Trauma Rounds Case Reports from the Mass General Hospital and Brigham & Women’s Hospital A Quarterly Case Study Volume 3, Spring 2012

John Y. Kwon, MD

Effect of a Steel Toe CapCrush injuries to the foot are a common work-place injury, causing significant morbidity, dis-ability and lost wages. A report by the Bureau of Labor Statistics estimated that more than 60%

of workplace injuries involve the musculoskeletal system, and 10% of these are foot and ankle injuries.1

Regulatory bodies like the Occupational Safety and Health Administration (OSHA) were developed to protect the work force and to establish guidelines to improve work conditions and safety standards. Since OSHA’s inception in 1971, occupa-tional injury and illness rates have declined 40% while the American work force has nearly doubled. However, while the total number of days lost from work due to occupational inju-ries has declined, the percentage of foot and ankle injuries has remained relatively constant.

Although steel toe capped boots are commonly accepted as a protective measure, there are no published data about the pro-tection afforded by a steel toe. There is a common belief that a significant crush injury sustained while wearing steel toe capped boots results in amputations of the toes and that not wearing them may be safer. This belief is so pervasive that a popular television show, Myth Busters, investigated this.2 We studied the influence of the steel toe cap on injury pattern after a crush injury to the forefoot.3

Methods

Five paired cadaver lower extremities were used for the study. The feet were measured and fitted into a corresponding size 9 work boot. Five pairs had a steel toe cap (ANSI Z-41 & ATSM 2315 compliant), while five corresponding pairs did not. One foot from each matched pair was fitted into a steel toe capped boot while the other foot was fitted into the regular work boot.

We constructed a custom jig to provide a reproducible crushing mechanism with a total weight of 150 lbs.

Each specimen was placed with the boom centered on the proximal edge of the steel toe cap. The boom was raised 3 feet and released to crush the ca-daveric foot. X-rays were ob-tained to assess for fracture loca-tion and commi-nution. Stress fluoroscopy was performed to as-sess for any liga-mentous Lisfranc injury.Results

Overall, the feet in the regular work boots averaged 8.2 frac-tures per foot while those protected in the steel toe boot aver-aged 3.6 fractures per foot. The steel toe boot had fewer meta-tarsal and toe fractures and less comminution to the bone. There were no bony nor ligamentous Lisfranc injuries. There were no traumatic amputations nor open fractures produced.Previous studies have shown that 4.4% of all occupational related injuries involve the foot and toes. This represents over 3 billion dollars in total cost, including lost wages and productivity, medical costs and administrative expenses.4

OSHA has recommended the use of safety shoes in certain occupa-tions, which must meet the American National Standards Institute (ANSI) minimum compression and impact performance stan-dards. ANSI has established testing and performance criteria for footwear safety and has standardized the impact and compression resistance characteristics of steel toe capped boots. The ANSI test-

Trauma Rounds, Volume 3, Spring 2012 1

P A R T N E R S O R T H O P A E D I C

Crush Injuries to the Forefoot

Figure 1: X-ray of cadaver extremity in steel toe capped work boot.

ing consists of a steel weight weighing 50 lbs (±0.5 lbs) dropped from a height of 3 feet. 5, 6

Conclusions

In our study we tripled this weight to ensure the creation of frac-tures in our non-protected specimens and to elucidate the protec-tive nature of the steel cap. Even when tripling the weight used by

the ANSI protocol we found no toe amputations nor complete failures of the steel toe cap. Although steel toe capped boots are commonly accepted as a pro-tective measure, there are no published data about how protection afforded by a steel toe influences foot fracture epidemiology. This study demonstrated that the steel toe protects the foot from crush injuries, limiting the number and severity of forefoot fractures. However, the steel toe cap does not fully protect the forefoot from injury and in addition to the use of safety shoes, strict adherence to workplace safety standards may limit the severity of crush injuries to the foot. Acknowledgements

I would like to acknowledge my fellow myth busters: John T. Campbell, MD, Mark S. Myerson, MD and Cliff L. Jeng, MD.

Dr. John Kwon (Jkwon@partners.org) is an orthopaedic surgeon at the Massa-chusetts General Hospital, Boston and a member of the Foot & Ankle Service, as well as the Partners Orthopaedic Trauma Service. Dr. Kwon specializes in foot & ankle fractures, sports injuries and correction of foot & ankle deformities.

Bibliography1. Bureau of Labor Statistics. Care and demographic characteristics for work-related

injury and illness involving days away from work. Washington, DC: Bureau of Labor Statistics, US Department of Labor; 1992 – 1999.

2. MythBusters, Episode 42, Discovery Channel: November 9, 20053. Kwon JY, Campbell JT, Myerson MS, Jeng CL, Effect of a steel toe cap on forefoot

injury pattern in a cadaveric model. Foot and Ankle Int. 2011 Apr; 32(4):443-7.4. Campbell, JT: Foot and ankle fractures in the industrial setting. Foot Ankle Clin.

7(2):323 – 50, 2002.5. Bureau of Labor Statistics. Labor force statistics from the current population sur-

vey. Washington, DC: Bureau of Labor Statistics. US Department of Labor; 2001.

6. Bureau of Labor Statistics. Lost worktime injuries and illnesses: characteristics and resulting time away from work, 1999. Washington, DC: Bureau of Labor Statistics, US Department of Labor; 1999.

P A R T N E R S O R T H O P A E D I C T R A U M A R O U N D S

2 Trauma Rounds, Volume 3, Spring 2012

Figure 3: Steel toe cap after crush impact (left) compared to an uncrushed steel toe cap (right).

Trauma FacultyMark Vrahas, MD — 617-726-2943Partners Chief of Orthopaedic Traumamvrahas@partners.org

Mitchel B Harris, MD — 617-732-5385Chief, BWH Orthopedic Traumambharris@partners.orgR Malcolm Smith, MD, FRCS — 617-726-2794Chief, MGH Orthopaedic Traumarmsmith1@partners.orgDavid Lhowe, MD — 617-724-2800MGH Orthopaedic Traumadlhowe@partners.org

Michael Weaver, MD — 617-525-8088BWH Orthopedic Traumamjweaver@partners.org

Jesse Jupiter, MD — 617-726-5100MGH Hand & Upper Extremity Servicejjupiter@partners.org

David Ring, MD — 617-724-3953MGH Hand & Upper Extremity Servicedring@partners.org

Brandon E Earp, MD — 617-732-8064BWH Hand & Upper Extremity Servicebearp@partners.org

George Dyer, MD — 617-732-6607BWH Hand & Upper Extremity Servicegdyer@partners.org

John Kwon, MD — 617-643-5701MGH Foot & Ankle Servicejkwon@partners.org

Please share your comments online, or by email:Mark Vrahas, MD / mvrahas@partners.orgYawkey Center for Outpatient Care, Suite 3C55 Fruit Street, Boston, MA 02114

Editor in Chief Mark Vrahas, MD

Program DirectorSuzanne Morrison, MPH(617) 525-8876smmorrison@partners.org

Editor, PublisherArun Shanbhag, PhD, MBAwww.MassGeneral.org/orthowww.BrighamAndWomens.org/orthopedics

AchesAndJoints.org/Trauma

In Memoriam

Edward "Teddy" KimSeptember 3, 1984 - April 6, 2012

We are saddened to report the passing of our friend and former col-league, Teddy Kim, who recently passed away after a yearlong battle with leukemia. Teddy worked with us as a research assistant during his junior and senior years at Boston College. He will be missed.

Figure 2: X-ray of a cadaveric forefoot after crush impact in a regular work boot (left) and in a steel toe capped work boot (right).