” science writer Paul Ingraham stated in an online interview with Guardian Liberty Voice. “A lot of exercise prescription for patellofemoral pain is based on the dubious assumption that the problem is caused by faulty biomechanics, such as the kneecap moving unevenly over the surface of the knee. Exercises are prescribed in the hope that such things can be corrected, usually by strengthening and stretching. Unfortunately, a lot of exercising for these goals is often out of tune with how exercise actually does help patients. And some of it is simply wrong: for instance, it’s an amazingly persistent myth that it’s possible to isolate the vastus medialis muscle – to train it to correct kneecap movement. And exercise intended to ‘correct’ is often aggressive – too much exercise, too soon.
“Another issue is that exercise is no kind of magic bullet,” Ingraham added. “The evidence supports it, but that doesn’t mean it works all the time. Patellofemoral pain has many faces, many possible causes and complications, and some cases do not respond to any kind of exercise, ‘corrective’ or otherwise.” In fact, another study from University of Pittsburgh’s Department of Physical Therapy that was published in Archives of Physical Medicine and Rehabilitation showed that psychological factors, such as fear-avoidance beliefs, played a more significant role in knee pain perception of muscle strength, flexibility and other physical impairments.
Even if corrective exercise is somewhat effective in the treatment of knee pain, checking in with a qualified healthcare professional is the wiser choice than self-care initially. Ingraham suggested that PFPS sufferers should consult with a physical therapist or sports medicine physician. The right massage therapist or a chiropractor can also work. “There’s no way to know in advance if a professional is qualified. It’s just a gamble,” Ingraham cautioned. “Patients have to be savvy consumers and proactively ‘shop around’ and seek second and third opinions, if not more. This can be expensive, but bad advice can be even more costly. Look for red flags indicating sloppy diagnosis or prescription. For instance, politely decline to return to see a therapist who focuses on allegedly correctable biomechanical factors or insists that you need to strengthen. Certainty about the cause or treatment is rarely justified, and a no-pain-no-gain attitude about exercise is the biggest red flag of all.”
Physiotherapist Tony Ingram, who practices in Halifax, Nova Scotia, gave his two cents to Guardian Liberty Voice about “shopping” for a therapist or physician. “Personally, I suggest to people to find a therapist who at least claims to practice in an ‘evidence-based’ way — they may not be perfect, but are probably ahead of the curve. Furthermore, someone who interacts with you, rather than operating on you. This is in fact easy to spot on your first visit.”
Indeed, there is no “magic bullet” or cookie-cutter approach to effectively treating knee pain, and corrective exercise is no exception. With the current evidence provided, a combination of movement, rest, and professional care is more likely to help PFPS patients better than any single modality.
By Nick Ng
IDEA Fitness Association
American Family Physician
Physiotherapy Theory and Practice
Archives of Physical Medicine and Rehabilitation
Journal of Orthopaedic and Sports Physical Therapy
European Journal of Physical and Rehabilitation Medicine
International Journal of Sports Physical Therapy
Interview with Paul Ingraham of Save Yourself
Interview with Tony Ingram, PT