Electromagnetic bone growth stimulation in patients with femoral neck fractures treated with screws: prospective randomized double-blind study

Background: To determine the effect of pulsed electro-magnetic fields (PEMF) on time to healing, onset of osteonecrosis of the femoral head and pain in patients with intracapsular femoral neck fracture. Methods: Seventy-seven patients had their fracture fixed with cannulated screws. After surgery, patients were randomized to receive either an active or placebo PEMF stimulator and were instructed to use it for at least 8 h per day for 90 days. Patient compliance was monitored by a clock inside the stimulator. The active stimulators generated PEMF at 75 Hz, 1.3 m/s impulse length, 2 mTesla peak magnetic field. Fracture healing and onset of osteonecrosis were evaluated on radiographs obtained 30, 60 and 90 days and then at 6, 12 and 24 months after surgery. During the first three visits pain was assessed by a visual analog scale (VAS). Results: Fracture healing was achieved in 94% of active compliant patients compared with 69% of the placebo group. The percentage of osteonecrosis was higher in the placebo group but does not reach statistical significance (37% vs. 49%). Pain assessment with the VAS evidenced significantly lower levels in the compliant active group compared with the placebo group at all visits. No differences were observed between patients who were noncompliant with the PEMF protocol and the placebo group. Conclusions: This study shows that stimulation with PEMF accelerates fracture healing and reduces pain, leading to a better quality of life in patients suffering femoral neck fractures.