Orthotic-Devices-for-the-Win

By Frank Layman, PT, DPT, EdD, MT; and April Wilson, PTA, BS, CI, CKTP, IASTM

Sponsored by an educational grant from medi USA.

Pronation is a triplanar movement and is the combination of rearfoot eversion, midfoot abduction, and talocrural dorsiflexion.1 Pronation in normal gait allows flexible, adaptive changes to varying types of terrain; it dissipates ground reaction forces; and encourages lower extremity internal rotation.

Foot pronation—often observed as inward tilting of the ankles and flattening of the arches—is a normal part of walking and running. But when it’s excessive (movement of the foot to the point that the medial longitudinal arch [MLA] flattens fully or close to it), it can lead to foot, ankle, or even knee pain.2 This can have a profound impact on athletes and their performance in the short term, and in the long term these biomechanical influences could exacerbate or contribute to other dysfunctions.

Most of the literature on excessive pronation has focused on runners;3-5 however, in our clinical experience, it can be associated with an increased incidence of injuries in other athletes—including basketball, tennis, and volleyball players—not always with respect to the direct mechanism of injury, but in association with the training these athletes do to be ready to play.

In athletes, excessive foot pronation has been shown to be associated with the incidence of:

  • Metatarsal stress fracture3,6
  • Plantar fasciitis4
  • Achilles tendinopathy;4,7
  • Patellar tendinopathy8
  • Medial tibial stress syndrome (MTSS)5
  • Patellofemoral pain5

In our clinical experience, excessive pronation in athletes can also be associated with pelvic misalignments, functional scoliosis, and excessive lumbar lordosis.

In 2013, Menz et al reported that pronated foot function may contribute to low back symptoms in older women,9 and suggested that interventions to modify foot function, such as orthoses, may therefore have a role in prevention and treatment of low back pain. Athletes suffering from low back pain who have had local treatment to no avail could potentially benefit from these types of interventions.

We aren’t suggesting a direct link between pronation and any of the dysfunctions mentioned above, but noting there is a relationship that needs to be acknowledged and addressed, if necessary, as part of clinical management. Other contributing factors—including body mass index, level of experience in a specific sport, training methods, history of injury, strength, endurance, stiffness, and neuromotor deficits—also have to be evaluated, considered, and addressed as warranted.10

Examination

Excessive pronation is a common lower extremity postural distortion pattern that can lead to other movement dysfunction patterns throughout the kinetic chain and ultimately contribute to injury. When conducting an examination to identify excessive pronation, a comprehensive analysis of the weightbearing structures—from the foot to the midspine—and their biomechanical linkage is important. Sometimes, the problem can be traced to a link in the superior aspect of the chain, and at other times it is located inferiorly. This discussion will focus on what should be included in a foot examination.

Static and dynamic assessments of the foot and ankle complex can help to identify lower extremity dysfunction patterns associated with excessive pronation. Once these have been identified, following a systematic corrective exercise strategy can help to improve functionality and movement quality, leading to decreased risk of injury.11

Components of the examination can include these static tests:

  • Navicular drop test12
  • Measurement of the rearfoot-to-leg angle13
  • Measurement of the medial longitudinal arch angle13
  • Jack’s test14
  • Too many toes sign15
  • Foot posture index16

In addition to static tests, we advocate a dynamic examination. Pronation is a necessary and protective mechanism during walking and running as it allows attenuation of impact forces.17-19 In the clinic it helps to assess pronation during gait before taking corrective action.

When we assess gait in the clinic we don’t use an external instrument to measure pronation. Instead, we record video of the patient walking barefoot, and then review the video at a slower speed using a movement analysis app. Posteriorly, we look at the angle created when a line bisecting the lower leg and a line bisecting the heel come together at the ankle. A similar assessment can be done from an anterior view, looking at the angle created by a line bisecting the lower leg and another line from the ankle to the second metatarsal joint. In a patient with a normal gait, these angles will vary by a few degrees through the course of the gait cycle, in particular at foot flat and just before toe-off. When the range of pronation slightly exceeds this expected range, we might employ interventions including biofeedback and verbal cueing. In patients with pronation that is more excessive but still relatively minor, we would recommend the same treatments plus therapeutic exercise, manual physical therapy, and corrective footwear. In patients with moderately excessive pronation that does not respond to the previously mentioned methods, we advocate adding foot orthoses.

