Heterotopic ossification (HO) is a metaplastic biological process in which there is
newly formed bone in soft tissues, resulting in joint mobility deficit and pain.
Different treatment modalities have been tried to prevent HO development, but there
is no consensus on a therapeutic approach. Since electrical stimulation is a widely
used resource in physiotherapy practice to stimulate joint mobility, with analgesic
and anti-inflammatory effects, its usefulness for HO treatment was investigated. We
aimed to identify the influence of electrical stimulation on induced HO in Wistar
rats. Thirty-six male rats (350-390 g) were used, and all animals were anesthetized
for blood sampling before HO induction, to quantify the serum alkaline phosphatase.
HO induction was performed by bone marrow implantation in both quadriceps of the
animals, which were then divided into 3 groups: control (CG), transcutaneous
electrical nerve stimulation (TENS) group (TG), and functional electrical stimulation
(FES) group (FG) with 12 rats each. All animals were anesthetized and electrically
stimulated twice per week, for 35 days from induction day. After this period, another
blood sample was collected and quadriceps muscles were bilaterally removed for
histological and calcium analysis and the rats were killed. Calcium levels in muscles
showed significantly lower results when comparing TG and FG (P<0.001) and between
TG and CG (P<0.001). Qualitative histological analyses confirmed 100% HO in FG and
CG, while in TG the HO was detected in 54.5% of the animals. The effects of the
muscle contractions caused by FES increased HO, while anti-inflammatory effects of
TENS reduced HO.