Industrial Safety- Preventing Work Related Foot and Ankle Injuries

It is estimated that the industrial market for safety shoes in the US is at nearly a billion dollars with approximately $70 per employees spent on foot protection per year.  Despite that,  National Safety Council estimates of foot related workplace injury average about 180,000 incidents per year, that is 400 cases per day at an estimated cost of $6000 per incident.  Indirect costs of foot injury such as time loss or loss of productivity may be added to this estimate.

Non-compliance with safety regulations can be an issue yet such regulations cannot anticipate all the scenarios that can lead to foot and ankle injuries in the workplace.  OSHA has set safety standards with respect to shoe characteristics such as anti-slip soles, sole puncture resistance and toe protection but does not address the basics of shoe or boot constructions as the basics are assumed to be present.  For example, steel toe work boots may protect the toes from crush injuries by light to moderate weight objects but it is the steel shank that protects the heel and arch.  Shanks are not mandated by any regulation.  Steel shanks have were invented almost 800 years ago and were present in most work boots until the last 10 years.  Outsourcing of work shoes has led to less than ideal shoe construction practices in which the midsole and shank of shoes has been omitted leading to an “epidemic” of heel and arch pain.

Beyond the mandated requirements of work shoes and boots, the following items are important in footwear selection:
  • Good fit.  Due to diversity of sourcing, shoegear sizing varies significantly.  One should not assume that the size that has been appropriate in the past still applies.  A good shoe fitter should not only measure the foot but understand how different shoe models and brands vary from their stated sizes.  There should be ample toe room and the length of the shoe should be a thumbnail or two fingers longer than the end of the longest toe.
  • Good support.  Softness and lightness sell more shoes but support always wins the day. Soft and light shoes always feel better when tried on but may have inadequate support causing fatigue or pain as they are worn for longer periods of time.   Shoes or boots should have midsole and rigid shank to provide torsional stability.  Lack of torsional stability of shoes can be a major contributor to arch and heel pain as well ankle instability.  Steel shanks have existed for over 800 years but only have started to be “missing” in the last decade.  Other materials such as graphite and hard plastics may be substituted for steel as a shank material.
  • Employees should own at least two pairs of work shoes or boots, changing between pairs regularly.
  • Wear the right shoegear type for the job.  Work on uneven surfaces requires ankle protection via a high top laced boot.  Laced boots generally provide better ankle protection than slip on boots or Western style boots.  Anti-slip soles needed for wet and greasy floors exist on shoes as well as overshoes.
  • Removable inlays or insoles are a good feature in shoes and boots as they allow for replacement with more supportive inlays or prescription foot orthotics.
Other work specific attributes of footwear may include:  
  • Conductive footwear – to prevent the buildup of static electricity.
  • Metatarsal footwear or footwear with metatatarsal protectors – extends the protection of steel toes backward to cover the top of the foot from falling objects.
  • Puncture resistant footwear – a steel or Kevlar layer in the sole prevents puncture by sharp objects.
  • Electrical hazard footwear – the sole of the shoe or boot is designed to protect workers from electrical shock.



Slip and Fall

Slip and fall injuries are often associated with flooring choices, conditions of walking surfaces, foot protection and employee perception of slip hazards. Slippery surfaces due to water or grease are a common concern in the food service industry.  Slipping can occurs when there is a change in the amount of friction from one surface area to another, that is, friction variations.  Slip resistant shoegear with it focus on rubber compounds that increase friction may not include other safety features such as toe protection or adequate support features such as rigid shanks.   
Injury can occur when transitioning from low friction to high friction surfaces such as ankle sprains.

Ankle Sprains

Ankle sprains are one of the most common industrial injuries treated by Podiatric specialists and, at times, injuries which lead to significant employee time loss due to potential under-diagnosis and under-treatment at the initial medical exam.

The term “sprain” describes a soft tissue injury but, in more common usage, a mechanism of injury.  An inversion sprain of an ankle describes the foot rolling outward at the ankle. There are a number of things that can occur when the foot rolls outward:

A stretching of the ankle ligaments, the ligaments that keep the ankle from rolling over.  This is known as the lateral ligament complex is includes 3 ligaments.  This is a true “sprain.”  Such injuries generally heal quickly without sequelae.
  1. A tearing of the ankle ligaments.  One or more of the ankle ligaments may tear or rupture during the sprain.  If undertreated or not recognized, the ankle may feel good over time but remains weak and subject to repeated sprains; a condition known as lateral ankle instability.  There are two ways this can be determined.  First, examination to include a “drawer test” in which the clinician attempts to pull the ankle forward and out of the ankle joint.  Second, imaging.  X-ray cannot determine the condition of ankle ligaments as it does not show soft tissue.  MRI may be used but diagnostic ultrasound is less costly and can be performed immediately.   Immediate casting after ankle ligament rupture can lead to healing but if proper immobilization is not used, the ligaments may later requires surgical repair.
  2. Fractures.   An ankle sprain may lead to a fracture with 3 areas being the most common:
a. The outside of the ankle bone (lateral malleolus of the fibula).
b. The front part of the heel bone (anterior beak of the calcaneus).
c. The bone on the outer border of the foot (base of the 5th metatarsal).
d. Less commonly – the tibia (bottom of the leg bone) or a separation of the ankle bones known as “diastasis.” 
e. A crack in the cartilage in the ankle joint (osteochondral fracture of talus)

Radiographs generally will reveal all but e. above.

