SLR - April 2023 - Dustin Moyer, DPM
Title: Bone Stress Injuries in Runners Using Carbon Fiber Plate FootwearReference: Tenforde, A., Hoenig T., Saxena A., and Hollander K. “Bone Stress Injuries in Runners Using Carbon Fiber Plate Footwear.” Sports Medicine, 2023. https://doi.org/10.1007/s40279-023-01818-z.
Level of Evidence: Level V, expert opinion
Reviewed by: Dustin Moyer, DPM
Residency Program: Rochester General Hospital, Rochester, NY
Podiatric Relevance: Bone stress injuries (BSI) within the foot are common among runners that can happen at different stages of their training. The recent advances in shoe technology introducing embedded Carbon Fiber Plates (CFP) within the shoes have produced personal bests for athletes while posing new challenges for providers. This case study of 5 reported incidents involving the navicular bone stress injuries amongst athletes as a result of CFP Footwear in training and competition. This article is aimed to raise awareness of the biomechanical interaction between the foot and shoegear.
Methods: A Level V Opinion Article was written after treating athletes with the presenting symptoms and use of CFP Footwear by the authors. No previous literature has been documented that met this criteria. The article reviews the biomechanics of the CFP shoes and the effect on the foot of endurance athletes.
Results: Five athletes that were diagnosed with Bone Stress Injuries (BSI) of the Navicular, in the authors’ opinion, a result of Carbon Fiber Plate Footwear use. Four athletes used CFP in training, 1 athlete used in competition. Age ranges from 17 to 38 years old. Sex distribution included 3 males and 2 females. Field of discipline included 2 Triathletes, 3 distance runners. The runners with CFP footwear displayed a decreased cadence, longer steps, and longer flight time, increased vertical ground reaction forces, and vertical impulse per step were higher. No changes were noted to the hip or knee joints, but peak dorsiflexion and moments of the ankle work were observed. The fulcrum of the CFP plate was proximal to the metatarsal heads when the foot and shoegear were radiographed and changed the lever effects on the ankle and a higher toe spring. Prior studies have found that both cavus and pes planus foot types display biomechanical risks of BSI at the navicular bone that include higher peak eversion and decreased subtalar joint range of motion. The navicular is susceptible to shear stress at the region of reduced blood supply and can result in BSI.
Conclusions: Clinical awareness and understanding of the biomechanical interactions of the foot and the CFP footwear can lead to sooner diagnosis of BSI in the navicular as well as sooner return to sport. The 5 athletes in this article all developed acute pain in the navicular. The training of faster velocities for athletes can also explain the demands of increased skeletal loading on the foot using CFP footwear. There is a potential for further studies as the authors estimate there are more injuries that are going undiagnosed. The authors suggest that a gradual introduction of CFP footwear during training to help reduce the number of BSI, similar to minimalist footwear was. As new technology is developed and used by athletes striving for improved performance, medical professionals can understand and recognize symptoms for the safety of the athletes.