Emerging Options for Biologic Enhancement of Stress Fracture Healing in Athletes

Timothy L. Miller, MD; Christopher C. Kaeding, MD; Scott A. Rodeo, MD

Disclosures

J Am Acad Orthop Surg. 2020;28(1):1-9. 

In This Article

Electrical Osseous Stimulation

Pulsed electromagnetic fields (PEMF) and low-intensity pulsed ultrasound (LIPUS) are FDA-approved, noninvasive modalities that increase the production of regulatory mediators required for physiological bone healing.[39] PEMF (Figure 5) creates a magnetic field and a secondary electronic impulse, activating a series of enzyme reactions that upregulate growth factors such as BMPs, transforming growth factor-β and calmodulin, leading to bone cell proliferation and fracture healing.[40] Benazzo et al were able to achieve union in 22 of 25 lower extremity stress fractures (navicular, second and fifth metatarsal, tibia, fibula, and talus) in athletes at an average of 52 days using an alternating electrical field.[41]

Figure 5.

Photograph showing a 21-year-old female college soccer player on whom a pulsed electromagnetic field bone stimulator is applied to treat a proximal tibial stress fracture.

PEMF bone stimulators have been shown to be the most effective for delayed unions of the tibial shaft and fifth metatarsal shaft. Streit et al[41] performed a randomized controlled trial of eight delayed unions or nonunions of the fifth metatarsal that were treated with active or inactive PEMF after biopsy of the fractures site. The average time to complete radiographic union for the active PEMF groups was 8.9 weeks compared with 14.7 weeks for the inactive PEMF group. The same study also noted that the group treated with active PEMF demonstrated increased production of placental growth factor as well as BMP-5 and BMP-7.[41]

The effect of low-intensity pulsed ultrasound occurs through its ability to stimulate osteocyte mechanoreceptors, thereby activating ion channels.[40] Definitive results of LIPUS are lacking; however, Tomohiko et al[42] described how they used it to treat five high school and collegiate soccer players with fifth metatarsal Jones fractures. All athletes healed or had no progression of the fracture despite being allowed to continue soccer activity. The authors suggested that treatment with LIPUS may allow in-season athletes to continue activity without time off despite a fifth metatarsal fracture.

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