## 2 Application Fields
### Joint Preservation
Improvements in the bone-healing process have been observed in subjects at risk of malunion, along with improvements in the symptoms reported in patients undergoing spinal surgery, better rates of osseointegration in the femoral components of cementless hip prostheses, effective results of core decompression and grafts of trabecular bone in the treatment of osteonecrosis of the femoral head, and improvements in inflammatory processes in the articular compartment. None of the authors of these studies suggest a generalized use of biophysical stimulation, but the importance of a reasoned therapeutic prescription is highlighted. In 2013, [PERSON] et al. recruited 34 patients with early knee osteoarthritis in a randomized, placebo-controlled, double-blind pilot clinical study. Results showed that the VAS pain score decreased in the active cohort by 50 \(\pm\) 11% versus the baseline, starting at day 1 and persisting to day 42 (\(p<0.001\)). The authors concluded that non-invasive PEMFs therapy can have a significant and rapid impact on pain from early knee osteoarthritis [49]. Similar results were also obtained by other authors [50; 51; 52]. In 2006 [PERSON] et al. retrospectively analyzed 76 hips in 66 patients with osteonecrosis of the femoral head. Patients with Ficat stage I, II, or III osteonecrosis of the femoral head were treated with pulsed electromagnetic field stimulation for eight hours per day for an average of five months. They found that PEMFs preserved 94% of Ficat stage-I or -II hips, recommending this treatment in the early stages of osteonecrosis of the femoral head [53]. Similar results were obtained by [PERSON]. et al. The authors found good to excellent clinical results in 75% of patients and protected 85.7% of knees with spontaneous osteonecrosis of the Koshino stage I knee from prosthetic surgery at the 24-month follow-up [54]. [PERSON] et al. analyzed 60 patients with knee osteoarthritis and persistent pain. After 1 month, a mean effect of treatment with PEMFs of \(-\)0.73 (95% CI \(-\)1.24 to \(-\)0.19) was observed in the VAS score, while the effect size was \(-\)0.34 (95% CI \(-\)0.85 to 0.17) for the WOMAC score. In total, 26% of patients in the PEMFs group discontinued NSAID/analgesic therapy. No adverse events were observed [55]. In contrast, [PERSON] et al. found that PEMFs does not have an additional effect on the classical physical treatment for reducing symptoms of knee osteoarthritis. However, in this study, PEMFs were used for 30 min per day, thus reducing any beneficial effects [56]. Finally, a recent narrative review found that PEMFs can improve symptoms and the function of joints, such as the knee, in patients with non-advanced osteoarthritis [57]. [PERSON] et al. in a recent review confirmed that PEMFs therapies are safe and effective treatments for the control of knee OA-related pain and disability in the short term [58]. In conclusion, PEMFs have proven to be a valid option for reducing pain, controlling inflammatory process, favoring functional recovery, and improving the quality of life of patients. Encouraging results have been obtained in preclinical studies, as well as on cartilage regeneration after surgery. There is a lack of knowledge of the effectiveness on cartilage regeneration.