## 3 Discussion  
Foot and ankle injuries are common in many sports. The main problem of most injuries in athletes is represented by the time taken for coming back to sports after trauma or surgery. In both cases, a possible way to shorten recovery time might be the application of PEMFs, for their capability of cell stimulation, inflammation reduction, articular cartilage preservation, and pain relief. These features seem very important in athletes for an early return to sport and, moreover, for reducing other possible tissue damages, in particular regarding joints arthritic evolution. The aim of this narrative review was to present some possible application of PEMFs in sport-related foot and ankle injuries, in particular BME, OCD, fractures, and nonunion. The effect of PEMFs stimulation on BME has been shown to promote osteogenic activity, preventing trabecular fracture, and subchondral bone collapse. Similarly, OCD seems to benefit from PEMFs application. In particular, PEMFs started soon after surgical OCD repair with bone marrow-derived cells transplantation, aided patient recovery leading to better clinical results. Bone marrow-derived cells are known to be able to differentiate into mature hyaline cartilage cells in vitro; however, the effect of microenvironment in vivo may lead to different results, and PEMFs may play a positive role in this field, in particular by decreasing some of the most relevant pro-inflammatory cytokines releases [29; 31]. It has to be also considered that any surgical procedure activates an inflammatory reaction, which is different for each patient. When inflammation is not controlled, it may negatively affect cartilage repair and therefore clinical outcomes. Future comparative studies using histological analysis would be useful to confirm the hypothesis that PEMFs can help bone marrow-derived cells in directing toward hyaline cartilage differentiation. The same approach seems to be interesting if applied to fractures, and nonunion, were the role of PEMFs is already well established. Apart from the above-mentioned sport-related injuries, PEMFs might be also used on other common athlete's pathological conditions, such as plantar fasciiits (PF) [52]. PF represent a common condition in athletes, resulting in approximately 8% of all running-related injuries. While PF treatment is mainly conservative, the period to resolution can be quite long, in some cases up to 2 years [52]. PEMFs may represent a valid tool in order to speed up the healing process. [PERSON] et al. [52] conducted a multicenter, prospective, randomized, double-blind, and placebo- and positive-controlled trial to determine the effects of nightly use of a wearable Pulsed Radiofrequency Electromagnetic Field (PRFE) device (ActiPatch, Bioelectronics) on \begin{table}
\begin{tabular}{p{85.4 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Disease** & **Study** & **Characteristics** & **Results** \\ \hline  & [PERSON] et al. [44] & EBI Bone Healing Duration: 10 h/day, within 2 weeks after the injury & No significant differences in preventing secondary surgical interventions for delayed union or nonunion \\ \hline  & [PERSON] et al. [50] & EBI Bone Healing Duration: 10 h/day & Significant increase in local factors and faster average time to radiographic union \\ \hline  & & Intensity: 3.5 \(\pm\) 0.5 mV for 1.3 ms Frequency: 75 Hz Duration: 7 days after surgery and was maintained until initial bone consolidation & Bone consolidation within 3 months \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._patients diagnosed with plantar fascitis. Seventy subjects were enrolled and randomly assigned a placebo or active PRFE device. The PRFE device was applied overnight, and pain was recorded using a 0- to 10-point VAS every morning, and evening. A significantly different pain reduction was registered between the two groups (\(p\) = 0.03). The study group (active PRFE device) showed progressive reduction in morning pain. After 7 days, pain was 40% lower than day 1.