Orthotics Cause Shin Splints in Runners?

Risk factors associated with medial tibial stress syndrome in runners: a systematic review and meta-analysis. Open Access J Sports Med. 2013 Nov 13;4:229-41. Newman P, Witchalls J, Waddington G, Adams R.

Abstract
BACKGROUND:
Medial tibial stress syndrome (MTSS) affects 5%-35% of runners. Research over the last 40 years investigating a range of interventions has not established any clearly effective management for MTSS that is better than prolonged rest. At the present time, understanding of the risk factors and potential causative factors for MTSS is inconclusive. The purpose of this review is to evaluate studies that have investigated various risk factors and their association with the development of MTSS in runners.

METHODS:
Medical research databases were searched for relevant literature, using the terms “MTSS AND prevention OR risk OR prediction OR incidence”.

RESULTS:
A systematic review of the literature identified ten papers suitable for inclusion in a meta-analysis. Measures with sufficient data for meta-analysis included dichotomous and continuous variables of body mass index (BMI), ankle dorsiflexion range of motion, navicular drop, orthotic use, foot type, previous history of MTSS, female gender, hip range of motion, and years of running experience. The following factors were found to have a statistically significant association with MTSS: increased hip external rotation in males (standard mean difference [SMD] 0.67, 95% confidence interval [CI] 0.29-1.04, P<0.001); prior use of orthotics (risk ratio [RR] 2.31, 95% CI 1.56-3.43, P<0.001); fewer years of running experience (SMD -0.74, 95% CI -1.26 to -0.23, P=0.005); female gender (RR 1.71, 95% CI 1.15-2.54, P=0.008); previous history of MTSS (RR 3.74, 95% CI 1.17-11.91, P=0.03); increased body mass index (SMD 0.24, 95% CI 0.08-0.41, P=0.003); navicular drop (SMD 0.26, 95% CI 0.02-0.50, P=0.03); and navicular drop >10 mm (RR 1.99, 95% CI 1.00-3.96, P=0.05).

CONCLUSION:
Female gender, previous history of MTSS, fewer years of running experience, orthotic use, increased body mass index, increased navicular drop, and increased external rotation hip range of motion in males are all significantly associated with an increased risk of developing MTSS. Future studies should analyze males and females separately because risk factors vary by gender. A continuum model of the development of MTSS that links the identified risk factors and known processes is proposed. These data can inform both screening and countermeasures for the prevention of MTSS in runners.

My comments

Medial tibial stress syndrome (MTSS) is the new term for shin splints. This review paper was the first to perform a meta-analysis of risk factors related to the condition.  Based on the paper the exact cause of the shin pain is unknown, but they noted that recent interpretations from imaging studies seem to be implicating the tibia bone itself as the most likely source of pain.

Navicular drop (an indicator for foot pronation) increased BMI, female gender, fewer years running experience and prior history of MTSS were all associated with increased risk, none of which was particularly surprising.  They noted ankle dorsiflexion range of motion was most certainly not a risk factor so time spent stretching the ankle should have no protective effects.  However, what was surprising to me were these findings:

“Prior use of orthotics was found to be a highly significant risk factor for developing MTSS. The effect size was large.”

“Orthotics are commonly prescribed to correct or support a foot that has been deemed to be in less than optimal alignment, but their role in prevention and intervention is unclear according to a recent systematic review. [56] Our analysis suggests their use is a causative risk factor and therefore they are not useful for prevention.”

“At least 25% of the participants included in this meta-analysis had been prescribed orthotics prior to developing MTSS.”

The authors weren’t sure why the orthotics might cause MTSS. They thought that the orthotics might cause deconditioning of the foot musculature, that they might decrease shock attenuation too much (preventing the tibial bone from positively adapting by increasing bone mineral density), or it was perhaps due to altered foot and ankle positions when running.  Given that foot Orthotics have little effect on plantar fasciitis, moderate effects on patellofemoral pain, and apparently increase risk of MTSS, they should probably not be used as a matter of course. The overall risk-reward profile might not be worth it.  The foot arch is better supported naturally through exercising the muscles of the foot, leg, hip and core.

As always, if you have any further questions or need for clarifications, please don’t hesitate to ask. Being aware that some of my blog ideas are contentious and occasionally a bit out of the field of my expertise, I encourage my readers to come forth with any questions/comments that are of interest or concern. Your comments are valued and welcomed.

Chad Reilly is a licensed physical therapist, located in North Phoenix, practicing science based medicine with treatment protocols unique and effective enough to proudly serve patients from Phoenix, Scottsdale, Mesa, Chandler, Tempe, Peoria, and Glendale.

2 thoughts on “Orthotics Cause Shin Splints in Runners?

  1. I think I might have some insight on this as someone who has been forced to run up to 30 miles/week at a body weight of 265lbs with flat feet. Orthotics are great at preventing pronation and critical to prevent foot and ankle issues for walking, but running is another matter entirely. Even though high quality cushion tops can be used to surface custom orthotics it doesn’t change the fact they’re made out of hard plastic. As a heavy runner this hard plastic beats the shit out of my feet, but is worth it so long as I’m heel striking and you have the money to spend on brand new gel asics every 6-8 months to help absorb the shock. If you midfoot or forefoot strike then orthotics are less than worthless though because you’re not going to pronate with a forefoot strike and the orthotics will beat the shit out of your feet even harder. Even with heel striking and buying new gel-asics frequently the orthotics will still need to be resurfaced every 12 months at a minimum. If the surface of the orthotic wears down and you heel strike the arch of your flat foot will be pronating with a lot of force into hard plastic every step you take which unsurprisingly makes the bottom of your arch hurt.

    • Interesting, I don’t sell orthotics myself but will sometimes send people to the Scottsdale Road Runner Sports Store where they have a large selection of OTC orthotics to try out and pick what’s most comfortable. But then one of the studies I read mentioned that if they were less comfortable (I think due to higher arches) they were more likely to help with patellofemoral pain. I still need to track down the original source, to see how reliable it is. I do know I just got some papers in on the relative benefits of foot strike pattern that you mention and if they are interesting I’ll do some blogs on them. Thanks for the insight.

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