Employees with ankle sprains need often be evaluated by a specialist so that a thorough diagnosis and treatment plan is instituted early.   Podiatrists have training that includes 4 years of podiatric medical school and up to 3 years of residency training with a focus on diagnosis of such ankle injuries as well a surgical, non-surgical treatment. There are other specialties that treat ankle injuries with a focus on surgical treatment but the comprehensive nature of podiatric training allows an approach that includes rehabilitation, bracing, use of orthotics and other modalities that may avoid surgery and employee time loss.

Other common workplace injuries that require attention:
  • Crushed or broken feet, amputation of toes or feet – causes include feet trapped between objects or caught in a crack/crevice, falls of heavy objects, moving vehicles. conveyor belts (feet drawn between belt and roller).
  • Punctures of the sole of the foot – loose nails, sharp metal or glass objects.
  • Cuts or severed feet or toes, lacerations – chain saws, rotary mowers, unguarded machinery.
  • Burns – molten metal splashes, contact with fire, flammable or explosive atmosheres.
  • Electric shocks – static electricity, contact with sources of electricity.
  • Injuries due to slips, trips and falls – slippery floors, inadequate shoegear,  litter or clutter on walkways and work areas, poor lighting.

Work related injuries vs. work related diseases

A work related injury occurs after a defined injury occurs at a specific place and time.  A work related disease is something that occurs due to the work environment but may occur gradually over time.  An example of this in the hand is carpal tunnel syndrome which is a repetitive motion or repetitive strain injury.  An example of this in the foot is plantar fasciitis, a condition in which the ligament that supports the foot becomes damaged or inflamed.

It is important, when possible, to identify the cause of work related diseases and focus on treating the cause.  The plantar fascia is the main support mechanism for the foot so if shoegear is inadequate or if there are faulty foot mechanics the fascia can become painful causing heel and arch pain.  Plantar fasciitis is often viewed as difficult to treat.  It is not. The reason heel and arch pain due to plantar fasciitis can persist is due to treatment which is symptom oriented such as cortisone injections, pain killers, massage, rest as opposed to treatment which is curative.  Podiatrists utilize training in Biomechanics to identify the mechanical issues which can cause plantar fasciitis to persist.

Stress Fractures

We generally view acute trauma as a reason for foot and ankle fractures but chronic repetitive strain can cause bones to fatigue and break.  One way to understand the mechanism is to think about a paper clip.  Bending a paper clip about 4 times can cause it to break in two.  What if I bend a paper clip 3 times and ask you what is wrong with it?  It does not appear broken to the naked eye but it is also not normal.  A magnifying glass or microscope may show tiny cracks in the metal so it is actually “broken” but not broken in two.

Stress fractures can occur anywhere in the foot but the metatarsals, the bones behind the toes, tend to be the most common area due to repetitive bending or repetitive loading.  Lack of a shoe midsole and shank can place torsional (twisting) strain on the metatarsals leading to stress fractures.  Certain mechanical issues such as oversupination (walking on the outside of the foot) can also make metatarsal stress fractures more likely to occur.   An arch support can create more supination by rolling the foot outward.

Stress fracture diagnosis can be delayed at times because stress fractures are generally not visible on x-rays.  Use of sonography (diagnostic ultrasound) provides a means of early diagnosis of metatarsal stress fractures and is a modality we frequently used.  MRI can also reveal stress fractures.  A stress fracture, left untreated, may progress to a “full” fracture or just result in chronic pain.

About Eddie Davis, DPM, FACFAS

Eddie Davis, DPM, FACFAS graduated from Rutgers College and the Temple University School of Podiatric Medicine in Philadelphia.  He completed his residency training at the Washington, DC Veterans Administration Medical Center.  Dr. Davis served as President of the West Virginia Podiatric Medical Association after finishing Federal Service in the National Health Service Corps of the Public Health Service in WV.  He later moved to Washington State where he maintained a private practice in a suburb of Seattle for 12 years and moved to San Antonio in 2007.
  • Board Certified in Foot Surgery by the American Board of Podiatric Surgery
  • Fellow, American College of Foot and Ankle Surgeons
  • Member of the Texas Podiatric Medical Association
  • Member of the American Podiatric Medical Association
  • Member of the American College of Foot and Ankle Pediatrics