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By J. Kim Ross, DC, PhD

Dr. Ross is Director of Education Year 1, and associate professor at Canadian Memorial Chiropractic College, in Toronto, Ontario, Canada. He conducts educational sessions on behalf of Orthotic Holdings Inc.

LER: Dr Ross, what problem do you see most commonly in chiropractic medicine among previously active patients who have had to curtail activity because of pain?

JKR: The most common condition related to the foot and ankle that I see in my practice is patellofemoral pain (PFP) syndrome. Clearly, this is a knee condition, but clinical wisdom has linked it with overpronation of the foot. It was this link that brought me to use foot orthoses as an option for treatment of overuse injuries of the lower limb. The first 20 pairs of foot orthoses that I prescribed in 1990 were for treatment of PFP. The results were impressive, and I started using foot orthoses as a treatment for various maladies of the lower limb.

LER: What is your diagnostic approach when you suspect PFP syndrome?

JKR: The patient’s history will provide important information, such as reports of anterior or retropatellar knee pain during running, squatting, hopping, kneeling, or prolonged sitting. Clark’s patellar grind test is a standard orthopedic test used in the diagnosis; patient is supine with a pad under the knee to maintain some degree of knee flexion while contracting the quadriceps muscle as the clinician applies force on the superior aspect of the patella in an inferior direction. The test is positive for PFP if it reproduces the knee pain, although it is not a definitive test.

The eccentric step test is, however, more likely to diagnose PFP. Standing on a block, the patient steps down toward the floor with 1 foot. The test is positive if the patient reports knee pain on the stance leg while the other foot is stepping toward the floor.1

LER: Is PFP syndrome associated with a particular foot type?

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JKR: As I mentioned earlier, it has been assumed that PFP syndrome results from overpronation of the foot, which is why foot orthoses are prescribed for these patients. Interestingly, PFP syndrome has not been associated with any particular foot type, and yet orthotic devices appear helpful in relieving pain.

This observation has inspired several researchers to examine prediction rules for whether a patient with PFP syndrome will benefit from use of foot orthoses. Sutlive and coworkers in 2004 discovered that a person was more likely to respond favorably to the orthotic intervention if any of following were present:

• valgus forefoot alignment, >2°
• navicular drop, ≤3 mm
• absence of crepitus
• relaxed calcaneal stance, <5° degrees valgus, or varus alignment
• great toe extension range of motion, <7°
• straight leg raise limited by hamstring tightness.2

Using no predictors, the success rate is approximately 60%. The presence of 3 of those factors—navicular drop, toe extension, and forefoot alignment—increases the success rate with an orthotic intervention to 86%.

Conducting a similar study in 2010, Vicenzino and colleagues identified additional predictors of better outcomes using foot orthoses:

• age, >25 years
• height, <165 cm
• worst pain, <53 on a 100-point visual analog scale
• midfoot width difference, >10.96 mm between weight-bearing and non-weight-bearing.3

The researchers noted a success rate of 52% with only 1 of those predictors present; the presence of 2 or 3 increased the success rate to 59% and 85%, respectively.

Barton and coworkers in 2011 identified additional predictors of clinical success. Their finding was that patients had better outcomes when using foot orthoses if—

• usual pain, <22 mm (on 100-point visual analog scale)
• reduced ankle dorsiflexion (equinus)
• pain was less during a squat if the patient wore foot orthoses.4

Patients whose footwear lacked motion control features also had better outcomes with foot orthoses.

Building on this work, Mills and coworkers included patients with PFP syndrome who had at least 2 of the predictors identified by Vicenzino, and assigned participants to either receive foot orthoses or no treatment.5 The authors found that although the foot orthoses used in the study were “off-the-shelf,” patients using them responded significantly better than the control group. They further reported that within the intervention group, participants were more likely to report a successful outcome when forefoot width from non-weight-bearing to weight bearing increased >11.25 mm.

LER: In your practice, does a patient’s lack of these predictors preclude the use of foot orthoses for PFP syndrome?

JKR: When you look at the studies together it appears clear that PFP syndrome is related to foot type, but not quite the way we originally thought it might be. The important point is that your success rate for treatment of PFP syndrome is likely to increase substantially for those patients with a number of these identified predictors present, compared with simply providing foot orthoses to anyone who has PFP.

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