Treatment strategies

We cannot underestimate the impact pronation has on lower extremity pain and the restrictions that can follow. Foot pain, planus foot posture, and pronated foot function are associated with self-
reported difficulty undertaking common weightbearing tasks.1 Interventions to reduce foot pain and improve foot posture and function may therefore have a role in improving mobility in athletes.

Excessive pronation can be a compensation for a lack of ankle dorsiflexion. Unlocking the midtarsal joint, to allow for dorsiflexion and abduction movements at the midtarsal joint’s oblique axis, can result in excessive pronation that can stress the plantar fascia.20

The use of foot orthoses, footwear, and other strategic clinical interventions can help mitigate the adverse effects of excessive pronation in athletes. Addressing lower extremity alignment to positively influence biomechanical changes is part of the intervention strategy we employ successfully in the clinic, which we also have recommended to other clinicians. Stretching can also be part of an effective treatment approach. It has been theorized that inflexibility of the gastrocsoleus complex can contribute to excessive pronation, as well as overcompensation of the plantar fascia at the first metatarsophalangeal joint.7

Orthotic intervention

10medi-istock_26926552-copyBoth the American Physical Therapy Association and the American College of Foot and Ankle Surgeons recommend multimodal interventions in patients with plantar fasciitis that include the use of custom or prefabricated foot orthoses.21,22 Findings that runners with plantar fasciitis have lower arches than their pain-free counterparts suggest that addressing pronation may be one component of foot orthosis effectiveness in this population.23

Research suggests foot orthoses can help reduce symptoms in runners with Achilles tendinopathy.24-26 The mechanism for these positive effects is likely multifactorial, but may involve reducing rearfoot eversion and vertically aligning the calcaneus.27

In a systematic literature review, Gross et al concluded that runners and other patients with patellofemoral pain (PFP) may benefit from foot orthoses as an adjunct to other interventions, if they also have excessive foot pronation, which may be accompanied by excessive lower-extremity internal rotation during weightbearing and a greater-than-normal Q angle (the angle formed by the thigh and shin).28 The authors suggested the mechanism for this positive effect might involve reducing internal rotation, reducing Q angle, reducing laterally-directed soft tissue forces, or reducing patello­femoral contact pressures.

A more recent study by Barton et al found limited ankle dorsiflexion and wearing unsupportive footwear—both potentially related to excessive pronation—were among the factors that were clinically predictive of foot orthosis efficacy in patients with PFP.29 Lower levels of pain and immediate reduction of pain with orthosis use were also clinically predictive variables.

Custom foot orthoses have been associated with reduced rates of MTSS in a military population, which has some similarities to athletes.30 Although that study did not control for foot posture, a systematic review and meta-analysis found strong evidence that excessive pronation was associated with an increased risk of MTSS.5

Farahpour et al found higher ground reaction forces during gait in people with pronation and low back pain than in those with low back pain alone.31 This finding suggests that in athletes with low back pain as well as pronation, orthotic intervention may need to provide shock absorption to reduce ground reaction forces, along with addressing any excessive pronation.

Clinical insights

Addressing excessive pronation in athletes as part of a comprehensive global approach to management of pain, the facilitation of mobility and fluid movement, and performance is strongly advocated and supported by research. Clinicians are advised to be familiar with relevant tests to detect excessive pronation and treatments to comprehensively address it while focusing on stretching, shoe design, and orthotic devices.

Keep in mind that the potential dysfunctions associated with excessive pronation are not limited to the foot and ankle. So the next time you are setting up a plan of care for an athlete with a knee or calf complaint, don’t just examine the local issues. Remember to look down.

Frank Layman, PT, DPT, EdD, MTC, is an administrator and clinician at Randolph Specialty Group in Asheboro, NC, an adjunct faculty member of the Department of Physical Therapy at High Point University in North Carolina, and a vice president of business development for Tapout Fitness in Raleigh, NC. April Wilson, PTA, BS, CI, CKTP, IASTM, is a physical therapy assistant at Randolph Specialty Group and the owner of Footwise, a company that offers individualized foot fittings for athletes, also in Asheboro, NC.

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