BRINGING SCIENCE TO TREATMENT

The best exercise for patellofemoral pain.

England and Chelsea striker Chris Sutton has his knee checked by a physiotherapist after an England training session.

Nearly 10% of adolescent athletes complain of patellofemoral pain (PFP)(1). When evaluating knee injuries in adults that present to the sports clinic, up to 25% involve the patellofemoral joint. This nagging injury likely starts during adolescents when young athletes begin to ramp up their training and increase the time spent in sport.

As Chris Mallac explains in the first of his two-part article on patellofemoral pain, the biomechanics and function of the patellofemoral joint depend largely on the ability of the patella to track well along the femur. Many believe that the greatest contributor to healthy patellar function is the vastus medialis obliquus (VMO). The debate on the role of the VMO is more than just an academic exercise. The participation of this muscle in correcting PFP is of considerable clinical relevance.

If the VMO, or other muscles for that matter, impact PFP, then a program devoted to load management and strengthening should decrease complaints of pain and improve function. Researchers in Denmark sought to determine if just such a plan improved outcomes in adolescents diagnosed with PFP(1). They enrolled 151 young athletes ages 10 to 14-years-old with complaints of PFP in a 12-week physical therapy intervention program.

For the first four weeks the subjects performed bridges and static quad holds. During weeks five through eight, the program instituted an activity ladder that slowly increased the amount of activity within the subject’s pain threshold. Resistance activities were introduced during the fifth week and progressed as tolerated to include gluteal, quadriceps, and hamstring strengthening using a resistance band and body weight.

After the 12-week intervention, 86% of participants reported a successful outcome. At three-months post-intervention, 68% of the subjects had returned to sport. One year later, 81% of the subjects had returned to sporting activities.

The investigators considered the outcomes of this exercise and activity modification program a success. Of note, this exercise program addressed global strength around the hip and knee, not just the VMO. In addition, each subject had a period of rest before a gradual reintroduction of modified activity. Without a control group and with two variables, it’s impossible to say which aspect of the program attributed the most to the successful outcomes.

Interestingly, soleus and gastrocnemius strengthening exercises were not specifically included in the study’s exercise program. Pat Gillham makes a case for the role of the soleus in PFP and offers some additional ways to increase the strength and flexibility of this muscle and thus improve PFP. Chris Mallac, in part II of his investigation of the contribution of the VMO to PFP, offers more advanced strengthening activities to incorporate as well. Both authors conclude, as do the Danish researchers, that strengthening the muscles in the lower extremity improves patellofemoral function and decrease pain. But which exercises are key?

Which exercise is best?

Perhaps it doesn’t actually matter which muscles the exercises target. Norwegian researchers compared three modes of exercise intervention for the treatment of PFP(3).  They randomly assigned 112 subjects, ages 16 to 40, with complaints of PFP lasting greater than three months, to one of three groups. Each group received similar patient education and performed hip-focused exercises, knee-focused exercises, or free-training activities.

After three months, the outcome measures between groups did not differ significantly or clinically. All patients, regardless of what intervention they received, showed improvement in the primary measurement, the Anterior Knee Pain Scale, as well as all secondary measurements. The only detected differences between groups were in hip abduction and knee extension strength, the very strength measures thought to contribute most to improving PFP. Yet, even those groups with weaker knee extensors and hip abductors got better.

So what exactly is the best exercise for PFP? Clearly, continued activity is part of the remedy. Grading exercise within the pain threshold of participants, along with patient education that continued loading within this threshold won’t make the condition worse, seem to be essential components of PFP rehab. As to which exercises or what types of movement are best, the jury is still out. The important thing is to keep the athlete moving!

References

  1. Am J Sports Med. 2019 May; online first
  2. Clinical Journal of Sport Med; 1997. 7:28-31
  3. Am J Sports Med. 2019 April;47(6):1312–1322

 

 

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